linux-kernel - [PATCHv2 2/3] video: hx8357: Make IM pins optional

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1374757513-2253-3-git-send-email-maxime.ripard@free-electrons.com>
Date:	Thu, 25 Jul 2013 15:05:12 +0200
From:	Maxime Ripard <maxime.ripard@...e-electrons.com>
To:	plagnioj@...osoft.com, tomi.valkeinen@...com
Cc:	Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
	hector.palacios@...i.com,
	Thomas Petazzoni <thomas@...e-electrons.com>,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-fbdev@...r.kernel.org,
	Maxime Ripard <maxime.ripard@...e-electrons.com>
Subject: [PATCHv2 2/3] video: hx8357: Make IM pins optional

The IM pins of the HX8357 controller are used to define the interface
used to feed pixel stream to the LCD panel.

Most of the time, these pins are directly routed to either the ground or
the VCC to set their values.

Remove the need to assign GPIOs to these pins when we are in such a case.

Signed-off-by: Maxime Ripard <maxime.ripard@...e-electrons.com>
---
 drivers/video/backlight/hx8357.c | 53 +++++++++++++++++++++++-----------------
 1 file changed, 31 insertions(+), 22 deletions(-)

diff --git a/drivers/video/backlight/hx8357.c b/drivers/video/backlight/hx8357.c
index a0482b5..00614ce 100644
--- a/drivers/video/backlight/hx8357.c
+++ b/drivers/video/backlight/hx8357.c
@@ -76,6 +76,7 @@ struct hx8357_data {
 	unsigned		reset;
 	struct spi_device	*spi;
 	int			state;
+	bool			use_im_pins;
 };
 
 static u8 hx8357_seq_power[] = {
@@ -250,9 +251,11 @@ static int hx8357_lcd_init(struct lcd_device *lcdev)
 	 * Set the interface selection pins to SPI mode, with three
 	 * wires
 	 */
-	gpio_set_value_cansleep(lcd->im_pins[0], 1);
-	gpio_set_value_cansleep(lcd->im_pins[1], 0);
-	gpio_set_value_cansleep(lcd->im_pins[2], 1);
+	if (lcd->use_im_pins) {
+		gpio_set_value_cansleep(lcd->im_pins[0], 1);
+		gpio_set_value_cansleep(lcd->im_pins[1], 0);
+		gpio_set_value_cansleep(lcd->im_pins[2], 1);
+	}
 
 	/* Reset the screen */
 	gpio_set_value(lcd->reset, 1);
@@ -424,26 +427,32 @@ static int hx8357_probe(struct spi_device *spi)
 		return -EINVAL;
 	}
 
-	for (i = 0; i < HX8357_NUM_IM_PINS; i++) {
-		lcd->im_pins[i] = of_get_named_gpio(spi->dev.of_node,
-						"im-gpios", i);
-		if (lcd->im_pins[i] == -EPROBE_DEFER) {
-			dev_info(&spi->dev, "GPIO requested is not here yet, deferring the probe\n");
-			return -EPROBE_DEFER;
-		}
-		if (!gpio_is_valid(lcd->im_pins[i])) {
-			dev_err(&spi->dev, "Missing dt property: im-gpios\n");
-			return -EINVAL;
+	if (of_find_property(spi->dev.of_node, "im-gpios", NULL)) {
+		lcd->use_im_pins = 1;
+
+		for (i = 0; i < HX8357_NUM_IM_PINS; i++) {
+			lcd->im_pins[i] = of_get_named_gpio(spi->dev.of_node,
+							    "im-gpios", i);
+			if (lcd->im_pins[i] == -EPROBE_DEFER) {
+				dev_info(&spi->dev, "GPIO requested is not here yet, deferring the probe\n");
+				return -EPROBE_DEFER;
+			}
+			if (!gpio_is_valid(lcd->im_pins[i])) {
+				dev_err(&spi->dev, "Missing dt property: im-gpios\n");
+				return -EINVAL;
+			}
+
+			ret = devm_gpio_request_one(&spi->dev, lcd->im_pins[i],
+						    GPIOF_OUT_INIT_LOW,
+						    "im_pins");
+			if (ret) {
+				dev_err(&spi->dev, "failed to request gpio %d: %d\n",
+					lcd->im_pins[i], ret);
+				return -EINVAL;
+			}
 		}
-
-		ret = devm_gpio_request_one(&spi->dev, lcd->im_pins[i],
-					GPIOF_OUT_INIT_LOW, "im_pins");
-		if (ret) {
-			dev_err(&spi->dev, "failed to request gpio %d: %d\n",
-				lcd->im_pins[i], ret);
-			return -EINVAL;
-		}
-	}
+	} else
+		lcd->use_im_pins = 0;
 
 	lcdev = lcd_device_register("mxsfb", &spi->dev, lcd, &hx8357_ops);
 	if (IS_ERR(lcdev)) {
-- 
1.8.3.2

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/