Re: [PATCH v2] Platform: Samsung Q10 backlight driver

[Frederick van der Wyck <fvanderwyck@gmail.com>]

Hi Dmitry,

Thanks for the further comments.

> If it is a bool the call it so.

Fixed.

> Hmm, if samsungq10_bl_set_intensity() can indeed run simultaneously with
> suspend/resume then you'd need to protect it with spinlock or mutex.

I guess it's OK to assume samsungq10_bl_set_intensity() will not be called
during suspend/resume so I've removed the check.

> Don't you need to restore backlight when resuming from hibernate? I
> think you need to guard you methods with CONFIG_PM_SLEEP and then
> use SIMPLE_DEV_PM_OPS().

You're right, thanks, I've made the change.

> Samsung is way too generic for driver name, maybe call it
> KBUILD_MODNAME?

I changed it from "samsung-q10" to "samsung" in reponse to Greg's feedback, 
but OK, I've made it KBUILD_MODNAME as you suggest.

Here's a new version of the patch.

Thanks,
Frederick

Signed-off-by: Frederick van der Wyck <fvanderwyck@gmail.com>
---
 drivers/platform/x86/Kconfig       |    7 ++
 drivers/platform/x86/Makefile      |    1 +
 drivers/platform/x86/samsung-q10.c |  179 ++++++++++++++++++++++++++++++++++++
 3 files changed, 187 insertions(+), 0 deletions(-)
 create mode 100644 drivers/platform/x86/samsung-q10.c

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index faec777..c390727 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -639,4 +639,11 @@ config XO1_RFKILL
 	  Support for enabling/disabling the WLAN interface on the OLPC XO-1
 	  laptop.
 
