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");
73