Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / drivers / video / backlight / ep93xx_bl.c

diff --git a/kernel/drivers/video/backlight/ep93xx_bl.c b/kernel/drivers/video/backlight/ep93xx_bl.c
new file mode 100644 (file)
index 0000000..0067931
--- /dev/null
+++ b/kernel/drivers/video/backlight/ep93xx_bl.c
@@ -0,0 +1,141 @@
+/*
+ * Driver for the Cirrus EP93xx lcd backlight
+ *
+ * Copyright (c) 2010 H Hartley Sweeten <hsweeten@visionengravers.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.
+ *
+ * This driver controls the pulse width modulated brightness control output,
+ * BRIGHT, on the Cirrus EP9307, EP9312, and EP9315 processors.
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/fb.h>
+#include <linux/backlight.h>
+
+#define EP93XX_MAX_COUNT               255
+#define EP93XX_MAX_BRIGHT              255
+#define EP93XX_DEF_BRIGHT              128
+
+struct ep93xxbl {
+       void __iomem *mmio;
+       int brightness;
+};
+
+static int ep93xxbl_set(struct backlight_device *bl, int brightness)
+{
+       struct ep93xxbl *ep93xxbl = bl_get_data(bl);
+
+       writel((brightness << 8) | EP93XX_MAX_COUNT, ep93xxbl->mmio);
+
+       ep93xxbl->brightness = brightness;
+
+       return 0;
+}
+
+static int ep93xxbl_update_status(struct backlight_device *bl)
+{
+       int brightness = bl->props.brightness;
+
+       if (bl->props.power != FB_BLANK_UNBLANK ||
+           bl->props.fb_blank != FB_BLANK_UNBLANK)
+               brightness = 0;
+
+       return ep93xxbl_set(bl, brightness);
+}
+
+static int ep93xxbl_get_brightness(struct backlight_device *bl)
+{
+       struct ep93xxbl *ep93xxbl = bl_get_data(bl);
+
+       return ep93xxbl->brightness;
+}
+
+static const struct backlight_ops ep93xxbl_ops = {
+       .update_status  = ep93xxbl_update_status,
+       .get_brightness = ep93xxbl_get_brightness,
+};
+
+static int ep93xxbl_probe(struct platform_device *dev)
+{
+       struct ep93xxbl *ep93xxbl;
+       struct backlight_device *bl;
+       struct backlight_properties props;
+       struct resource *res;
+
+       ep93xxbl = devm_kzalloc(&dev->dev, sizeof(*ep93xxbl), GFP_KERNEL);
+       if (!ep93xxbl)
+               return -ENOMEM;
+
+       res = platform_get_resource(dev, IORESOURCE_MEM, 0);
+       if (!res)
+               return -ENXIO;
+
+       /*
+        * FIXME - We don't do a request_mem_region here because we are
+        * sharing the register space with the framebuffer driver (see
+        * drivers/video/ep93xx-fb.c) and doing so will cause the second
+        * loaded driver to return -EBUSY.
+        *
+        * NOTE: No locking is required; the framebuffer does not touch
+        * this register.
+        */
+       ep93xxbl->mmio = devm_ioremap(&dev->dev, res->start,
+                                     resource_size(res));
+       if (!ep93xxbl->mmio)
+               return -ENXIO;
+
+       memset(&props, 0, sizeof(struct backlight_properties));
+       props.type = BACKLIGHT_RAW;
+       props.max_brightness = EP93XX_MAX_BRIGHT;
+       bl = devm_backlight_device_register(&dev->dev, dev->name, &dev->dev,
+                                       ep93xxbl, &ep93xxbl_ops, &props);
+       if (IS_ERR(bl))
+               return PTR_ERR(bl);
+
+       bl->props.brightness = EP93XX_DEF_BRIGHT;
+
+       platform_set_drvdata(dev, bl);
+
+       ep93xxbl_update_status(bl);
+
+       return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int ep93xxbl_suspend(struct device *dev)
+{
+       struct backlight_device *bl = dev_get_drvdata(dev);
+
+       return ep93xxbl_set(bl, 0);
+}
+
+static int ep93xxbl_resume(struct device *dev)
+{
+       struct backlight_device *bl = dev_get_drvdata(dev);
+
+       backlight_update_status(bl);
+       return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(ep93xxbl_pm_ops, ep93xxbl_suspend, ep93xxbl_resume);
+
+static struct platform_driver ep93xxbl_driver = {
+       .driver         = {
+               .name   = "ep93xx-bl",
+               .pm     = &ep93xxbl_pm_ops,
+       },
+       .probe          = ep93xxbl_probe,
+};
+
+module_platform_driver(ep93xxbl_driver);
+
+MODULE_DESCRIPTION("EP93xx Backlight Driver");
+MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:ep93xx-bl");