backlight: Add support for the Avionic Design Xanthos backlight device.

This patch adds support for the backlight device found on Avionic Design
Xanthos-based boards.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

drivers/video/backlight/Kconfig

@@ -243,3 +243,11 @@ config BACKLIGHT_WM831X
 	help
 	  If you have a backlight driven by the ISINK and DCDC of a
 	  WM831x PMIC say y to enable the backlight driver for it.
+
+config BACKLIGHT_ADX
+	tristate "Avionic Design Xanthos Backlight Driver"
+	depends on BACKLIGHT_CLASS_DEVICE && ARCH_PXA_ADX
+	default y
+	help
+	  Say Y to enable the backlight driver on Avionic Design Xanthos-based
+	  boards.

drivers/video/backlight/Makefile

@@ -26,4 +26,4 @@ obj-$(CONFIG_BACKLIGHT_MBP_NVIDIA) += mbp_nvidia_bl.o
 obj-$(CONFIG_BACKLIGHT_TOSA)	+= tosa_bl.o
 obj-$(CONFIG_BACKLIGHT_SAHARA)	+= kb3886_bl.o
 obj-$(CONFIG_BACKLIGHT_WM831X)	+= wm831x_bl.o
-
+obj-$(CONFIG_BACKLIGHT_ADX)    += adx_bl.o

drivers/video/backlight/adx_bl.c

@@ -0,0 +1,178 @@
+/*
+ * linux/drivers/video/backlight/adx.c
+ *
+ * Copyright (C) 2009 Avionic Design GmbH
+ *
+ * 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.
+ *
+ * Written by Thierry Reding <thierry.reding@avionic-design.de>
+ */
+
+#include <linux/backlight.h>
+#include <linux/fb.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+/* register definitions */
+#define ADX_BACKLIGHT_CONTROL		0x00
+#define ADX_BACKLIGHT_CONTROL_ENABLE	(1 << 0)
+#define ADX_BACKLIGHT_BRIGHTNESS	0x08
+#define ADX_BACKLIGHT_STATUS		0x10
+#define ADX_BACKLIGHT_ERROR		0x18
+
+struct adxbl {
+	void __iomem *base;
+};
+
+static int adx_backlight_update_status(struct backlight_device *bldev)
+{
+	struct adxbl *bl = bl_get_data(bldev);
+	u32 value;
+
+	value = bldev->props.brightness;
+	writel(value, bl->base + ADX_BACKLIGHT_BRIGHTNESS);
+
+	value = readl(bl->base + ADX_BACKLIGHT_CONTROL);
+
+	if (bldev->props.state & BL_CORE_FBBLANK)
+		value &= ~ADX_BACKLIGHT_CONTROL_ENABLE;
+	else
+		value |= ADX_BACKLIGHT_CONTROL_ENABLE;
+
+	writel(value, bl->base + ADX_BACKLIGHT_CONTROL);
+
+	return 0;
+}
+
+static int adx_backlight_get_brightness(struct backlight_device *bldev)
+{
+	struct adxbl *bl = bl_get_data(bldev);
+	u32 brightness;
+
+	brightness = readl(bl->base + ADX_BACKLIGHT_BRIGHTNESS);
+	return brightness & 0xff;
+}
+
+static int adx_backlight_check_fb(struct fb_info *fb)
+{
+	return 1;
+}
+
+static struct backlight_ops adx_backlight_ops = {
+	.options = 0,
+	.update_status = adx_backlight_update_status,
+	.get_brightness = adx_backlight_get_brightness,
+	.check_fb = adx_backlight_check_fb,
+};
+
+static int __devinit adx_backlight_probe(struct platform_device *pdev)
+{
+	struct backlight_device *bldev;
+	struct resource *res;
+	struct adxbl *bl;
+	int ret = 0;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		ret = -ENXIO;
+		goto out;
+	}
+
+	res = devm_request_mem_region(&pdev->dev, res->start,
+			resource_size(res), res->name);
+	if (!res) {
+		ret = -ENXIO;
+		goto out;
+	}
+
+	bl = devm_kzalloc(&pdev->dev, sizeof(*bl), GFP_KERNEL);
+	if (!bl) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	bl->base = devm_ioremap_nocache(&pdev->dev, res->start,
+			resource_size(res));
+	if (!bl->base) {
+		ret = -ENXIO;
+		goto out;
+	}
+
+	bldev = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, bl,
+			&adx_backlight_ops);
+	if (!bldev) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	bldev->props.max_brightness = 0xff;
+	bldev->props.brightness = 0xff;
+	bldev->props.power = FB_BLANK_UNBLANK;
+
+	platform_set_drvdata(pdev, bldev);
+
+out:
+	return ret;
+}
+
+static int __devexit adx_backlight_remove(struct platform_device *pdev)
+{
+	struct backlight_device *bldev;
+	int ret = 0;
+
+	bldev = platform_get_drvdata(pdev);
+	bldev->props.power = FB_BLANK_UNBLANK;
+	bldev->props.brightness = 0xff;
+	backlight_update_status(bldev);
+	backlight_device_unregister(bldev);
+	platform_set_drvdata(pdev, NULL);
+
+	return ret;
+}
+
+#ifdef CONFIG_PM
+static int adx_backlight_suspend(struct platform_device *pdev,
+		pm_message_t state)
+{
+	return 0;
+}
+
+static int adx_backlight_resume(struct platform_device *pdev)
+{
+	return 0;
+}
+#else
+#define adx_backlight_suspend NULL
+#define adx_backlight_resume NULL
+#endif
+
+static struct platform_driver adx_backlight_driver = {
+	.probe = adx_backlight_probe,
+	.remove = __devexit_p(adx_backlight_remove),
+	.suspend = adx_backlight_suspend,
+	.resume = adx_backlight_resume,
+	.driver = {
+		.name = "adx-backlight",
+		.owner = THIS_MODULE,
+	},
+};
+
+static int __init adx_backlight_init(void)
+{
+	return platform_driver_register(&adx_backlight_driver);
+}
+
+static void __exit adx_backlight_exit(void)
+{
+	platform_driver_unregister(&adx_backlight_driver);
+}
+
+module_init(adx_backlight_init);
+module_exit(adx_backlight_exit);
+
+MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
+MODULE_DESCRIPTION("Avionic Design Xanthos Backlight Driver");
+MODULE_LICENSE("GPL v2");