/*
 * Pin controller and GPIO driver for Amlogic Meson SoCs
 *
 * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

/*
 * The available pins are organized in banks (A,B,C,D,E,X,Y,Z,AO,
 * BOOT,CARD for meson6, X,Y,DV,H,Z,AO,BOOT,CARD for meson8 and
 * X,Y,DV,H,AO,BOOT,CARD,DIF for meson8b) and each bank has a
 * variable number of pins.
 *
 * The AO bank is special because it belongs to the Always-On power
 * domain which can't be powered off; the bank also uses a set of
 * registers different from the other banks.
 *
 * For each of the two power domains (regular and always-on) there are
 * 4 different register ranges that control the following properties
 * of the pins:
 *  1) pin muxing
 *  2) pull enable/disable
 *  3) pull up/down
 *  4) GPIO direction, output value, input value
 *
 * In some cases the register ranges for pull enable and pull
 * direction are the same and thus there are only 3 register ranges.
 *
 * Every pinmux group can be enabled by a specific bit in the first
 * register range of the domain; when all groups for a given pin are
 * disabled the pin acts as a GPIO.
 *
 * For the pull and GPIO configuration every bank uses a contiguous
 * set of bits in the register sets described above; the same register
 * can be shared by more banks with different offsets.
 *
 * In addition to this there are some registers shared between all
 * banks that control the IRQ functionality. This feature is not
 * supported at the moment by the driver.
 */

#include <linux/device.h>
#include <linux/gpio.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/pinctrl/pinconf-generic.h>
#include <linux/pinctrl/pinconf.h>
#include <linux/pinctrl/pinctrl.h>
#include <linux/pinctrl/pinmux.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/seq_file.h>

#include "../core.h"
#include "../pinctrl-utils.h"
#include "pinctrl-meson.h"

/**
 * meson_get_bank() - find the bank containing a given pin
 *
 * @domain:     the domain containing the pin
 * @pin:        the pin number
 * @bank:       the found bank
 *
 * Return:      0 on success, a negative value on error
 */
static int meson_get_bank(struct meson_domain *domain, unsigned int pin,
                          struct meson_bank **bank)
{
        int i;

        for (i = 0; i < domain->data->num_banks; i++) {
                if (pin >= domain->data->banks[i].first &&
                    pin <= domain->data->banks[i].last) {
                        *bank = &domain->data->banks[i];
                        return 0;
                }
        }

        return -EINVAL;
}

/**
 * meson_get_domain_and_bank() - find domain and bank containing a given pin
 *
 * @pc:         Meson pin controller device
 * @pin:        the pin number
 * @domain:     the found domain
 * @bank:       the found bank
 *
 * Return:      0 on success, a negative value on error
 */
static int meson_get_domain_and_bank(struct meson_pinctrl *pc, unsigned int pin,
                                     struct meson_domain **domain,
                                     struct meson_bank **bank)
{
        struct meson_domain *d;
        int i;

        for (i = 0; i < pc->data->num_domains; i++) {
                d = &pc->domains[i];
                if (pin >= d->data->pin_base &&
                    pin < d->data->pin_base + d->data->num_pins) {
                        *domain = d;
                        return meson_get_bank(d, pin, bank);
                }
        }

        return -EINVAL;
}

/**
 * meson_calc_reg_and_bit() - calculate register and bit for a pin
 *
 * @bank:       the bank containing the pin
 * @pin:        the pin number
 * @reg_type:   the type of register needed (pull-enable, pull, etc...)
 * @reg:        the computed register offset
 * @bit:        the computed bit
 */
static void meson_calc_reg_and_bit(struct meson_bank *bank, unsigned int pin,
                                   enum meson_reg_type reg_type,
                                   unsigned int *reg, unsigned int *bit)
{
        struct meson_reg_desc *desc = &bank->regs[reg_type];

