drivers/mfd/stmpe-spi.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * ST Microelectronics MFD: stmpe's spi client specific driver
   4  *
   5  * Copyright (C) ST Microelectronics SA 2011
   6  *
   7  * Author: Viresh Kumar <vireshk@kernel.org> for ST Microelectronics
   8  */
   9
  10 #include <linux/spi/spi.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/of.h>
  15 #include <linux/types.h>
  16 #include "stmpe.h"
  17
  18 #define READ_CMD        (1 << 7)
  19
  20 static int spi_reg_read(struct stmpe *stmpe, u8 reg)
  21 {
  22         struct spi_device *spi = stmpe->client;
  23         int status = spi_w8r16(spi, reg | READ_CMD);
  24
  25         return (status < 0) ? status : status >> 8;
  26 }
  27
  28 static int spi_reg_write(struct stmpe *stmpe, u8 reg, u8 val)
  29 {
  30         struct spi_device *spi = stmpe->client;
  31         u16 cmd = (val << 8) | reg;
  32
  33         return spi_write(spi, (const u8 *)&cmd, 2);
  34 }
  35
  36 static int spi_block_read(struct stmpe *stmpe, u8 reg, u8 length, u8 *values)
  37 {
  38         int ret, i;
  39
  40         for (i = 0; i < length; i++) {
  41                 ret = spi_reg_read(stmpe, reg + i);
  42                 if (ret < 0)
  43                         return ret;
  44                 *(values + i) = ret;
  45         }
  46
  47         return 0;
  48 }
  49
  50 static int spi_block_write(struct stmpe *stmpe, u8 reg, u8 length,
  51                 const u8 *values)
  52 {
  53         int ret = 0, i;
  54
  55         for (i = length; i > 0; i--, reg++) {
  56                 ret = spi_reg_write(stmpe, reg, *(values + i - 1));
  57                 if (ret < 0)
  58                         return ret;
  59         }
  60
  61         return ret;
  62 }
  63
  64 static void spi_init(struct stmpe *stmpe)
  65 {
  66         struct spi_device *spi = stmpe->client;
  67
  68         spi->bits_per_word = 8;
  69
  70         /* This register is only present for stmpe811 */
  71         if (stmpe->variant->id_val == 0x0811)
  72                 spi_reg_write(stmpe, STMPE811_REG_SPI_CFG, spi->mode);
  73
  74         if (spi_setup(spi) < 0)
  75                 dev_dbg(&spi->dev, "spi_setup failed\n");
  76 }
  77
  78 static struct stmpe_client_info spi_ci = {
  79         .read_byte = spi_reg_read,
  80         .write_byte = spi_reg_write,
  81         .read_block = spi_block_read,
  82         .write_block = spi_block_write,
  83         .init = spi_init,
  84 };
  85
  86 static int
  87 stmpe_spi_probe(struct spi_device *spi)
  88 {
  89         const struct spi_device_id *id = spi_get_device_id(spi);
  90
  91         /* don't exceed max specified rate - 1MHz - Limitation of STMPE */
  92         if (spi->max_speed_hz > 1000000) {
  93                 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
  94                                 (spi->max_speed_hz/1000));
  95                 return -EINVAL;
  96         }
  97
  98         spi_ci.irq = spi->irq;
  99         spi_ci.client = spi;
 100         spi_ci.dev = &spi->dev;
 101
 102         return stmpe_probe(&spi_ci, id->driver_data);
 103 }
 104
 105 static void stmpe_spi_remove(struct spi_device *spi)
 106 {
 107         struct stmpe *stmpe = spi_get_drvdata(spi);
 108
 109         stmpe_remove(stmpe);
 110 }
 111
 112 static const struct of_device_id stmpe_spi_of_match[] = {
 113         { .compatible = "st,stmpe610", },
 114         { .compatible = "st,stmpe801", },
 115         { .compatible = "st,stmpe811", },
 116         { .compatible = "st,stmpe1601", },
 117         { .compatible = "st,stmpe2401", },
 118         { .compatible = "st,stmpe2403", },
 119         { /* sentinel */ },
 120 };
 121 MODULE_DEVICE_TABLE(of, stmpe_spi_of_match);
 122
 123 static const struct spi_device_id stmpe_spi_id[] = {
 124         { "stmpe610", STMPE610 },
 125         { "stmpe801", STMPE801 },
 126         { "stmpe811", STMPE811 },
 127         { "stmpe1601", STMPE1601 },
 128         { "stmpe2401", STMPE2401 },
 129         { "stmpe2403", STMPE2403 },
 130         { }
 131 };
 132 MODULE_DEVICE_TABLE(spi, stmpe_id);
 133
 134 static struct spi_driver stmpe_spi_driver = {
 135         .driver = {
 136                 .name   = "stmpe-spi",
 137                 .of_match_table = of_match_ptr(stmpe_spi_of_match),
 138 #ifdef CONFIG_PM
 139                 .pm     = &stmpe_dev_pm_ops,
 140 #endif
 141         },
 142         .probe          = stmpe_spi_probe,
 143         .remove         = stmpe_spi_remove,
 144         .id_table       = stmpe_spi_id,
 145 };
 146
 147 static int __init stmpe_init(void)
 148 {
 149         return spi_register_driver(&stmpe_spi_driver);
 150 }
 151 subsys_initcall(stmpe_init);
 152
 153 static void __exit stmpe_exit(void)
 154 {
 155         spi_unregister_driver(&stmpe_spi_driver);
 156 }
 157 module_exit(stmpe_exit);
 158
 159 MODULE_LICENSE("GPL v2");
 160 MODULE_DESCRIPTION("STMPE MFD SPI Interface Driver");
 161 MODULE_AUTHOR("Viresh Kumar <vireshk@kernel.org>");