/*
 * Copyright 2009-2010 Pengutronix
 * Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
 *
 * loosely based on an earlier driver that has
 * Copyright 2009 Pengutronix, Sascha Hauer <s.hauer@pengutronix.de>
 *
 * 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/slab.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/mutex.h>
#include <linux/interrupt.h>
#include <linux/mfd/core.h>
#include <linux/mfd/mc13xxx.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_gpio.h>
#include <linux/err.h>
#include <linux/spi/spi.h>

#include "mc13xxx.h"

static const struct spi_device_id mc13xxx_device_id[] = {
        {
                .name = "mc13783",
                .driver_data = (kernel_ulong_t)&mc13xxx_variant_mc13783,
        }, {
                .name = "mc13892",
                .driver_data = (kernel_ulong_t)&mc13xxx_variant_mc13892,
        }, {
                .name = "mc34708",
                .driver_data = (kernel_ulong_t)&mc13xxx_variant_mc34708,
        }, {
                /* sentinel */
        }
};
MODULE_DEVICE_TABLE(spi, mc13xxx_device_id);

static const struct of_device_id mc13xxx_dt_ids[] = {
        { .compatible = "fsl,mc13783", .data = &mc13xxx_variant_mc13783, },
        { .compatible = "fsl,mc13892", .data = &mc13xxx_variant_mc13892, },
        { .compatible = "fsl,mc34708", .data = &mc13xxx_variant_mc34708, },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, mc13xxx_dt_ids);

static struct regmap_config mc13xxx_regmap_spi_config = {
        .reg_bits = 7,
        .pad_bits = 1,
        .val_bits = 24,
        .write_flag_mask = 0x80,

        .max_register = MC13XXX_NUMREGS,

        .cache_type = REGCACHE_NONE,
        .use_single_rw = 1,
};

static int mc13xxx_spi_read(void *context, const void *reg, size_t reg_size,
                                void *val, size_t val_size)
{
        unsigned char w[4] = { *((unsigned char *) reg), 0, 0, 0};
        unsigned char r[4];
        unsigned char *p = val;
        struct device *dev = context;
        struct spi_device *spi = to_spi_device(dev);
        struct spi_transfer t = {
                .tx_buf = w,
                .rx_buf = r,
                .len = 4,
        };

        struct spi_message m;
        int ret;

        if (val_size != 3 || reg_size != 1)
                return -ENOTSUPP;

        spi_message_init(&m);
        spi_message_add_tail(&t, &m);
        ret = spi_sync(spi, &m);

        memcpy(p, &r[1], 3);

        return ret;
}

static int mc13xxx_spi_write(void *context, const void *data, size_t count)
{
        struct device *dev = context;
        struct spi_device *spi = to_spi_device(dev);

        if (count != 4)
                return -ENOTSUPP;

        return spi_write(spi, data, count);
}

/*
 * We cannot use regmap-spi generic bus implementation here.
 * The MC13783 chip will get corrupted if CS signal is deasserted
 * and on i.Mx31 SoC (the target SoC for MC13783 PMIC) the SPI controller
 * has the following errata (DSPhl22960):
 * "The CSPI negates SS when the FIFO becomes empty with
 * SSCTL= 0. Software cannot guarantee that the FIFO will not
 * drain because of higher priority interrupts and the
 * non-realtime characteristics of the operating system. As a
 * result, the SS will negate before all of the data has been
 * transferred to/from the peripheral."
 * We workaround this by accessing the SPI controller with a
 * single transfert.
 */

static struct regmap_bus regmap_mc13xxx_bus = {
        .write = mc13xxx_spi_write,
        .read = mc13xxx_spi_read,
};

static int mc13xxx_spi_probe(struct spi_device *spi)
{
        struct mc13xxx *mc13xxx;
        struct mc13xxx_platform_data *pdata = dev_get_platdata(&spi->dev);
        int ret;

        mc13xxx = devm_kzalloc(&spi->dev, sizeof(*mc13xxx), GFP_KERNEL);
        if (!mc13xxx)
                return -ENOMEM;

        spi_set_drvdata(spi, mc13xxx);
        spi->mode = SPI_MODE_0 | SPI_CS_HIGH;

        mc13xxx->dev = &spi->dev;
        mutex_init(&mc13xxx->lock);

        mc13xxx->regmap = devm_regmap_init(&spi->dev, &regmap_mc13xxx_bus,
                                           &spi->dev,
                                           &mc13xxx_regmap_spi_config);
        if (IS_ERR(mc13xxx->regmap)) {
                ret = PTR_ERR(mc13xxx->regmap);
                dev_err(mc13xxx->dev, "Failed to initialize register map: %d\n",
                                ret);
                spi_set_drvdata(spi, NULL);
                return ret;
        }

        if (spi->dev.of_node) {
                const struct of_device_id *of_id =
                        of_match_device(mc13xxx_dt_ids, &spi->dev);

                mc13xxx->variant = of_id->data;
        } else {
                const struct spi_device_id *id_entry = spi_get_device_id(spi);

                mc13xxx->variant = (void *)id_entry->driver_data;
        }

        return mc13xxx_common_init(mc13xxx, pdata, spi->irq);
}

static int mc13xxx_spi_remove(struct spi_device *spi)
{
        struct mc13xxx *mc13xxx = spi_get_drvdata(spi);

        mc13xxx_common_cleanup(mc13xxx);

        return 0;
}

static struct spi_driver mc13xxx_spi_driver = {
        .id_table = mc13xxx_device_id,
        .driver = {
                .name = "mc13xxx",
                .owner = THIS_MODULE,
                .of_match_table = mc13xxx_dt_ids,
        },
        .probe = mc13xxx_spi_probe,
        .remove = mc13xxx_spi_remove,
};

static int __init mc13xxx_init(void)
{
        return spi_register_driver(&mc13xxx_spi_driver);
}
subsys_initcall(mc13xxx_init);

static void __exit mc13xxx_exit(void)
{
        spi_unregister_driver(&mc13xxx_spi_driver);
}
module_exit(mc13xxx_exit);

MODULE_DESCRIPTION("Core driver for Freescale MC13XXX PMIC");
MODULE_AUTHOR("Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>");
MODULE_LICENSE("GPL v2");