        *reg = desc->reg * 4;
        *bit = desc->bit + pin - bank->first;
}

static int meson_get_groups_count(struct pinctrl_dev *pcdev)
{
        struct meson_pinctrl *pc = pinctrl_dev_get_drvdata(pcdev);

        return pc->data->num_groups;
}

static const char *meson_get_group_name(struct pinctrl_dev *pcdev,
                                        unsigned selector)
{
        struct meson_pinctrl *pc = pinctrl_dev_get_drvdata(pcdev);

        return pc->data->groups[selector].name;
}

static int meson_get_group_pins(struct pinctrl_dev *pcdev, unsigned selector,
                                const unsigned **pins, unsigned *num_pins)
{
        struct meson_pinctrl *pc = pinctrl_dev_get_drvdata(pcdev);

        *pins = pc->data->groups[selector].pins;
        *num_pins = pc->data->groups[selector].num_pins;

        return 0;
}

static void meson_pin_dbg_show(struct pinctrl_dev *pcdev, struct seq_file *s,
                               unsigned offset)
{
        seq_printf(s, " %s", dev_name(pcdev->dev));
}

static const struct pinctrl_ops meson_pctrl_ops = {
        .get_groups_count       = meson_get_groups_count,
        .get_group_name         = meson_get_group_name,
        .get_group_pins         = meson_get_group_pins,
        .dt_node_to_map         = pinconf_generic_dt_node_to_map_all,
        .dt_free_map            = pinctrl_utils_dt_free_map,
        .pin_dbg_show           = meson_pin_dbg_show,
};

/**
 * meson_pmx_disable_other_groups() - disable other groups using a given pin
 *
 * @pc:         meson pin controller device
 * @pin:        number of the pin
 * @sel_group:  index of the selected group, or -1 if none
 *
 * The function disables all pinmux groups using a pin except the
 * selected one. If @sel_group is -1 all groups are disabled, leaving
 * the pin in GPIO mode.
 */
static void meson_pmx_disable_other_groups(struct meson_pinctrl *pc,
                                           unsigned int pin, int sel_group)
{
        struct meson_pmx_group *group;
        struct meson_domain *domain;
        int i, j;

        for (i = 0; i < pc->data->num_groups; i++) {
                group = &pc->data->groups[i];
                if (group->is_gpio || i == sel_group)
                        continue;

                for (j = 0; j < group->num_pins; j++) {
                        if (group->pins[j] == pin) {
                                /* We have found a group using the pin */
                                domain = &pc->domains[group->domain];
                                regmap_update_bits(domain->reg_mux,
                                                   group->reg * 4,
                                                   BIT(group->bit), 0);
                        }
                }
        }
}

static int meson_pmx_set_mux(struct pinctrl_dev *pcdev, unsigned func_num,
                             unsigned group_num)
{
        struct meson_pinctrl *pc = pinctrl_dev_get_drvdata(pcdev);
        struct meson_pmx_func *func = &pc->data->funcs[func_num];
        struct meson_pmx_group *group = &pc->data->groups[group_num];
        struct meson_domain *domain = &pc->domains[group->domain];
        int i, ret = 0;

        dev_dbg(pc->dev, "enable function %s, group %s\n", func->name,
                group->name);

        /*
         * Disable groups using the same pin.
         * The selected group is not disabled to avoid glitches.
         */
        for (i = 0; i < group->num_pins; i++)
                meson_pmx_disable_other_groups(pc, group->pins[i], group_num);

        /* Function 0 (GPIO) doesn't need any additional setting */
        if (func_num)
                ret = regmap_update_bits(domain->reg_mux, group->reg * 4,
                                         BIT(group->bit), BIT(group->bit));

        return ret;
}

static int meson_pmx_request_gpio(struct pinctrl_dev *pcdev,
                                  struct pinctrl_gpio_range *range,
                                  unsigned offset)
{
        struct meson_pinctrl *pc = pinctrl_dev_get_drvdata(pcdev);

        meson_pmx_disable_other_groups(pc, range->pin_base + offset, -1);

        return 0;
}

static int meson_pmx_get_funcs_count(struct pinctrl_dev *pcdev)
{
        struct meson_pinctrl *pc = pinctrl_dev_get_drvdata(pcdev);

        return pc->data->num_funcs;
}

static const char *meson_pmx_get_func_name(struct pinctrl_dev *pcdev,
                                           unsigned selector)
{
        struct meson_pinctrl *pc = pinctrl_dev_get_drvdata(pcdev);

        return pc->data->funcs[selector].name;
}

static int meson_pmx_get_groups(struct pinctrl_dev *pcdev, unsigned selector,
                                const char * const **groups,
                                unsigned * const num_groups)
{
        struct meson_pinctrl *pc = pinctrl_dev_get_drvdata(pcdev);

