linux/drivers/mfd/stmpe-spi.c
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   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
  19static 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
  27static 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
  35static 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
  49static 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
  63static 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
  77static 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
  85static int
  86stmpe_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
 104static 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
 111static 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};
 120MODULE_DEVICE_TABLE(spi, stmpe_id);
 121
 122static 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
 135static int __init stmpe_init(void)
 136{
 137        return spi_register_driver(&stmpe_spi_driver);
 138}
 139subsys_initcall(stmpe_init);
 140
 141static void __exit stmpe_exit(void)
 142{
 143        spi_unregister_driver(&stmpe_spi_driver);
 144}
 145module_exit(stmpe_exit);
 146
 147MODULE_LICENSE("GPL v2");
 148MODULE_DESCRIPTION("STMPE MFD SPI Interface Driver");
 149MODULE_AUTHOR("Viresh Kumar <viresh.linux@gmail.com>");
 150
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