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path: root/drivers/input/touchscreen/ad7879-spi.c
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Diffstat (limited to 'drivers/input/touchscreen/ad7879-spi.c')
-rw-r--r--drivers/input/touchscreen/ad7879-spi.c198
1 files changed, 198 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..59c6e68c4325
--- /dev/null
+++ b/drivers/input/touchscreen/ad7879-spi.c
@@ -0,0 +1,198 @@
+/*
+ * 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_suspend(ts);
+
+ return 0;
+}
+
+static int ad7879_spi_resume(struct spi_device *spi)
+{
+ struct ad7879 *ts = spi_get_drvdata(spi);
+
+ ad7879_resume(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;
+ 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",
+ .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");