LXR linux/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
  20static 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
  28static 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
  36static 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
  50static 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
  64static 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
  78static 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
  86static int
  87stmpe_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
 105static int stmpe_spi_remove(struct spi_device *spi)
 106{
 107        struct stmpe *stmpe = spi_get_drvdata(spi);
 108
 109        return stmpe_remove(stmpe);
 110}
 111
 112static 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};
 121MODULE_DEVICE_TABLE(of, stmpe_spi_of_match);
 122
 123static 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};
 132MODULE_DEVICE_TABLE(spi, stmpe_id);
 133
 134static 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
 147static int __init stmpe_init(void)
 148{
 149        return spi_register_driver(&stmpe_spi_driver);
 150}
 151subsys_initcall(stmpe_init);
 152
 153static void __exit stmpe_exit(void)
 154{
 155        spi_unregister_driver(&stmpe_spi_driver);
 156}
 157module_exit(stmpe_exit);
 158
 159MODULE_LICENSE("GPL v2");
 160MODULE_DESCRIPTION("STMPE MFD SPI Interface Driver");
 161MODULE_AUTHOR("Viresh Kumar <vireshk@kernel.org>");
 162