        *groups = pc->data->funcs[selector].groups;
        *num_groups = pc->data->funcs[selector].num_groups;

        return 0;
}

static const struct pinmux_ops meson_pmx_ops = {
        .set_mux = meson_pmx_set_mux,
        .get_functions_count = meson_pmx_get_funcs_count,
        .get_function_name = meson_pmx_get_func_name,
        .get_function_groups = meson_pmx_get_groups,
        .gpio_request_enable = meson_pmx_request_gpio,
};

static int meson_pinconf_set(struct pinctrl_dev *pcdev, unsigned int pin,
                             unsigned long *configs, unsigned num_configs)
{
        struct meson_pinctrl *pc = pinctrl_dev_get_drvdata(pcdev);
        struct meson_domain *domain;
        struct meson_bank *bank;
        enum pin_config_param param;
        unsigned int reg, bit;
        int i, ret;
        u16 arg;

        ret = meson_get_domain_and_bank(pc, pin, &domain, &bank);
        if (ret)
                return ret;

        for (i = 0; i < num_configs; i++) {
                param = pinconf_to_config_param(configs[i]);
                arg = pinconf_to_config_argument(configs[i]);

                switch (param) {
                case PIN_CONFIG_BIAS_DISABLE:
                        dev_dbg(pc->dev, "pin %u: disable bias\n", pin);

                        meson_calc_reg_and_bit(bank, pin, REG_PULL, &reg, &bit);
                        ret = regmap_update_bits(domain->reg_pull, reg,
                                                 BIT(bit), 0);
                        if (ret)
                                return ret;
                        break;
                case PIN_CONFIG_BIAS_PULL_UP:
                        dev_dbg(pc->dev, "pin %u: enable pull-up\n", pin);

                        meson_calc_reg_and_bit(bank, pin, REG_PULLEN,
                                               &reg, &bit);
                        ret = regmap_update_bits(domain->reg_pullen, reg,
                                                 BIT(bit), BIT(bit));
                        if (ret)
                                return ret;

                        meson_calc_reg_and_bit(bank, pin, REG_PULL, &reg, &bit);
                        ret = regmap_update_bits(domain->reg_pull, reg,
                                                 BIT(bit), BIT(bit));
                        if (ret)
                                return ret;
                        break;
                case PIN_CONFIG_BIAS_PULL_DOWN:
                        dev_dbg(pc->dev, "pin %u: enable pull-down\n", pin);

                        meson_calc_reg_and_bit(bank, pin, REG_PULLEN,
                                               &reg, &bit);
                        ret = regmap_update_bits(domain->reg_pullen, reg,
                                                 BIT(bit), BIT(bit));
                        if (ret)
                                return ret;

                        meson_calc_reg_and_bit(bank, pin, REG_PULL, &reg, &bit);
                        ret = regmap_update_bits(domain->reg_pull, reg,
                                                 BIT(bit), 0);
                        if (ret)
                                return ret;
                        break;
                default:
                        return -ENOTSUPP;
                }
        }

        return 0;
}

static int meson_pinconf_get_pull(struct meson_pinctrl *pc, unsigned int pin)
{
        struct meson_domain *domain;
        struct meson_bank *bank;
        unsigned int reg, bit, val;
        int ret, conf;

        ret = meson_get_domain_and_bank(pc, pin, &domain, &bank);
        if (ret)
                return ret;

        meson_calc_reg_and_bit(bank, pin, REG_PULLEN, &reg, &bit);

        ret = regmap_read(domain->reg_pullen, reg, &val);
        if (ret)
                return ret;

        if (!(val & BIT(bit))) {
                conf = PIN_CONFIG_BIAS_DISABLE;
        } else {
                meson_calc_reg_and_bit(bank, pin, REG_PULL, &reg, &bit);

                ret = regmap_read(domain->reg_pull, reg, &val);
                if (ret)
                        return ret;

