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Date:	Wed, 24 Mar 2010 23:51:49 +0100
From:	Bruno Prémont <bonbons@...ux-vserver.org>
To:	Jiri Kosina <jkosina@...e.cz>
Cc:	linux-input@...r.kernel.org, linux-usb@...r.kernel.org,
	linux-fbdev@...r.kernel.org, linux-kernel@...r.kernel.org,
	"Rick L. Vinyard Jr." <rvinyard@...nmsu.edu>,
	Nicu Pavel <npavel@...ner.com>,
	Oliver Neukum <oliver@...kum.org>,
	Jaya Kumar <jayakumar.lkml@...il.com>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Richard Purdie <rpurdie@...ys.net>
Subject: [PATCH v3 3/6] hid: add backlight support to PicoLCD device

Add backlight support to PicoLCD device.

Backlight support depends on backlight class and is only being
compiled if backlight class has been selected.

Changes since v2:
 - Drop inline keyword on non-stub functions

Signed-off-by: Bruno Prémont <bonbons@...ux-vserver.org>
---
 drivers/hid/Kconfig       |    2 +-
 drivers/hid/hid-picolcd.c |  136 ++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 136 insertions(+), 2 deletions(-)

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index a813ea9..588b9ac 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -278,8 +278,8 @@ config HID_PICOLCD
 	  - Keypad
 	  - Switching between Firmware and Flash mode
 	  - Framebuffer for monochrome 256x64 display
+	  - Backlight control    (needs CONFIG_BACKLIGHT_CLASS_DEVICE)
 	  Features that are not (yet) supported:
-	  - Backlight control
 	  - Contrast control
 	  - IR
 	  - General purpose outputs
diff --git a/drivers/hid/hid-picolcd.c b/drivers/hid/hid-picolcd.c
index 6d17d89..2417a9d 100644
--- a/drivers/hid/hid-picolcd.c
+++ b/drivers/hid/hid-picolcd.c
@@ -26,6 +26,7 @@
 
 #include <linux/fb.h>
 #include <linux/vmalloc.h>
+#include <linux/backlight.h>
 
 #include <linux/seq_file.h>
 #include <linux/debugfs.h>
@@ -183,6 +184,11 @@ struct picolcd_data {
 	struct fb_info *fb_info;
 	struct fb_deferred_io fb_defio;
 #endif /* CONFIG_FB */
+#if defined(CONFIG_BACKLIGHT_CLASS_DEVICE) || defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)
+	struct backlight_device *backlight;
+	u8 lcd_brightness;
+	u8 lcd_power;
+#endif /* CONFIG_BACKLIGHT_CLASS_DEVICE */
 
 	/* Housekeeping stuff */
 	spinlock_t lock;
@@ -703,7 +709,7 @@ static void picolcd_exit_framebuffer(struct picolcd_data *data)
 	kfree(fb_vbitmap);
 }
 
-
+#define picolcd_fbinfo(d) ((d)->fb_info)
 #else
 static inline int picolcd_fb_reset(struct picolcd_data *data, int clear)
 {
@@ -716,8 +722,120 @@ static inline int picolcd_init_framebuffer(struct picolcd_data *data)
 static void picolcd_exit_framebuffer(struct picolcd_data *data)
 {
 }
+#define picolcd_fbinfo(d) NULL
 #endif /* CONFIG_FB */
 
