/*
 * Generic device tree based pinctrl driver for one register per pin
 * type pinmux controllers
 *
 * Copyright (C) 2012 Texas Instruments, Inc.
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/list.h>

#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_address.h>

#include <linux/pinctrl/pinctrl.h>
#include <linux/pinctrl/pinmux.h>
#include <linux/pinctrl/pinconf-generic.h>

#include "core.h"
#include "pinconf.h"

#define DRIVER_NAME                     "pinctrl-single"
#define PCS_MUX_PINS_NAME               "pinctrl-single,pins"
#define PCS_MUX_BITS_NAME               "pinctrl-single,bits"
#define PCS_REG_NAME_LEN                ((sizeof(unsigned long) * 2) + 1)
#define PCS_OFF_DISABLED                ~0U

/**
 * struct pcs_pingroup - pingroups for a function
 * @np:         pingroup device node pointer
 * @name:       pingroup name
 * @gpins:      array of the pins in the group
 * @ngpins:     number of pins in the group
 * @node:       list node
 */
struct pcs_pingroup {
        struct device_node *np;
        const char *name;
        int *gpins;
        int ngpins;
        struct list_head node;
};

/**
 * struct pcs_func_vals - mux function register offset and value pair
 * @reg:        register virtual address
 * @val:        register value
 */
struct pcs_func_vals {
        void __iomem *reg;
        unsigned val;
        unsigned mask;
};

/**
 * struct pcs_conf_vals - pinconf parameter, pinconf register offset
 * and value, enable, disable, mask
 * @param:      config parameter
 * @val:        user input bits in the pinconf register
 * @enable:     enable bits in the pinconf register
 * @disable:    disable bits in the pinconf register
 * @mask:       mask bits in the register value
 */
struct pcs_conf_vals {
        enum pin_config_param param;
        unsigned val;
        unsigned enable;
        unsigned disable;
        unsigned mask;
};

/**
 * struct pcs_conf_type - pinconf property name, pinconf param pair
 * @name:       property name in DTS file
 * @param:      config parameter
 */
struct pcs_conf_type {
        const char *name;
        enum pin_config_param param;
};

/**
 * struct pcs_function - pinctrl function
 * @name:       pinctrl function name
 * @vals:       register and vals array
 * @nvals:      number of entries in vals array
 * @pgnames:    array of pingroup names the function uses
 * @npgnames:   number of pingroup names the function uses
 * @node:       list node
 */
struct pcs_function {
        const char *name;
        struct pcs_func_vals *vals;
        unsigned nvals;
        const char **pgnames;
        int npgnames;
        struct pcs_conf_vals *conf;
        int nconfs;
        struct list_head node;
};

/**
 * struct pcs_gpiofunc_range - pin ranges with same mux value of gpio function
 * @offset:     offset base of pins
 * @npins:      number pins with the same mux value of gpio function
 * @gpiofunc:   mux value of gpio function
 * @node:       list node
 */
struct pcs_gpiofunc_range {
        unsigned offset;
        unsigned npins;
        unsigned gpiofunc;
        struct list_head node;
};

/**
 * struct pcs_data - wrapper for data needed by pinctrl framework
 * @pa:         pindesc array
 * @cur:        index to current element
 *
 * REVISIT: We should be able to drop this eventually by adding
 * support for registering pins individually in the pinctrl
 * framework for those drivers that don't need a static array.
 */
struct pcs_data {
        struct pinctrl_pin_desc *pa;
        int cur;
};

/**
 * struct pcs_name - register name for a pin
 * @name:       name of the pinctrl register
 *
 * REVISIT: We may want to make names optional in the pinctrl
 * framework as some drivers may not care about pin names to
 * avoid kernel bloat. The pin names can be deciphered by user
 * space tools using debugfs based on the register address and
 * SoC packaging information.
 */
struct pcs_name {
        char name[PCS_REG_NAME_LEN];
};

/**
 * struct pcs_device - pinctrl device instance
 * @res:        resources
 * @base:       virtual address of the controller
 * @size:       size of the ioremapped area
 * @dev:        device entry
 * @pctl:       pin controller device
 * @mutex:      mutex protecting the lists
 * @width:      bits per mux register
 * @fmask:      function register mask
 * @fshift:     function register shift
 * @foff:       value to turn mux off
 * @fmax:       max number of functions in fmask
 * @is_pinconf: whether supports pinconf
 * @names:      array of register names for pins
 * @pins:       physical pins on the SoC
 * @pgtree:     pingroup index radix tree
 * @ftree:      function index radix tree
 * @pingroups:  list of pingroups
 * @functions:  list of functions
 * @gpiofuncs:  list of gpio functions
 * @ngroups:    number of pingroups
 * @nfuncs:     number of functions
 * @desc:       pin controller descriptor
 * @read:       register read function to use
 * @write:      register write function to use
 */
struct pcs_device {
        struct resource *res;
        void __iomem *base;
        unsigned size;
        struct device *dev;
        struct pinctrl_dev *pctl;
        struct mutex mutex;
        unsigned width;
        unsigned fmask;
        unsigned fshift;
        unsigned foff;
        unsigned fmax;
        bool bits_per_mux;
        bool is_pinconf;
        struct pcs_name *names;
        struct pcs_data pins;
        struct radix_tree_root pgtree;
        struct radix_tree_root ftree;
        struct list_head pingroups;
        struct list_head functions;
        struct list_head gpiofuncs;
        unsigned ngroups;
        unsigned nfuncs;
        struct pinctrl_desc desc;
        unsigned (*read)(void __iomem *reg);
        void (*write)(unsigned val, void __iomem *reg);
};

static int pcs_pinconf_get(struct pinctrl_dev *pctldev, unsigned pin,
                           unsigned long *config);
static int pcs_pinconf_set(struct pinctrl_dev *pctldev, unsigned pin,
                           unsigned long config);

static enum pin_config_param pcs_bias[] = {
        PIN_CONFIG_BIAS_PULL_DOWN,
        PIN_CONFIG_BIAS_PULL_UP,
};

