linux/drivers/mfd/mc13xxx-spi.c
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   1/*
   2 * Copyright 2009-2010 Pengutronix
   3 * Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
   4 *
   5 * loosely based on an earlier driver that has
   6 * Copyright 2009 Pengutronix, Sascha Hauer <s.hauer@pengutronix.de>
   7 *
   8 * This program is free software; you can redistribute it and/or modify it under
   9 * the terms of the GNU General Public License version 2 as published by the
  10 * Free Software Foundation.
  11 */
  12
  13#include <linux/slab.h>
  14#include <linux/module.h>
  15#include <linux/platform_device.h>
  16#include <linux/mutex.h>
  17#include <linux/interrupt.h>
  18#include <linux/mfd/core.h>
  19#include <linux/mfd/mc13xxx.h>
  20#include <linux/of.h>
  21#include <linux/of_device.h>
  22#include <linux/of_gpio.h>
  23#include <linux/err.h>
  24#include <linux/spi/spi.h>
  25
  26#include "mc13xxx.h"
  27
  28static const struct spi_device_id mc13xxx_device_id[] = {
  29        {
  30                .name = "mc13783",
  31                .driver_data = MC13XXX_ID_MC13783,
  32        }, {
  33                .name = "mc13892",
  34                .driver_data = MC13XXX_ID_MC13892,
  35        }, {
  36                /* sentinel */
  37        }
  38};
  39MODULE_DEVICE_TABLE(spi, mc13xxx_device_id);
  40
  41static const struct of_device_id mc13xxx_dt_ids[] = {
  42        { .compatible = "fsl,mc13783", .data = (void *) MC13XXX_ID_MC13783, },
  43        { .compatible = "fsl,mc13892", .data = (void *) MC13XXX_ID_MC13892, },
  44        { /* sentinel */ }
  45};
  46MODULE_DEVICE_TABLE(of, mc13xxx_dt_ids);
  47
  48static struct regmap_config mc13xxx_regmap_spi_config = {
  49        .reg_bits = 7,
  50        .pad_bits = 1,
  51        .val_bits = 24,
  52        .write_flag_mask = 0x80,
  53
  54        .max_register = MC13XXX_NUMREGS,
  55
  56        .cache_type = REGCACHE_NONE,
  57        .use_single_rw = 1,
  58};
  59
  60static int mc13xxx_spi_read(void *context, const void *reg, size_t reg_size,
  61                                void *val, size_t val_size)
  62{
  63        unsigned char w[4] = { *((unsigned char *) reg), 0, 0, 0};
  64        unsigned char r[4];
  65        unsigned char *p = val;
  66        struct device *dev = context;
  67        struct spi_device *spi = to_spi_device(dev);
  68        struct spi_transfer t = {
  69                .tx_buf = w,
  70                .rx_buf = r,
  71                .len = 4,
  72        };
  73
  74        struct spi_message m;
  75        int ret;
  76
  77        if (val_size != 3 || reg_size != 1)
  78                return -ENOTSUPP;
  79
  80        spi_message_init(&m);
  81        spi_message_add_tail(&t, &m);
  82        ret = spi_sync(spi, &m);
  83
  84        memcpy(p, &r[1], 3);
  85
  86        return ret;
  87}
  88
  89static int mc13xxx_spi_write(void *context, const void *data, size_t count)
  90{
  91        struct device *dev = context;
  92        struct spi_device *spi = to_spi_device(dev);
  93
  94        if (count != 4)
  95                return -ENOTSUPP;
  96
  97        return spi_write(spi, data, count);
  98}
  99
 100/*
 101 * We cannot use regmap-spi generic bus implementation here.
 102 * The MC13783 chip will get corrupted if CS signal is deasserted
 103 * and on i.Mx31 SoC (the target SoC for MC13783 PMIC) the SPI controller
 104 * has the following errata (DSPhl22960):
 105 * "The CSPI negates SS when the FIFO becomes empty with
 106 * SSCTL= 0. Software cannot guarantee that the FIFO will not
 107 * drain because of higher priority interrupts and the
 108 * non-realtime characteristics of the operating system. As a
 109 * result, the SS will negate before all of the data has been
 110 * transferred to/from the peripheral."
 111 * We workaround this by accessing the SPI controller with a
 112 * single transfert.
 113 */
 114
 115static struct regmap_bus regmap_mc13xxx_bus = {
 116        .write = mc13xxx_spi_write,
 117        .read = mc13xxx_spi_read,
 118};
 119
 120static int mc13xxx_spi_probe(struct spi_device *spi)
 121{
 122        struct mc13xxx *mc13xxx;
 123        struct mc13xxx_platform_data *pdata = dev_get_platdata(&spi->dev);
 124        int ret;
 125
 126        mc13xxx = devm_kzalloc(&spi->dev, sizeof(*mc13xxx), GFP_KERNEL);
 127        if (!mc13xxx)
 128                return -ENOMEM;
 129
 130        dev_set_drvdata(&spi->dev, mc13xxx);
 131        spi->mode = SPI_MODE_0 | SPI_CS_HIGH;
 132
 133        mc13xxx->dev = &spi->dev;
 134        mutex_init(&mc13xxx->lock);
 135
 136        mc13xxx->regmap = devm_regmap_init(&spi->dev, &regmap_mc13xxx_bus,
 137                                           &spi->dev,
 138                                           &mc13xxx_regmap_spi_config);
 139        if (IS_ERR(mc13xxx->regmap)) {
 140                ret = PTR_ERR(mc13xxx->regmap);
 141                dev_err(mc13xxx->dev, "Failed to initialize register map: %d\n",
 142                                ret);
 143                dev_set_drvdata(&spi->dev, NULL);
 144                return ret;
 145        }
 146
 147        ret = mc13xxx_common_init(mc13xxx, pdata, spi->irq);
 148
 149        if (ret) {
 150                dev_set_drvdata(&spi->dev, NULL);
 151        } else {
 152                const struct spi_device_id *devid =
 153                        spi_get_device_id(spi);
 154                if (!devid || devid->driver_data != mc13xxx->ictype)
 155                        dev_warn(mc13xxx->dev,
 156                                "device id doesn't match auto detection!\n");
 157        }
 158
 159        return ret;
 160}
 161
 162static int __devexit mc13xxx_spi_remove(struct spi_device *spi)
 163{
 164        struct mc13xxx *mc13xxx = dev_get_drvdata(&spi->dev);
 165
 166        mc13xxx_common_cleanup(mc13xxx);
 167
 168        return 0;
 169}
 170
 171static struct spi_driver mc13xxx_spi_driver = {
 172        .id_table = mc13xxx_device_id,
 173        .driver = {
 174                .name = "mc13xxx",
 175                .owner = THIS_MODULE,
 176                .of_match_table = mc13xxx_dt_ids,
 177        },
 178        .probe = mc13xxx_spi_probe,
 179        .remove = __devexit_p(mc13xxx_spi_remove),
 180};
 181
 182static int __init mc13xxx_init(void)
 183{
 184        return spi_register_driver(&mc13xxx_spi_driver);
 185}
 186subsys_initcall(mc13xxx_init);
 187
 188static void __exit mc13xxx_exit(void)
 189{
 190        spi_unregister_driver(&mc13xxx_spi_driver);
 191}
 192module_exit(mc13xxx_exit);
 193
 194MODULE_DESCRIPTION("Core driver for Freescale MC13XXX PMIC");
 195MODULE_AUTHOR("Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>");
 196MODULE_LICENSE("GPL v2");
 197
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