[PATCH v6 1/1] input: ideapad_slidebar: new input driver

diff --git a/MAINTAINERS b/MAINTAINERS
index defc053..2ff3dd8 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS

@@ -4096,6 +4096,13 @@ W:	http://launchpad.net/ideapad-laptop
 S:	Maintained
 F:	drivers/platform/x86/ideapad-laptop.c
 
+IDEAPAD LAPTOP SLIDEBAR DRIVER
+M:	Andrey Moiseev <o2g.org.ru@gmail.com>
+L:	linux-input@vger.kernel.org
+W:	https://github.com/o2genum/ideapad-slidebar
+S:	Maintained
+F:	drivers/input/misc/ideapad_slidebar.c
+
 IDE/ATAPI DRIVERS
 M:	Borislav Petkov <bp@alien8.de>
 L:	linux-ide@vger.kernel.org

diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
index 0b541cd..45729a9 100644
--- a/drivers/input/misc/Kconfig
+++ b/drivers/input/misc/Kconfig

@@ -647,4 +647,13 @@ config INPUT_SIRFSOC_ONKEY
 
 	  If unsure, say N.
 
+config INPUT_IDEAPAD_SLIDEBAR
+	tristate "IdeaPad Laptop Slidebar"
+	depends on INPUT
+	help
+	  Input driver for slidebars on some Lenovo IdeaPad laptops.
+
+	  If you have an IdeaPad laptop with a slidebar, say Y or M here.
+	  Module name is ideapad_slidebar.
+
 endif

diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
index 829de43..0ebfb6d 100644
--- a/drivers/input/misc/Makefile
+++ b/drivers/input/misc/Makefile

@@ -61,3 +61,4 @@ obj-$(CONFIG_INPUT_WISTRON_BTNS)	+= wistron_btns.o
 obj-$(CONFIG_INPUT_WM831X_ON)		+= wm831x-on.o
 obj-$(CONFIG_INPUT_XEN_KBDDEV_FRONTEND)	+= xen-kbdfront.o
 obj-$(CONFIG_INPUT_YEALINK)		+= yealink.o
+obj-$(CONFIG_INPUT_IDEAPAD_SLIDEBAR)	+= ideapad_slidebar.o

diff --git a/drivers/input/misc/ideapad_slidebar.c b/drivers/input/misc/ideapad_slidebar.c
new file mode 100644
index 0000000..5725d88
--- /dev/null
+++ b/drivers/input/misc/ideapad_slidebar.c

@@ -0,0 +1,348 @@
+/*
+ * Input driver for slidebars on some Lenovo IdeaPad laptops
+ *
+ * Copyright (C) 2013 Andrey Moiseev <o2g.org.ru@gmail.com>
+ *
+ * Reverse-engineered from Lenovo SlideNav software (SBarHook.dll).
+ *
+ * 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.
+ *
+ * Trademarks are the property of their respective owners.
+ */
+
+/*
+ * Currently tested and works on:
+ *	Lenovo IdeaPad Y550
+ *	Lenovo IdeaPad Y550P
+ *
+ * Other models can be added easily. To test,
+ * load with 'force' parameter set 'true'.
+ *
+ * LEDs blinking and input mode are managed via sysfs,
+ * (hex, unsigned byte value):
+ * /sys/devices/platform/ideapad_slidebar/input/inputX/slidebar_mode
+ *
+ * The value is in byte range, however, I only figured out
+ * how bits 0b10011001 work. Some other bits, probably,
+ * are meaningfull too.
