root/drivers/mfd/mc13xxx-spi.c

DEFINITIONS

1. mc13xxx_spi_read
2. mc13xxx_spi_write
3. mc13xxx_spi_probe
4. mc13xxx_spi_remove
5. mc13xxx_init
6. mc13xxx_exit

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