From 6ed5e2db52b1e27a70241ef8749780f6f5d553bf Mon Sep 17 00:00:00 2001 From: =?utf8?q?Thomas=20Niederpr=C3=BCm?= Date: Tue, 31 Mar 2015 20:27:15 +0200 Subject: [PATCH] fbdev: ssd1307fb: add backlight controls for setting the contrast MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The backlight class is used to create userspace handles for setting the OLED contrast. Signed-off-by: Thomas Niederprüm Acked-by: Maxime Ripard Signed-off-by: Tomi Valkeinen --- drivers/video/fbdev/Kconfig | 1 + drivers/video/fbdev/ssd1307fb.c | 58 +++++++++++++++++++++++++++++++++ 2 files changed, 59 insertions(+) diff --git a/drivers/video/fbdev/Kconfig b/drivers/video/fbdev/Kconfig index 109462303087..54fb8f86b68d 100644 --- a/drivers/video/fbdev/Kconfig +++ b/drivers/video/fbdev/Kconfig @@ -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. diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c index 5f3d5a810c54..77efed7a42a3 100644 --- a/drivers/video/fbdev/ssd1307fb.c +++ b/drivers/video/fbdev/ssd1307fb.c @@ -7,6 +7,7 @@ */ #include +#include #include #include #include @@ -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); -- 2.20.1