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fbdev: ssd1307fb: add backlight controls for setting the contrast 

The backlight class is used to create userspace handles for
setting the OLED contrast.

Signed-off-by: Thomas Niederprüm <niederp@physik.uni-kl.de>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
This commit is contained in:
Thomas Niederprüm 2015-03-31 20:27:15 +02:00 committed by Tomi Valkeinen
parent 13bad59730
commit 6ed5e2db52
2 changed files with 59 additions and 0 deletions
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1
drivers/video/fbdev/Kconfig
View File

@ -2478,6 +2478,7 @@ config FB_SSD1307
select FB_SYS_IMAGEBLIT
select FB_DEFERRED_IO
select PWM
select FB_BACKLIGHT
help
This driver implements support for the Solomon SSD1307
OLED controller over I2C.

58
drivers/video/fbdev/ssd1307fb.c
View File

@ -7,6 +7,7 @@
*/
#include <linux/module.h>
#include <linux/backlight.h>
#include <linux/kernel.h>
#include <linux/i2c.h>
#include <linux/fb.h>
@ -38,6 +39,8 @@
#define SSD1307FB_SET_COM_PINS_CONFIG 0xda
#define SSD1307FB_SET_VCOMH 0xdb
#define MAX_CONTRAST 255
#define REFRESHRATE 1
static u_int refreshrate = REFRESHRATE;
@ -424,6 +427,43 @@ static int ssd1307fb_init(struct ssd1307fb_par *par)
return 0;
}
static int ssd1307fb_update_bl(struct backlight_device *bdev)
{
struct ssd1307fb_par *par = bl_get_data(bdev);
int ret;
int brightness = bdev->props.brightness;
par->contrast = brightness;
ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CONTRAST);
if (ret < 0)
return ret;
ret = ssd1307fb_write_cmd(par->client, par->contrast);
if (ret < 0)
return ret;
return 0;
}
static int ssd1307fb_get_brightness(struct backlight_device *bdev)
{
struct ssd1307fb_par *par = bl_get_data(bdev);
return par->contrast;
}
static int ssd1307fb_check_fb(struct backlight_device *bdev,
struct fb_info *info)
{
return (info->bl_dev == bdev);
}
static const struct backlight_ops ssd1307fb_bl_ops = {
.options = BL_CORE_SUSPENDRESUME,
.update_status = ssd1307fb_update_bl,
.get_brightness = ssd1307fb_get_brightness,
.check_fb = ssd1307fb_check_fb,
};
static struct ssd1307fb_deviceinfo ssd1307fb_ssd1305_deviceinfo = {
.default_vcomh = 0x34,
.default_dclk_div = 1,
@ -464,6 +504,8 @@ MODULE_DEVICE_TABLE(of, ssd1307fb_of_match);
static int ssd1307fb_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct backlight_device *bl;
char bl_name[12];
struct fb_info *info;
struct device_node *node = client->dev.of_node;
struct fb_deferred_io *ssd1307fb_defio;
@ -599,10 +641,24 @@ static int ssd1307fb_probe(struct i2c_client *client,
goto panel_init_error;
}
snprintf(bl_name, sizeof(bl_name), "ssd1307fb%d", info->node);
bl = backlight_device_register(bl_name, &client->dev, par,
&ssd1307fb_bl_ops, NULL);
bl->props.brightness = par->contrast;
bl->props.max_brightness = MAX_CONTRAST;
info->bl_dev = bl;
if (IS_ERR(bl)) {
dev_err(&client->dev, "unable to register backlight device: %ld\n",
PTR_ERR(bl));
goto bl_init_error;
}
dev_info(&client->dev, "fb%d: %s framebuffer device registered, using %d bytes of video memory\n", info->node, info->fix.id, vmem_size);
return 0;
bl_init_error:
unregister_framebuffer(info);
panel_init_error:
if (par->device_info->need_pwm) {
pwm_disable(par->pwm);
@ -622,6 +678,8 @@ static int ssd1307fb_remove(struct i2c_client *client)
ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_OFF);
backlight_device_unregister(info->bl_dev);
unregister_framebuffer(info);
if (par->device_info->need_pwm) {
pwm_disable(par->pwm);