drivers/input/touchscreen/ad7879-spi.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * AD7879/AD7889 touchscreen (SPI bus)
   4  *
   5  * Copyright (C) 2008-2010 Michael Hennerich, Analog Devices Inc.
   6  */
   7
   8 #include <linux/input.h>        /* BUS_SPI */
   9 #include <linux/pm.h>
  10 #include <linux/spi/spi.h>
  11 #include <linux/module.h>
  12 #include <linux/of.h>
  13 #include <linux/regmap.h>
  14
  15 #include "ad7879.h"
  16
  17 #define AD7879_DEVID            0x7A    /* AD7879/AD7889 */
  18
  19 #define MAX_SPI_FREQ_HZ      5000000
  20
  21 #define AD7879_CMD_MAGIC     0xE0
  22 #define AD7879_CMD_READ      BIT(2)
  23
  24 static const struct regmap_config ad7879_spi_regmap_config = {
  25         .reg_bits = 16,
  26         .val_bits = 16,
  27         .max_register = 15,
  28         .read_flag_mask = AD7879_CMD_MAGIC | AD7879_CMD_READ,
  29         .write_flag_mask = AD7879_CMD_MAGIC,
  30 };
  31
  32 static int ad7879_spi_probe(struct spi_device *spi)
  33 {
  34         struct regmap *regmap;
  35
  36         /* don't exceed max specified SPI CLK frequency */
  37         if (spi->max_speed_hz > MAX_SPI_FREQ_HZ) {
  38                 dev_err(&spi->dev, "SPI CLK %d Hz?\n", spi->max_speed_hz);
  39                 return -EINVAL;
  40         }
  41
  42         regmap = devm_regmap_init_spi(spi, &ad7879_spi_regmap_config);
  43         if (IS_ERR(regmap))
  44                 return PTR_ERR(regmap);
  45
  46         return ad7879_probe(&spi->dev, regmap, spi->irq, BUS_SPI, AD7879_DEVID);
  47 }
  48
  49 #ifdef CONFIG_OF
  50 static const struct of_device_id ad7879_spi_dt_ids[] = {
  51         { .compatible = "adi,ad7879", },
  52         { }
  53 };
  54 MODULE_DEVICE_TABLE(of, ad7879_spi_dt_ids);
  55 #endif
  56
  57 static struct spi_driver ad7879_spi_driver = {
  58         .driver = {
  59                 .name           = "ad7879",
  60                 .dev_groups     = ad7879_groups,
  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");