1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * AD714X CapTouch Programmable Controller driver (SPI bus) 4 * 5 * Copyright 2009-2011 Analog Devices Inc. 6 */ 7 8 #include <linux/input.h> /* BUS_SPI */ 9 #include <linux/module.h> 10 #include <linux/spi/spi.h> 11 #include <linux/pm.h> 12 #include <linux/types.h> 13 #include "ad714x.h" 14 15 #define AD714x_SPI_CMD_PREFIX 0xE000 /* bits 15:11 */ 16 #define AD714x_SPI_READ BIT(10) 17 18 static int ad714x_spi_read(struct ad714x_chip *chip, 19 unsigned short reg, unsigned short *data, size_t len) 20 { 21 struct spi_device *spi = to_spi_device(chip->dev); 22 struct spi_message message; 23 struct spi_transfer xfer[2]; 24 int i; 25 int error; 26 27 spi_message_init(&message); 28 memset(xfer, 0, sizeof(xfer)); 29 30 chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX | 31 AD714x_SPI_READ | reg); 32 xfer[0].tx_buf = &chip->xfer_buf[0]; 33 xfer[0].len = sizeof(chip->xfer_buf[0]); 34 spi_message_add_tail(&xfer[0], &message); 35 36 xfer[1].rx_buf = &chip->xfer_buf[1]; 37 xfer[1].len = sizeof(chip->xfer_buf[1]) * len; 38 spi_message_add_tail(&xfer[1], &message); 39 40 error = spi_sync(spi, &message); 41 if (unlikely(error)) { 42 dev_err(chip->dev, "SPI read error: %d\n", error); 43 return error; 44 } 45 46 for (i = 0; i < len; i++) 47 data[i] = be16_to_cpu(chip->xfer_buf[i + 1]); 48 49 return 0; 50 } 51 52 static int ad714x_spi_write(struct ad714x_chip *chip, 53 unsigned short reg, unsigned short data) 54 { 55 struct spi_device *spi = to_spi_device(chip->dev); 56 int error; 57 58 chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX | reg); 59 chip->xfer_buf[1] = cpu_to_be16(data); 60 61 error = spi_write(spi, (u8 *)chip->xfer_buf, 62 2 * sizeof(*chip->xfer_buf)); 63 if (unlikely(error)) { 64 dev_err(chip->dev, "SPI write error: %d\n", error); 65 return error; 66 } 67 68 return 0; 69 } 70 71 static int ad714x_spi_probe(struct spi_device *spi) 72 { 73 struct ad714x_chip *chip; 74 int err; 75 76 spi->bits_per_word = 8; 77 err = spi_setup(spi); 78 if (err < 0) 79 return err; 80 81 chip = ad714x_probe(&spi->dev, BUS_SPI, spi->irq, 82 ad714x_spi_read, ad714x_spi_write); 83 if (IS_ERR(chip)) 84 return PTR_ERR(chip); 85 86 spi_set_drvdata(spi, chip); 87 88 return 0; 89 } 90 91 static struct spi_driver ad714x_spi_driver = { 92 .driver = { 93 .name = "ad714x_captouch", 94 .pm = pm_sleep_ptr(&ad714x_pm), 95 }, 96 .probe = ad714x_spi_probe, 97 }; 98 99 module_spi_driver(ad714x_spi_driver); 100 101 MODULE_DESCRIPTION("Analog Devices AD714X Capacitance Touch Sensor SPI Bus Driver"); 102 MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>"); 103 MODULE_LICENSE("GPL"); 104