Make reset gpio devicetree property optional. Depending on the board
designing there may not be a dedicated gpio for resetting the
display. Without a proper reset there may be some junk in the display
memory at probe time, so in such a case the display memory is cleared
before turning it on. The devicetree binding document is also updated.
Signed-off-by: Jyri Sarha <jsarha@xxxxxx>
---
.../devicetree/bindings/display/ssd1307fb.txt | 4 ++--
drivers/video/fbdev/ssd1307fb.c | 19 +++++++++++++------
2 files changed, 15 insertions(+), 8 deletions(-)
diff --git a/Documentation/devicetree/bindings/display/ssd1307fb.txt b/Documentation/devicetree/bindings/display/ssd1307fb.txt
index 4aee67f..6617df6 100644
--- a/Documentation/devicetree/bindings/display/ssd1307fb.txt
+++ b/Documentation/devicetree/bindings/display/ssd1307fb.txt
@@ -8,14 +8,14 @@ Required properties:
0x3c or 0x3d
- pwm: Should contain the pwm to use according to the OF device tree PWM
specification [0]. Only required for the ssd1307.
- - reset-gpios: Should contain the GPIO used to reset the OLED display. See
- Documentation/devicetree/bindings/gpio/gpio.txt for details.
- solomon,height: Height in pixel of the screen driven by the controller
- solomon,width: Width in pixel of the screen driven by the controller
- solomon,page-offset: Offset of pages (band of 8 pixels) that the screen is
mapped to.
Optional properties:
+ - reset-gpios: The GPIO used to reset the OLED display, if available. See
+ Documentation/devicetree/bindings/gpio/gpio.txt for details.
- solomon,segment-no-remap: Display needs normal (non-inverted) data column
to segment mapping
- solomon,com-seq: Display uses sequential COM pin configuration
diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c
index 8ffaaee..89372af 100644
--- a/drivers/video/fbdev/ssd1307fb.c
+++ b/drivers/video/fbdev/ssd1307fb.c
@@ -439,6 +439,10 @@ static int ssd1307fb_init(struct ssd1307fb_par *par)
if (ret < 0)
return ret;
+ /* Clear the screen if we could not give reset at probe time */
+ if (!par->reset)
+ ssd1307fb_update_display(par);
+
/* Turn on the display */
ret = ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_ON);
if (ret < 0)
@@ -561,7 +565,8 @@ static int ssd1307fb_probe(struct i2c_client *client,
par->device_info = of_device_get_match_data(&client->dev);
- par->reset = devm_gpiod_get(&client->dev, "reset", GPIOD_OUT_LOW);
+ par->reset = devm_gpiod_get_optional(&client->dev, "reset",
+ GPIOD_OUT_LOW);
if (IS_ERR(par->reset)) {
dev_err(&client->dev, "failed to get reset gpio: %ld\n",
PTR_ERR(par->reset));
@@ -645,11 +650,13 @@ static int ssd1307fb_probe(struct i2c_client *client,
i2c_set_clientdata(client, info);
- /* Reset the screen */
- gpiod_set_value(par->reset, 0);
- udelay(4);
- gpiod_set_value(par->reset, 1);
- udelay(4);
+ if (par->reset) {
+ /* Reset the screen */
+ gpiod_set_value(par->reset, 0);
+ udelay(4);
+ gpiod_set_value(par->reset, 1);
+ udelay(4);
+ }
ret = ssd1307fb_init(par);
if (ret)
--
1.9.1
--
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