[PATCH] Added backlight driver for Acer Aspire 4736

[Pradeep Subrahmanion]

Added backlight driver for Acer Aspire 4736

Signed-off-by: Pradeep Subrahmanion <subrahmanion.pradeep@xxxxxxxxx>
---
 drivers/video/backlight/acer4736_bl.c |  110 +++++++++++++++++++++++++++++++++
 1 files changed, 110 insertions(+), 0 deletions(-)
 create mode 100644 drivers/video/backlight/acer4736_bl.c

diff --git a/drivers/video/backlight/acer4736_bl.c b/drivers/video/backlight/acer4736_bl.c
new file mode 100644
index 0000000..6fe2937
--- /dev/null
+++ b/drivers/video/backlight/acer4736_bl.c
@@ -0,0 +1,110 @@
+/*
+ * Backlight driver for Acer Aspire 4736
+ *
+ * Copyright (C) Pradeep Subrahmanion <subrahmanion.pradeep@xxxxxxxxx>
+ *
+ * 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.
+ *
+ * This driver uses LBB PCI configuration register to change the
+ * backlight brightness.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/backlight.h>
+#include <linux/err.h>
+#include <linux/dmi.h>
+#include <linux/io.h>
+#include <linux/pci.h>
+
+static u8 max_brightness = 0xFF;
+static u8 lbb_offset =  0xF4;
+static unsigned int device_id = 0x2a42;
+static unsigned int vendor_id = 0x8086;
+
+struct backlight_device *acer_backlight_device;
+struct pci_dev *pdev;
+
+static int acer_dmi_match(const struct dmi_system_id *id)
+{
+	printk(KERN_INFO "acer4736_bl: %s detected\n", id->ident);
+	return 1;
+}
+
+static const struct dmi_system_id __initdata acer_device_table[] = {
+{
+		.callback	= acer_dmi_match,
+		.ident		= "Aspire 4736",
+		.matches	= {
+			DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 4736"),
+		},
+	},
+	{}
+};
+static int read_brightness(struct backlight_device *bd)
+{
+	u8 result;
+	pci_read_config_byte(pdev, lbb_offset, &result);
+	return result;
+}
+
+static int update_brightness(struct backlight_device *bd)
+{
+	u8 intensity = bd->props.brightness;
+	if (intensity > max_brightness) {
+		printk(KERN_INFO "Acer4736_bl: Invalid parameter. Maximum value is %d"
+		, max_brightness);
+		return -1;
+	}
+	pci_write_config_byte(pdev, lbb_offset, intensity);
+	return 0;
+}
+static const struct  backlight_ops acer_backlight_ops = {
+	.get_brightness = read_brightness,
+	.update_status  = update_brightness,
+};
+
+static int __init acer4736_bl_init(void)
+{
+	struct backlight_properties props;
+	if (!dmi_check_system(acer_device_table))
+		return -ENODEV;
+
+	pdev = pci_get_device(vendor_id, device_id, NULL);
+
+	if (!pdev)
+		return -ENODEV;
+
+	printk(KERN_INFO "Loading Acer 4736 backlight driver\n");
+	memset(&props, 0, sizeof(struct backlight_properties));
+	props.type = BACKLIGHT_RAW;
+	props.max_brightness = max_brightness;
+
+	acer_backlight_device = backlight_device_register("acer_backlight",
+		NULL, NULL, &acer_backlight_ops, &props);
+	acer_backlight_device->props.max_brightness = max_brightness;
+	acer_backlight_device->props.brightness  =
+		read_brightness(acer_backlight_device);
+	backlight_update_status(acer_backlight_device);
+
+	return 0;
+}
+
+static void __exit acer4736_bl_exit(void)
+{
+	pci_dev_put(pdev);
+	backlight_device_unregister(acer_backlight_device);
+}
+
+module_init(acer4736_bl_init);
+module_exit(acer4736_bl_exit);
+
+MODULE_AUTHOR("Pradeep Subrahmanion <subrahmanion.pradeep@xxxxxxxxx>");
+MODULE_DESCRIPTION("Acer Aspire 4736 Backlight Driver");
+MODULE_LICENSE("GPL");
+MODULE_DEVICE_TABLE(dmi, acer_device_table);
-- 
1.7.2.5



------

Thanks , 

Pradeep Subrahmanion


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