                if (val & BIT(bit))
                        conf = PIN_CONFIG_BIAS_PULL_UP;
                else
                        conf = PIN_CONFIG_BIAS_PULL_DOWN;
        }

        return conf;
}

static int meson_pinconf_get(struct pinctrl_dev *pcdev, unsigned int pin,
                             unsigned long *config)
{
        struct meson_pinctrl *pc = pinctrl_dev_get_drvdata(pcdev);
        enum pin_config_param param = pinconf_to_config_param(*config);
        u16 arg;

        switch (param) {
        case PIN_CONFIG_BIAS_DISABLE:
        case PIN_CONFIG_BIAS_PULL_DOWN:
        case PIN_CONFIG_BIAS_PULL_UP:
                if (meson_pinconf_get_pull(pc, pin) == param)
                        arg = 1;
                else
                        return -EINVAL;
                break;
        default:
                return -ENOTSUPP;
        }

        *config = pinconf_to_config_packed(param, arg);
        dev_dbg(pc->dev, "pinconf for pin %u is %lu\n", pin, *config);

        return 0;
}

static int meson_pinconf_group_set(struct pinctrl_dev *pcdev,
                                   unsigned int num_group,
                                   unsigned long *configs, unsigned num_configs)
{
        struct meson_pinctrl *pc = pinctrl_dev_get_drvdata(pcdev);
        struct meson_pmx_group *group = &pc->data->groups[num_group];
        int i;

        dev_dbg(pc->dev, "set pinconf for group %s\n", group->name);

        for (i = 0; i < group->num_pins; i++) {
                meson_pinconf_set(pcdev, group->pins[i], configs,
                                  num_configs);
        }

        return 0;
}

static int meson_pinconf_group_get(struct pinctrl_dev *pcdev,
                                   unsigned int group, unsigned long *config)
{
        return -ENOSYS;
}

static const struct pinconf_ops meson_pinconf_ops = {
        .pin_config_get         = meson_pinconf_get,
        .pin_config_set         = meson_pinconf_set,
        .pin_config_group_get   = meson_pinconf_group_get,
        .pin_config_group_set   = meson_pinconf_group_set,
        .is_generic             = true,
};

static inline struct meson_domain *to_meson_domain(struct gpio_chip *chip)
{
        return container_of(chip, struct meson_domain, chip);
}

static int meson_gpio_request(struct gpio_chip *chip, unsigned gpio)
{
        return pinctrl_request_gpio(chip->base + gpio);
}

static void meson_gpio_free(struct gpio_chip *chip, unsigned gpio)
{
        struct meson_domain *domain = to_meson_domain(chip);

        pinctrl_free_gpio(domain->data->pin_base + gpio);
}

static int meson_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
{
        struct meson_domain *domain = to_meson_domain(chip);
        unsigned int reg, bit, pin;
        struct meson_bank *bank;
        int ret;

        pin = domain->data->pin_base + gpio;
        ret = meson_get_bank(domain, pin, &bank);
        if (ret)
                return ret;

        meson_calc_reg_and_bit(bank, pin, REG_DIR, &reg, &bit);

        return regmap_update_bits(domain->reg_gpio, reg, BIT(bit), BIT(bit));
}

static int meson_gpio_direction_output(struct gpio_chip *chip, unsigned gpio,
                                       int value)
{
        struct meson_domain *domain = to_meson_domain(chip);
        unsigned int reg, bit, pin;
        struct meson_bank *bank;
        int ret;

        pin = domain->data->pin_base + gpio;
        ret = meson_get_bank(domain, pin, &bank);
        if (ret)
                return ret;

        meson_calc_reg_and_bit(bank, pin, REG_DIR, &reg, &bit);
        ret = regmap_update_bits(domain->reg_gpio, reg, BIT(bit), 0);
        if (ret)
                return ret;

        meson_calc_reg_and_bit(bank, pin, REG_OUT, &reg, &bit);
        return regmap_update_bits(domain->reg_gpio, reg, BIT(bit),
                                  value ? BIT(bit) : 0);
}

