| /* |
| * 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/pm.h> |
| #include <linux/spi/spi.h> |
| #include <linux/module.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) |
| |
| /* |
| * 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; |
| int err; |
| |
| /* 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; |
| } |
| |
| spi->bits_per_word = 16; |
| err = spi_setup(spi); |
| if (err) { |
| dev_dbg(&spi->dev, "spi master doesn't support 16 bits/word\n"); |
| return err; |
| } |
| |
| 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", |
| .owner = THIS_MODULE, |
| .pm = &ad7879_pm_ops, |
| }, |
| .probe = ad7879_spi_probe, |
| .remove = __devexit_p(ad7879_spi_remove), |
| }; |
| |
| 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"); |