diff mbox

[v2] video: mx3fb: Add backlight support

Message ID 1399273010-24706-1-git-send-email-alexander.stein@systec-electronic.com (mailing list archive)
State New, archived
Headers show

Commit Message

Alexander Stein May 5, 2014, 6:56 a.m. UTC 
Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
---
Changes in v2:
* rebased to v3.15-rc4

 drivers/video/fbdev/mx3fb.c | 98 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 98 insertions(+)

Comments

Tomi Valkeinen May 8, 2014, 10:47 a.m. UTC | #1 
Hi,

On 05/05/14 09:56, Alexander Stein wrote:
> Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
> ---

Please always have a commit description, even if it's more or less the
same as the subject.

Is the backlight PWM hardware part of the display hardware on mx3fb? If
so, I guess it's ok to have the backlight in the fb driver, as you're
doing here.

 Tomi
Tomi Valkeinen May 8, 2014, 10:48 a.m. UTC | #2 
On 08/05/14 13:47, Tomi Valkeinen wrote:
> Hi,
> 
> On 05/05/14 09:56, Alexander Stein wrote:
>> Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
>> ---
> 
> Please always have a commit description, even if it's more or less the
> same as the subject.

Oh, and I'd rather have a bit more explanation than "add backlight
support". The current driver seems to have some backlight code. So what
are you actually adding with this patch? Etc.

 Tomi
diff mbox

Patch

diff --git a/drivers/video/fbdev/mx3fb.c b/drivers/video/fbdev/mx3fb.c
index 142e860..10a7244 100644
--- a/drivers/video/fbdev/mx3fb.c
+++ b/drivers/video/fbdev/mx3fb.c
@@ -27,6 +27,7 @@ 
 #include <linux/clk.h>
 #include <linux/mutex.h>
 #include <linux/dma/ipu-dma.h>
+#include <linux/backlight.h>
 
 #include <linux/platform_data/dma-imx.h>
 #include <linux/platform_data/video-mx3fb.h>
@@ -34,6 +35,12 @@ 
 #include <asm/io.h>
 #include <asm/uaccess.h>
 
+#if defined(CONFIG_BACKLIGHT_CLASS_DEVICE) || \
+	(defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE) && \
+		defined(CONFIG_MX3FB_MODULE))
+#define PWM_BACKLIGHT_AVAILABLE
+#endif
+
 #define MX3FB_NAME		"mx3_sdc_fb"
 
 #define MX3FB_REG_OFFSET	0xB4
@@ -242,6 +249,10 @@  struct mx3fb_data {
 	spinlock_t		lock;
 	struct device		*dev;
 
+#ifdef PWM_BACKLIGHT_AVAILABLE
+	struct backlight_device	*bl;
+#endif
+
 	uint32_t		h_start_width;
 	uint32_t		v_start_width;
 	enum disp_data_mapping	disp_data_fmt;
@@ -271,6 +282,74 @@  struct mx3fb_info {
 	struct fb_var_screeninfo	cur_var; /* current var info */
 };
 
+static void sdc_set_brightness(struct mx3fb_data *mx3fb, uint8_t value);
+
+#ifdef PWM_BACKLIGHT_AVAILABLE
+static u32 sdc_get_brightness(struct mx3fb_data *mx3fb);
+
+static int mx3fb_bl_get_brightness(struct backlight_device *bl)
+{
+	struct mx3fb_data *fbd = bl_get_data(bl);
+
+	return sdc_get_brightness(fbd);
+}
+
+static int mx3fb_bl_update_status(struct backlight_device *bl)
+{
+	struct mx3fb_data *fbd = bl_get_data(bl);
+	int brightness = bl->props.brightness;
+
+	if (bl->props.power != FB_BLANK_UNBLANK)
+		brightness = 0;
+	if (bl->props.fb_blank != FB_BLANK_UNBLANK)
+		brightness = 0;
+
+	fbd->backlight_level = (fbd->backlight_level & ~0xFF) | brightness;
+
+	sdc_set_brightness(fbd, fbd->backlight_level);
+
+	return 0;
+}
+
+static const struct backlight_ops mx3fb_lcdc_bl_ops = {
+	.update_status = mx3fb_bl_update_status,
+	.get_brightness = mx3fb_bl_get_brightness,
+};
+
+static void mx3fb_init_backlight(struct mx3fb_data *fbd)
+{
+	struct backlight_properties props;
+	struct backlight_device	*bl;
+
+	if (fbd->bl)
+		return;
+
+	memset(&props, 0, sizeof(struct backlight_properties));
+	props.max_brightness = 0xff;
+	props.type = BACKLIGHT_RAW;
+	sdc_set_brightness(fbd, fbd->backlight_level);
+
+	bl = backlight_device_register("mx3fb-bl", fbd->dev, fbd,
+				       &mx3fb_lcdc_bl_ops, &props);
+	if (IS_ERR(bl)) {
+		dev_err(fbd->dev, "error %ld on backlight register\n",
+				PTR_ERR(bl));
+		return;
+	}
+
+	fbd->bl = bl;
+	bl->props.power = FB_BLANK_UNBLANK;
+	bl->props.fb_blank = FB_BLANK_UNBLANK;
+	bl->props.brightness = mx3fb_bl_get_brightness(bl);
+}
+
+static void mx3fb_exit_backlight(struct mx3fb_data *fbd)
+{
+	if (fbd->bl)
+		backlight_device_unregister(fbd->bl);
+}
+#endif
+
 static void mx3fb_dma_done(void *);
 
 /* Used fb-mode and bpp. Can be set on kernel command line, therefore file-static. */
@@ -628,6 +707,18 @@  static int sdc_set_global_alpha(struct mx3fb_data *mx3fb, bool enable, uint8_t a
 	return 0;
 }
 
+#ifdef PWM_BACKLIGHT_AVAILABLE
+static u32 sdc_get_brightness(struct mx3fb_data *mx3fb)
+{
+	u32 brightness;
+
+	brightness = mx3fb_read_reg(mx3fb, SDC_PWM_CTRL);
+	brightness = (brightness >> 16) & 0xFF;
+
+	return brightness;
+}
+#endif
+
 static void sdc_set_brightness(struct mx3fb_data *mx3fb, uint8_t value)
 {
 	dev_dbg(mx3fb->dev, "%s: value = %d\n", __func__, value);
@@ -1534,6 +1625,9 @@  static int mx3fb_probe(struct platform_device *pdev)
 	if (ret < 0)
 		goto eisdc0;
 
+#ifdef PWM_BACKLIGHT_AVAILABLE
+	mx3fb_init_backlight(mx3fb);
+#endif
 	return 0;
 
 eisdc0:
@@ -1557,6 +1651,10 @@  static int mx3fb_remove(struct platform_device *dev)
 	chan = &mx3_fbi->idmac_channel->dma_chan;
 	release_fbi(fbi);
 
+#ifdef PWM_BACKLIGHT_AVAILABLE
+	mx3fb_exit_backlight(mx3fb);
+#endif
+
 	dma_release_channel(chan);
 	dmaengine_put();