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video: mx3fb: Add backlight control support 

This patch add backlight control support to allow dimming the backlight
using the internal PWM. Currently the brightness is set fixed to a
maximum of 255.

Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
This commit is contained in:
Alexander Stein 2014-05-12 08:34:14 +02:00 committed by Tomi Valkeinen
parent 7ceb1892c0
commit 7edaa761ee
2 changed files with 82 additions and 0 deletions
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1
drivers/video/fbdev/Kconfig
View File

@ -2336,6 +2336,7 @@ config FB_MX3
select FB_CFB_FILLRECT
select FB_CFB_COPYAREA
select FB_CFB_IMAGEBLIT
select BACKLIGHT_CLASS_DEVICE
default y
help
This is a framebuffer device for the i.MX31 LCD Controller. So

81
drivers/video/fbdev/mx3fb.c
View File

@ -27,6 +27,7 @@
#include <linux/clk.h>
#include <linux/mutex.h>
#include <linux/dma/ipu-dma.h>
#include <linux/backlight.h>
#include <linux/platform_data/dma-imx.h>
#include <linux/platform_data/video-mx3fb.h>
@ -241,6 +242,7 @@ struct mx3fb_data {
void __iomem *reg_base;
spinlock_t lock;
struct device *dev;
struct backlight_device *bl;
uint32_t h_start_width;
uint32_t v_start_width;
@ -271,6 +273,71 @@ struct mx3fb_info {
struct fb_var_screeninfo cur_var; /* current var info */
};
static void sdc_set_brightness(struct mx3fb_data *mx3fb, uint8_t value);
static u32 sdc_get_brightness(struct mx3fb_data *mx3fb);
static int mx3fb_bl_get_brightness(struct backlight_device *bl)
{
struct mx3fb_data *fbd = bl_get_data(bl);
return sdc_get_brightness(fbd);
}
static int mx3fb_bl_update_status(struct backlight_device *bl)
{
struct mx3fb_data *fbd = bl_get_data(bl);
int brightness = bl->props.brightness;
if (bl->props.power != FB_BLANK_UNBLANK)
brightness = 0;
if (bl->props.fb_blank != FB_BLANK_UNBLANK)
brightness = 0;
fbd->backlight_level = (fbd->backlight_level & ~0xFF) | brightness;
sdc_set_brightness(fbd, fbd->backlight_level);
return 0;
}
static const struct backlight_ops mx3fb_lcdc_bl_ops = {
.update_status = mx3fb_bl_update_status,
.get_brightness = mx3fb_bl_get_brightness,
};
static void mx3fb_init_backlight(struct mx3fb_data *fbd)
{
struct backlight_properties props;
struct backlight_device *bl;
if (fbd->bl)
return;
memset(&props, 0, sizeof(struct backlight_properties));
props.max_brightness = 0xff;
props.type = BACKLIGHT_RAW;
sdc_set_brightness(fbd, fbd->backlight_level);
bl = backlight_device_register("mx3fb-bl", fbd->dev, fbd,
&mx3fb_lcdc_bl_ops, &props);
if (IS_ERR(bl)) {
dev_err(fbd->dev, "error %ld on backlight register\n",
PTR_ERR(bl));
return;
}
fbd->bl = bl;
bl->props.power = FB_BLANK_UNBLANK;
bl->props.fb_blank = FB_BLANK_UNBLANK;
bl->props.brightness = mx3fb_bl_get_brightness(bl);
}
static void mx3fb_exit_backlight(struct mx3fb_data *fbd)
{
if (fbd->bl)
backlight_device_unregister(fbd->bl);
}
static void mx3fb_dma_done(void *);
/* Used fb-mode and bpp. Can be set on kernel command line, therefore file-static. */
@ -628,6 +695,16 @@ static int sdc_set_global_alpha(struct mx3fb_data *mx3fb, bool enable, uint8_t a
return 0;
}
static u32 sdc_get_brightness(struct mx3fb_data *mx3fb)
{
u32 brightness;
brightness = mx3fb_read_reg(mx3fb, SDC_PWM_CTRL);
brightness = (brightness >> 16) & 0xFF;
return brightness;
}
static void sdc_set_brightness(struct mx3fb_data *mx3fb, uint8_t value)
{
dev_dbg(mx3fb->dev, "%s: value = %d\n", __func__, value);
@ -1534,6 +1611,8 @@ static int mx3fb_probe(struct platform_device *pdev)
if (ret < 0)
goto eisdc0;
mx3fb_init_backlight(mx3fb);
return 0;
eisdc0:
@ -1556,6 +1635,8 @@ static int mx3fb_remove(struct platform_device *dev)
chan = &mx3_fbi->idmac_channel->dma_chan;
release_fbi(fbi);
mx3fb_exit_backlight(mx3fb);
dma_release_channel(chan);
dmaengine_put();