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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: Jyri Sarha <jsarha@ti.com> Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
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commit
fdde1a8148
2 changed files with 15 additions and 8 deletions
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@ -8,14 +8,14 @@ Required properties:
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0x3c or 0x3d
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- pwm: Should contain the pwm to use according to the OF device tree PWM
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specification [0]. Only required for the ssd1307.
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- reset-gpios: Should contain the GPIO used to reset the OLED display. See
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Documentation/devicetree/bindings/gpio/gpio.txt for details.
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- solomon,height: Height in pixel of the screen driven by the controller
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- solomon,width: Width in pixel of the screen driven by the controller
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- solomon,page-offset: Offset of pages (band of 8 pixels) that the screen is
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mapped to.
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Optional properties:
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- reset-gpios: The GPIO used to reset the OLED display, if available. See
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Documentation/devicetree/bindings/gpio/gpio.txt for details.
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- solomon,segment-no-remap: Display needs normal (non-inverted) data column
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to segment mapping
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- solomon,com-seq: Display uses sequential COM pin configuration
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@ -439,6 +439,10 @@ static int ssd1307fb_init(struct ssd1307fb_par *par)
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if (ret < 0)
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return ret;
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/* Clear the screen if we could not give reset at probe time */
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if (!par->reset)
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ssd1307fb_update_display(par);
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/* Turn on the display */
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ret = ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_ON);
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if (ret < 0)
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@ -561,7 +565,8 @@ static int ssd1307fb_probe(struct i2c_client *client,
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par->device_info = of_device_get_match_data(&client->dev);
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par->reset = devm_gpiod_get(&client->dev, "reset", GPIOD_OUT_LOW);
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par->reset = devm_gpiod_get_optional(&client->dev, "reset",
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GPIOD_OUT_LOW);
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if (IS_ERR(par->reset)) {
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dev_err(&client->dev, "failed to get reset gpio: %ld\n",
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PTR_ERR(par->reset));
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@ -645,11 +650,13 @@ static int ssd1307fb_probe(struct i2c_client *client,
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i2c_set_clientdata(client, info);
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/* Reset the screen */
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gpiod_set_value(par->reset, 0);
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udelay(4);
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gpiod_set_value(par->reset, 1);
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udelay(4);
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if (par->reset) {
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/* Reset the screen */
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gpiod_set_value(par->reset, 0);
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udelay(4);
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gpiod_set_value(par->reset, 1);
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udelay(4);
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}
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ret = ssd1307fb_init(par);
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if (ret)
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