/*
 * REVISIT: Reads and writes could eventually use regmap or something
 * generic. But at least on omaps, some mux registers are performance
 * critical as they may need to be remuxed every time before and after
 * idle. Adding tests for register access width for every read and
 * write like regmap is doing is not desired, and caching the registers
 * does not help in this case.
 */

static unsigned __maybe_unused pcs_readb(void __iomem *reg)
{
        return readb(reg);
}

static unsigned __maybe_unused pcs_readw(void __iomem *reg)
{
        return readw(reg);
}

static unsigned __maybe_unused pcs_readl(void __iomem *reg)
{
        return readl(reg);
}

static void __maybe_unused pcs_writeb(unsigned val, void __iomem *reg)
{
        writeb(val, reg);
}

static void __maybe_unused pcs_writew(unsigned val, void __iomem *reg)
{
        writew(val, reg);
}

static void __maybe_unused pcs_writel(unsigned val, void __iomem *reg)
{
        writel(val, reg);
}

static int pcs_get_groups_count(struct pinctrl_dev *pctldev)
{
        struct pcs_device *pcs;

        pcs = pinctrl_dev_get_drvdata(pctldev);

        return pcs->ngroups;
}

static const char *pcs_get_group_name(struct pinctrl_dev *pctldev,
                                        unsigned gselector)
{
        struct pcs_device *pcs;
        struct pcs_pingroup *group;

        pcs = pinctrl_dev_get_drvdata(pctldev);
        group = radix_tree_lookup(&pcs->pgtree, gselector);
        if (!group) {
                dev_err(pcs->dev, "%s could not find pingroup%i\n",
                        __func__, gselector);
                return NULL;
        }

        return group->name;
}

static int pcs_get_group_pins(struct pinctrl_dev *pctldev,
                                        unsigned gselector,
                                        const unsigned **pins,
                                        unsigned *npins)
{
        struct pcs_device *pcs;
        struct pcs_pingroup *group;

        pcs = pinctrl_dev_get_drvdata(pctldev);
        group = radix_tree_lookup(&pcs->pgtree, gselector);
        if (!group) {
                dev_err(pcs->dev, "%s could not find pingroup%i\n",
                        __func__, gselector);
                return -EINVAL;
        }

        *pins = group->gpins;
        *npins = group->ngpins;

        return 0;
}

static void pcs_pin_dbg_show(struct pinctrl_dev *pctldev,
                                        struct seq_file *s,
                                        unsigned pin)
{
        struct pcs_device *pcs;
        unsigned val, mux_bytes;

        pcs = pinctrl_dev_get_drvdata(pctldev);

        mux_bytes = pcs->width / BITS_PER_BYTE;
        val = pcs->read(pcs->base + pin * mux_bytes);

        seq_printf(s, "%08x %s " , val, DRIVER_NAME);
}

static void pcs_dt_free_map(struct pinctrl_dev *pctldev,
                                struct pinctrl_map *map, unsigned num_maps)
{
        struct pcs_device *pcs;

        pcs = pinctrl_dev_get_drvdata(pctldev);
        devm_kfree(pcs->dev, map);
}

static int pcs_dt_node_to_map(struct pinctrl_dev *pctldev,
                                struct device_node *np_config,
                                struct pinctrl_map **map, unsigned *num_maps);

static const struct pinctrl_ops pcs_pinctrl_ops = {
        .get_groups_count = pcs_get_groups_count,
        .get_group_name = pcs_get_group_name,
        .get_group_pins = pcs_get_group_pins,
        .pin_dbg_show = pcs_pin_dbg_show,
        .dt_node_to_map = pcs_dt_node_to_map,
        .dt_free_map = pcs_dt_free_map,
};

static int pcs_get_functions_count(struct pinctrl_dev *pctldev)
{
        struct pcs_device *pcs;

        pcs = pinctrl_dev_get_drvdata(pctldev);

        return pcs->nfuncs;
}

static const char *pcs_get_function_name(struct pinctrl_dev *pctldev,
                                                unsigned fselector)
{
        struct pcs_device *pcs;
        struct pcs_function *func;

        pcs = pinctrl_dev_get_drvdata(pctldev);
        func = radix_tree_lookup(&pcs->ftree, fselector);
        if (!func) {
                dev_err(pcs->dev, "%s could not find function%i\n",
                        __func__, fselector);
                return NULL;
        }

        return func->name;
}

static int pcs_get_function_groups(struct pinctrl_dev *pctldev,
                                        unsigned fselector,
                                        const char * const **groups,
                                        unsigned * const ngroups)
{
        struct pcs_device *pcs;
        struct pcs_function *func;

        pcs = pinctrl_dev_get_drvdata(pctldev);
        func = radix_tree_lookup(&pcs->ftree, fselector);
        if (!func) {
                dev_err(pcs->dev, "%s could not find function%i\n",
                        __func__, fselector);
                return -EINVAL;
        }
        *groups = func->pgnames;
        *ngroups = func->npgnames;

        return 0;
}

static int pcs_get_function(struct pinctrl_dev *pctldev, unsigned pin,
                            struct pcs_function **func)
{
        struct pcs_device *pcs = pinctrl_dev_get_drvdata(pctldev);
        struct pin_desc *pdesc = pin_desc_get(pctldev, pin);
        const struct pinctrl_setting_mux *setting;
        unsigned fselector;

