[PATCH 4/4] input: Pegatron Lucid accelerometer

[Andy Ross <andy.ross@windriver.com>]

Add driver for the ACPI accelerometer interface on the Pegatron Lucid
tablet.

Signed-off-by: Andy Ross <andy.ross@windriver.com>
---
 drivers/input/misc/Kconfig      |   10 +++
 drivers/input/misc/Makefile     |    2 +-
 drivers/input/misc/pega-accel.c |  130 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 141 insertions(+), 1 deletions(-)
 create mode 100644 drivers/input/misc/pega-accel.c

diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
index b99b8cb..e60af95 100644
--- a/drivers/input/misc/Kconfig
+++ b/drivers/input/misc/Kconfig
@@ -74,6 +74,16 @@ config INPUT_PCSPKR
 	  To compile this driver as a module, choose M here: the
 	  module will be called pcspkr.
 
+config INPUT_PEGA_ACCEL
+       tristate "Support Pegatron Lucid accelerometer"
+       depends on ASUS_LAPTOP
+       help
+         Say Y here if you want support for the built-in ACPI
+         accelerometer device on Pegatron Lucid tablet devices.
+
+	 To compile this driver as a module, choose M here: the module
+	 will be called pega_accel.
+
 config INPUT_SPARCSPKR
 	tristate "SPARC Speaker support"
 	depends on PCI && SPARC64
diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
index 1fe1f6c..79aca4d 100644
--- a/drivers/input/misc/Makefile
+++ b/drivers/input/misc/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_INPUT_PCAP)		+= pcap_keys.o
 obj-$(CONFIG_INPUT_PCF50633_PMU)	+= pcf50633-input.o
 obj-$(CONFIG_INPUT_PCF8574)		+= pcf8574_keypad.o
 obj-$(CONFIG_INPUT_PCSPKR)		+= pcspkr.o
+obj-$(CONFIG_INPUT_PEGA_ACCEL)		+= pega-accel.o
 obj-$(CONFIG_INPUT_POWERMATE)		+= powermate.o
 obj-$(CONFIG_INPUT_PWM_BEEPER)		+= pwm-beeper.o
 obj-$(CONFIG_INPUT_RB532_BUTTON)	+= rb532_button.o
@@ -42,4 +43,3 @@ obj-$(CONFIG_INPUT_WINBOND_CIR)		+= winbond-cir.o
 obj-$(CONFIG_INPUT_WISTRON_BTNS)	+= wistron_btns.o
 obj-$(CONFIG_INPUT_WM831X_ON)		+= wm831x-on.o
 obj-$(CONFIG_INPUT_YEALINK)		+= yealink.o
-
diff --git a/drivers/input/misc/pega-accel.c b/drivers/input/misc/pega-accel.c
new file mode 100644
index 0000000..7005b46
--- /dev/null
+++ b/drivers/input/misc/pega-accel.c
@@ -0,0 +1,130 @@
+/*
+ * Driver for accelerometer in Pegatron Lucid tablets
+ *
+ * Copyright (c) 2011 Wind River Systems
+ *
+ * Author: Andy Ross <andy.ross@windriver.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/input-polldev.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <acpi/acpi_bus.h>
+
+#define DRIVER_NAME "pega_accel"
+#define DRIVER_DESC "Pegatron Lucid Tablet Accelerometer"
+
+/* 1G accel is reported as ~256, so clamp to 2G */
+#define CLAMP 512
+
+static struct input_polled_dev *ipdev;
+
+/* FIXME: this mechanism is *very* slow: ~50ms to read the three
+ * values.  Pre-caching an acpi handle with acpi_get_handle has no
+ * effect, so the issue isn't in the parsing or tree walking... */
+static int acpi_s16(char *method)
+{
+	unsigned long long val = 0;
+	acpi_evaluate_integer(NULL, method, NULL, &val);
+	return (short)val;
+}
+
+static void pega_accel_poll(struct input_polled_dev *ipdev)
+{
+	/* Note transform, convert to "right/up/out" in the native
+	 * landscape orientation (i.e. the vector is the direction of
+	 * "real up" in the device's cartiesian coordinates).  FIXME:
+	 * is there a relevant convention to adhere to? */
+	int x = -acpi_s16("\\_SB.ATKD.XLRX");
+	int y = -acpi_s16("\\_SB.ATKD.XLRY");
+	int z =  acpi_s16("\\_SB.ATKD.XLRZ");
+
+	x = clamp_val(x, -CLAMP, CLAMP);
+	y = clamp_val(y, -CLAMP, CLAMP);
+	z = clamp_val(z, -CLAMP, CLAMP);
+
+	input_report_abs(ipdev->input, ABS_X, x);
+	input_report_abs(ipdev->input, ABS_Y, y);
+	input_report_abs(ipdev->input, ABS_Z, z);
+	input_sync(ipdev->input);
+}
+
+static int __devinit platform_probe(struct platform_device *pd)
+{
+	int err;
+
+	ipdev = input_allocate_polled_device();
+	if (!ipdev)
+		return -ENOMEM;
+
+	ipdev->poll = pega_accel_poll;
+	ipdev->poll_interval = 100;
+	ipdev->poll_interval_min = 10;
+	ipdev->poll_interval_max = 2000;
+
+	ipdev->input->dev.parent = &pd->dev;
+	ipdev->input->id.bustype = BUS_HOST;
+
+	ipdev->input->name = DRIVER_DESC;
+	ipdev->input->phys = DRIVER_NAME "/input0";
+
+	set_bit(EV_ABS, ipdev->input->evbit);
+	input_set_abs_params(ipdev->input, ABS_X, -CLAMP, CLAMP, 0, 0);
+	input_set_abs_params(ipdev->input, ABS_Y, -CLAMP, CLAMP, 0, 0);
+	input_set_abs_params(ipdev->input, ABS_Z, -CLAMP, CLAMP, 0, 0);
+
+	err = input_register_polled_device(ipdev);
+	if (err)
+		input_free_polled_device(ipdev);
+
+	return err;
+}
+
+static int __devexit platform_remove(struct platform_device *pd)
+{
+	input_unregister_polled_device(ipdev);
+	input_free_polled_device(ipdev);
+	ipdev = NULL;
+	return 0;
+}
+
+static struct platform_driver platform_driver = {
+	.driver = {
+		.owner = THIS_MODULE,
+		.name  = DRIVER_NAME,
+	},
+	.probe  = platform_probe,
+	.remove = __devexit_p(platform_remove),
+};
+
+static int __init mod_init(void)
+{
+	return platform_driver_register(&platform_driver);
+}
+
+static void __exit mod_exit(void)
+{
+	platform_driver_unregister(&platform_driver);
+}
+
+module_init(mod_init);
+module_exit(mod_exit);
+
+MODULE_AUTHOR("Andy Ross <andy.ross@windriver.com>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_ALIAS("dmi:*:bvrLucid-CE-133:*");
-- 
1.7.1