drivers/input/misc/ad714x-spi.c

   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
  18 static int __maybe_unused ad714x_spi_suspend(struct device *dev)
  19 {
  20         return ad714x_disable(spi_get_drvdata(to_spi_device(dev)));
  21 }
  22
  23 static int __maybe_unused ad714x_spi_resume(struct device *dev)
  24 {
  25         return ad714x_enable(spi_get_drvdata(to_spi_device(dev)));
  26 }
  27
  28 static SIMPLE_DEV_PM_OPS(ad714x_spi_pm, ad714x_spi_suspend, ad714x_spi_resume);
  29
  30 static 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
  64 static 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
  83 static 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
 103 static 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
 111 module_spi_driver(ad714x_spi_driver);
 112
 113 MODULE_DESCRIPTION("Analog Devices AD714X Capacitance Touch Sensor SPI Bus Driver");
 114 MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
 115 MODULE_LICENSE("GPL");