drivers/mfd/mc13xxx-spi.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright 2009-2010 Pengutronix
   4  * Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
   5  *
   6  * loosely based on an earlier driver that has
   7  * Copyright 2009 Pengutronix, Sascha Hauer <s.hauer@pengutronix.de>
   8  */
   9
  10 #include <linux/slab.h>
  11 #include <linux/mod_devicetable.h>
  12 #include <linux/module.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/mfd/core.h>
  16 #include <linux/mfd/mc13xxx.h>
  17 #include <linux/err.h>
  18 #include <linux/spi/spi.h>
  19
  20 #include "mc13xxx.h"
  21
  22 static const struct spi_device_id mc13xxx_device_id[] = {
  23         {
  24                 .name = "mc13783",
  25                 .driver_data = (kernel_ulong_t)&mc13xxx_variant_mc13783,
  26         }, {
  27                 .name = "mc13892",
  28                 .driver_data = (kernel_ulong_t)&mc13xxx_variant_mc13892,
  29         }, {
  30                 .name = "mc34708",
  31                 .driver_data = (kernel_ulong_t)&mc13xxx_variant_mc34708,
  32         }, {
  33                 /* sentinel */
  34         }
  35 };
  36 MODULE_DEVICE_TABLE(spi, mc13xxx_device_id);
  37
  38 static const struct of_device_id mc13xxx_dt_ids[] = {
  39         { .compatible = "fsl,mc13783", .data = &mc13xxx_variant_mc13783, },
  40         { .compatible = "fsl,mc13892", .data = &mc13xxx_variant_mc13892, },
  41         { .compatible = "fsl,mc34708", .data = &mc13xxx_variant_mc34708, },
  42         { /* sentinel */ }
  43 };
  44 MODULE_DEVICE_TABLE(of, mc13xxx_dt_ids);
  45
  46 static const struct regmap_config mc13xxx_regmap_spi_config = {
  47         .reg_bits = 7,
  48         .pad_bits = 1,
  49         .val_bits = 24,
  50         .write_flag_mask = 0x80,
  51
  52         .max_register = MC13XXX_NUMREGS,
  53
  54         .cache_type = REGCACHE_NONE,
  55         .use_single_read = true,
  56         .use_single_write = true,
  57 };
  58
  59 static int mc13xxx_spi_read(void *context, const void *reg, size_t reg_size,
  60                                 void *val, size_t val_size)
  61 {
  62         unsigned char w[4] = { *((unsigned char *) reg), 0, 0, 0};
  63         unsigned char r[4];
  64         unsigned char *p = val;
  65         struct device *dev = context;
  66         struct spi_device *spi = to_spi_device(dev);
  67         struct spi_transfer t = {
  68                 .tx_buf = w,
  69                 .rx_buf = r,
  70                 .len = 4,
  71         };
  72
  73         struct spi_message m;
  74         int ret;
  75
  76         if (val_size != 3 || reg_size != 1)
  77                 return -ENOTSUPP;
  78
  79         spi_message_init(&m);
  80         spi_message_add_tail(&t, &m);
  81         ret = spi_sync(spi, &m);
  82
  83         memcpy(p, &r[1], 3);
  84
  85         return ret;
  86 }
  87
  88 static int mc13xxx_spi_write(void *context, const void *data, size_t count)
  89 {
  90         struct device *dev = context;
  91         struct spi_device *spi = to_spi_device(dev);
  92         const char *reg = data;
  93
  94         if (count != 4)
  95                 return -ENOTSUPP;
  96
  97         /* include errata fix for spi audio problems */
  98         if (*reg == MC13783_AUDIO_CODEC || *reg == MC13783_AUDIO_DAC)
  99                 spi_write(spi, data, count);
 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 transfer.
 117  */
 118
 119 static const 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         int ret;
 128
 129         mc13xxx = devm_kzalloc(&spi->dev, sizeof(*mc13xxx), GFP_KERNEL);
 130         if (!mc13xxx)
 131                 return -ENOMEM;
 132
 133         dev_set_drvdata(&spi->dev, mc13xxx);
 134
 135         spi->mode = SPI_MODE_0 | SPI_CS_HIGH;
 136
 137         mc13xxx->irq = spi->irq;
 138
 139         spi->max_speed_hz = spi->max_speed_hz ? : 26000000;
 140         ret = spi_setup(spi);
 141         if (ret)
 142                 return ret;
 143
 144         mc13xxx->regmap = devm_regmap_init(&spi->dev, &regmap_mc13xxx_bus,
 145                                            &spi->dev,
 146                                            &mc13xxx_regmap_spi_config);
 147         if (IS_ERR(mc13xxx->regmap)) {
 148                 ret = PTR_ERR(mc13xxx->regmap);
 149                 dev_err(&spi->dev, "Failed to initialize regmap: %d\n", ret);
 150                 return ret;
 151         }
 152
 153         mc13xxx->variant = spi_get_device_match_data(spi);
 154
 155         return mc13xxx_common_init(&spi->dev);
 156 }
 157
 158 static void mc13xxx_spi_remove(struct spi_device *spi)
 159 {
 160         mc13xxx_common_exit(&spi->dev);
 161 }
 162
 163 static struct spi_driver mc13xxx_spi_driver = {
 164         .id_table = mc13xxx_device_id,
 165         .driver = {
 166                 .name = "mc13xxx",
 167                 .of_match_table = mc13xxx_dt_ids,
 168         },
 169         .probe = mc13xxx_spi_probe,
 170         .remove = mc13xxx_spi_remove,
 171 };
 172
 173 static int __init mc13xxx_init(void)
 174 {
 175         return spi_register_driver(&mc13xxx_spi_driver);
 176 }
 177 subsys_initcall(mc13xxx_init);
 178
 179 static void __exit mc13xxx_exit(void)
 180 {
 181         spi_unregister_driver(&mc13xxx_spi_driver);
 182 }
 183 module_exit(mc13xxx_exit);
 184
 185 MODULE_DESCRIPTION("Core driver for Freescale MC13XXX PMIC");
 186 MODULE_AUTHOR("Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>");
 187 MODULE_LICENSE("GPL v2");