drivers/mfd/stmpe-spi.c

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