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 .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