+ *
+ * Possible states:
+ *
+ * STD_INT, ONMOV_INT, OFF_INT, LAST_POLL, OFF_POLL
+ *
+ * Meaning:
+ *           released      touched
+ * STD       'heartbeat'   lights follow the finger
+ * ONMOV     no lights     lights follow the finger
+ * LAST      at last pos   lights follow the finger
+ * OFF       no lights     no lights
+ *
+ * INT       all input events are generated, interrupts are used
+ * POLL      no input events by default, to get them,
+ *	     send 0b10000000 (read below)
+ *
+ * Commands: write
+ *
+ * All      |  0b01001 -> STD_INT
+ * possible |  0b10001 -> ONMOV_INT
+ * states   |  0b01000 -> OFF_INT
+ *
+ *                      |  0b0 -> LAST_POLL
+ * STD_INT or ONMOV_INT |
+ *                      |  0b1 -> STD_INT
+ *
+ *                      |  0b0 -> OFF_POLL
+ * OFF_INT or OFF_POLL  |
+ *                      |  0b1 -> OFF_INT
+ *
+ * Any state |   0b10000000 ->  if the slidebar has updated data,
+ *				produce one input event (last position),
+ *				switch to respective POLL mode
+ *				(like 0x0), if not in POLL mode yet.
+ *
+ * Get current state: read
+ *
+ * masked by 0x11 read value means:
+ *
+ * 0x00   LAST
+ * 0x01   STD
+ * 0x10   OFF
+ * 0x11   ONMOV
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/dmi.h>
+#include <linux/spinlock.h>
+#include <linux/platform_device.h>
+#include <linux/input.h>
+#include <linux/io.h>
+#include <linux/i8042.h>
+
+static bool force;
+module_param(force, bool, 0);
+MODULE_PARM_DESC(force, "Force driver load, ignore DMI data");
+
+static spinlock_t sio_lock = __SPIN_LOCK_UNLOCKED(sio_lock);
+
+static struct input_dev *slidebar_input_dev;
+static struct platform_device *slidebar_platform_dev;
+
+/* Hardware interacting */
+static unsigned char slidebar_pos_get(void)
+{
+	int res;
+	unsigned long flags;
+
+	spin_lock_irqsave(&sio_lock, flags);
+	outb(0xf4, 0xff29);
+	outb(0xbf, 0xff2a);
+	res = inb(0xff2b);
+	spin_unlock_irqrestore(&sio_lock, flags);
+	return res;
+}
+
+static unsigned char slidebar_mode_get(void)
+{
+	int res;
+	unsigned long flags;
+
+	spin_lock_irqsave(&sio_lock, flags);
+	outb(0xf7, 0xff29);
+	outb(0x8b, 0xff2a);
+	res = inb(0xff2b);
+	spin_unlock_irqrestore(&sio_lock, flags);
+	return res;
+}
+
+static void slidebar_mode_set(unsigned char mode)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&sio_lock, flags);
+	outb(0xf7, 0xff29);
+	outb(0x8b, 0xff2a);
+	outb(mode, 0xff2b);
+	spin_unlock_irqrestore(&sio_lock, flags);
+}
+
+/* Listening the keyboard (i8042 filter) */
+static bool slidebar_i8042_filter(unsigned char data, unsigned char str,
+				struct serio *port)
+{
+	static bool extended = false, touched = false;
+
+	/* Scancodes: e03b on move, e0bb on release */
+	if (unlikely(data == 0xe0)) {
+		extended = true;
+		return false;
+	} else if (unlikely(extended && (data == 0x3b))) {
+		extended = false;
+		if (!touched)
+			input_report_key(slidebar_input_dev, BTN_TOUCH, 1);
+		touched = true;
+		input_report_abs(slidebar_input_dev, ABS_X, slidebar_pos_get());
+		input_sync(slidebar_input_dev);
+		return false;
+	} else if (unlikely(extended && (data == 0xbb))) {
+		touched = false;
+		input_report_key(slidebar_input_dev, BTN_TOUCH, 0);
+		input_sync(slidebar_input_dev);
+	}
+	return false;
+}
+
+/* Sysfs slidebar_mode interface */
+static ssize_t show_slidebar_mode(struct device *dev,
