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 		.pm	= &ad7879_pm_ops,
61 		.of_match_table = of_match_ptr(ad7879_spi_dt_ids),
62 	},
63 	.probe		= ad7879_spi_probe,
64 };
65 
66 module_spi_driver(ad7879_spi_driver);
67 
68 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
69 MODULE_DESCRIPTION("AD7879(-1) touchscreen SPI bus driver");
70 MODULE_LICENSE("GPL");
71 MODULE_ALIAS("spi:ad7879");
72