/*
 * Copyright (c) 2011-2016 Synaptics Incorporated
 * Copyright (c) 2011 Unixphere
 *
 * 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.
 */

#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/list.h>
#include <linux/pm.h>
#include <linux/rmi.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/of.h>
#include "rmi_bus.h"
#include "rmi_driver.h"

static int debug_flags;
module_param(debug_flags, int, 0644);
MODULE_PARM_DESC(debug_flags, "control debugging information");

void rmi_dbg(int flags, struct device *dev, const char *fmt, ...)
{
        struct va_format vaf;
        va_list args;

        if (flags & debug_flags) {
                va_start(args, fmt);

                vaf.fmt = fmt;
                vaf.va = &args;

                dev_printk(KERN_DEBUG, dev, "%pV", &vaf);

                va_end(args);
        }
}
EXPORT_SYMBOL_GPL(rmi_dbg);

/*
 * RMI Physical devices
 *
 * Physical RMI device consists of several functions serving particular
 * purpose. For example F11 is a 2D touch sensor while F01 is a generic
 * function present in every RMI device.
 */

static void rmi_release_device(struct device *dev)
{
        struct rmi_device *rmi_dev = to_rmi_device(dev);

        kfree(rmi_dev);
}

static const struct device_type rmi_device_type = {
        .name           = "rmi4_sensor",
        .release        = rmi_release_device,
};

bool rmi_is_physical_device(struct device *dev)
{
        return dev->type == &rmi_device_type;
}

/**
 * rmi_register_transport_device - register a transport device connection
 * on the RMI bus.  Transport drivers provide communication from the devices
 * on a bus (such as SPI, I2C, and so on) to the RMI4 sensor.
 *
 * @xport: the transport device to register
 */
int rmi_register_transport_device(struct rmi_transport_dev *xport)
{
        static atomic_t transport_device_count = ATOMIC_INIT(0);
        struct rmi_device *rmi_dev;
        int error;

        rmi_dev = kzalloc(sizeof(struct rmi_device), GFP_KERNEL);
        if (!rmi_dev)
                return -ENOMEM;

        device_initialize(&rmi_dev->dev);

        rmi_dev->xport = xport;
        rmi_dev->number = atomic_inc_return(&transport_device_count) - 1;

        dev_set_name(&rmi_dev->dev, "rmi4-%02d", rmi_dev->number);

        rmi_dev->dev.bus = &rmi_bus_type;
        rmi_dev->dev.type = &rmi_device_type;

        xport->rmi_dev = rmi_dev;

        error = device_add(&rmi_dev->dev);
        if (error)
                goto err_put_device;

        rmi_dbg(RMI_DEBUG_CORE, xport->dev,
                "%s: Registered %s as %s.\n", __func__,
                dev_name(rmi_dev->xport->dev), dev_name(&rmi_dev->dev));

        return 0;

err_put_device:
        put_device(&rmi_dev->dev);
        return error;
}
EXPORT_SYMBOL_GPL(rmi_register_transport_device);

/**
 * rmi_unregister_transport_device - unregister a transport device connection
 * @xport: the transport driver to unregister
 *
 */
void rmi_unregister_transport_device(struct rmi_transport_dev *xport)
{
        struct rmi_device *rmi_dev = xport->rmi_dev;

        device_del(&rmi_dev->dev);
        put_device(&rmi_dev->dev);
}
EXPORT_SYMBOL(rmi_unregister_transport_device);


