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 ad714x_spi_read(struct ad714x_chip *chip,
  19                            unsigned short reg, unsigned short *data, size_t len)
  20 {
  21         struct spi_device *spi = to_spi_device(chip->dev);
  22         struct spi_message message;
  23         struct spi_transfer xfer[2];
  24         int i;
  25         int error;
  26
  27         spi_message_init(&message);
  28         memset(xfer, 0, sizeof(xfer));
  29
  30         chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX |
  31                                         AD714x_SPI_READ | reg);
  32         xfer[0].tx_buf = &chip->xfer_buf[0];
  33         xfer[0].len = sizeof(chip->xfer_buf[0]);
  34         spi_message_add_tail(&xfer[0], &message);
  35
  36         xfer[1].rx_buf = &chip->xfer_buf[1];
  37         xfer[1].len = sizeof(chip->xfer_buf[1]) * len;
  38         spi_message_add_tail(&xfer[1], &message);
  39
  40         error = spi_sync(spi, &message);
  41         if (unlikely(error)) {
  42                 dev_err(chip->dev, "SPI read error: %d\n", error);
  43                 return error;
  44         }
  45
  46         for (i = 0; i < len; i++)
  47                 data[i] = be16_to_cpu(chip->xfer_buf[i + 1]);
  48
  49         return 0;
  50 }
  51
  52 static int ad714x_spi_write(struct ad714x_chip *chip,
  53                             unsigned short reg, unsigned short data)
  54 {
  55         struct spi_device *spi = to_spi_device(chip->dev);
  56         int error;
  57
  58         chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX | reg);
  59         chip->xfer_buf[1] = cpu_to_be16(data);
  60
  61         error = spi_write(spi, (u8 *)chip->xfer_buf,
  62                           2 * sizeof(*chip->xfer_buf));
  63         if (unlikely(error)) {
  64                 dev_err(chip->dev, "SPI write error: %d\n", error);
  65                 return error;
  66         }
  67
  68         return 0;
  69 }
  70
  71 static int ad714x_spi_probe(struct spi_device *spi)
  72 {
  73         struct ad714x_chip *chip;
  74         int err;
  75
  76         spi->bits_per_word = 8;
  77         err = spi_setup(spi);
  78         if (err < 0)
  79                 return err;
  80
  81         chip = ad714x_probe(&spi->dev, BUS_SPI, spi->irq,
  82                             ad714x_spi_read, ad714x_spi_write);
  83         if (IS_ERR(chip))
  84                 return PTR_ERR(chip);
  85
  86         spi_set_drvdata(spi, chip);
  87
  88         return 0;
  89 }
  90
  91 static struct spi_driver ad714x_spi_driver = {
  92         .driver = {
  93                 .name   = "ad714x_captouch",
  94                 .pm     = pm_sleep_ptr(&ad714x_pm),
  95         },
  96         .probe          = ad714x_spi_probe,
  97 };
  98
  99 module_spi_driver(ad714x_spi_driver);
 100
 101 MODULE_DESCRIPTION("Analog Devices AD714X Capacitance Touch Sensor SPI Bus Driver");
 102 MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
 103 MODULE_LICENSE("GPL");