+#if defined(CONFIG_BACKLIGHT_CLASS_DEVICE) || defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)
+/*
+ * backlight class device
+ */
+static int picolcd_get_brightness(struct backlight_device *bdev)
+{
+	struct picolcd_data *data = bl_get_data(bdev);
+	return data->lcd_brightness;
+}
+
+static int picolcd_set_brightness(struct backlight_device *bdev)
+{
+	struct picolcd_data *data = bl_get_data(bdev);
+	struct hid_report *report = picolcd_out_report(REPORT_BRIGHTNESS, data->hdev);
+	unsigned long flags;
+
+	if (!report || report->maxfield != 1 || report->field[0]->report_count != 1)
+		return -ENODEV;
+
+	data->lcd_brightness = bdev->props.brightness & 0x0ff;
+	data->lcd_power      = bdev->props.power;
+	spin_lock_irqsave(&data->lock, flags);
+	hid_set_field(report->field[0], 0, data->lcd_power == FB_BLANK_UNBLANK ? data->lcd_brightness : 0);
+	usbhid_submit_report(data->hdev, report, USB_DIR_OUT);
+	spin_unlock_irqrestore(&data->lock, flags);
+	return 0;
+}
+
+static int picolcd_check_bl_fb(struct backlight_device *bdev, struct fb_info *fb)
+{
+	return fb && fb == picolcd_fbinfo((struct picolcd_data *)bl_get_data(bdev));
+}
+
+static const struct backlight_ops picolcd_blops = {
+	.update_status  = picolcd_set_brightness,
+	.get_brightness = picolcd_get_brightness,
+	.check_fb       = picolcd_check_bl_fb,
+};
+
+static int picolcd_init_backlight(struct picolcd_data *data, struct hid_report *report)
+{
+	struct device *dev = &data->hdev->dev;
+	struct backlight_device *bdev;
+	struct backlight_properties props;
+	if (!report)
+		return -ENODEV;
+	if (report->maxfield != 1 || report->field[0]->report_count != 1 ||
+			report->field[0]->report_size != 8) {
+		dev_err(dev, "unsupported BRIGHTNESS report");
+		return -EINVAL;
+	}
+
+	memset(&props, 0, sizeof(props));
+	props.max_brightness = 0xff;
+	bdev = backlight_device_register(dev_name(dev), dev, data,
+			&picolcd_blops, &props);
+	if (IS_ERR(bdev)) {
+		dev_err(dev, "failed to register backlight\n");
+		return PTR_ERR(bdev);
+	}
+	bdev->props.brightness     = 0xff;
+	data->lcd_brightness       = 0xff;
+	data->backlight            = bdev;
+	picolcd_set_brightness(bdev);
+	return 0;
+}
+
+static void picolcd_exit_backlight(struct picolcd_data *data)
+{
+	struct backlight_device *bdev = data->backlight;
+
+	data->backlight = NULL;
+	if (bdev)
+		backlight_device_unregister(bdev);
+}
+
+static inline int picolcd_resume_backlight(struct picolcd_data *data)
+{
+	if (!data->backlight)
+		return 0;
+	return picolcd_set_brightness(data->backlight);
+}
+
+static void picolcd_suspend_backlight(struct picolcd_data *data)
+{
+	int bl_power = data->lcd_power;
+	if (!data->backlight)
+		return;
+
+	data->backlight->props.power = FB_BLANK_POWERDOWN;
+	picolcd_set_brightness(data->backlight);
+	data->lcd_power = data->backlight->props.power = bl_power;
+}
+#else
+static inline int picolcd_init_backlight(struct picolcd_data *data,
+		struct hid_report *report)
+{
+	return 0;
+}
+static inline void picolcd_exit_backlight(struct picolcd_data *data)
+{
+}
+static inline int picolcd_resume_backlight(struct picolcd_data *data)
+{
+	return 0;
+}
+static void picolcd_suspend_backlight(struct picolcd_data *data)
+{
+}
+#endif /* CONFIG_BACKLIGHT_CLASS_DEVICE */
+
 /*
  * input class device
  */
@@ -853,6 +971,7 @@ static int picolcd_reset(struct hid_device *hdev)
 	if (error)
 		return error;
 
+	picolcd_resume_backlight(data);
 #if defined(CONFIG_FB) || defined(CONFIG_FB_MODULE)
 	if (data->fb_info)
 		schedule_delayed_work(&data->fb_info->deferred_work, 0);
@@ -1447,12 +1566,17 @@ static int picolcd_raw_event(struct hid_device *hdev,
 #ifdef CONFIG_PM
 static int picolcd_suspend(struct hid_device *hdev)
 {
+	picolcd_suspend_backlight(hid_get_drvdata(hdev));
 	dbg_hid(PICOLCD_NAME " device ready for suspend\n");
 	return 0;
 }
 
 static int picolcd_resume(struct hid_device *hdev)
 {
+	int ret;
+	ret = picolcd_resume_backlight(hid_get_drvdata(hdev));
+	if (ret)
+		dbg_hid(PICOLCD_NAME " restoring backlight failed: %d\n", ret);
 	return 0;
 }
 
@@ -1465,6 +1589,9 @@ static int picolcd_reset_resume(struct hid_device *hdev)
 	ret = picolcd_fb_reset(hid_get_drvdata(hdev), 0);
 	if (ret)
 		dbg_hid(PICOLCD_NAME " restoring framebuffer content failed: %d\n", ret);
+	ret = picolcd_resume_backlight(hid_get_drvdata(hdev));
+	if (ret)
+		dbg_hid(PICOLCD_NAME " restoring backlight failed: %d\n", ret);
 	return 0;
 }
 #endif
@@ -1569,6 +1696,11 @@ static int picolcd_probe_lcd(struct hid_device *hdev, struct picolcd_data *data)
 	if (error)
 		goto err;
 
+	/* Setup backlight class device */
+	error = picolcd_init_backlight(data, picolcd_out_report(REPORT_BRIGHTNESS, hdev));
+	if (error)
+		goto err;
+
 #ifdef CONFIG_DEBUG_FS
 	report = picolcd_out_report(REPORT_READ_MEMORY, hdev);
 	if (report && report->maxfield == 1 && report->field[0]->report_size == 8)
@@ -1578,6 +1710,7 @@ static int picolcd_probe_lcd(struct hid_device *hdev, struct picolcd_data *data)
 #endif
 	return 0;
 err:
+	picolcd_exit_backlight(data);
 	picolcd_exit_framebuffer(data);
 	picolcd_exit_cir(data);
 	picolcd_exit_keys(data);
@@ -1709,6 +1842,7 @@ static void picolcd_remove(struct hid_device *hdev)
 	spin_unlock_irqrestore(&data->lock, flags);
 
 	/* Clean up the framebuffer */
+	picolcd_exit_backlight(data);
 	picolcd_exit_framebuffer(data);
 	/* Cleanup input */
 	picolcd_exit_cir(data);
-- 
1.6.4.4

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