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 14 #include "ad7879.h" 15 16 #define AD7879_DEVID 0x7A /* AD7879/AD7889 */ 17 18 #define MAX_SPI_FREQ_HZ 5000000 19 #define AD7879_CMD_MAGIC 0xE000 20 #define AD7879_CMD_READ (1 << 10) 21 #define AD7879_CMD(reg) (AD7879_CMD_MAGIC | ((reg) & 0xF)) 22 #define AD7879_WRITECMD(reg) (AD7879_CMD(reg)) 23 #define AD7879_READCMD(reg) (AD7879_CMD(reg) | AD7879_CMD_READ) 24 25 #ifdef CONFIG_PM_SLEEP 26 static int ad7879_spi_suspend(struct device *dev) 27 { 28 struct spi_device *spi = to_spi_device(dev); 29 struct ad7879 *ts = spi_get_drvdata(spi); 30 31 ad7879_suspend(ts); 32 33 return 0; 34 } 35 36 static int ad7879_spi_resume(struct device *dev) 37 { 38 struct spi_device *spi = to_spi_device(dev); 39 struct ad7879 *ts = spi_get_drvdata(spi); 40 41 ad7879_resume(ts); 42 43 return 0; 44 } 45 #endif 46 47 static SIMPLE_DEV_PM_OPS(ad7879_spi_pm, ad7879_spi_suspend, ad7879_spi_resume); 48 49 /* 50 * ad7879_read/write are only used for initial setup and for sysfs controls. 51 * The main traffic is done in ad7879_collect(). 52 */ 53 54 static int ad7879_spi_xfer(struct spi_device *spi, 55 u16 cmd, u8 count, u16 *tx_buf, u16 *rx_buf) 56 { 57 struct spi_message msg; 58 struct spi_transfer *xfers; 59 void *spi_data; 60 u16 *command; 61 u16 *_rx_buf = _rx_buf; /* shut gcc up */ 62 u8 idx; 63 int ret; 64 65 xfers = spi_data = kzalloc(sizeof(*xfers) * (count + 2), GFP_KERNEL); 66 if (!spi_data) 67 return -ENOMEM; 68 69 spi_message_init(&msg); 70 71 command = spi_data; 72 command[0] = cmd; 73 if (count == 1) { 74 /* ad7879_spi_{read,write} gave us buf on stack */ 75 command[1] = *tx_buf; 76 tx_buf = &command[1]; 77 _rx_buf = rx_buf; 78 rx_buf = &command[2]; 79 } 80 81 ++xfers; 82 xfers[0].tx_buf = command; 83 xfers[0].len = 2; 84 spi_message_add_tail(&xfers[0], &msg); 85 ++xfers; 86 87 for (idx = 0; idx < count; ++idx) { 88 if (rx_buf) 89 xfers[idx].rx_buf = &rx_buf[idx]; 90 if (tx_buf) 91 xfers[idx].tx_buf = &tx_buf[idx]; 92 xfers[idx].len = 2; 93 spi_message_add_tail(&xfers[idx], &msg); 94 } 95 96 ret = spi_sync(spi, &msg); 97 98 if (count == 1) 99 _rx_buf[0] = command[2]; 100 101 kfree(spi_data); 102 103 return ret; 104 } 105 106 static int ad7879_spi_multi_read(struct device *dev, 107 u8 first_reg, u8 count, u16 *buf) 108 { 109 struct spi_device *spi = to_spi_device(dev); 110 111 return ad7879_spi_xfer(spi, AD7879_READCMD(first_reg), count, NULL, buf); 112 } 113 114 static int ad7879_spi_read(struct device *dev, u8 reg) 115 { 116 struct spi_device *spi = to_spi_device(dev); 117 u16 ret, dummy; 118 119 return ad7879_spi_xfer(spi, AD7879_READCMD(reg), 1, &dummy, &ret) ? : ret; 120 } 121 122 static int ad7879_spi_write(struct device *dev, u8 reg, u16 val) 123 { 124 struct spi_device *spi = to_spi_device(dev); 125 u16 dummy; 126 127 return ad7879_spi_xfer(spi, AD7879_WRITECMD(reg), 1, &val, &dummy); 128 } 129 130 static const struct ad7879_bus_ops ad7879_spi_bus_ops = { 131 .bustype = BUS_SPI, 132 .read = ad7879_spi_read, 133 .multi_read = ad7879_spi_multi_read, 134 .write = ad7879_spi_write, 135 }; 136 137 static int __devinit ad7879_spi_probe(struct spi_device *spi) 138 { 139 struct ad7879 *ts; 140 int err; 141 142 /* don't exceed max specified SPI CLK frequency */ 143 if (spi->max_speed_hz > MAX_SPI_FREQ_HZ) { 144 dev_err(&spi->dev, "SPI CLK %d Hz?\n", spi->max_speed_hz); 145 return -EINVAL; 146 } 147 148 spi->bits_per_word = 16; 149 err = spi_setup(spi); 150 if (err) { 151 dev_dbg(&spi->dev, "spi master doesn't support 16 bits/word\n"); 152 return err; 153 } 154 155 ts = ad7879_probe(&spi->dev, AD7879_DEVID, spi->irq, &ad7879_spi_bus_ops); 156 if (IS_ERR(ts)) 157 return PTR_ERR(ts); 158 159 spi_set_drvdata(spi, ts); 160 161 return 0; 162 } 163 164 static int __devexit ad7879_spi_remove(struct spi_device *spi) 165 { 166 struct ad7879 *ts = spi_get_drvdata(spi); 167 168 ad7879_remove(ts); 169 spi_set_drvdata(spi, NULL); 170 171 return 0; 172 } 173 174 static struct spi_driver ad7879_spi_driver = { 175 .driver = { 176 .name = "ad7879", 177 .bus = &spi_bus_type, 178 .owner = THIS_MODULE, 179 .pm = &ad7879_spi_pm, 180 }, 181 .probe = ad7879_spi_probe, 182 .remove = __devexit_p(ad7879_spi_remove), 183 }; 184 185 static int __init ad7879_spi_init(void) 186 { 187 return spi_register_driver(&ad7879_spi_driver); 188 } 189 module_init(ad7879_spi_init); 190 191 static void __exit ad7879_spi_exit(void) 192 { 193 spi_unregister_driver(&ad7879_spi_driver); 194 } 195 module_exit(ad7879_spi_exit); 196 197 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>"); 198 MODULE_DESCRIPTION("AD7879(-1) touchscreen SPI bus driver"); 199 MODULE_LICENSE("GPL"); 200 MODULE_ALIAS("spi:ad7879"); 201