        /* If pin is not described in DTS & enabled, mux_setting is NULL. */
        setting = pdesc->mux_setting;
        if (!setting)
                return -ENOTSUPP;
        fselector = setting->func;
        *func = radix_tree_lookup(&pcs->ftree, fselector);
        if (!(*func)) {
                dev_err(pcs->dev, "%s could not find function%i\n",
                        __func__, fselector);
                return -ENOTSUPP;
        }
        return 0;
}

static int pcs_enable(struct pinctrl_dev *pctldev, unsigned fselector,
        unsigned group)
{
        struct pcs_device *pcs;
        struct pcs_function *func;
        int i;

        pcs = pinctrl_dev_get_drvdata(pctldev);
        /* If function mask is null, needn't enable it. */
        if (!pcs->fmask)
                return 0;
        func = radix_tree_lookup(&pcs->ftree, fselector);
        if (!func)
                return -EINVAL;

        dev_dbg(pcs->dev, "enabling %s function%i\n",
                func->name, fselector);

        for (i = 0; i < func->nvals; i++) {
                struct pcs_func_vals *vals;
                unsigned val, mask;

                vals = &func->vals[i];
                val = pcs->read(vals->reg);
                if (!vals->mask)
                        mask = pcs->fmask;
                else
                        mask = pcs->fmask & vals->mask;

                val &= ~mask;
                val |= (vals->val & mask);
                pcs->write(val, vals->reg);
        }

        return 0;
}

static void pcs_disable(struct pinctrl_dev *pctldev, unsigned fselector,
                                        unsigned group)
{
        struct pcs_device *pcs;
        struct pcs_function *func;
        int i;

        pcs = pinctrl_dev_get_drvdata(pctldev);
        /* If function mask is null, needn't disable it. */
        if (!pcs->fmask)
                return;

        func = radix_tree_lookup(&pcs->ftree, fselector);
        if (!func) {
                dev_err(pcs->dev, "%s could not find function%i\n",
                        __func__, fselector);
                return;
        }

        /*
         * Ignore disable if function-off is not specified. Some hardware
         * does not have clearly defined disable function. For pin specific
         * off modes, you can use alternate named states as described in
         * pinctrl-bindings.txt.
         */
        if (pcs->foff == PCS_OFF_DISABLED) {
                dev_dbg(pcs->dev, "ignoring disable for %s function%i\n",
                        func->name, fselector);
                return;
        }

        dev_dbg(pcs->dev, "disabling function%i %s\n",
                fselector, func->name);

        for (i = 0; i < func->nvals; i++) {
                struct pcs_func_vals *vals;
                unsigned val;

                vals = &func->vals[i];
                val = pcs->read(vals->reg);
                val &= ~pcs->fmask;
                val |= pcs->foff << pcs->fshift;
                pcs->write(val, vals->reg);
        }
}

static int pcs_request_gpio(struct pinctrl_dev *pctldev,
                            struct pinctrl_gpio_range *range, unsigned pin)
{
        struct pcs_device *pcs = pinctrl_dev_get_drvdata(pctldev);
        struct pcs_gpiofunc_range *frange = NULL;
        struct list_head *pos, *tmp;
        int mux_bytes = 0;
        unsigned data;

        /* If function mask is null, return directly. */
        if (!pcs->fmask)
                return -ENOTSUPP;

        list_for_each_safe(pos, tmp, &pcs->gpiofuncs) {
                frange = list_entry(pos, struct pcs_gpiofunc_range, node);
                if (pin >= frange->offset + frange->npins
                        || pin < frange->offset)
                        continue;
                mux_bytes = pcs->width / BITS_PER_BYTE;
                data = pcs->read(pcs->base + pin * mux_bytes) & ~pcs->fmask;
                data |= frange->gpiofunc;
                pcs->write(data, pcs->base + pin * mux_bytes);
                break;
        }
        return 0;
}

static const struct pinmux_ops pcs_pinmux_ops = {
        .get_functions_count = pcs_get_functions_count,
        .get_function_name = pcs_get_function_name,
        .get_function_groups = pcs_get_function_groups,
        .enable = pcs_enable,
        .disable = pcs_disable,
        .gpio_request_enable = pcs_request_gpio,
};

/* Clear BIAS value */
static void pcs_pinconf_clear_bias(struct pinctrl_dev *pctldev, unsigned pin)
{
        unsigned long config;
        int i;
        for (i = 0; i < ARRAY_SIZE(pcs_bias); i++) {
                config = pinconf_to_config_packed(pcs_bias[i], 0);
                pcs_pinconf_set(pctldev, pin, config);
        }
}

/*
 * Check whether PIN_CONFIG_BIAS_DISABLE is valid.
 * It's depend on that PULL_DOWN & PULL_UP configs are all invalid.
 */
static bool pcs_pinconf_bias_disable(struct pinctrl_dev *pctldev, unsigned pin)
{
        unsigned long config;
        int i;

        for (i = 0; i < ARRAY_SIZE(pcs_bias); i++) {
                config = pinconf_to_config_packed(pcs_bias[i], 0);
                if (!pcs_pinconf_get(pctldev, pin, &config))
                        goto out;
        }
        return true;
out:
        return false;
}

static int pcs_pinconf_get(struct pinctrl_dev *pctldev,
                                unsigned pin, unsigned long *config)
{
        struct pcs_device *pcs = pinctrl_dev_get_drvdata(pctldev);
        struct pcs_function *func;
        enum pin_config_param param;
        unsigned offset = 0, data = 0, i, j, ret;

        ret = pcs_get_function(pctldev, pin, &func);
        if (ret)
                return ret;

        for (i = 0; i < func->nconfs; i++) {
                param = pinconf_to_config_param(*config);
                if (param == PIN_CONFIG_BIAS_DISABLE) {
                        if (pcs_pinconf_bias_disable(pctldev, pin)) {
                                *config = 0;
                                return 0;
                        } else {
                                return -ENOTSUPP;
                        }
                } else if (param != func->conf[i].param) {
                        continue;
                }

