Commit fdde1a81 authored by Jyri Sarha's avatar Jyri Sarha Committed by Bartlomiej Zolnierkiewicz
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fbdev: ssd1307fb: Make reset gpio devicetree property optional 



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.

Cc: Rob Herring <robh+dt@kernel.org>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Benoît Cousson <bcousson@baylibre.com>
Signed-off-by: default avatarJyri Sarha <jsarha@ti.com>
Signed-off-by: default avatarBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
parent 519b4dba

Documentation/devicetree/bindings/display/ssd1307fb.txt

+2 −2
Original line number Diff line number Diff line
@@ -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

drivers/video/fbdev/ssd1307fb.c

+13 −6
Original line number Diff line number Diff line
@@ -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);



	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)

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