[PATCH 1/1] PXAFB: Support for backlight control

Rodolfo Giometti
2007-02-21T14:53:31Z

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Backlight control support for the PXA fram buffer.

Signed-off-by: Rodolfo Giometti <giometti@enneenne.com>

---

Each platform should define the backlight properties in its own setup
file in "linux/arch/arm/mach-pxa/" as follow:

static int pxafb_bl_get_brightness(struct backlight_device *bl_dev)
{
return read_the_backlight_brightness();
}

static int pxafb_bl_update_status(struct backlight_device *bl_dev)
{
int perc, ret;

if (bl_dev->props->power != FB_BLANK_UNBLANK ||
bl_dev->props->fb_blank != FB_BLANK_UNBLANK)
perc = 0;
else
perc = bl_dev->props->brightness;

write_the_backlight_brightness(perc);

return 0;
}

static struct backlight_properties wwpc1100_backlight_props = {
.get_brightness = pxafb_bl_get_brightness,
.update_status = pxafb_bl_update_status,
.max_brightness = 100,
};

and then seting up the fb info as follow:

wwpc1100_pxafb_info.modes = &special_modes;
wwpc1100_pxafb_info.bl_props = &wwpc1100_backlight_props;
set_pxa_fb_info(&wwpc1100_pxafb_info);

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diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index c1536d7..1ee589e 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -1514,6 +1514,14 @@ config FB_PXA_PARAMETERS

<file:Documentation/fb/pxafb.txt> describes the available parameters.

+config FB_PXA_BACKLIGHT
+ bool "Support for backlight control"
+ default y
+ depends on FB_PXA
+ select FB_BACKLIGHT
+ help
+ Say Y here if you want to control the backlight of your display.
+
config FB_MBX
tristate "2700G LCD framebuffer support"
depends on FB && ARCH_PXA
diff --git a/drivers/video/pxafb.c b/drivers/video/pxafb.c
index b4947c8..489174a 100644
--- a/drivers/video/pxafb.c
+++ b/drivers/video/pxafb.c
@@ -9,6 +9,8 @@
* which in turn is
* Based on acornfb.c Copyright (C) Russell King.
*
+ * Backlight support by Rodolfo Giometti <giometti@linux.it>
+ *
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file COPYING in the main directory of this archive for
* more details.
@@ -37,6 +39,7 @@
#include <linux/cpufreq.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
+#include <linux/backlight.h>

#include <asm/hardware.h>
#include <asm/io.h>
@@ -58,7 +61,6 @@
#define LCCR0_INVALID_CONFIG_MASK (LCCR0_OUM|LCCR0_BM|LCCR0_QDM|LCCR0_DIS|LCCR0_EFM|LCCR0_IUM|LCCR0_SFM|LCCR0_LDM|LCCR0_ENB)
#define LCCR3_INVALID_CONFIG_MASK (LCCR3_HSP|LCCR3_VSP|LCCR3_PCD|LCCR3_BPP)

-static void (*pxafb_backlight_power)(int);
static void (*pxafb_lcd_power)(int, struct fb_var_screeninfo *);

static int pxafb_activate_var(struct fb_var_screeninfo *var, struct pxafb_info *);
@@ -69,6 +71,71 @@ static void set_ctrlr_state(struct pxafb_info *fbi, u_int state);
static char g_options[PXAFB_OPTIONS_SIZE] __initdata = "";
#endif

