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 = (kernel_ulong_t)&mc13xxx_variant_mc13783,
  32         }, {
  33                 .name = "mc13892",
  34                 .driver_data = (kernel_ulong_t)&mc13xxx_variant_mc13892,
  35         }, {
  36                 .name = "mc34708",
  37                 .driver_data = (kernel_ulong_t)&mc13xxx_variant_mc34708,
  38         }, {
  39                 /* sentinel */
  40         }
  41 };
  42 MODULE_DEVICE_TABLE(spi, mc13xxx_device_id);
  43
  44 static const struct of_device_id mc13xxx_dt_ids[] = {
  45         { .compatible = "fsl,mc13783", .data = &mc13xxx_variant_mc13783, },
  46         { .compatible = "fsl,mc13892", .data = &mc13xxx_variant_mc13892, },
  47         { .compatible = "fsl,mc34708", .data = &mc13xxx_variant_mc34708, },
  48         { /* sentinel */ }
  49 };
  50 MODULE_DEVICE_TABLE(of, mc13xxx_dt_ids);
  51
  52 static struct regmap_config mc13xxx_regmap_spi_config = {
  53         .reg_bits = 7,
  54         .pad_bits = 1,
  55         .val_bits = 24,
  56         .write_flag_mask = 0x80,
  57
  58         .max_register = MC13XXX_NUMREGS,
  59
  60         .cache_type = REGCACHE_NONE,
  61         .use_single_rw = 1,
  62 };
  63
  64 static int mc13xxx_spi_read(void *context, const void *reg, size_t reg_size,
  65                                 void *val, size_t val_size)
  66 {
  67         unsigned char w[4] = { *((unsigned char *) reg), 0, 0, 0};
  68         unsigned char r[4];
  69         unsigned char *p = val;
  70         struct device *dev = context;
  71         struct spi_device *spi = to_spi_device(dev);
  72         struct spi_transfer t = {
  73                 .tx_buf = w,
  74                 .rx_buf = r,
  75                 .len = 4,
  76         };
  77
  78         struct spi_message m;
  79         int ret;
  80
  81         if (val_size != 3 || reg_size != 1)
  82                 return -ENOTSUPP;
  83
  84         spi_message_init(&m);
  85         spi_message_add_tail(&t, &m);
  86         ret = spi_sync(spi, &m);
  87
  88         memcpy(p, &r[1], 3);
  89
  90         return ret;
  91 }
  92
  93 static int mc13xxx_spi_write(void *context, const void *data, size_t count)
  94 {
  95         struct device *dev = context;
  96         struct spi_device *spi = to_spi_device(dev);
  97
  98         if (count != 4)
  99                 return -ENOTSUPP;
 100
 101         return spi_write(spi, data, count);
 102 }
 103
 104 /*
 105  * We cannot use regmap-spi generic bus implementation here.
 106  * The MC13783 chip will get corrupted if CS signal is deasserted
 107  * and on i.Mx31 SoC (the target SoC for MC13783 PMIC) the SPI controller
 108  * has the following errata (DSPhl22960):
 109  * "The CSPI negates SS when the FIFO becomes empty with
 110  * SSCTL= 0. Software cannot guarantee that the FIFO will not
 111  * drain because of higher priority interrupts and the
 112  * non-realtime characteristics of the operating system. As a
 113  * result, the SS will negate before all of the data has been
 114  * transferred to/from the peripheral."
 115  * We workaround this by accessing the SPI controller with a
 116  * single transfert.
 117  */
 118
 119 static struct regmap_bus regmap_mc13xxx_bus = {
 120         .write = mc13xxx_spi_write,
 121         .read = mc13xxx_spi_read,
 122 };
 123
 124 static int mc13xxx_spi_probe(struct spi_device *spi)
 125 {
 126         struct mc13xxx *mc13xxx;
 127         struct mc13xxx_platform_data *pdata = dev_get_platdata(&spi->dev);
 128         int ret;
 129
 130         mc13xxx = devm_kzalloc(&spi->dev, sizeof(*mc13xxx), GFP_KERNEL);
 131         if (!mc13xxx)
 132                 return -ENOMEM;
 133
 134         spi_set_drvdata(spi, mc13xxx);
 135         spi->mode = SPI_MODE_0 | SPI_CS_HIGH;
 136
 137         mc13xxx->dev = &spi->dev;
 138         mutex_init(&mc13xxx->lock);
 139
 140         mc13xxx->regmap = devm_regmap_init(&spi->dev, &regmap_mc13xxx_bus,
 141                                            &spi->dev,
 142                                            &mc13xxx_regmap_spi_config);
 143         if (IS_ERR(mc13xxx->regmap)) {
 144                 ret = PTR_ERR(mc13xxx->regmap);
 145                 dev_err(mc13xxx->dev, "Failed to initialize register map: %d\n",
 146                                 ret);
 147                 spi_set_drvdata(spi, NULL);
 148                 return ret;
 149         }
 150
 151         if (spi->dev.of_node) {
 152                 const struct of_device_id *of_id =
 153                         of_match_device(mc13xxx_dt_ids, &spi->dev);
 154
 155                 mc13xxx->variant = of_id->data;
 156         } else {
 157                 const struct spi_device_id *id_entry = spi_get_device_id(spi);
 158
 159                 mc13xxx->variant = (void *)id_entry->driver_data;
 160         }
 161
 162         return mc13xxx_common_init(mc13xxx, pdata, spi->irq);
 163 }
 164
 165 static int mc13xxx_spi_remove(struct spi_device *spi)
 166 {
 167         struct mc13xxx *mc13xxx = spi_get_drvdata(spi);
 168
 169         mc13xxx_common_cleanup(mc13xxx);
 170
 171         return 0;
 172 }
 173
 174 static struct spi_driver mc13xxx_spi_driver = {
 175         .id_table = mc13xxx_device_id,
 176         .driver = {
 177                 .name = "mc13xxx",
 178                 .owner = THIS_MODULE,
 179                 .of_match_table = mc13xxx_dt_ids,
 180         },
 181         .probe = mc13xxx_spi_probe,
 182         .remove = mc13xxx_spi_remove,
 183 };
 184
 185 static int __init mc13xxx_init(void)
 186 {
 187         return spi_register_driver(&mc13xxx_spi_driver);
 188 }
 189 subsys_initcall(mc13xxx_init);
 190
 191 static void __exit mc13xxx_exit(void)
 192 {
 193         spi_unregister_driver(&mc13xxx_spi_driver);
 194 }
 195 module_exit(mc13xxx_exit);
 196
 197 MODULE_DESCRIPTION("Core driver for Freescale MC13XXX PMIC");
 198 MODULE_AUTHOR("Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>");
 199 MODULE_LICENSE("GPL v2");