+				struct device_attribute *attr,
+				char *buf)
+{
+	return sprintf(buf, "%x\n", slidebar_mode_get());
+}
+
+static ssize_t store_slidebar_mode(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t count)
+{
+	int mode;
+
+	if (!count)
+		return 0;
+	if (sscanf(buf, "%x", &mode) != 1)
+		return -EINVAL;
+	slidebar_mode_set(mode);
+	return count;
+}
+
+static DEVICE_ATTR(slidebar_mode, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH,
+				show_slidebar_mode, store_slidebar_mode);
+
+static struct attribute *ideapad_attrs[] = {
+	&dev_attr_slidebar_mode.attr,
+	NULL
+};
+
+static struct attribute_group ideapad_attr_group = {
+	.attrs = ideapad_attrs
+};
+
+static const struct attribute_group *ideapad_attr_groups[] = {
+	&ideapad_attr_group,
+	NULL
+};
+
+/* Input device */
+static int __init setup_input_dev(void)
+{
+	int err;
+
+	slidebar_input_dev = input_allocate_device();
+	if (!slidebar_input_dev) {
+		pr_err("ideapad_slidebar: Not enough memory\n");
+		return -ENOMEM;
+	}
+
+	slidebar_input_dev->name = "IdeaPad Slidebar";
+	slidebar_input_dev->id.bustype = BUS_HOST;
+	slidebar_input_dev->dev.parent = &slidebar_platform_dev->dev;
+	slidebar_input_dev->dev.groups = ideapad_attr_groups;
+	input_set_capability(slidebar_input_dev, EV_KEY, BTN_TOUCH);
+	input_set_capability(slidebar_input_dev, EV_ABS, ABS_X);
+	input_set_abs_params(slidebar_input_dev, ABS_X, 0, 0xff, 0, 0);
+
+	err = i8042_install_filter(slidebar_i8042_filter);
+	if (err) {
+		pr_err("ideapad_slidebar: Can't install i8042 filter \n");
+		goto err_free_dev;
+	}
+	err = input_register_device(slidebar_input_dev);
+	if (err) {
+		pr_err("ideapad_slidebar: Failed to register device\n");
+		goto err_remove_filter;
+	}
+	return 0;
+
+err_remove_filter:
+	i8042_remove_filter(slidebar_i8042_filter);
+err_free_dev:
+	input_free_device(slidebar_input_dev);
+	return err;
+}
+
+static void remove_input_dev(void)
+{
+	i8042_remove_filter(slidebar_i8042_filter);
+	input_unregister_device(slidebar_input_dev);
+}
+
+/* Platform device */
+static int __init setup_platform_dev(void)
+{
+	int err;
+	slidebar_platform_dev = platform_device_alloc("ideapad_slidebar", -1);
+	if (!slidebar_platform_dev) {
+		pr_err("ideapad_slidebar: Not enough memory\n");
+		return -ENOMEM;
+	}
+	err = platform_device_add(slidebar_platform_dev);
+	if (err) {
+		pr_err("ideapad_slidebar: Failed to register plarform device\n");
+		goto err_free_platform_device;
+	}
+	return 0;
+
+err_free_platform_device:
+	platform_device_put(slidebar_platform_dev);
+	return err;
+}
+
+/* Platform driver */
+static struct platform_driver slidebar_drv = {
+	.driver = {
+		.name = "ideapad_slidebar",
+		.owner = THIS_MODULE,
+	},
+};
+
+static int __init register_platform_drv(void)
+{
+	int err;
+
+	err = platform_driver_register(&slidebar_drv);
+	if (err)
+		pr_err("ideapad_slidebar: Failed to register platform driver\n");
+
+	return err;
+}
+
+/* DMI */
+static int __init ideapad_dmi_check(const struct dmi_system_id *id)
+{
+	pr_info("ideapad_slidebar: Laptop model '%s'\n", id->ident);
+	return 1;
+}
+
+static const struct dmi_system_id ideapad_dmi[] __initconst = {
+	{
+		.ident = "Lenovo IdeaPad Y550",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "20017"),
+			DMI_MATCH(DMI_PRODUCT_VERSION, "Lenovo IdeaPad Y550")
