diff options
Diffstat (limited to 'drivers/input/touchscreen/ad7879-spi.c')
| -rw-r--r-- | drivers/input/touchscreen/ad7879-spi.c | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/drivers/input/touchscreen/ad7879-spi.c b/drivers/input/touchscreen/ad7879-spi.c new file mode 100644 index 000000000000..5d1e5a050332 --- /dev/null +++ b/drivers/input/touchscreen/ad7879-spi.c @@ -0,0 +1,190 @@ +/* + * AD7879/AD7889 touchscreen (SPI bus) + * + * Copyright (C) 2008-2010 Michael Hennerich, Analog Devices Inc. + * + * Licensed under the GPL-2 or later. + */ + +#include <linux/input.h> /* BUS_SPI */ +#include <linux/spi/spi.h> + +#include "ad7879.h" + +#define AD7879_DEVID 0x7A /* AD7879/AD7889 */ + +#define MAX_SPI_FREQ_HZ 5000000 +#define AD7879_CMD_MAGIC 0xE000 +#define AD7879_CMD_READ (1 << 10) +#define AD7879_CMD(reg) (AD7879_CMD_MAGIC | ((reg) & 0xF)) +#define AD7879_WRITECMD(reg) (AD7879_CMD(reg)) +#define AD7879_READCMD(reg) (AD7879_CMD(reg) | AD7879_CMD_READ) + +#ifdef CONFIG_PM +static int ad7879_spi_suspend(struct spi_device *spi, pm_message_t message) +{ + struct ad7879 *ts = spi_get_drvdata(spi); + + ad7879_disable(ts); + + return 0; +} + +static int ad7879_spi_resume(struct spi_device *spi) +{ + struct ad7879 *ts = spi_get_drvdata(spi); + + ad7879_enable(ts); + + return 0; +} +#else +# define ad7879_spi_suspend NULL +# define ad7879_spi_resume NULL +#endif + +/* + * ad7879_read/write are only used for initial setup and for sysfs controls. + * The main traffic is done in ad7879_collect(). + */ + +static int ad7879_spi_xfer(struct spi_device *spi, + u16 cmd, u8 count, u16 *tx_buf, u16 *rx_buf) +{ + struct spi_message msg; + struct spi_transfer *xfers; + void *spi_data; + u16 *command; + u16 *_rx_buf = _rx_buf; /* shut gcc up */ + u8 idx; + int ret; + + xfers = spi_data = kzalloc(sizeof(*xfers) * (count + 2), GFP_KERNEL); + if (!spi_data) + return -ENOMEM; + + spi_message_init(&msg); + + command = spi_data; + command[0] = cmd; + if (count == 1) { + /* ad7879_spi_{read,write} gave us buf on stack */ + command[1] = *tx_buf; + tx_buf = &command[1]; + _rx_buf = rx_buf; + rx_buf = &command[2]; + } + + ++xfers; + xfers[0].tx_buf = command; + xfers[0].len = 2; + spi_message_add_tail(&xfers[0], &msg); + ++xfers; + + for (idx = 0; idx < count; ++idx) { + if (rx_buf) + xfers[idx].rx_buf = &rx_buf[idx]; + if (tx_buf) + xfers[idx].tx_buf = &tx_buf[idx]; + xfers[idx].len = 2; + spi_message_add_tail(&xfers[idx], &msg); + } + + ret = spi_sync(spi, &msg); + + if (count == 1) + _rx_buf[0] = command[2]; + + kfree(spi_data); + + return ret; +} + +static int ad7879_spi_multi_read(struct device *dev, + u8 first_reg, u8 count, u16 *buf) +{ + struct spi_device *spi = to_spi_device(dev); + + return ad7879_spi_xfer(spi, AD7879_READCMD(first_reg), count, NULL, buf); +} + +static int ad7879_spi_read(struct device *dev, u8 reg) +{ + struct spi_device *spi = to_spi_device(dev); + u16 ret, dummy; + + return ad7879_spi_xfer(spi, AD7879_READCMD(reg), 1, &dummy, &ret) ? : ret; +} + +static int ad7879_spi_write(struct device *dev, u8 reg, u16 val) +{ + struct spi_device *spi = to_spi_device(dev); + u16 dummy; + + return ad7879_spi_xfer(spi, AD7879_WRITECMD(reg), 1, &val, &dummy); +} + +static const struct ad7879_bus_ops ad7879_spi_bus_ops = { + .bustype = BUS_SPI, + .read = ad7879_spi_read, + .multi_read = ad7879_spi_multi_read, + .write = ad7879_spi_write, +}; + +static int __devinit ad7879_spi_probe(struct spi_device *spi) +{ + struct ad7879 *ts; + + /* don't exceed max specified SPI CLK frequency */ + if (spi->max_speed_hz > MAX_SPI_FREQ_HZ) { + dev_err(&spi->dev, "SPI CLK %d Hz?\n", spi->max_speed_hz); + return -EINVAL; + } + + ts = ad7879_probe(&spi->dev, AD7879_DEVID, spi->irq, &ad7879_spi_bus_ops); + if (IS_ERR(ts)) + return PTR_ERR(ts); + + spi_set_drvdata(spi, ts); + + return 0; +} + +static int __devexit ad7879_spi_remove(struct spi_device *spi) +{ + struct ad7879 *ts = spi_get_drvdata(spi); + + ad7879_remove(ts); + spi_set_drvdata(spi, NULL); + + return 0; +} + +static struct spi_driver ad7879_spi_driver = { + .driver = { + .name = "ad7879", + .bus = &spi_bus_type, + .owner = THIS_MODULE, + }, + .probe = ad7879_spi_probe, + .remove = __devexit_p(ad7879_spi_remove), + .suspend = ad7879_spi_suspend, + .resume = ad7879_spi_resume, +}; + +static int __init ad7879_spi_init(void) +{ + return spi_register_driver(&ad7879_spi_driver); +} +module_init(ad7879_spi_init); + +static void __exit ad7879_spi_exit(void) +{ + spi_unregister_driver(&ad7879_spi_driver); +} +module_exit(ad7879_spi_exit); + +MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>"); +MODULE_DESCRIPTION("AD7879(-1) touchscreen SPI bus driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("spi:ad7879"); |