/* Function specific stuff */

static void rmi_release_function(struct device *dev)
{
        struct rmi_function *fn = to_rmi_function(dev);

        kfree(fn);
}

static const struct device_type rmi_function_type = {
        .name           = "rmi4_function",
        .release        = rmi_release_function,
};

bool rmi_is_function_device(struct device *dev)
{
        return dev->type == &rmi_function_type;
}

static int rmi_function_match(struct device *dev, struct device_driver *drv)
{
        struct rmi_function_handler *handler = to_rmi_function_handler(drv);
        struct rmi_function *fn = to_rmi_function(dev);

        return fn->fd.function_number == handler->func;
}

#ifdef CONFIG_OF
static void rmi_function_of_probe(struct rmi_function *fn)
{
        char of_name[9];
        struct device_node *node = fn->rmi_dev->xport->dev->of_node;

        snprintf(of_name, sizeof(of_name), "rmi4-f%02x",
                fn->fd.function_number);
        fn->dev.of_node = of_get_child_by_name(node, of_name);
}
#else
static inline void rmi_function_of_probe(struct rmi_function *fn)
{}
#endif

static int rmi_function_probe(struct device *dev)
{
        struct rmi_function *fn = to_rmi_function(dev);
        struct rmi_function_handler *handler =
                                        to_rmi_function_handler(dev->driver);
        int error;

        rmi_function_of_probe(fn);

        if (handler->probe) {
                error = handler->probe(fn);
                return error;
        }

        return 0;
}

static int rmi_function_remove(struct device *dev)
{
        struct rmi_function *fn = to_rmi_function(dev);
        struct rmi_function_handler *handler =
                                        to_rmi_function_handler(dev->driver);

        if (handler->remove)
                handler->remove(fn);

        return 0;
}

int rmi_register_function(struct rmi_function *fn)
{
        struct rmi_device *rmi_dev = fn->rmi_dev;
        int error;

        device_initialize(&fn->dev);

        dev_set_name(&fn->dev, "%s.fn%02x",
                     dev_name(&rmi_dev->dev), fn->fd.function_number);

        fn->dev.parent = &rmi_dev->dev;
        fn->dev.type = &rmi_function_type;
        fn->dev.bus = &rmi_bus_type;

        error = device_add(&fn->dev);
        if (error) {
                dev_err(&rmi_dev->dev,
                        "Failed device_register function device %s\n",
                        dev_name(&fn->dev));
                goto err_put_device;
        }

        rmi_dbg(RMI_DEBUG_CORE, &rmi_dev->dev, "Registered F%02X.\n",
                        fn->fd.function_number);

        return 0;

err_put_device:
        put_device(&fn->dev);
        return error;
}

void rmi_unregister_function(struct rmi_function *fn)
{
        rmi_dbg(RMI_DEBUG_CORE, &fn->dev, "Unregistering F%02X.\n",
                        fn->fd.function_number);

        device_del(&fn->dev);
        of_node_put(fn->dev.of_node);
        put_device(&fn->dev);
}

/**
 * rmi_register_function_handler - register a handler for an RMI function
 * @handler: RMI handler that should be registered.
 * @module: pointer to module that implements the handler
 * @mod_name: name of the module implementing the handler
 *
 * This function performs additional setup of RMI function handler and
 * registers it with the RMI core so that it can be bound to
 * RMI function devices.
 */
int __rmi_register_function_handler(struct rmi_function_handler *handler,
                                     struct module *owner,
                                     const char *mod_name)
{
        struct device_driver *driver = &handler->driver;
        int error;

        driver->bus = &rmi_bus_type;
        driver->owner = owner;
        driver->mod_name = mod_name;
        driver->probe = rmi_function_probe;
        driver->remove = rmi_function_remove;

        error = driver_register(driver);
        if (error) {
                pr_err("driver_register() failed for %s, error: %d\n",
                        driver->name, error);
                return error;
        }

        return 0;
}
EXPORT_SYMBOL_GPL(__rmi_register_function_handler);

/**
 * rmi_unregister_function_handler - unregister given RMI function handler
 * @handler: RMI handler that should be unregistered.
 *
 * This function unregisters given function handler from RMI core which
 * causes it to be unbound from the function devices.
 */
void rmi_unregister_function_handler(struct rmi_function_handler *handler)
{
        driver_unregister(&handler->driver);
}
EXPORT_SYMBOL_GPL(rmi_unregister_function_handler);

