video: ARM CLCD: backlight support for OF

If the device is probed from device tree, we can support
backlight. This is used with some systems such as the
ST Microelectronics Nomadik.

We have to add HAS_IOMEM to the dependencies of CLCD since
the backlight class device will now be selected, and if it
gets selected on an arch that does not have IOMEM,
compilation will fail.

Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

1 files changed, 40 insertions, 0 deletions

diff --git a/drivers/video/fbdev/amba-clcd.c b/drivers/video/fbdev/amba-clcd.c
index 9b158869cb89..52a33d3926ac 100644
--- a/drivers/video/fbdev/amba-clcd.c
+++ b/drivers/video/fbdev/amba-clcd.c
@@ -30,6 +30,7 @@
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/of_graph.h>
+#include <linux/backlight.h>
 #include <video/display_timing.h>
 #include <video/of_display_timing.h>
 #include <video/videomode.h>
@@ -71,6 +72,11 @@ static void clcdfb_disable(struct clcd_fb *fb)
 	if (fb->board->disable)
 		fb->board->disable(fb);
 
+	if (fb->panel->backlight) {
+		fb->panel->backlight->props.power = FB_BLANK_POWERDOWN;
+		backlight_update_status(fb->panel->backlight);
+	}
+
 	val = readl(fb->regs + fb->off_cntl);
 	if (val & CNTL_LCDPWR) {
 		val &= ~CNTL_LCDPWR;
@@ -117,6 +123,14 @@ static void clcdfb_enable(struct clcd_fb *fb, u32 cntl)
 	writel(cntl, fb->regs + fb->off_cntl);
 
 	/*
+	 * Turn on backlight
+	 */
+	if (fb->panel->backlight) {
+		fb->panel->backlight->props.power = FB_BLANK_UNBLANK;
+		backlight_update_status(fb->panel->backlight);
+	}
+
+	/*
 	 * finally, enable the interface.
 	 */
 	if (fb->board->enable)
@@ -576,6 +590,28 @@ static int clcdfb_snprintf_mode(char *buf, int size, struct fb_videomode *mode)
 			mode->refresh);
 }
 
+static int clcdfb_of_get_backlight(struct device_node *endpoint,
+				   struct clcd_panel *clcd_panel)
+{
+	struct device_node *panel;
+	struct device_node *backlight;
+
+	panel = of_graph_get_remote_port_parent(endpoint);
+	if (!panel)
+		return -ENODEV;
+
+	/* Look up the optional backlight phandle */
+	backlight = of_parse_phandle(panel, "backlight", 0);
+	if (backlight) {
+		clcd_panel->backlight = of_find_backlight_by_node(backlight);
+		of_node_put(backlight);
+
+		if (!clcd_panel->backlight)
+			return -EPROBE_DEFER;
+	}
+	return 0;
+}
+
 static int clcdfb_of_get_mode(struct device *dev, struct device_node *endpoint,
 		struct fb_videomode *mode)
 {
@@ -662,6 +698,10 @@ static int clcdfb_of_init_display(struct clcd_fb *fb)
 	if (!endpoint)
 		return -ENODEV;
 
+	err = clcdfb_of_get_backlight(endpoint, fb->panel);
+	if (err)
+		return err;
+
 	err = clcdfb_of_get_mode(&fb->dev->dev, endpoint, &fb->panel->mode);
 	if (err)
 		return err;