backlight: Adds HP Jornada 700 series backlight driver

Signed-off-by: Kristoffer Ericson <kristoffer.ericson@gmail.com>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

1 files changed, 161 insertions, 0 deletions

diff --git a/drivers/video/backlight/jornada720_bl.c b/drivers/video/backlight/jornada720_bl.c
new file mode 100644
index 00000000000..c3ebb6b41ce
--- /dev/null
+++ b/drivers/video/backlight/jornada720_bl.c
@@ -0,0 +1,161 @@
+/*
+ *
+ * Backlight driver for HP Jornada 700 series (710/720/728)
+ * Copyright (C) 2006-2009 Kristoffer Ericson <kristoffer.ericson@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 or any later version as published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/backlight.h>
+#include <linux/device.h>
+#include <linux/fb.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include <mach/jornada720.h>
+#include <mach/hardware.h>
+
+#include <video/s1d13xxxfb.h>
+
+#define BL_MAX_BRIGHT	255
+#define BL_DEF_BRIGHT	25
+
+static int jornada_bl_get_brightness(struct backlight_device *bd)
+{
+	int ret;
+
+	/* check if backlight is on */
+	if (!(PPSR & PPC_LDD1))
+		return 0;
+
+	jornada_ssp_start();
+
+	/* cmd should return txdummy */
+	ret = jornada_ssp_byte(GETBRIGHTNESS);
+
+	if (jornada_ssp_byte(GETBRIGHTNESS) != TXDUMMY) {
+		printk(KERN_ERR "bl : get brightness timeout\n");
+		jornada_ssp_end();
+		return -ETIMEDOUT;
+	} else /* exchange txdummy for value */
+		ret = jornada_ssp_byte(TXDUMMY);
+
+	jornada_ssp_end();
+
+	return (BL_MAX_BRIGHT - ret);
+}
+
+static int jornada_bl_update_status(struct backlight_device *bd)
+{
+	int ret = 0;
+
+	jornada_ssp_start();
+
+	/* If backlight is off then really turn it off */
+	if ((bd->props.power != FB_BLANK_UNBLANK) || (bd->props.fb_blank != FB_BLANK_UNBLANK)) {
+		ret = jornada_ssp_byte(BRIGHTNESSOFF);
+		if (ret != TXDUMMY) {
+			printk(KERN_INFO "bl : brightness off timeout\n");
+			/* turn off backlight */
+			PPSR &= ~PPC_LDD1;
+			PPDR |= PPC_LDD1;
+			ret = -ETIMEDOUT;
+		}
+	} else  /* turn on backlight */
+		PPSR |= PPC_LDD1;
+
+		/* send command to our mcu */
+		if (jornada_ssp_byte(SETBRIGHTNESS) != TXDUMMY) {
+			printk(KERN_INFO "bl : failed to set brightness\n");
+			ret = -ETIMEDOUT;
+			goto out
+		}
+
+		/* at this point we expect that the mcu has accepted
+		   our command and is waiting for our new value
+		   please note that maximum brightness is 255,
+		   but due to physical layout it is equal to 0, so we simply
+		   invert the value (MAX VALUE - NEW VALUE). */
+		if (jornada_ssp_byte(BL_MAX_BRIGHT - bd->props.brightness) != TXDUMMY) {
+			printk(KERN_ERR "bl : set brightness failed\n");
+			ret = -ETIMEDOUT;
+		}
+
+		/* If infact we get an TXDUMMY as output we are happy and dont
+		   make any further comments about it */
+out:
+	jornada_ssp_end();
+
+	return ret;
+}
+
+static struct backlight_ops jornada_bl_ops = {
+	.get_brightness = jornada_bl_get_brightness,
+	.update_status = jornada_bl_update_status,
+	.options = BL_CORE_SUSPENDRESUME,
+};
+
+static int jornada_bl_probe(struct platform_device *pdev)
+{
+	int ret;
+	struct backlight_device *bd;
+
+	bd = backlight_device_register(S1D_DEVICENAME, &pdev->dev, NULL, &jornada_bl_ops);
+
+	if (IS_ERR(bd)) {
+		ret = PTR_ERR(bd);
+		printk(KERN_ERR "bl : failed to register device, err=%x\n", ret);
+		return ret;
+	}
+
+	bd->props.power = FB_BLANK_UNBLANK;
+	bd->props.brightness = BL_DEF_BRIGHT;
+	/* note. make sure max brightness is set otherwise
+	   you will get seemingly non-related errors when
+	   trying to change brightness */
+	bd->props.max_brightness = BL_MAX_BRIGHT;
+	jornada_bl_update_status(bd);
+
+	platform_set_drvdata(pdev, bd);
+	printk(KERN_INFO "HP Jornada 700 series backlight driver\n");
+
+	return 0;
+}
+
+static int jornada_bl_remove(struct platform_device *pdev)
+{
+	struct backlight_device *bd = platform_get_drvdata(pdev);
+
+	backlight_device_unregister(bd);
+
+	return 0;
+}
+
+static struct platform_driver jornada_bl_driver = {
+	.probe		= jornada_bl_probe,
+	.remove		= jornada_bl_remove,
+	.driver	= {
+		.name	= "jornada_bl",
+	},
+};
+
+int __init jornada_bl_init(void)
+{
+	return platform_driver_register(&jornada_bl_driver);
+}
+
+void __exit jornada_bl_exit(void)
+{
+	platform_driver_unregister(&jornada_bl_driver);
+}
+
+MODULE_AUTHOR("Kristoffer Ericson <kristoffer.ericson>");
+MODULE_DESCRIPTION("HP Jornada 710/720/728 Backlight driver");
+MODULE_LICENSE("GPL");
+
+module_init(jornada_bl_init);
+module_exit(jornada_bl_exit);