backlight: Add driver for iPAQ micro backlight

This adds a driver for the backlight controlled by the microcontroller
on the Compaq iPAQ series of handheld computers: h3100, h3600
and h3700.

Acked-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

3 files changed, 93 insertions, 0 deletions

diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index 5d449059a556..cc153f55d9f9 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -207,6 +207,15 @@ config BACKLIGHT_GENERIC
           known as the Corgi backlight driver. If you have a Sharp Zaurus
           SL-C7xx, SL-Cxx00 or SL-6000x say y.
 
+config BACKLIGHT_IPAQ_MICRO
+        tristate "iPAQ microcontroller backlight driver"
+        depends on MFD_IPAQ_MICRO
+        default y
+        help
+          Say y to enable the backlight driver for Compaq iPAQ handheld
+          computers. Say yes if you have one of the h3100/h3600/h3700
+          machines.
+
 config BACKLIGHT_LM3533
         tristate "Backlight Driver for LM3533"
         depends on BACKLIGHT_CLASS_DEVICE
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index bb820024f346..a9ea34a39cad 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -36,6 +36,7 @@ obj-$(CONFIG_BACKLIGHT_GENERIC)		+= generic_bl.o
 obj-$(CONFIG_BACKLIGHT_GPIO)            += gpio_backlight.o
 obj-$(CONFIG_BACKLIGHT_HP680)           += hp680_bl.o
 obj-$(CONFIG_BACKLIGHT_HP700)           += jornada720_bl.o
+obj-$(CONFIG_BACKLIGHT_IPAQ_MICRO)      += ipaq_micro_bl.o
 obj-$(CONFIG_BACKLIGHT_LM3533)          += lm3533_bl.o
 obj-$(CONFIG_BACKLIGHT_LM3630A)         += lm3630a_bl.o
 obj-$(CONFIG_BACKLIGHT_LM3639)          += lm3639_bl.o
diff --git a/drivers/video/backlight/ipaq_micro_bl.c b/drivers/video/backlight/ipaq_micro_bl.c
new file mode 100644
index 000000000000..feab29c6b255
--- /dev/null
+++ b/drivers/video/backlight/ipaq_micro_bl.c
@@ -0,0 +1,83 @@
+/*
+ * 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.
+ *
+ * iPAQ microcontroller backlight support
+ * Author : Linus Walleij <linus.walleij@linaro.org>
+ */
+
+#include <linux/backlight.h>
+#include <linux/err.h>
+#include <linux/fb.h>
+#include <linux/init.h>
+#include <linux/mfd/ipaq-micro.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+static int micro_bl_update_status(struct backlight_device *bd)
+{
+        struct ipaq_micro *micro = dev_get_drvdata(&bd->dev);
+        int intensity = bd->props.brightness;
+        struct ipaq_micro_msg msg = {
+                .id = MSG_BACKLIGHT,
+                .tx_len = 3,
+        };
+
+        if (bd->props.power != FB_BLANK_UNBLANK)
+                intensity = 0;
+        if (bd->props.state & (BL_CORE_FBBLANK | BL_CORE_SUSPENDED))
+                intensity = 0;
+
+        /*
+         * Message format:
+         * Byte 0: backlight instance (usually 1)
+         * Byte 1: on/off
+         * Byte 2: intensity, 0-255
+         */
+        msg.tx_data[0] = 0x01;
+        msg.tx_data[1] = intensity > 0 ? 1 : 0;
+        msg.tx_data[2] = intensity;
+        return ipaq_micro_tx_msg_sync(micro, &msg);
+}
+
+static const struct backlight_ops micro_bl_ops = {
+        .options = BL_CORE_SUSPENDRESUME,
+        .update_status  = micro_bl_update_status,
+};
+
+static struct backlight_properties micro_bl_props = {
+        .type = BACKLIGHT_RAW,
+        .max_brightness = 255,
+        .power = FB_BLANK_UNBLANK,
+        .brightness = 64,
+};
+
+static int micro_backlight_probe(struct platform_device *pdev)
+{
+        struct backlight_device *bd;
+        struct ipaq_micro *micro = dev_get_drvdata(pdev->dev.parent);
+
+        bd = devm_backlight_device_register(&pdev->dev, "ipaq-micro-backlight",
+                                            &pdev->dev, micro, &micro_bl_ops,
+                                            &micro_bl_props);
+        if (IS_ERR(bd))
+                return PTR_ERR(bd);
+
+        platform_set_drvdata(pdev, bd);
+        backlight_update_status(bd);
+
+        return 0;
+}
+
+struct platform_driver micro_backlight_device_driver = {
+        .driver = {
+                .name    = "ipaq-micro-backlight",
+        },
+        .probe   = micro_backlight_probe,
+};
+module_platform_driver(micro_backlight_device_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("driver for iPAQ Atmel micro backlight");
+MODULE_ALIAS("platform:ipaq-micro-backlight");