Input: add Analog Devices AD714x captouch input driver

AD7142 and AD7147 are integrated capacitance-to-digital converters
(CDCs) with on-chip environmental calibration for use in systems
requiring a novel user input method. The AD7142 and AD7147 can interface
to external capacitance sensors implementing functions such as buttons,
scrollwheels, sliders, touchpads and so on.

The chips don't restrict the specific usage. Depending on the hardware
connection, one special target board can include one or several these
components. The platform_data for the device's "struct device" holds
these information. The data-struct defined in head file descript the
hardware feature of button/scrollwheel/slider/touchpad components on
target boards, which need be filled in the arch/mach-/.

As the result, the driver is independent of boards. It gets the
components layout from the platform_data, registers related devices,
fullfills the algorithms and state machines for these components and
report related input events to up level.

Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Barry Song <21cnbao@gmail.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 103 insertions, 0 deletions

diff --git a/drivers/input/misc/ad714x-spi.c b/drivers/input/misc/ad714x-spi.c
new file mode 100644
index 000000000000..7f8dedfd1bfe
--- /dev/null
+++ b/drivers/input/misc/ad714x-spi.c
@@ -0,0 +1,103 @@
+/*
+ * AD714X CapTouch Programmable Controller driver (SPI bus)
+ *
+ * Copyright 2009 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/input.h>	/* BUS_I2C */
+#include <linux/module.h>
+#include <linux/spi/spi.h>
+#include <linux/types.h>
+#include "ad714x.h"
+
+#define AD714x_SPI_CMD_PREFIX      0xE000   /* bits 15:11 */
+#define AD714x_SPI_READ            BIT(10)
+
+#ifdef CONFIG_PM
+static int ad714x_spi_suspend(struct spi_device *spi, pm_message_t message)
+{
+	return ad714x_disable(spi_get_drvdata(spi));
+}
+
+static int ad714x_spi_resume(struct spi_device *spi)
+{
+	return ad714x_enable(spi_get_drvdata(spi));
+}
+#else
+# define ad714x_spi_suspend NULL
+# define ad714x_spi_resume  NULL
+#endif
+
+static int ad714x_spi_read(struct device *dev, unsigned short reg,
+		unsigned short *data)
+{
+	struct spi_device *spi = to_spi_device(dev);
+	unsigned short tx = AD714x_SPI_CMD_PREFIX | AD714x_SPI_READ | reg;
+
+	return spi_write_then_read(spi, (u8 *)&tx, 2, (u8 *)data, 2);
+}
+
+static int ad714x_spi_write(struct device *dev, unsigned short reg,
+		unsigned short data)
+{
+	struct spi_device *spi = to_spi_device(dev);
+	unsigned short tx[2] = {
+		AD714x_SPI_CMD_PREFIX | reg,
+		data
+	};
+
+	return spi_write(spi, (u8 *)tx, 4);
+}
+
+static int __devinit ad714x_spi_probe(struct spi_device *spi)
+{
+	struct ad714x_chip *chip;
+
+	chip = ad714x_probe(&spi->dev, BUS_SPI, spi->irq,
+			    ad714x_spi_read, ad714x_spi_write);
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+
+	spi_set_drvdata(spi, chip);
+
+	return 0;
+}
+
+static int __devexit ad714x_spi_remove(struct spi_device *spi)
+{
+	struct ad714x_chip *chip = spi_get_drvdata(spi);
+
+	ad714x_remove(chip);
+	spi_set_drvdata(spi, NULL);
+
+	return 0;
+}
+
+static struct spi_driver ad714x_spi_driver = {
+	.driver = {
+		.name	= "ad714x_captouch",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= ad714x_spi_probe,
+	.remove		= __devexit_p(ad714x_spi_remove),
+	.suspend	= ad714x_spi_suspend,
+	.resume		= ad714x_spi_resume,
+};
+
+static __init int ad714x_spi_init(void)
+{
+	return spi_register_driver(&ad714x_spi_driver);
+}
+module_init(ad714x_spi_init);
+
+static __exit void ad714x_spi_exit(void)
+{
+	spi_unregister_driver(&ad714x_spi_driver);
+}
+module_exit(ad714x_spi_exit);
+
+MODULE_DESCRIPTION("Analog Devices AD714X Capacitance Touch Sensor SPI Bus Driver");
+MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
+MODULE_LICENSE("GPL");