1 /* 2 * AD714X CapTouch Programmable Controller driver (SPI bus) 3 * 4 * Copyright 2009-2011 Analog Devices Inc. 5 * 6 * Licensed under the GPL-2 or later. 7 */ 8 9 #include <linux/input.h> /* BUS_SPI */ 10 #include <linux/module.h> 11 #include <linux/spi/spi.h> 12 #include <linux/pm.h> 13 #include <linux/types.h> 14 #include "ad714x.h" 15 16 #define AD714x_SPI_CMD_PREFIX 0xE000 /* bits 15:11 */ 17 #define AD714x_SPI_READ BIT(10) 18 19 #ifdef CONFIG_PM 20 static int ad714x_spi_suspend(struct device *dev) 21 { 22 return ad714x_disable(spi_get_drvdata(to_spi_device(dev))); 23 } 24 25 static int ad714x_spi_resume(struct device *dev) 26 { 27 return ad714x_enable(spi_get_drvdata(to_spi_device(dev))); 28 } 29 #endif 30 31 static SIMPLE_DEV_PM_OPS(ad714x_spi_pm, ad714x_spi_suspend, ad714x_spi_resume); 32 33 static int ad714x_spi_read(struct ad714x_chip *chip, 34 unsigned short reg, unsigned short *data, size_t len) 35 { 36 struct spi_device *spi = to_spi_device(chip->dev); 37 struct spi_message message; 38 struct spi_transfer xfer[2]; 39 int i; 40 int error; 41 42 spi_message_init(&message); 43 memset(xfer, 0, sizeof(xfer)); 44 45 chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX | 46 AD714x_SPI_READ | reg); 47 xfer[0].tx_buf = &chip->xfer_buf[0]; 48 xfer[0].len = sizeof(chip->xfer_buf[0]); 49 spi_message_add_tail(&xfer[0], &message); 50 51 xfer[1].rx_buf = &chip->xfer_buf[1]; 52 xfer[1].len = sizeof(chip->xfer_buf[1]) * len; 53 spi_message_add_tail(&xfer[1], &message); 54 55 error = spi_sync(spi, &message); 56 if (unlikely(error)) { 57 dev_err(chip->dev, "SPI read error: %d\n", error); 58 return error; 59 } 60 61 for (i = 0; i < len; i++) 62 data[i] = be16_to_cpu(chip->xfer_buf[i + 1]); 63 64 return 0; 65 } 66 67 static int ad714x_spi_write(struct ad714x_chip *chip, 68 unsigned short reg, unsigned short data) 69 { 70 struct spi_device *spi = to_spi_device(chip->dev); 71 int error; 72 73 chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX | reg); 74 chip->xfer_buf[1] = cpu_to_be16(data); 75 76 error = spi_write(spi, (u8 *)chip->xfer_buf, 77 2 * sizeof(*chip->xfer_buf)); 78 if (unlikely(error)) { 79 dev_err(chip->dev, "SPI write error: %d\n", error); 80 return error; 81 } 82 83 return 0; 84 } 85 86 static int ad714x_spi_probe(struct spi_device *spi) 87 { 88 struct ad714x_chip *chip; 89 int err; 90 91 spi->bits_per_word = 8; 92 err = spi_setup(spi); 93 if (err < 0) 94 return err; 95 96 chip = ad714x_probe(&spi->dev, BUS_SPI, spi->irq, 97 ad714x_spi_read, ad714x_spi_write); 98 if (IS_ERR(chip)) 99 return PTR_ERR(chip); 100 101 spi_set_drvdata(spi, chip); 102 103 return 0; 104 } 105 106 static int ad714x_spi_remove(struct spi_device *spi) 107 { 108 struct ad714x_chip *chip = spi_get_drvdata(spi); 109 110 ad714x_remove(chip); 111 spi_set_drvdata(spi, NULL); 112 113 return 0; 114 } 115 116 static struct spi_driver ad714x_spi_driver = { 117 .driver = { 118 .name = "ad714x_captouch", 119 .owner = THIS_MODULE, 120 .pm = &ad714x_spi_pm, 121 }, 122 .probe = ad714x_spi_probe, 123 .remove = ad714x_spi_remove, 124 }; 125 126 module_spi_driver(ad714x_spi_driver); 127 128 MODULE_DESCRIPTION("Analog Devices AD714X Capacitance Touch Sensor SPI Bus Driver"); 129 MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>"); 130 MODULE_LICENSE("GPL"); 131