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