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Add generic GPIO-tilt driver

PATCH Superseded Heiko Stübner 1 participant 1 message Nov 16, 2011

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v2 of 3 Superseded Latest is v3 →

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PATCH v2 1/1 Add generic GPIO-tilt driver

There exist tilt switches that simply report their tilt-state via some gpios.

The number and orientation of their axes can vary depending on the switch used and the build of the device. Also two or more one-axis switches could be combined to provide multi-dimensional orientation.

One example of a device using such a switch is the family of Qisda ebook readers, where the switch provides information about the landscape / portrait orientation of the device. The example in Documentation/input/gpio-tilt.txt documents exactly this one-axis device.

---
changes since v1: address comments from Dmitry Torokhov
* bdev -> tdev
* report initial axis state during open and not during probe
* don't clone platform data and use the original instead

 Documentation/input/gpio-tilt.txt     |  103 +++++++++++++++
 drivers/input/misc/Kconfig            |   14 ++
 drivers/input/misc/Makefile           |    1 +
 drivers/input/misc/gpio_tilt_polled.c |  225 +++++++++++++++++++++++++++++++++
 include/linux/gpio_tilt.h             |   73 +++++++++++
 5 files changed, 416 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/input/gpio-tilt.txt
 create mode 100644 drivers/input/misc/gpio_tilt_polled.c
 create mode 100644 include/linux/gpio_tilt.h
Documentation/input/gpio-tilt.txt new file +103 -0
new file mode 100644
index 0000000..06d60c3
@@ -0,0 +1,103 @@
+Driver for tilt-switches connected via GPIOs
+============================================
+
+Generic driver to read data from tilt switches connected via gpios.
+Orientation can be provided by one or more than one tilt switches,
+i.e. each tilt switch providing one axis, and the number of axes
+is also not limited.
+
+
+Data structures:
+----------------
+
+The array of struct gpio in the gpios field is used to list the gpios
+that represent the current tilt state.
+
+The array of struct gpio_tilt_axis describes the axes that are reported
+to the input system. The values set therein are used for the
+input_set_abs_params calls needed to init the axes.
+
+The array of struct gpio_tilt_state maps gpio states to the corresponding
+values to report. The gpio state is represented as a bitfield where the
+bit-index corresponds to the index of the gpio in the struct gpio array.
+In the same manner the values stored in the axes array correspond to
+the elements of the gpio_tilt_axis-array.
+
+
+Example:
+--------
+
+Example configuration for a single TS1003 tilt switch that rotates around
+one axis in 4 steps and emitts the current tilt via two GPIOs.
+
+static int sg060_tilt_enable(struct device *dev) {
+	/* code to enable the sensors */
+};
+
+static void sg060_tilt_disable(struct device *dev) {
+	/* code to disable the sensors */
+};
+
+static struct gpio sg060_tilt_gpios[] = {
+	{ SG060_TILT_GPIO_SENSOR1, GPIOF_IN, "tilt_sensor1" },
+	{ SG060_TILT_GPIO_SENSOR2, GPIOF_IN, "tilt_sensor2" },
+};
+
+static struct gpio_tilt_state sg060_tilt_states[] = {
+	{
+		.gpios = (0 << 1) | (0 << 0),
+		.axes = (int[]) {
+			0,
+		},
+	}, {
+		.gpios = (0 << 1) | (1 << 0),
+		.axes = (int[]) {
+			1, /* 90 degrees */
+		},
+	}, {
+		.gpios = (1 << 1) | (1 << 0),
+		.axes = (int[]) {
+			2, /* 180 degrees */
+		},
+	}, {
+		.gpios = (1 << 1) | (0 << 0),
+		.axes = (int[]) {
+			3, /* 270 degrees */
+		},
+	},
+};
+
+static struct gpio_tilt_axis sg060_tilt_axes[] = {
+	{
+		.axis = ABS_RY,
+		.min = 0,
+		.max = 3,
+		.fuzz = 0,
+		.flat = 0,
+	},
+};
+
+static struct gpio_tilt_platform_data sg060_tilt_pdata= {
+	.gpios = sg060_tilt_gpios,
+	.nr_gpios = ARRAY_SIZE(sg060_tilt_gpios),
+
+	.axes = sg060_tilt_axes,
+	.nr_axes = ARRAY_SIZE(sg060_tilt_axes),
+
+	.states = sg060_tilt_states,
+	.nr_states = ARRAY_SIZE(sg060_tilt_states),
+
+	.debounce_interval = 100,
+
+	.poll_interval = 1000,
+	.enable = sg060_tilt_enable,
+	.disable = sg060_tilt_disable,
+};
+
+static struct platform_device sg060_device_tilt = {
+	.name = "gpio-tilt-polled",
+	.id = -1,
+	.dev = {
+		.platform_data = &sg060_tilt_pdata,
+	},
+};
drivers/input/misc/Kconfig +14 -0
index 22d875f..e53b443 100644
@@ -179,6 +179,20 @@ config INPUT_APANEL
 	 To compile this driver as a module, choose M here: the module will
 	 be called apanel.
 
+config INPUT_GPIO_TILT_POLLED
+	tristate "Polled GPIO tilt switch"
+	depends on GENERIC_GPIO
+	select INPUT_POLLDEV
+	help
+	  This driver implements support for tilt switches connected
+	  to GPIO pins that are not capable of generating interrupts.
+
+	  The list of gpios to use and the mapping of their states
+	  to specific angles is done via platform data.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called gpio_tilt_polled.
+
 config INPUT_IXP4XX_BEEPER
 	tristate "IXP4XX Beeper support"
 	depends on ARCH_IXP4XX
drivers/input/misc/Makefile +1 -0
index a244fc6..90070c1 100644
@@ -23,6 +23,7 @@ obj-$(CONFIG_INPUT_CMA3000_I2C)		+= cma3000_d0x_i2c.o
 obj-$(CONFIG_INPUT_COBALT_BTNS)		+= cobalt_btns.o
 obj-$(CONFIG_INPUT_DM355EVM)		+= dm355evm_keys.o
 obj-$(CONFIG_HP_SDC_RTC)		+= hp_sdc_rtc.o
+obj-$(CONFIG_INPUT_GPIO_TILT_POLLED)	+= gpio_tilt_polled.o
 obj-$(CONFIG_INPUT_IXP4XX_BEEPER)	+= ixp4xx-beeper.o
 obj-$(CONFIG_INPUT_KEYSPAN_REMOTE)	+= keyspan_remote.o
 obj-$(CONFIG_INPUT_KXTJ9)		+= kxtj9.o
drivers/input/misc/gpio_tilt_polled.c new file +225 -0

225 lines not on this page · raw message

include/linux/gpio_tilt.h new file +73 -0

73 lines not on this page · raw message

Signature · 1 line
1.7.2.3