drivers/mfd/mc13xxx-spi.c

   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
  28 static 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 };
  39 MODULE_DEVICE_TABLE(spi, mc13xxx_device_id);
  40
  41 static 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 };
  46 MODULE_DEVICE_TABLE(of, mc13xxx_dt_ids);
  47
  48 static 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
  60 static 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
  89 static 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
 115 static struct regmap_bus regmap_mc13xxx_bus = {
 116         .write = mc13xxx_spi_write,
 117         .read = mc13xxx_spi_read,
 118 };
 119
 120 static 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
 162 static 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
 171 static 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
 182 static int __init mc13xxx_init(void)
 183 {
 184         return spi_register_driver(&mc13xxx_spi_driver);
 185 }
 186 subsys_initcall(mc13xxx_init);
 187
 188 static void __exit mc13xxx_exit(void)
 189 {
 190         spi_unregister_driver(&mc13xxx_spi_driver);
 191 }
 192 module_exit(mc13xxx_exit);
 193
 194 MODULE_DESCRIPTION("Core driver for Freescale MC13XXX PMIC");
 195 MODULE_AUTHOR("Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>");
 196 MODULE_LICENSE("GPL v2");