+		},
+		.callback = ideapad_dmi_check
+	},
+	{
+		.ident = "Lenovo IdeaPad Y550P",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "20035"),
+			DMI_MATCH(DMI_PRODUCT_VERSION, "Lenovo IdeaPad Y550P")
+		},
+		.callback = ideapad_dmi_check
+	},
+	{ NULL, }
+};
+MODULE_DEVICE_TABLE(dmi, ideapad_dmi);
+
+/* Init and cleanup */
+static int __init slidebar_init(void)
+{
+	int err;
+
+	if (!force && !dmi_check_system(ideapad_dmi))
+		return -ENODEV;
+	err = setup_platform_dev();
+	if (err)
+		return err;
+	err = register_platform_drv();
+	if (err)
+		goto err_unregister_platform_dev;
+	err = setup_input_dev();
+	if (err)
+		goto err_unregister_platform_drv;
+	return 0;
+
+err_unregister_platform_drv:
+	platform_driver_unregister(&slidebar_drv);
+err_unregister_platform_dev:
+	platform_device_unregister(slidebar_platform_dev);
+	return err;
+}
+
+static void __exit slidebar_exit(void)
+{
+	remove_input_dev();
+	platform_device_unregister(slidebar_platform_dev);
+	platform_driver_unregister(&slidebar_drv);
+}
+
+module_init(slidebar_init);
+module_exit(slidebar_exit);
+
+MODULE_AUTHOR("Andrey Moiseev <o2g.org.ru@gmail.com>");
+MODULE_DESCRIPTION("Slidebar input support for some Lenovo IdeaPad laptops");
+MODULE_LICENSE("GPL");

-- 
1.8.3.4

---
Quoted Re: to v5:
> Hi Andrey,
> 
> On Mon, Aug 12, 2013 at 02:23:23PM +0400, Andrey Moiseev wrote:
>> v5: __initconst goes after var name
>> 
>> ideapad_slidebar is a new driver which enables slidebars on some
>> Lenovo IdeaPad laptops (the slidebars work with SlideNav/Desktop
>> Navigator under Windows)
>> 
>> Fixes this: https://bugzilla.kernel.org/show_bug.cgi?id=16004
>> 
>> Registers 'IdeaPad Slidebar' input device and
>> /sys/devices/platform/ideapad_slidebar/slidebar_mode
>> for switching slidebar's modes.
>> 
>> Now works on:
>> IdeaPad Y550, Y550P.
>> 
>> May work on (testing and adding new models is needed):
>> Ideapad Y560, Y460, Y450, Y650,
>> and, probably, some others.
>> 
>> Driver source: https://github.com/o2genum/ideapad-slidebar.git
>> 
>> Patch is generated against current mainline kernel.
>> 
>> Signed-off-by: Andrey Moiseev <o2g.org.ru@gmail.com>
>> ---
>>  MAINTAINERS                           |   7 +
>>  drivers/input/misc/Kconfig            |   9 +
>>  drivers/input/misc/Makefile           |   1 +
>>  drivers/input/misc/ideapad_slidebar.c | 380 ++++++++++++++++++++++++++++++++++
>>  4 files changed, 397 insertions(+)
>>  create mode 100644 drivers/input/misc/ideapad_slidebar.c
>> 
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index defc053..2ff3dd8 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -4096,6 +4096,13 @@ W:	http://launchpad.net/ideapad-laptop
>>  S:	Maintained
>>  F:	drivers/platform/x86/ideapad-laptop.c
>>  
>> +IDEAPAD LAPTOP SLIDEBAR DRIVER
>> +M:	Andrey Moiseev <o2g.org.ru@gmail.com>
>> +L:	linux-input@vger.kernel.org
>> +W:	https://github.com/o2genum/ideapad-slidebar
>> +S:	Maintained
>> +F:	drivers/input/misc/ideapad_slidebar.c
>> +
>>  IDE/ATAPI DRIVERS
>>  M:	Borislav Petkov <bp@alien8.de>
>>  L:	linux-ide@vger.kernel.org
>> diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
>> index 0b541cd..45729a9 100644
>> --- a/drivers/input/misc/Kconfig
>> +++ b/drivers/input/misc/Kconfig
>> @@ -647,4 +647,13 @@ config INPUT_SIRFSOC_ONKEY
>>  
>>  	  If unsure, say N.
