drivers/input/touchscreen/ad7879-spi.c

   1 /*
   2  * AD7879/AD7889 touchscreen (SPI bus)
   3  *
   4  * Copyright (C) 2008-2010 Michael Hennerich, Analog Devices Inc.
   5  *
   6  * Licensed under the GPL-2 or later.
   7  */
   8
   9 #include <linux/input.h>        /* BUS_SPI */
  10 #include <linux/pm.h>
  11 #include <linux/spi/spi.h>
  12 #include <linux/module.h>
  13 #include <linux/of.h>
  14 #include <linux/regmap.h>
  15
  16 #include "ad7879.h"
  17
  18 #define AD7879_DEVID            0x7A    /* AD7879/AD7889 */
  19
  20 #define MAX_SPI_FREQ_HZ      5000000
  21
  22 #define AD7879_CMD_MAGIC     0xE0
  23 #define AD7879_CMD_READ      BIT(2)
  24
  25 static const struct regmap_config ad7879_spi_regmap_config = {
  26         .reg_bits = 16,
  27         .val_bits = 16,
  28         .max_register = 15,
  29         .read_flag_mask = AD7879_CMD_MAGIC | AD7879_CMD_READ,
  30         .write_flag_mask = AD7879_CMD_MAGIC,
  31 };
  32
  33 static int ad7879_spi_probe(struct spi_device *spi)
  34 {
  35         struct regmap *regmap;
  36
  37         /* don't exceed max specified SPI CLK frequency */
  38         if (spi->max_speed_hz > MAX_SPI_FREQ_HZ) {
  39                 dev_err(&spi->dev, "SPI CLK %d Hz?\n", spi->max_speed_hz);
  40                 return -EINVAL;
  41         }
  42
  43         regmap = devm_regmap_init_spi(spi, &ad7879_spi_regmap_config);
  44         if (IS_ERR(regmap))
  45                 return PTR_ERR(regmap);
  46
  47         return ad7879_probe(&spi->dev, regmap, spi->irq, BUS_SPI, AD7879_DEVID);
  48 }
  49
  50 #ifdef CONFIG_OF
  51 static const struct of_device_id ad7879_spi_dt_ids[] = {
  52         { .compatible = "adi,ad7879", },
  53         { }
  54 };
  55 MODULE_DEVICE_TABLE(of, ad7879_spi_dt_ids);
  56 #endif
  57
  58 static struct spi_driver ad7879_spi_driver = {
  59         .driver = {
  60                 .name   = "ad7879",
  61                 .pm     = &ad7879_pm_ops,
  62                 .of_match_table = of_match_ptr(ad7879_spi_dt_ids),
  63         },
  64         .probe          = ad7879_spi_probe,
  65 };
  66
  67 module_spi_driver(ad7879_spi_driver);
  68
  69 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
  70 MODULE_DESCRIPTION("AD7879(-1) touchscreen SPI bus driver");
  71 MODULE_LICENSE("GPL");
  72 MODULE_ALIAS("spi:ad7879");