Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / drivers / input / touchscreen / ad7879-spi.c

diff --git a/kernel/drivers/input/touchscreen/ad7879-spi.c b/kernel/drivers/input/touchscreen/ad7879-spi.c
new file mode 100644 (file)
index 0000000..1a7b114
--- /dev/null
+++ b/kernel/drivers/input/touchscreen/ad7879-spi.c
@@ -0,0 +1,164 @@
+/*
+ * 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 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 ad7879_spi_remove(struct spi_device *spi)
+{
+       struct ad7879 *ts = spi_get_drvdata(spi);
+
+       ad7879_remove(ts);
+
+       return 0;
+}
+
+static struct spi_driver ad7879_spi_driver = {
+       .driver = {
+               .name   = "ad7879",
+               .owner  = THIS_MODULE,
+               .pm     = &ad7879_pm_ops,
+       },
+       .probe          = ad7879_spi_probe,
+       .remove         = ad7879_spi_remove,
+};
+
+module_spi_driver(ad7879_spi_driver);
+
+MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
+MODULE_DESCRIPTION("AD7879(-1) touchscreen SPI bus driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("spi:ad7879");