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
ad7879_spi_probe(struct spi_device * spi)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");
73