                offset = pin * (pcs->width / BITS_PER_BYTE);
                data = pcs->read(pcs->base + offset) & func->conf[i].mask;
                switch (func->conf[i].param) {
                /* 4 parameters */
                case PIN_CONFIG_BIAS_PULL_DOWN:
                case PIN_CONFIG_BIAS_PULL_UP:
                case PIN_CONFIG_INPUT_SCHMITT_ENABLE:
                        if ((data != func->conf[i].enable) ||
                            (data == func->conf[i].disable))
                                return -ENOTSUPP;
                        *config = 0;
                        break;
                /* 2 parameters */
                case PIN_CONFIG_INPUT_SCHMITT:
                        for (j = 0; j < func->nconfs; j++) {
                                switch (func->conf[j].param) {
                                case PIN_CONFIG_INPUT_SCHMITT_ENABLE:
                                        if (data != func->conf[j].enable)
                                                return -ENOTSUPP;
                                        break;
                                default:
                                        break;
                                }
                        }
                        *config = data;
                        break;
                case PIN_CONFIG_DRIVE_STRENGTH:
                case PIN_CONFIG_SLEW_RATE:
                default:
                        *config = data;
                        break;
                }
                return 0;
        }
        return -ENOTSUPP;
}

static int pcs_pinconf_set(struct pinctrl_dev *pctldev,
                                unsigned pin, unsigned long config)
{
        struct pcs_device *pcs = pinctrl_dev_get_drvdata(pctldev);
        struct pcs_function *func;
        unsigned offset = 0, shift = 0, i, data, ret;
        u16 arg;

        ret = pcs_get_function(pctldev, pin, &func);
        if (ret)
                return ret;

        for (i = 0; i < func->nconfs; i++) {
                if (pinconf_to_config_param(config) == func->conf[i].param) {
                        offset = pin * (pcs->width / BITS_PER_BYTE);
                        data = pcs->read(pcs->base + offset);
                        arg = pinconf_to_config_argument(config);
                        switch (func->conf[i].param) {
                        /* 2 parameters */
                        case PIN_CONFIG_INPUT_SCHMITT:
                        case PIN_CONFIG_DRIVE_STRENGTH:
                        case PIN_CONFIG_SLEW_RATE:
                                shift = ffs(func->conf[i].mask) - 1;
                                data &= ~func->conf[i].mask;
                                data |= (arg << shift) & func->conf[i].mask;
                                break;
                        /* 4 parameters */
                        case PIN_CONFIG_BIAS_DISABLE:
                                pcs_pinconf_clear_bias(pctldev, pin);
                                break;
                        case PIN_CONFIG_BIAS_PULL_DOWN:
                        case PIN_CONFIG_BIAS_PULL_UP:
                                if (arg)
                                        pcs_pinconf_clear_bias(pctldev, pin);
                                /* fall through */
                        case PIN_CONFIG_INPUT_SCHMITT_ENABLE:
                                data &= ~func->conf[i].mask;
                                if (arg)
                                        data |= func->conf[i].enable;
                                else
                                        data |= func->conf[i].disable;
                                break;
                        default:
                                return -ENOTSUPP;
                        }
                        pcs->write(data, pcs->base + offset);
                        return 0;
                }
        }
        return -ENOTSUPP;
}

static int pcs_pinconf_group_get(struct pinctrl_dev *pctldev,
                                unsigned group, unsigned long *config)
{
        const unsigned *pins;
        unsigned npins, old = 0;
        int i, ret;

        ret = pcs_get_group_pins(pctldev, group, &pins, &npins);
        if (ret)
                return ret;
        for (i = 0; i < npins; i++) {
                if (pcs_pinconf_get(pctldev, pins[i], config))
                        return -ENOTSUPP;
                /* configs do not match between two pins */
                if (i && (old != *config))
                        return -ENOTSUPP;
                old = *config;
        }
        return 0;
}

static int pcs_pinconf_group_set(struct pinctrl_dev *pctldev,
                                unsigned group, unsigned long config)
{
        const unsigned *pins;
        unsigned npins;
        int i, ret;

        ret = pcs_get_group_pins(pctldev, group, &pins, &npins);
        if (ret)
                return ret;
        for (i = 0; i < npins; i++) {
                if (pcs_pinconf_set(pctldev, pins[i], config))
                        return -ENOTSUPP;
        }
        return 0;
}

static void pcs_pinconf_dbg_show(struct pinctrl_dev *pctldev,
                                struct seq_file *s, unsigned pin)
{
}

static void pcs_pinconf_group_dbg_show(struct pinctrl_dev *pctldev,
                                struct seq_file *s, unsigned selector)
{
}

static void pcs_pinconf_config_dbg_show(struct pinctrl_dev *pctldev,
                                        struct seq_file *s,
                                        unsigned long config)
{
        pinconf_generic_dump_config(pctldev, s, config);
}

static const struct pinconf_ops pcs_pinconf_ops = {
        .pin_config_get = pcs_pinconf_get,
        .pin_config_set = pcs_pinconf_set,
        .pin_config_group_get = pcs_pinconf_group_get,
        .pin_config_group_set = pcs_pinconf_group_set,
        .pin_config_dbg_show = pcs_pinconf_dbg_show,
        .pin_config_group_dbg_show = pcs_pinconf_group_dbg_show,
        .pin_config_config_dbg_show = pcs_pinconf_config_dbg_show,
        .is_generic = true,
};