+config SAMSUNG_Q10
+	tristate "Samsung Q10 Extras"
+	select BACKLIGHT_CLASS_DEVICE
+	---help---
+          This driver provides support for backlight control on Samsung Q10
+          and some other laptops, including Dell Latitude X200.
+
 endif # X86_PLATFORM_DEVICES
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index 9950ccc..2cd3e52 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -33,3 +33,4 @@ obj-$(CONFIG_INTEL_IPS)		+= intel_ips.o
 obj-$(CONFIG_GPIO_INTEL_PMIC)	+= intel_pmic_gpio.o
 obj-$(CONFIG_XO1_RFKILL)	+= xo1-rfkill.o
 obj-$(CONFIG_IBM_RTL)		+= ibm_rtl.o
+obj-$(CONFIG_SAMSUNG_Q10)	+= samsung-q10.o
diff --git a/drivers/platform/x86/samsung-q10.c b/drivers/platform/x86/samsung-q10.c
new file mode 100644
index 0000000..7b60c67
--- /dev/null
+++ b/drivers/platform/x86/samsung-q10.c
@@ -0,1 +1,179 @@
+/*
+ *  Driver for Samsung Q10: controls the backlight
+ *
+ *  Copyright (c) 2011 Frederick van der Wyck <fvanderwyck@gmail.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 as
+ *  published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/backlight.h>
+#include <linux/i8042.h>
+#include <linux/dmi.h>
+
+#define SAMSUNGQ10_BL_MAX_INTENSITY      255
+#define SAMSUNGQ10_BL_DEFAULT_INTENSITY  185
+
+#define SAMSUNGQ10_BL_8042_CMD           0xbe
+#define SAMSUNGQ10_BL_8042_DATA          { 0x89, 0x91 }
+
+static int samsungq10_bl_brightness;
+
+static bool force;
+module_param(force, bool, 0);
+MODULE_PARM_DESC(force,
+		"Disable the DMI check and force the driver to be loaded");
+
+static int samsungq10_bl_set_intensity(struct backlight_device *bd)
+{
+
+	int brightness = bd->props.brightness;
+	unsigned char c[3] = SAMSUNGQ10_BL_8042_DATA;
+
+	c[2] = (unsigned char)brightness;
+	i8042_lock_chip();
+	i8042_command(c, (0x30 << 8) | SAMSUNGQ10_BL_8042_CMD);
+	i8042_unlock_chip();
+	samsungq10_bl_brightness = brightness;
+
+	return 0;
+}
+
+static int samsungq10_bl_get_intensity(struct backlight_device *bd)
+{
+	return samsungq10_bl_brightness;
+}
+
+static const struct backlight_ops samsungq10_bl_ops = {
+	.get_brightness = samsungq10_bl_get_intensity,
+	.update_status	= samsungq10_bl_set_intensity,
+};
+
+#ifdef CONFIG_PM_SLEEP
+static int samsungq10_suspend(struct device *dev)
+{
+	return 0;
+}
+
+static int samsungq10_resume(struct device *dev)
+{
+
+	struct backlight_device *bd = dev_get_drvdata(dev);
+
+	samsungq10_bl_set_intensity(bd);
+	return 0;
+}
+#else
+#define samsungq10_suspend NULL
+#define samsungq10_resume  NULL
+#endif
+
+static SIMPLE_DEV_PM_OPS(samsungq10_pm_ops,
+			  samsungq10_suspend, samsungq10_resume);
+
+static int __devinit samsungq10_probe(struct platform_device *pdev)
+{
+
+	struct backlight_properties props;
+	struct backlight_device *bd;
+
+	memset(&props, 0, sizeof(struct backlight_properties));
+	props.max_brightness = SAMSUNGQ10_BL_MAX_INTENSITY;
+	bd = backlight_device_register("samsung", &pdev->dev, NULL,
+				       &samsungq10_bl_ops, &props);
+	if (IS_ERR(bd))
+		return PTR_ERR(bd);
+
+	platform_set_drvdata(pdev, bd);
+
+	bd->props.brightness = SAMSUNGQ10_BL_DEFAULT_INTENSITY;
+	samsungq10_bl_set_intensity(bd);
+
+	return 0;
+}
+
+static int __devexit samsungq10_remove(struct platform_device *pdev)
+{
+
+	struct backlight_device *bd = platform_get_drvdata(pdev);
+
+	bd->props.brightness = SAMSUNGQ10_BL_DEFAULT_INTENSITY;
+	samsungq10_bl_set_intensity(bd);
+
+	backlight_device_unregister(bd);
+
+	return 0;
+}
+
+static struct platform_driver samsungq10_driver = {
+	.driver		= {
+		.name	= KBUILD_MODNAME,
+		.owner	= THIS_MODULE,
+		.pm	= &samsungq10_pm_ops,
+	},
+	.probe		= samsungq10_probe,
+	.remove		= __devexit_p(samsungq10_remove),
+};
+
+static struct platform_device *samsungq10_device;
+
+static int __init dmi_check_callback(const struct dmi_system_id *id)
+{
+	printk(KERN_INFO KBUILD_MODNAME ": found model '%s'\n", id->ident);
+	return 0;
+}
+
+static struct dmi_system_id __initdata samsungq10_dmi_table[] = {
+	{
+		.ident = "Samsung Q10",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Samsung"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "SQ10"),
+		},
+		.callback = dmi_check_callback,
+	},
+	{
+		.ident = "Dell Latitude X200",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "X200"),
+		},
+		.callback = dmi_check_callback,
+	},
+	{ },
+};
+MODULE_DEVICE_TABLE(dmi, samsungq10_dmi_table);
+
+static int __init samsungq10_init(void)
+{
+	if (!force && !dmi_check_system(samsungq10_dmi_table))
+		return -ENODEV;
+
+	samsungq10_device = platform_create_bundle(&samsungq10_driver,
+						   samsungq10_probe,
+						   NULL, 0, NULL, 0);
+
+	if (IS_ERR(samsungq10_device))
+		return PTR_ERR(samsungq10_device);
+
+	return 0;
+}
+
+static void __exit samsungq10_exit(void)
+{
+	platform_device_unregister(samsungq10_device);
+	platform_driver_unregister(&samsungq10_driver);
+}
+
+module_init(samsungq10_init);
+module_exit(samsungq10_exit);
+
+MODULE_AUTHOR("Frederick van der Wyck <fvanderwyck@gmail.com>");
+MODULE_DESCRIPTION("Samsung Q10 Driver");
+MODULE_LICENSE("GPL");
--