>>  
>> +config INPUT_IDEAPAD_SLIDEBAR
>> +	tristate "IdeaPad Laptop Slidebar"
>> +	depends on INPUT
>> +	help
>> +	  Input driver for slidebars on some Lenovo IdeaPad laptops.
>> +
>> +	  If you have an IdeaPad laptop with a slidebar, say Y or M here.
>> +	  Module name is ideapad_slidebar.
>> +
>>  endif
>> diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
>> index 829de43..0ebfb6d 100644
>> --- a/drivers/input/misc/Makefile
>> +++ b/drivers/input/misc/Makefile
>> @@ -61,3 +61,4 @@ obj-$(CONFIG_INPUT_WISTRON_BTNS)	+= wistron_btns.o
>>  obj-$(CONFIG_INPUT_WM831X_ON)		+= wm831x-on.o
>>  obj-$(CONFIG_INPUT_XEN_KBDDEV_FRONTEND)	+= xen-kbdfront.o
>>  obj-$(CONFIG_INPUT_YEALINK)		+= yealink.o
>> +obj-$(CONFIG_INPUT_IDEAPAD_SLIDEBAR)	+= ideapad_slidebar.o
>> diff --git a/drivers/input/misc/ideapad_slidebar.c b/drivers/input/misc/ideapad_slidebar.c
>> new file mode 100644
>> index 0000000..df437a4
>> --- /dev/null
>> +++ b/drivers/input/misc/ideapad_slidebar.c
>> @@ -0,0 +1,380 @@
>> +/*
>> + * Input driver for slidebars on some Lenovo IdeaPad laptops
>> + *
>> + * Copyright (C) 2013 Andrey Moiseev <o2g.org.ru@gmail.com>
>> + *
>> + * Reverse-engineered from Lenovo SlideNav software (SBarHook.dll).
>> + *
>> + * 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.
>> + *
>> + * Trademarks are the property of their respective owners.
>> + */
>> +
>> +/*
>> + * Currently tested and works on:
>> + *	Lenovo IdeaPad Y550
>> + *	Lenovo IdeaPad Y550P
>> + *
>> + * Other models can be added easily. To test,
>> + * load with 'force' parameter set 'true'.
>> + *
>> + * LEDs blinking and input mode are managed via sysfs,
>> + * (hex, unsigned byte value):
>> + * /sys/devices/platform/ideapad_slidebar/slidebar_mode
>> + *
>> + * The value is in byte range, however, I only figured out
>> + * how bits 0b10011001 work. Some other bits, probably,
>> + * are meaningfull too.
>> + *
>> + * Possible states:
>> + *
>> + * STD_INT, ONMOV_INT, OFF_INT, LAST_POLL, OFF_POLL
>> + *
>> + * Meaning:
>> + *           released      touched
>> + * STD       'heartbeat'   lights follow the finger
>> + * ONMOV     no lights     lights follow the finger
>> + * LAST      at last pos   lights follow the finger
>> + * OFF       no lights     no lights
>> + *
>> + * INT       all input events are generated, interrupts are used
>> + * POLL      no input events by default, to get them,
>> + *	     send 0b10000000 (read below)
>> + *
>> + * Commands: write
>> + *
>> + * All      |  0b01001 -> STD_INT
>> + * possible |  0b10001 -> ONMOV_INT
>> + * states   |  0b01000 -> OFF_INT
>> + *
>> + *                      |  0b0 -> LAST_POLL
>> + * STD_INT or ONMOV_INT |
>> + *                      |  0b1 -> STD_INT
>> + *
>> + *                      |  0b0 -> OFF_POLL
>> + * OFF_INT or OFF_POLL  |
>> + *                      |  0b1 -> OFF_INT
>> + *
>> + * Any state |   0b10000000 ->  if the slidebar has updated data,
>> + *				produce one input event (last position),
>> + *				switch to respective POLL mode
>> + *				(like 0x0), if not in POLL mode yet.