/**
 * pcs_add_pin() - add a pin to the static per controller pin array
 * @pcs: pcs driver instance
 * @offset: register offset from base
 */
static int pcs_add_pin(struct pcs_device *pcs, unsigned offset)
{
        struct pinctrl_pin_desc *pin;
        struct pcs_name *pn;
        int i;

        i = pcs->pins.cur;
        if (i >= pcs->desc.npins) {
                dev_err(pcs->dev, "too many pins, max %i\n",
                        pcs->desc.npins);
                return -ENOMEM;
        }

        pin = &pcs->pins.pa[i];
        pn = &pcs->names[i];
        sprintf(pn->name, "%lx",
                (unsigned long)pcs->res->start + offset);
        pin->name = pn->name;
        pin->number = i;
        pcs->pins.cur++;

        return i;
}

/**
 * pcs_allocate_pin_table() - adds all the pins for the pinctrl driver
 * @pcs: pcs driver instance
 *
 * In case of errors, resources are freed in pcs_free_resources.
 *
 * If your hardware needs holes in the address space, then just set
 * up multiple driver instances.
 */
static int pcs_allocate_pin_table(struct pcs_device *pcs)
{
        int mux_bytes, nr_pins, i;

        mux_bytes = pcs->width / BITS_PER_BYTE;
        nr_pins = pcs->size / mux_bytes;

        dev_dbg(pcs->dev, "allocating %i pins\n", nr_pins);
        pcs->pins.pa = devm_kzalloc(pcs->dev,
                                sizeof(*pcs->pins.pa) * nr_pins,
                                GFP_KERNEL);
        if (!pcs->pins.pa)
                return -ENOMEM;

        pcs->names = devm_kzalloc(pcs->dev,
                                sizeof(struct pcs_name) * nr_pins,
                                GFP_KERNEL);
        if (!pcs->names)
                return -ENOMEM;

        pcs->desc.pins = pcs->pins.pa;
        pcs->desc.npins = nr_pins;

        for (i = 0; i < pcs->desc.npins; i++) {
                unsigned offset;
                int res;

                offset = i * mux_bytes;
                res = pcs_add_pin(pcs, offset);
                if (res < 0) {
                        dev_err(pcs->dev, "error adding pins: %i\n", res);
                        return res;
                }
        }

        return 0;
}

/**
 * pcs_add_function() - adds a new function to the function list
 * @pcs: pcs driver instance
 * @np: device node of the mux entry
 * @name: name of the function
 * @vals: array of mux register value pairs used by the function
 * @nvals: number of mux register value pairs
 * @pgnames: array of pingroup names for the function
 * @npgnames: number of pingroup names
 */
static struct pcs_function *pcs_add_function(struct pcs_device *pcs,
                                        struct device_node *np,
                                        const char *name,
                                        struct pcs_func_vals *vals,
                                        unsigned nvals,
                                        const char **pgnames,
                                        unsigned npgnames)
{
        struct pcs_function *function;

        function = devm_kzalloc(pcs->dev, sizeof(*function), GFP_KERNEL);
        if (!function)
                return NULL;

        function->name = name;
        function->vals = vals;
        function->nvals = nvals;
        function->pgnames = pgnames;
        function->npgnames = npgnames;

        mutex_lock(&pcs->mutex);
        list_add_tail(&function->node, &pcs->functions);
        radix_tree_insert(&pcs->ftree, pcs->nfuncs, function);
        pcs->nfuncs++;
        mutex_unlock(&pcs->mutex);

        return function;
}

static void pcs_remove_function(struct pcs_device *pcs,
                                struct pcs_function *function)
{
        int i;

        mutex_lock(&pcs->mutex);
        for (i = 0; i < pcs->nfuncs; i++) {
                struct pcs_function *found;

                found = radix_tree_lookup(&pcs->ftree, i);
                if (found == function)
                        radix_tree_delete(&pcs->ftree, i);
        }
        list_del(&function->node);
        mutex_unlock(&pcs->mutex);
}

/**
 * pcs_add_pingroup() - add a pingroup to the pingroup list
 * @pcs: pcs driver instance
 * @np: device node of the mux entry
 * @name: name of the pingroup
 * @gpins: array of the pins that belong to the group
 * @ngpins: number of pins in the group
 */
static int pcs_add_pingroup(struct pcs_device *pcs,
                                        struct device_node *np,
                                        const char *name,
                                        int *gpins,
                                        int ngpins)
{
        struct pcs_pingroup *pingroup;

        pingroup = devm_kzalloc(pcs->dev, sizeof(*pingroup), GFP_KERNEL);
        if (!pingroup)
                return -ENOMEM;

        pingroup->name = name;
        pingroup->np = np;
        pingroup->gpins = gpins;
        pingroup->ngpins = ngpins;

        mutex_lock(&pcs->mutex);
        list_add_tail(&pingroup->node, &pcs->pingroups);
        radix_tree_insert(&pcs->pgtree, pcs->ngroups, pingroup);
        pcs->ngroups++;
        mutex_unlock(&pcs->mutex);

        return 0;
}

/**
 * pcs_get_pin_by_offset() - get a pin index based on the register offset
 * @pcs: pcs driver instance
 * @offset: register offset from the base
 *
 * Note that this is OK as long as the pins are in a static array.
 */
static int pcs_get_pin_by_offset(struct pcs_device *pcs, unsigned offset)
{
        unsigned index;

        if (offset >= pcs->size) {
                dev_err(pcs->dev, "mux offset out of range: 0x%x (0x%x)\n",
                        offset, pcs->size);
                return -EINVAL;
        }

        index = offset / (pcs->width / BITS_PER_BYTE);

        return index;
}

/*
 * check whether data matches enable bits or disable bits
 * Return value: 1 for matching enable bits, 0 for matching disable bits,
 *               and negative value for matching failure.
 */
static int pcs_config_match(unsigned data, unsigned enable, unsigned disable)
{
        int ret = -EINVAL;

        if (data == enable)
                ret = 1;
        else if (data == disable)
                ret = 0;
        return ret;
}

static void add_config(struct pcs_conf_vals **conf, enum pin_config_param param,
                       unsigned value, unsigned enable, unsigned disable,
                       unsigned mask)
{
        (*conf)->param = param;
        (*conf)->val = value;
        (*conf)->enable = enable;
        (*conf)->disable = disable;
        (*conf)->mask = mask;
        (*conf)++;
}

static void add_setting(unsigned long **setting, enum pin_config_param param,
                        unsigned arg)
{
        **setting = pinconf_to_config_packed(param, arg);
        (*setting)++;
}

