linux/drivers/input/misc/ad714x-spi.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * AD714X CapTouch Programmable Controller driver (SPI bus)
   4 *
   5 * Copyright 2009-2011 Analog Devices Inc.
   6 */
   7
   8#include <linux/input.h>        /* BUS_SPI */
   9#include <linux/module.h>
  10#include <linux/spi/spi.h>
  11#include <linux/pm.h>
  12#include <linux/types.h>
  13#include "ad714x.h"
  14
  15#define AD714x_SPI_CMD_PREFIX      0xE000   /* bits 15:11 */
  16#define AD714x_SPI_READ            BIT(10)
  17
  18static int __maybe_unused ad714x_spi_suspend(struct device *dev)
  19{
  20        return ad714x_disable(spi_get_drvdata(to_spi_device(dev)));
  21}
  22
  23static int __maybe_unused ad714x_spi_resume(struct device *dev)
  24{
  25        return ad714x_enable(spi_get_drvdata(to_spi_device(dev)));
  26}
  27
  28static SIMPLE_DEV_PM_OPS(ad714x_spi_pm, ad714x_spi_suspend, ad714x_spi_resume);
  29
  30static int ad714x_spi_read(struct ad714x_chip *chip,
  31                           unsigned short reg, unsigned short *data, size_t len)
  32{
  33        struct spi_device *spi = to_spi_device(chip->dev);
  34        struct spi_message message;
  35        struct spi_transfer xfer[2];
  36        int i;
  37        int error;
  38
  39        spi_message_init(&message);
  40        memset(xfer, 0, sizeof(xfer));
  41
  42        chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX |
  43                                        AD714x_SPI_READ | reg);
  44        xfer[0].tx_buf = &chip->xfer_buf[0];
  45        xfer[0].len = sizeof(chip->xfer_buf[0]);
  46        spi_message_add_tail(&xfer[0], &message);
  47
  48        xfer[1].rx_buf = &chip->xfer_buf[1];
  49        xfer[1].len = sizeof(chip->xfer_buf[1]) * len;
  50        spi_message_add_tail(&xfer[1], &message);
  51
  52        error = spi_sync(spi, &message);
  53        if (unlikely(error)) {
  54                dev_err(chip->dev, "SPI read error: %d\n", error);
  55                return error;
  56        }
  57
  58        for (i = 0; i < len; i++)
  59                data[i] = be16_to_cpu(chip->xfer_buf[i + 1]);
  60
  61        return 0;
  62}
  63
  64static int ad714x_spi_write(struct ad714x_chip *chip,
  65                            unsigned short reg, unsigned short data)
  66{
  67        struct spi_device *spi = to_spi_device(chip->dev);
  68        int error;
  69
  70        chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX | reg);
  71        chip->xfer_buf[1] = cpu_to_be16(data);
  72
  73        error = spi_write(spi, (u8 *)chip->xfer_buf,
  74                          2 * sizeof(*chip->xfer_buf));
  75        if (unlikely(error)) {
  76                dev_err(chip->dev, "SPI write error: %d\n", error);
  77                return error;
  78        }
  79
  80        return 0;
  81}
  82
  83static int ad714x_spi_probe(struct spi_device *spi)
  84{
  85        struct ad714x_chip *chip;
  86        int err;
  87
  88        spi->bits_per_word = 8;
  89        err = spi_setup(spi);
  90        if (err < 0)
  91                return err;
  92
  93        chip = ad714x_probe(&spi->dev, BUS_SPI, spi->irq,
  94                            ad714x_spi_read, ad714x_spi_write);
  95        if (IS_ERR(chip))
  96                return PTR_ERR(chip);
  97
  98        spi_set_drvdata(spi, chip);
  99
 100        return 0;
 101}
 102
 103static struct spi_driver ad714x_spi_driver = {
 104        .driver = {
 105                .name   = "ad714x_captouch",
 106                .pm     = &ad714x_spi_pm,
 107        },
 108        .probe          = ad714x_spi_probe,
 109};
 110
 111module_spi_driver(ad714x_spi_driver);
 112
 113MODULE_DESCRIPTION("Analog Devices AD714X Capacitance Touch Sensor SPI Bus Driver");
 114MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
 115MODULE_LICENSE("GPL");
 116