[PATCH v6 3/8] hid: add backlight support to PicoLCD device

Bruno Prémont
2010-03-30T20:46:33Z

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 v3:
- Moved PM support to separate patch
Changes since v2:
- Drop inline keyword on non-stub functions

Signed-off-by: Bruno Prémont <bonbons@linux-vserver.org>
---
drivers/hid/Kconfig | 2 +-
drivers/hid/hid-picolcd.c | 128 ++++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 128 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 0fa3ca3..4d5fc2d 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;
@@ -729,7 +735,7 @@ 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)
{
@@ -742,8 +748,120 @@ 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
*/
@@ -879,6 +997,7 @@ 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);
@@ -1567,6 +1686,11 @@ 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)
@@ -1576,6 +1700,7 @@ 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);
@@ -1707,6 +1832,7 @@ 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