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