>> + *
>> + * Get current state: read
>> + *
>> + * masked by 0x11 read value means:
>> + *
>> + * 0x00   LAST
>> + * 0x01   STD
>> + * 0x10   OFF
>> + * 0x11   ONMOV
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <linux/kernel.h>
>> +#include <linux/dmi.h>
>> +#include <linux/spinlock.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/input.h>
>> +#include <linux/io.h>
>> +#include <linux/i8042.h>
>> +
>> +static bool force;
>> +module_param(force, bool, 0);
>> +MODULE_PARM_DESC(force, "Force driver load, ignore DMI data");
>> +
>> +static spinlock_t sio_lock = __SPIN_LOCK_UNLOCKED(sio_lock);
>> +
>> +static struct input_dev *slidebar_input_dev;
>> +static struct platform_device *slidebar_platform_dev;
>> +
>> +/* Hardware interacting */
>> +static int slidebar_pos_get(void)
>> +{
>> +	int res;
>> +	unsigned long flags;
> 
> A blank line between variables and code is appreciated.
> 
>> +	spin_lock_irqsave(&sio_lock, flags);
>> +	outb(0xf4, 0xff29);
>> +	outb(0xbf, 0xff2a);
>> +	res = inb(0xff2b);
>> +	spin_unlock_irqrestore(&sio_lock, flags);
>> +	return res;
>> +}
>> +
>> +static unsigned char slidebar_mode_get(void)
>> +{
>> +	int res;
>> +	unsigned long flags;
>> +	spin_lock_irqsave(&sio_lock, flags);
>> +	outb(0xf7, 0xff29);
>> +	outb(0x8b, 0xff2a);
>> +	res = inb(0xff2b);
>> +	spin_unlock_irqrestore(&sio_lock, flags);
>> +	return res;
>> +}
>> +
>> +static void slidebar_mode_set(unsigned char mode)
>> +{
>> +	unsigned long flags;
>> +	spin_lock_irqsave(&sio_lock, flags);
>> +	outb(0xf7, 0xff29);
>> +	outb(0x8b, 0xff2a);
>> +	outb(mode, 0xff2b);
>> +	spin_unlock_irqrestore(&sio_lock, flags);
>> +}
>> +
>> +/* Listening the keyboard (i8042 filter) */
>> +static bool slidebar_i8042_filter(unsigned char data, unsigned char str,
>> +				struct serio *port)
>> +{
>> +	static bool extended = false, touched = false;
>> +
>> +	/* Scancodes: e03b on move, e0bb on release */
>> +	if (unlikely(data == 0xe0)) {
>> +		extended = true;
>> +		return false;
>> +	} else if (unlikely(extended && (data == 0x3b))) {
>> +		extended = false;
>> +		if (!touched)
>> +			input_report_key(slidebar_input_dev, BTN_TOUCH, 1);
>> +		touched = true;
>> +		input_report_abs(slidebar_input_dev, ABS_X, slidebar_pos_get());
>> +		input_sync(slidebar_input_dev);
>> +		return false;
>> +	} else if (unlikely(extended && (data == 0xbb))) {
>> +		touched = false;
>> +		input_report_key(slidebar_input_dev, BTN_TOUCH, 0);
>> +		input_sync(slidebar_input_dev);
>> +	}
>> +
>> +	return false;
>> +}
>> +
>> +/* Input device */
>> +static int setup_input_dev(void)
>> +{
>> +	int err;
>> +
>> +	slidebar_input_dev = input_allocate_device();
>> +	if (!slidebar_input_dev) {
>> +		pr_err("ideapad_slidebar: Not enough memory\n");
>> +		return -ENOMEM;
>> +	}
>> +
>> +	slidebar_input_dev->name = "IdeaPad Slidebar";
>> +	slidebar_input_dev->id.bustype = BUS_HOST;
>> +	slidebar_input_dev->dev.parent = &slidebar_platform_dev->dev;
>> +	input_set_capability(slidebar_input_dev, EV_KEY, BTN_TOUCH);
>> +	input_set_capability(slidebar_input_dev, EV_ABS, ABS_X);
>> +	input_alloc_absinfo(slidebar_input_dev);
> 
> This call is not needed, it will be done for you.
