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/interrupt.h>
  17 #include <linux/mfd/core.h>
  18 #include <linux/mfd/mc13xxx.h>
  19 #include <linux/of.h>
  20 #include <linux/of_device.h>
  21 #include <linux/of_gpio.h>
  22 #include <linux/err.h>
  23 #include <linux/spi/spi.h>
  24
  25 #include "mc13xxx.h"
  26
  27 static const struct spi_device_id mc13xxx_device_id[] = {
  28         {
  29                 .name = "mc13783",
  30                 .driver_data = (kernel_ulong_t)&mc13xxx_variant_mc13783,
  31         }, {
  32                 .name = "mc13892",
  33                 .driver_data = (kernel_ulong_t)&mc13xxx_variant_mc13892,
  34         }, {
  35                 .name = "mc34708",
  36                 .driver_data = (kernel_ulong_t)&mc13xxx_variant_mc34708,
  37         }, {
  38                 /* sentinel */
  39         }
  40 };
  41 MODULE_DEVICE_TABLE(spi, mc13xxx_device_id);
  42
  43 static const struct of_device_id mc13xxx_dt_ids[] = {
  44         { .compatible = "fsl,mc13783", .data = &mc13xxx_variant_mc13783, },
  45         { .compatible = "fsl,mc13892", .data = &mc13xxx_variant_mc13892, },
  46         { .compatible = "fsl,mc34708", .data = &mc13xxx_variant_mc34708, },
  47         { /* sentinel */ }
  48 };
  49 MODULE_DEVICE_TABLE(of, mc13xxx_dt_ids);
  50
  51 static const struct regmap_config mc13xxx_regmap_spi_config = {
  52         .reg_bits = 7,
  53         .pad_bits = 1,
  54         .val_bits = 24,
  55         .write_flag_mask = 0x80,
  56
  57         .max_register = MC13XXX_NUMREGS,
  58
  59         .cache_type = REGCACHE_NONE,
  60         .use_single_rw = 1,
  61 };
  62
  63 static int mc13xxx_spi_read(void *context, const void *reg, size_t reg_size,
  64                                 void *val, size_t val_size)
  65 {
  66         unsigned char w[4] = { *((unsigned char *) reg), 0, 0, 0};
  67         unsigned char r[4];
  68         unsigned char *p = val;
  69         struct device *dev = context;
  70         struct spi_device *spi = to_spi_device(dev);
  71         struct spi_transfer t = {
  72                 .tx_buf = w,
  73                 .rx_buf = r,
  74                 .len = 4,
  75         };
  76
  77         struct spi_message m;
  78         int ret;
  79
  80         if (val_size != 3 || reg_size != 1)
  81                 return -ENOTSUPP;
  82
  83         spi_message_init(&m);
  84         spi_message_add_tail(&t, &m);
  85         ret = spi_sync(spi, &m);
  86
  87         memcpy(p, &r[1], 3);
  88
  89         return ret;
  90 }
  91
  92 static int mc13xxx_spi_write(void *context, const void *data, size_t count)
  93 {
  94         struct device *dev = context;
  95         struct spi_device *spi = to_spi_device(dev);
  96         const char *reg = data;
  97
  98         if (count != 4)
  99                 return -ENOTSUPP;
 100
 101         /* include errata fix for spi audio problems */
 102         if (*reg == MC13783_AUDIO_CODEC || *reg == MC13783_AUDIO_DAC)
 103                 spi_write(spi, data, count);
 104
 105         return spi_write(spi, data, count);
 106 }
 107
 108 /*
 109  * We cannot use regmap-spi generic bus implementation here.
 110  * The MC13783 chip will get corrupted if CS signal is deasserted
 111  * and on i.Mx31 SoC (the target SoC for MC13783 PMIC) the SPI controller
 112  * has the following errata (DSPhl22960):
 113  * "The CSPI negates SS when the FIFO becomes empty with
 114  * SSCTL= 0. Software cannot guarantee that the FIFO will not
 115  * drain because of higher priority interrupts and the
 116  * non-realtime characteristics of the operating system. As a
 117  * result, the SS will negate before all of the data has been
 118  * transferred to/from the peripheral."
 119  * We workaround this by accessing the SPI controller with a
 120  * single transfert.
 121  */
 122
 123 static struct regmap_bus regmap_mc13xxx_bus = {
 124         .write = mc13xxx_spi_write,
 125         .read = mc13xxx_spi_read,
 126 };
 127
 128 static int mc13xxx_spi_probe(struct spi_device *spi)
 129 {
 130         struct mc13xxx *mc13xxx;
 131         int ret;
 132
 133         mc13xxx = devm_kzalloc(&spi->dev, sizeof(*mc13xxx), GFP_KERNEL);
 134         if (!mc13xxx)
 135                 return -ENOMEM;
 136
 137         dev_set_drvdata(&spi->dev, mc13xxx);
 138
 139         spi->mode = SPI_MODE_0 | SPI_CS_HIGH;
 140
 141         mc13xxx->irq = spi->irq;
 142
 143         spi->max_speed_hz = spi->max_speed_hz ? : 26000000;
 144         ret = spi_setup(spi);
 145         if (ret)
 146                 return ret;
 147
 148         mc13xxx->regmap = devm_regmap_init(&spi->dev, &regmap_mc13xxx_bus,
 149                                            &spi->dev,
 150                                            &mc13xxx_regmap_spi_config);
 151         if (IS_ERR(mc13xxx->regmap)) {
 152                 ret = PTR_ERR(mc13xxx->regmap);
 153                 dev_err(&spi->dev, "Failed to initialize regmap: %d\n", ret);
 154                 return ret;
 155         }
 156
 157         if (spi->dev.of_node) {
 158                 const struct of_device_id *of_id =
 159                         of_match_device(mc13xxx_dt_ids, &spi->dev);
 160
 161                 mc13xxx->variant = of_id->data;
 162         } else {
 163                 const struct spi_device_id *id_entry = spi_get_device_id(spi);
 164
 165                 mc13xxx->variant = (void *)id_entry->driver_data;
 166         }
 167
 168         return mc13xxx_common_init(&spi->dev);
 169 }
 170
 171 static int mc13xxx_spi_remove(struct spi_device *spi)
 172 {
 173         return mc13xxx_common_exit(&spi->dev);
 174 }
 175
 176 static struct spi_driver mc13xxx_spi_driver = {
 177         .id_table = mc13xxx_device_id,
 178         .driver = {
 179                 .name = "mc13xxx",
 180                 .owner = THIS_MODULE,
 181                 .of_match_table = mc13xxx_dt_ids,
 182         },
 183         .probe = mc13xxx_spi_probe,
 184         .remove = mc13xxx_spi_remove,
 185 };
 186
 187 static int __init mc13xxx_init(void)
 188 {
 189         return spi_register_driver(&mc13xxx_spi_driver);
 190 }
 191 subsys_initcall(mc13xxx_init);
 192
 193 static void __exit mc13xxx_exit(void)
 194 {
 195         spi_unregister_driver(&mc13xxx_spi_driver);
 196 }
 197 module_exit(mc13xxx_exit);
 198
 199 MODULE_DESCRIPTION("Core driver for Freescale MC13XXX PMIC");
 200 MODULE_AUTHOR("Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>");
 201 MODULE_LICENSE("GPL v2");