+
+/*
+ * Backlight control
+ */
+#ifdef CONFIG_FB_BACKLIGHT
+static void pxafb_bl_suspend(struct pxafb_info *fbi)
+{
+ struct backlight_device *bl_dev = fbi->fb.bl_dev;
+
+ if (bl_dev) {
+ down(&bl_dev->sem);
+ bl_dev->props->fb_blank = FB_BLANK_POWERDOWN;
+ bl_dev->props->update_status(bl_dev);
+ up(&bl_dev->sem);
+ }
+}
+
+static void pxafb_bl_resume(struct pxafb_info *fbi)
+{
+ struct backlight_device *bl_dev = fbi->fb.bl_dev;
+
+ if (bl_dev) {
+ down(&bl_dev->sem);
+ bl_dev->props->fb_blank = FB_BLANK_UNBLANK;
+ bl_dev->props->update_status(bl_dev);
+ up(&bl_dev->sem);
+ }
+}
+
+static void pxafb_bl_init(struct fb_info *info, struct backlight_properties *bl_props)
+{
+ struct backlight_device *bl_dev;
+ char name[16];
+
+ snprintf(name, sizeof(name), "pxabl%d", info->node);
+
+ bl_dev = backlight_device_register(name, info->dev, info, bl_props);
+ if (IS_ERR(bl_dev)) {
+ info->bl_dev = NULL;
+ printk(KERN_WARNING "pxafb: backlight registration failed\n");
+ return;
+ }
+
+ mutex_lock(&info->bl_mutex);
+ info->bl_dev = bl_dev;
+ fb_bl_default_curve(info, 0, 0, 100); /* level: 0 - 100 */
+ mutex_unlock(&info->bl_mutex);
+
+ down(&bl_dev->sem);
+ bl_dev->props->brightness = bl_props->max_brightness;
+ bl_dev->props->power = FB_BLANK_UNBLANK;
+ bl_dev->props->update_status(bl_dev);
+ up(&bl_dev->sem);
+
+ printk("pxafb: backlight initialized (%s)\n", name);
+}
+#else
+static inline void pxafb_bl_init(struct fb_info *info, struct backlight_properties *bl_props) {}
+static inline void pxafb_bl_suspend(struct pxafb_info *fbi) {}
+static inline void pxafb_bl_resume(struct pxafb_info *fbi) {}
+#endif /* CONFIG_FB_BACKLIGHT */
+
+/*
+ *
+ */
static inline void pxafb_schedule_work(struct pxafb_info *fbi, u_int state)
{
unsigned long flags;
@@ -736,14 +803,6 @@ static int pxafb_activate_var(struct fb_var_screeninfo *var, struct pxafb_info *
* to ensure that things happen in the right way 100% of time time.
* -- rmk
*/
-static inline void __pxafb_backlight_power(struct pxafb_info *fbi, int on)
-{
- pr_debug("pxafb: backlight o%s\n", on ? "n" : "ff");
-
- if (pxafb_backlight_power)
- pxafb_backlight_power(on);
-}
-
static inline void __pxafb_lcd_power(struct pxafb_info *fbi, int on)
{
pr_debug("pxafb: LCD power o%s\n", on ? "n" : "ff");
@@ -899,7 +958,7 @@ static void set_ctrlr_state(struct pxafb_info *fbi, u_int state)
*/
if (old_state != C_DISABLE) {
fbi->state = state;
- __pxafb_backlight_power(fbi, 0);
+ pxafb_bl_suspend(fbi);
__pxafb_lcd_power(fbi, 0);
if (old_state != C_DISABLE_CLKCHANGE)
pxafb_disable_controller(fbi);
@@ -953,7 +1012,7 @@ static void set_ctrlr_state(struct pxafb_info *fbi, u_int state)
pxafb_setup_gpio(fbi);
pxafb_enable_controller(fbi);
__pxafb_lcd_power(fbi, 1);
- __pxafb_backlight_power(fbi, 1);
+ pxafb_bl_resume(fbi);
}
break;
}
@@ -1112,11 +1171,10 @@ static struct pxafb_info * __init pxafb_init_fbinfo(struct device *dev)
int i, smemlen;

/* Alloc the pxafb_info and pseudo_palette in one step */
- fbi = kmalloc(sizeof(struct pxafb_info) + sizeof(u32) * 16, GFP_KERNEL);
+ fbi = (struct pxafb_info *) framebuffer_alloc(sizeof(u32) * 16, dev);
if (!fbi)
return NULL;

- memset(fbi, 0, sizeof(struct pxafb_info));
fbi->dev = dev;

strcpy(fbi->fb.fix.id, PXA_NAME);
@@ -1368,7 +1426,6 @@ int __init pxafb_probe(struct platform_device *dev)
ret = -EINVAL;
goto failed;
}
- pxafb_backlight_power = inf->pxafb_backlight_power;
pxafb_lcd_power = inf->pxafb_lcd_power;
fbi = pxafb_init_fbinfo(&dev->dev);
if (!fbi) {
@@ -1407,6 +1464,9 @@ int __init pxafb_probe(struct platform_device *dev)
goto failed;
}

+ /* Register the backlight support */
+ pxafb_bl_init(&fbi->fb, inf->bl_props);
+
#ifdef CONFIG_PM
// TODO
#endif
diff --git a/include/asm-arm/arch-pxa/pxafb.h b/include/asm-arm/arch-pxa/pxafb.h
index 81c3928..5c89664 100644
--- a/include/asm-arm/arch-pxa/pxafb.h
+++ b/include/asm-arm/arch-pxa/pxafb.h
@@ -71,7 +71,7 @@ struct pxafb_mach_info {
*/
u_int lccr3;

- void (*pxafb_backlight_power)(int);
+ struct backlight_properties *bl_props;
void (*pxafb_lcd_power)(int, struct fb_var_screeninfo *);

};