static void meson_gpio_set(struct gpio_chip *chip, unsigned gpio, int value)
{
        struct meson_domain *domain = to_meson_domain(chip);
        unsigned int reg, bit, pin;
        struct meson_bank *bank;
        int ret;

        pin = domain->data->pin_base + gpio;
        ret = meson_get_bank(domain, pin, &bank);
        if (ret)
                return;

        meson_calc_reg_and_bit(bank, pin, REG_OUT, &reg, &bit);
        regmap_update_bits(domain->reg_gpio, reg, BIT(bit),
                           value ? BIT(bit) : 0);
}

static int meson_gpio_get(struct gpio_chip *chip, unsigned gpio)
{
        struct meson_domain *domain = to_meson_domain(chip);
        unsigned int reg, bit, val, pin;
        struct meson_bank *bank;
        int ret;

        pin = domain->data->pin_base + gpio;
        ret = meson_get_bank(domain, pin, &bank);
        if (ret)
                return ret;

        meson_calc_reg_and_bit(bank, pin, REG_IN, &reg, &bit);
        regmap_read(domain->reg_gpio, reg, &val);

        return !!(val & BIT(bit));
}

static const struct of_device_id meson_pinctrl_dt_match[] = {
        {
                .compatible = "amlogic,meson8-pinctrl",
                .data = &meson8_pinctrl_data,
        },
        {
                .compatible = "amlogic,meson8b-pinctrl",
                .data = &meson8b_pinctrl_data,
        },
        { },
};
MODULE_DEVICE_TABLE(of, meson_pinctrl_dt_match);

static int meson_gpiolib_register(struct meson_pinctrl *pc)
{
        struct meson_domain *domain;
        int i, ret;

        for (i = 0; i < pc->data->num_domains; i++) {
                domain = &pc->domains[i];

                domain->chip.label = domain->data->name;
                domain->chip.dev = pc->dev;
                domain->chip.request = meson_gpio_request;
                domain->chip.free = meson_gpio_free;
                domain->chip.direction_input = meson_gpio_direction_input;
                domain->chip.direction_output = meson_gpio_direction_output;
                domain->chip.get = meson_gpio_get;
                domain->chip.set = meson_gpio_set;
                domain->chip.base = domain->data->pin_base;
                domain->chip.ngpio = domain->data->num_pins;
                domain->chip.can_sleep = false;
                domain->chip.of_node = domain->of_node;
                domain->chip.of_gpio_n_cells = 2;

                ret = gpiochip_add(&domain->chip);
                if (ret) {
                        dev_err(pc->dev, "can't add gpio chip %s\n",
                                domain->data->name);
                        goto fail;
                }

                ret = gpiochip_add_pin_range(&domain->chip, dev_name(pc->dev),
                                             0, domain->data->pin_base,
                                             domain->chip.ngpio);
                if (ret) {
                        dev_err(pc->dev, "can't add pin range\n");
                        goto fail;
                }
        }

        return 0;
fail:
        for (i--; i >= 0; i--)
                gpiochip_remove(&pc->domains[i].chip);

        return ret;
}

static struct meson_domain_data *meson_get_domain_data(struct meson_pinctrl *pc,
                                                       struct device_node *np)
{
        int i;

        for (i = 0; i < pc->data->num_domains; i++) {
                if (!strcmp(np->name, pc->data->domain_data[i].name))
                        return &pc->data->domain_data[i];
        }

        return NULL;
}

static struct regmap_config meson_regmap_config = {
        .reg_bits = 32,
        .val_bits = 32,
        .reg_stride = 4,
};

static struct regmap *meson_map_resource(struct meson_pinctrl *pc,
                                         struct device_node *node, char *name)
{
        struct resource res;
        void __iomem *base;
        int i;

        i = of_property_match_string(node, "reg-names", name);
        if (of_address_to_resource(node, i, &res))
                return ERR_PTR(-ENOENT);

        base = devm_ioremap_resource(pc->dev, &res);
        if (IS_ERR(base))
                return ERR_CAST(base);

        meson_regmap_config.max_register = resource_size(&res) - 4;
        meson_regmap_config.name = devm_kasprintf(pc->dev, GFP_KERNEL,
                                                  "%s-%s", node->name,
                                                  name);
        if (!meson_regmap_config.name)
                return ERR_PTR(-ENOMEM);