/* add pinconf setting with 2 parameters */
static void pcs_add_conf2(struct pcs_device *pcs, struct device_node *np,
                          const char *name, enum pin_config_param param,
                          struct pcs_conf_vals **conf, unsigned long **settings)
{
        unsigned value[2], shift;
        int ret;

        ret = of_property_read_u32_array(np, name, value, 2);
        if (ret)
                return;
        /* set value & mask */
        value[0] &= value[1];
        shift = ffs(value[1]) - 1;
        /* skip enable & disable */
        add_config(conf, param, value[0], 0, 0, value[1]);
        add_setting(settings, param, value[0] >> shift);
}

/* add pinconf setting with 4 parameters */
static void pcs_add_conf4(struct pcs_device *pcs, struct device_node *np,
                          const char *name, enum pin_config_param param,
                          struct pcs_conf_vals **conf, unsigned long **settings)
{
        unsigned value[4];
        int ret;

        /* value to set, enable, disable, mask */
        ret = of_property_read_u32_array(np, name, value, 4);
        if (ret)
                return;
        if (!value[3]) {
                dev_err(pcs->dev, "mask field of the property can't be 0\n");
                return;
        }
        value[0] &= value[3];
        value[1] &= value[3];
        value[2] &= value[3];
        ret = pcs_config_match(value[0], value[1], value[2]);

        if (ret < 0)
                dev_dbg(pcs->dev, "failed to match enable or disable bits\n");
        add_config(conf, param, value[0], value[1], value[2], value[3]);
        add_setting(settings, param, ret);
}

static int pcs_parse_pinconf(struct pcs_device *pcs, struct device_node *np,
                             struct pcs_function *func,
                             struct pinctrl_map **map)

{
        struct pinctrl_map *m = *map;
        int i = 0, nconfs = 0;
        unsigned long *settings = NULL, *s = NULL;
        struct pcs_conf_vals *conf = NULL;
        struct pcs_conf_type prop2[] = {
                { "pinctrl-single,drive-strength", PIN_CONFIG_DRIVE_STRENGTH, },
                { "pinctrl-single,slew-rate", PIN_CONFIG_SLEW_RATE, },
                { "pinctrl-single,input-schmitt", PIN_CONFIG_INPUT_SCHMITT, },
        };
        struct pcs_conf_type prop4[] = {
                { "pinctrl-single,bias-pullup", PIN_CONFIG_BIAS_PULL_UP, },
                { "pinctrl-single,bias-pulldown", PIN_CONFIG_BIAS_PULL_DOWN, },
                { "pinctrl-single,input-schmitt-enable",
                        PIN_CONFIG_INPUT_SCHMITT_ENABLE, },
        };

        /* If pinconf isn't supported, don't parse properties in below. */
        if (!pcs->is_pinconf)
                return 0;

        /* cacluate how much properties are supported in current node */
        for (i = 0; i < ARRAY_SIZE(prop2); i++) {
                if (of_find_property(np, prop2[i].name, NULL))
                        nconfs++;
        }
        for (i = 0; i < ARRAY_SIZE(prop4); i++) {
                if (of_find_property(np, prop4[i].name, NULL))
                        nconfs++;
        }
        if (!nconfs)
                return 0;

        func->conf = devm_kzalloc(pcs->dev,
                                  sizeof(struct pcs_conf_vals) * nconfs,
                                  GFP_KERNEL);
        if (!func->conf)
                return -ENOMEM;
        func->nconfs = nconfs;
        conf = &(func->conf[0]);
        m++;
        settings = devm_kzalloc(pcs->dev, sizeof(unsigned long) * nconfs,
                                GFP_KERNEL);
        if (!settings)
                return -ENOMEM;
        s = &settings[0];

        for (i = 0; i < ARRAY_SIZE(prop2); i++)
                pcs_add_conf2(pcs, np, prop2[i].name, prop2[i].param,
                              &conf, &s);
        for (i = 0; i < ARRAY_SIZE(prop4); i++)
                pcs_add_conf4(pcs, np, prop4[i].name, prop4[i].param,
                              &conf, &s);
        m->type = PIN_MAP_TYPE_CONFIGS_GROUP;
        m->data.configs.group_or_pin = np->name;
        m->data.configs.configs = settings;
        m->data.configs.num_configs = nconfs;
        return 0;
}

static void pcs_free_pingroups(struct pcs_device *pcs);

/**
 * smux_parse_one_pinctrl_entry() - parses a device tree mux entry
 * @pcs: pinctrl driver instance
 * @np: device node of the mux entry
 * @map: map entry
 * @num_maps: number of map
 * @pgnames: pingroup names
 *
 * Note that this binding currently supports only sets of one register + value.
 *
 * Also note that this driver tries to avoid understanding pin and function
 * names because of the extra bloat they would cause especially in the case of
 * a large number of pins. This driver just sets what is specified for the board
 * in the .dts file. Further user space debugging tools can be developed to
 * decipher the pin and function names using debugfs.
 *
 * If you are concerned about the boot time, set up the static pins in
 * the bootloader, and only set up selected pins as device tree entries.
 */
static int pcs_parse_one_pinctrl_entry(struct pcs_device *pcs,
                                                struct device_node *np,
                                                struct pinctrl_map **map,
                                                unsigned *num_maps,
                                                const char **pgnames)
{
        struct pcs_func_vals *vals;
        const __be32 *mux;
        int size, params, rows, *pins, index = 0, found = 0, res = -ENOMEM;
        struct pcs_function *function;

        if (pcs->bits_per_mux) {
                params = 3;
                mux = of_get_property(np, PCS_MUX_BITS_NAME, &size);
        } else {
                params = 2;
                mux = of_get_property(np, PCS_MUX_PINS_NAME, &size);
        }

        if (!mux) {
                dev_err(pcs->dev, "no valid property for %s\n", np->name);
                return -EINVAL;
        }

        if (size < (sizeof(*mux) * params)) {
                dev_err(pcs->dev, "bad data for %s\n", np->name);
                return -EINVAL;
        }