> 
>> +	input_set_abs_params(slidebar_input_dev, ABS_X, 0, 0xff, 0, 0);
>> +
>> +	err = input_register_device(slidebar_input_dev);
>> +	if (err) {
>> +		pr_err("ideapad_slidebar: Failed to register device\n");
>> +		goto err_free_dev;
>> +	}
>> +
>> +	err = i8042_install_filter(slidebar_i8042_filter);
>> +	if (err) {
>> +		pr_err("ideapad_slidebar: Can't install i8042 filter \n");
>> +		goto err_unregister_dev;
>> +	}
>> +	return 0;
>> +
>> +err_unregister_dev:
>> +	input_unregister_device(slidebar_input_dev);
>> +err_free_dev:
>> +	input_free_device(slidebar_input_dev);
> 
> No free after unregister for input devices. Consider swapping
> registering device and installing the filter (allocated but not
> registered input device can take events emitted by the filter just
> fine).
> 
>> +	return err;
>> +}
>> +
>> +static void remove_input_dev(void)
>> +{
>> +	i8042_remove_filter(slidebar_i8042_filter);
>> +	input_unregister_device(slidebar_input_dev);
>> +	input_free_device(slidebar_input_dev);
> 
> No free after unregister for input devices.
> 
>> +}
>> +
>> +/* Sysfs slidebar_mode interface */
>> +static ssize_t show_slidebar_mode(struct device *dev,
>> +				struct device_attribute *attr,
>> +				char *buf)
>> +{
>> +	return sprintf(buf, "%x\n", slidebar_mode_get());
>> +}
>> +
>> +static ssize_t store_slidebar_mode(struct device *dev,
>> +				struct device_attribute *attr,
>> +				const char *buf, size_t count)
>> +{
>> +	int mode;
>> +	if (!count)
>> +		return 0;
>> +
>> +	if (sscanf(buf, "%x", &mode) != 1)
>> +		return -EINVAL;
>> +
>> +	slidebar_mode_set(mode);
>> +	return count;
>> +}
>> +
>> +static DEVICE_ATTR(slidebar_mode, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH,
>> +				show_slidebar_mode, store_slidebar_mode);
>> +
>> +static struct attribute *ideapad_attributes[] = {
>> +	&dev_attr_slidebar_mode.attr,
>> +	NULL
>> +};
>> +
>> +static struct attribute_group ideapad_attribute_group = {
>> +	.attrs = ideapad_attributes
>> +};
>> +
>> +static int setup_slidebar_mode_dev(void)
>> +{
>> +	return sysfs_create_group(&slidebar_platform_dev->dev.kobj,
>> +				  &ideapad_attribute_group);
> 
> To avoid races between creating device and attributes you want to simply
> assign your group to the devices group pointer and then it will be
> created for you by device core.
> 
>> +}
>> +
>> +static void remove_slidebar_mode_dev(void)
>> +{
>> +	return sysfs_remove_group(&slidebar_platform_dev->dev.kobj,
>> +				  &ideapad_attribute_group);
>> +}
>> +
>> +/* Platform device */
>> +static int setup_platform_dev(void)
>> +{
>> +	int err;
>> +	slidebar_platform_dev = platform_device_alloc("ideapad_slidebar", -1);
>> +	if (!slidebar_platform_dev) {
>> +		pr_err("ideapad_slidebar: Not enough memory\n");
>> +		return -ENOMEM;
>> +	}
>> +
>> +	err = platform_device_add(slidebar_platform_dev);
>> +	if (err) {
>> +		pr_err("ideapad_slidebar: Failed to register plarform device\n");
>> +		goto err_free_platform_device;
>> +	}
>> +	return 0;
>> +
>> +err_free_platform_device:
>> +	platform_device_put(slidebar_platform_dev);
>> +	return err;
>> +}
>> +
>> +static void remove_platform_dev(void)
>> +{
>> +	platform_device_del(slidebar_platform_dev);
>> +	platform_device_put(slidebar_platform_dev);
> 
> I do nto understand why you need all these wrappers when you can simply
> call platform_device_unregister().
