From fdde1a8148d81617582c138cd1fbdc4594d4c941 Mon Sep 17 00:00:00 2001 From: Jyri Sarha Date: Wed, 8 Feb 2017 16:43:59 +0100 Subject: fbdev: ssd1307fb: Make reset gpio devicetree property optional MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Cc: Tomi Valkeinen Cc: Maxime Ripard Cc: Benoît Cousson Signed-off-by: Jyri Sarha Signed-off-by: Bartlomiej Zolnierkiewicz --- drivers/video/fbdev/ssd1307fb.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) (limited to 'drivers/video/fbdev') diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c index 8ffaaeeb2f84..89372af7bc5b 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) -- cgit v1.2.3