        size /= sizeof(*mux);   /* Number of elements in array */
        rows = size / params;

        vals = devm_kzalloc(pcs->dev, sizeof(*vals) * rows, GFP_KERNEL);
        if (!vals)
                return -ENOMEM;

        pins = devm_kzalloc(pcs->dev, sizeof(*pins) * rows, GFP_KERNEL);
        if (!pins)
                goto free_vals;

        while (index < size) {
                unsigned offset, val;
                int pin;

                offset = be32_to_cpup(mux + index++);
                val = be32_to_cpup(mux + index++);
                vals[found].reg = pcs->base + offset;
                vals[found].val = val;
                if (params == 3) {
                        val = be32_to_cpup(mux + index++);
                        vals[found].mask = val;
                }

                pin = pcs_get_pin_by_offset(pcs, offset);
                if (pin < 0) {
                        dev_err(pcs->dev,
                                "could not add functions for %s %ux\n",
                                np->name, offset);
                        break;
                }
                pins[found++] = pin;
        }

        pgnames[0] = np->name;
        function = pcs_add_function(pcs, np, np->name, vals, found, pgnames, 1);
        if (!function)
                goto free_pins;

        res = pcs_add_pingroup(pcs, np, np->name, pins, found);
        if (res < 0)
                goto free_function;

        (*map)->type = PIN_MAP_TYPE_MUX_GROUP;
        (*map)->data.mux.group = np->name;
        (*map)->data.mux.function = np->name;

        if (pcs->is_pinconf) {
                res = pcs_parse_pinconf(pcs, np, function, map);
                if (res)
                        goto free_pingroups;
                *num_maps = 2;
        } else {
                *num_maps = 1;
        }
        return 0;

free_pingroups:
        pcs_free_pingroups(pcs);
        *num_maps = 1;
free_function:
        pcs_remove_function(pcs, function);

free_pins:
        devm_kfree(pcs->dev, pins);

free_vals:
        devm_kfree(pcs->dev, vals);

        return res;
}
/**
 * pcs_dt_node_to_map() - allocates and parses pinctrl maps
 * @pctldev: pinctrl instance
 * @np_config: device tree pinmux entry
 * @map: array of map entries
 * @num_maps: number of maps
 */
static int pcs_dt_node_to_map(struct pinctrl_dev *pctldev,
                                struct device_node *np_config,
                                struct pinctrl_map **map, unsigned *num_maps)
{
        struct pcs_device *pcs;
        const char **pgnames;
        int ret;

        pcs = pinctrl_dev_get_drvdata(pctldev);

        /* create 2 maps. One is for pinmux, and the other is for pinconf. */
        *map = devm_kzalloc(pcs->dev, sizeof(**map) * 2, GFP_KERNEL);
        if (!*map)
                return -ENOMEM;

        *num_maps = 0;

        pgnames = devm_kzalloc(pcs->dev, sizeof(*pgnames), GFP_KERNEL);
        if (!pgnames) {
                ret = -ENOMEM;
                goto free_map;
        }

        ret = pcs_parse_one_pinctrl_entry(pcs, np_config, map, num_maps,
                                          pgnames);
        if (ret < 0) {
                dev_err(pcs->dev, "no pins entries for %s\n",
                        np_config->name);
                goto free_pgnames;
        }

        return 0;

free_pgnames:
        devm_kfree(pcs->dev, pgnames);
free_map:
        devm_kfree(pcs->dev, *map);

        return ret;
}

/**
 * pcs_free_funcs() - free memory used by functions
 * @pcs: pcs driver instance
 */
static void pcs_free_funcs(struct pcs_device *pcs)
{
        struct list_head *pos, *tmp;
        int i;

        mutex_lock(&pcs->mutex);
        for (i = 0; i < pcs->nfuncs; i++) {
                struct pcs_function *func;

                func = radix_tree_lookup(&pcs->ftree, i);
                if (!func)
                        continue;
                radix_tree_delete(&pcs->ftree, i);
        }
        list_for_each_safe(pos, tmp, &pcs->functions) {
                struct pcs_function *function;

                function = list_entry(pos, struct pcs_function, node);
                list_del(&function->node);
        }
        mutex_unlock(&pcs->mutex);
}

/**
 * pcs_free_pingroups() - free memory used by pingroups
 * @pcs: pcs driver instance
 */
static void pcs_free_pingroups(struct pcs_device *pcs)
{
        struct list_head *pos, *tmp;
        int i;

        mutex_lock(&pcs->mutex);
        for (i = 0; i < pcs->ngroups; i++) {
                struct pcs_pingroup *pingroup;

                pingroup = radix_tree_lookup(&pcs->pgtree, i);
                if (!pingroup)
                        continue;
                radix_tree_delete(&pcs->pgtree, i);
        }
        list_for_each_safe(pos, tmp, &pcs->pingroups) {
                struct pcs_pingroup *pingroup;

                pingroup = list_entry(pos, struct pcs_pingroup, node);
                list_del(&pingroup->node);
        }
        mutex_unlock(&pcs->mutex);
}