        return devm_regmap_init_mmio(pc->dev, base, &meson_regmap_config);
}

static int meson_pinctrl_parse_dt(struct meson_pinctrl *pc,
                                  struct device_node *node)
{
        struct device_node *np;
        struct meson_domain *domain;
        int i = 0, num_domains = 0;

        for_each_child_of_node(node, np) {
                if (!of_find_property(np, "gpio-controller", NULL))
                        continue;
                num_domains++;
        }

        if (num_domains != pc->data->num_domains) {
                dev_err(pc->dev, "wrong number of subnodes\n");
                return -EINVAL;
        }

        pc->domains = devm_kzalloc(pc->dev, num_domains *
                                   sizeof(struct meson_domain), GFP_KERNEL);
        if (!pc->domains)
                return -ENOMEM;

        for_each_child_of_node(node, np) {
                if (!of_find_property(np, "gpio-controller", NULL))
                        continue;

                domain = &pc->domains[i];

                domain->data = meson_get_domain_data(pc, np);
                if (!domain->data) {
                        dev_err(pc->dev, "domain data not found for node %s\n",
                                np->name);
                        return -ENODEV;
                }

                domain->of_node = np;

                domain->reg_mux = meson_map_resource(pc, np, "mux");
                if (IS_ERR(domain->reg_mux)) {
                        dev_err(pc->dev, "mux registers not found\n");
                        return PTR_ERR(domain->reg_mux);
                }

                domain->reg_pull = meson_map_resource(pc, np, "pull");
                if (IS_ERR(domain->reg_pull)) {
                        dev_err(pc->dev, "pull registers not found\n");
                        return PTR_ERR(domain->reg_pull);
                }

                domain->reg_pullen = meson_map_resource(pc, np, "pull-enable");
                /* Use pull region if pull-enable one is not present */
                if (IS_ERR(domain->reg_pullen))
                        domain->reg_pullen = domain->reg_pull;

                domain->reg_gpio = meson_map_resource(pc, np, "gpio");
                if (IS_ERR(domain->reg_gpio)) {
                        dev_err(pc->dev, "gpio registers not found\n");
                        return PTR_ERR(domain->reg_gpio);
                }

                i++;
        }

        return 0;
}

static int meson_pinctrl_probe(struct platform_device *pdev)
{
        const struct of_device_id *match;
        struct device *dev = &pdev->dev;
        struct meson_pinctrl *pc;
        int ret;

        pc = devm_kzalloc(dev, sizeof(struct meson_pinctrl), GFP_KERNEL);
        if (!pc)
                return -ENOMEM;

        pc->dev = dev;
        match = of_match_node(meson_pinctrl_dt_match, pdev->dev.of_node);
        pc->data = (struct meson_pinctrl_data *)match->data;

        ret = meson_pinctrl_parse_dt(pc, pdev->dev.of_node);
        if (ret)
                return ret;

        pc->desc.name           = "pinctrl-meson";
        pc->desc.owner          = THIS_MODULE;
        pc->desc.pctlops        = &meson_pctrl_ops;
        pc->desc.pmxops         = &meson_pmx_ops;
        pc->desc.confops        = &meson_pinconf_ops;
        pc->desc.pins           = pc->data->pins;
        pc->desc.npins          = pc->data->num_pins;

        pc->pcdev = pinctrl_register(&pc->desc, pc->dev, pc);
        if (IS_ERR(pc->pcdev)) {
                dev_err(pc->dev, "can't register pinctrl device");
                return PTR_ERR(pc->pcdev);
        }

        ret = meson_gpiolib_register(pc);
        if (ret) {
                pinctrl_unregister(pc->pcdev);
                return ret;
        }

        return 0;
}

static struct platform_driver meson_pinctrl_driver = {
        .probe          = meson_pinctrl_probe,
        .driver = {
                .name   = "meson-pinctrl",
                .of_match_table = meson_pinctrl_dt_match,
        },
};
module_platform_driver(meson_pinctrl_driver);

MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");
MODULE_DESCRIPTION("Amlogic Meson pinctrl driver");
MODULE_LICENSE("GPL v2");