> 
>> +}
>> +
>> +/* Platform driver */
>> +static struct platform_driver slidebar_drv = {
>> +	.driver = {
>> +		.name = "ideapad_slidebar",
>> +		.owner = THIS_MODULE,
>> +	},
>> +};
>> +
>> +static int register_platform_drv(void)
>> +{
>> +	int err;
>> +	err = platform_driver_register(&slidebar_drv);
>> +	if (err)
>> +		pr_err("ideapad_slidebar: Failed to register platform driver\n");
>> +
>> +	return err;
>> +}
>> +
>> +static void unregister_platform_drv(void)
>> +{
>> +	platform_driver_unregister(&slidebar_drv);
>> +}
>> +
>> +/* DMI */
>> +static int ideapad_dmi_check(const struct dmi_system_id *id)
>> +{
>> +	pr_info("ideapad_slidebar: Laptop model '%s'\n", id->ident);
>> +	return 1;
>> +}
>> +
>> +static struct dmi_system_id ideapad_dmi_table[] __initconst = {
>> +	{
>> +		.ident = "Lenovo IdeaPad Y550",
>> +		.matches = {
>> +			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
>> +			DMI_MATCH(DMI_PRODUCT_NAME, "20017"),
>> +			DMI_MATCH(DMI_PRODUCT_VERSION, "Lenovo IdeaPad Y550")
>> +		},
>> +		.callback = ideapad_dmi_check
>> +	},
>> +	{
>> +		.ident = "Lenovo IdeaPad Y550P",
>> +		.matches = {
>> +			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
>> +			DMI_MATCH(DMI_PRODUCT_NAME, "20035"),
>> +			DMI_MATCH(DMI_PRODUCT_VERSION, "Lenovo IdeaPad Y550P")
>> +		},
>> +		.callback = ideapad_dmi_check
>> +	},
>> +	{ }
>> +};
>> +
>> +/* Init and cleanup */
>> +static int __init slidebar_init(void)
>> +{
>> +	int err;
>> +
>> +	if (!force && !dmi_check_system(ideapad_dmi_table))
>> +		return -ENODEV;
>> +
>> +	err = setup_platform_dev();
>> +	if (err)
>> +		return err;
>> +
>> +	err = register_platform_drv();
>> +	if (err)
>> +		goto err_remove_platform_dev;
>> +
>> +	err = setup_input_dev();
>> +	if (err)
>> +		goto err_unregister_platform_drv;
>> +	
>> +	err = setup_slidebar_mode_dev();
>> +	if (err)
>> +		goto err_remove_input_dev;
>> +	return 0;
>> +
>> +err_remove_input_dev:
>> +	remove_input_dev();
>> +err_unregister_platform_drv:
>> +	unregister_platform_drv();
>> +err_remove_platform_dev:
>> +	remove_platform_dev();
>> +	return err;
>> +}
>> +
>> +static void __exit slidebar_exit(void)
>> +{
>> +	remove_slidebar_mode_dev();
>> +	remove_input_dev();
>> +	remove_platform_dev();
>> +	unregister_platform_drv();
>> +}
>> +
>> +module_init(slidebar_init);
>> +module_exit(slidebar_exit);
>> +
>> +MODULE_AUTHOR("Andrey Moiseev <o2g.org.ru@gmail.com>");
>> +MODULE_DESCRIPTION("Slidebar input support for some Lenovo IdeaPad laptops");
>> +MODULE_LICENSE("GPL");
>> +MODULE_VERSION("0.1");
>> +
>> +MODULE_ALIAS("dmi:*:svnLENOVO:pn20017:pvrLenovoIdeaPadY550:*");
>> +MODULE_ALIAS("dmi:*:svnLENOVO:pn20035:pvrLenovoIdeaPadY550P:*");
> 
> Why not create MODULE_DEVICE_TABLE from dmi table instead of doing it by
> hand?
> 
> Thanks.
> 
> -- 
> Dmitry