/**
 * pcs_free_resources() - free memory used by this driver
 * @pcs: pcs driver instance
 */
static void pcs_free_resources(struct pcs_device *pcs)
{
        if (pcs->pctl)
                pinctrl_unregister(pcs->pctl);

        pcs_free_funcs(pcs);
        pcs_free_pingroups(pcs);
}

#define PCS_GET_PROP_U32(name, reg, err)                                \
        do {                                                            \
                ret = of_property_read_u32(np, name, reg);              \
                if (ret) {                                              \
                        dev_err(pcs->dev, err);                         \
                        return ret;                                     \
                }                                                       \
        } while (0);

static struct of_device_id pcs_of_match[];

static int pcs_add_gpio_func(struct device_node *node, struct pcs_device *pcs)
{
        const char *propname = "pinctrl-single,gpio-range";
        const char *cellname = "#pinctrl-single,gpio-range-cells";
        struct of_phandle_args gpiospec;
        struct pcs_gpiofunc_range *range;
        int ret, i;

        for (i = 0; ; i++) {
                ret = of_parse_phandle_with_args(node, propname, cellname,
                                                 i, &gpiospec);
                /* Do not treat it as error. Only treat it as end condition. */
                if (ret) {
                        ret = 0;
                        break;
                }
                range = devm_kzalloc(pcs->dev, sizeof(*range), GFP_KERNEL);
                if (!range) {
                        ret = -ENOMEM;
                        break;
                }
                range->offset = gpiospec.args[0];
                range->npins = gpiospec.args[1];
                range->gpiofunc = gpiospec.args[2];
                mutex_lock(&pcs->mutex);
                list_add_tail(&range->node, &pcs->gpiofuncs);
                mutex_unlock(&pcs->mutex);
        }
        return ret;
}

static int pcs_probe(struct platform_device *pdev)
{
        struct device_node *np = pdev->dev.of_node;
        const struct of_device_id *match;
        struct resource *res;
        struct pcs_device *pcs;
        int ret;

        match = of_match_device(pcs_of_match, &pdev->dev);
        if (!match)
                return -EINVAL;

        pcs = devm_kzalloc(&pdev->dev, sizeof(*pcs), GFP_KERNEL);
        if (!pcs) {
                dev_err(&pdev->dev, "could not allocate\n");
                return -ENOMEM;
        }
        pcs->dev = &pdev->dev;
        mutex_init(&pcs->mutex);
        INIT_LIST_HEAD(&pcs->pingroups);
        INIT_LIST_HEAD(&pcs->functions);
        INIT_LIST_HEAD(&pcs->gpiofuncs);
        pcs->is_pinconf = match->data;

        PCS_GET_PROP_U32("pinctrl-single,register-width", &pcs->width,
                         "register width not specified\n");

        ret = of_property_read_u32(np, "pinctrl-single,function-mask",
                                   &pcs->fmask);
        if (!ret) {
                pcs->fshift = ffs(pcs->fmask) - 1;
                pcs->fmax = pcs->fmask >> pcs->fshift;
        } else {
                /* If mask property doesn't exist, function mux is invalid. */
                pcs->fmask = 0;
                pcs->fshift = 0;
                pcs->fmax = 0;
        }

        ret = of_property_read_u32(np, "pinctrl-single,function-off",
                                        &pcs->foff);
        if (ret)
                pcs->foff = PCS_OFF_DISABLED;

        pcs->bits_per_mux = of_property_read_bool(np,
                                                  "pinctrl-single,bit-per-mux");

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!res) {
                dev_err(pcs->dev, "could not get resource\n");
                return -ENODEV;
        }

        pcs->res = devm_request_mem_region(pcs->dev, res->start,
                        resource_size(res), DRIVER_NAME);
        if (!pcs->res) {
                dev_err(pcs->dev, "could not get mem_region\n");
                return -EBUSY;
        }

        pcs->size = resource_size(pcs->res);
        pcs->base = devm_ioremap(pcs->dev, pcs->res->start, pcs->size);
        if (!pcs->base) {
                dev_err(pcs->dev, "could not ioremap\n");
                return -ENODEV;
        }

        INIT_RADIX_TREE(&pcs->pgtree, GFP_KERNEL);
        INIT_RADIX_TREE(&pcs->ftree, GFP_KERNEL);
        platform_set_drvdata(pdev, pcs);

        switch (pcs->width) {
        case 8:
                pcs->read = pcs_readb;
                pcs->write = pcs_writeb;
                break;
        case 16:
                pcs->read = pcs_readw;
                pcs->write = pcs_writew;
                break;
        case 32:
                pcs->read = pcs_readl;
                pcs->write = pcs_writel;
                break;
        default:
                break;
        }

        pcs->desc.name = DRIVER_NAME;
        pcs->desc.pctlops = &pcs_pinctrl_ops;
        pcs->desc.pmxops = &pcs_pinmux_ops;
        if (pcs->is_pinconf)
                pcs->desc.confops = &pcs_pinconf_ops;
        pcs->desc.owner = THIS_MODULE;

        ret = pcs_allocate_pin_table(pcs);
        if (ret < 0)
                goto free;

        pcs->pctl = pinctrl_register(&pcs->desc, pcs->dev, pcs);
        if (IS_ERR(pcs->pctl)) {
                dev_err(pcs->dev, "could not register single pinctrl driver\n");
                ret = PTR_ERR(pcs->pctl);
                goto free;
        }

        ret = pcs_add_gpio_func(np, pcs);
        if (ret < 0)
                goto free;

        dev_info(pcs->dev, "%i pins at pa %p size %u\n",
                 pcs->desc.npins, pcs->base, pcs->size);

        return 0;

free:
        pcs_free_resources(pcs);

        return ret;
}

static int pcs_remove(struct platform_device *pdev)
{
        struct pcs_device *pcs = platform_get_drvdata(pdev);

        if (!pcs)
                return 0;

        pcs_free_resources(pcs);

        return 0;
}

static struct of_device_id pcs_of_match[] = {
        { .compatible = "pinctrl-single", .data = (void *)false },
        { .compatible = "pinconf-single", .data = (void *)true },
        { },
};
MODULE_DEVICE_TABLE(of, pcs_of_match);

static struct platform_driver pcs_driver = {
        .probe          = pcs_probe,
        .remove         = pcs_remove,
        .driver = {
                .owner          = THIS_MODULE,
                .name           = DRIVER_NAME,
                .of_match_table = pcs_of_match,
        },
};

module_platform_driver(pcs_driver);

MODULE_AUTHOR("Tony Lindgren <tony@atomide.com>");
MODULE_DESCRIPTION("One-register-per-pin type device tree based pinctrl driver");
MODULE_LICENSE("GPL v2");