/* Bus specific stuff */

static int rmi_bus_match(struct device *dev, struct device_driver *drv)
{
        bool physical = rmi_is_physical_device(dev);

        /* First see if types are not compatible */
        if (physical != rmi_is_physical_driver(drv))
                return 0;

        return physical || rmi_function_match(dev, drv);
}

struct bus_type rmi_bus_type = {
        .match          = rmi_bus_match,
        .name           = "rmi4",
};

static struct rmi_function_handler *fn_handlers[] = {
        &rmi_f01_handler,
#ifdef CONFIG_RMI4_F03
        &rmi_f03_handler,
#endif
#ifdef CONFIG_RMI4_F11
        &rmi_f11_handler,
#endif
#ifdef CONFIG_RMI4_F12
        &rmi_f12_handler,
#endif
#ifdef CONFIG_RMI4_F30
        &rmi_f30_handler,
#endif
#ifdef CONFIG_RMI4_F34
        &rmi_f34_handler,
#endif
#ifdef CONFIG_RMI4_F54
        &rmi_f54_handler,
#endif
#ifdef CONFIG_RMI4_F55
        &rmi_f55_handler,
#endif
};

static void __rmi_unregister_function_handlers(int start_idx)
{
        int i;

        for (i = start_idx; i >= 0; i--)
                rmi_unregister_function_handler(fn_handlers[i]);
}

static void rmi_unregister_function_handlers(void)
{
        __rmi_unregister_function_handlers(ARRAY_SIZE(fn_handlers) - 1);
}

static int rmi_register_function_handlers(void)
{
        int ret;
        int i;

        for (i = 0; i < ARRAY_SIZE(fn_handlers); i++)   {
                ret = rmi_register_function_handler(fn_handlers[i]);
                if (ret) {
                        pr_err("%s: error registering the RMI F%02x handler: %d\n",
                                __func__, fn_handlers[i]->func, ret);
                        goto err_unregister_function_handlers;
                }
        }

        return 0;

err_unregister_function_handlers:
        __rmi_unregister_function_handlers(i - 1);
        return ret;
}

int rmi_of_property_read_u32(struct device *dev, u32 *result,
                                const char *prop, bool optional)
{
        int retval;
        u32 val = 0;

        retval = of_property_read_u32(dev->of_node, prop, &val);
        if (retval && (!optional && retval == -EINVAL)) {
                dev_err(dev, "Failed to get %s value: %d\n",
                        prop, retval);
                return retval;
        }
        *result = val;

        return 0;
}
EXPORT_SYMBOL_GPL(rmi_of_property_read_u32);

static int __init rmi_bus_init(void)
{
        int error;

        error = bus_register(&rmi_bus_type);
        if (error) {
                pr_err("%s: error registering the RMI bus: %d\n",
                        __func__, error);
                return error;
        }

        error = rmi_register_function_handlers();
        if (error)
                goto err_unregister_bus;

        error = rmi_register_physical_driver();
        if (error) {
                pr_err("%s: error registering the RMI physical driver: %d\n",
                        __func__, error);
                goto err_unregister_bus;
        }

        return 0;

err_unregister_bus:
        bus_unregister(&rmi_bus_type);
        return error;
}
module_init(rmi_bus_init);

static void __exit rmi_bus_exit(void)
{
        /*
         * We should only ever get here if all drivers are unloaded, so
         * all we have to do at this point is unregister ourselves.
         */

        rmi_unregister_physical_driver();
        rmi_unregister_function_handlers();
        bus_unregister(&rmi_bus_type);
}
module_exit(rmi_bus_exit);

MODULE_AUTHOR("Christopher Heiny <cheiny@synaptics.com");
MODULE_AUTHOR("Andrew Duggan <aduggan@synaptics.com");
MODULE_DESCRIPTION("RMI bus");
MODULE_LICENSE("GPL");
MODULE_VERSION(RMI_DRIVER_VERSION);