1 files changed, 132 insertions, 0 deletions
diff --git a/drivers/video/backlight/ep93xx_bl.c b/drivers/video/backlight/ep93xx_bl.c
new file mode 100644
index 0000000000..2387009d45
--- /dev/null
+++ b/drivers/video/backlight/ep93xx_bl.c
@@ -0,0 +1,132 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for the Cirrus EP93xx lcd backlight
+ *
+ * Copyright (c) 2010 H Hartley Sweeten <hsweeten@visionengravers.com>
+ *
+ * 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)
+{
+	return ep93xxbl_set(bl, backlight_get_brightness(bl));
+}
+
+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");