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video: da8xx-fb: am335x DT support

PATCH New Afzal Mohammed 1 participant 13 messages Jan 28, 2013

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Afzal Mohammed

author
#0 lore raw

v5 cover video: da8xx-fb: am335x DT support

Hi,

This series adds DT support to da8xx-fb driver (device found on DaVinci and AM335x SoC's). It does certain cleanup's in the process.

This series as compared to previous version goes back to v2 way of configuring pixel clock rate. i.e. set divider if rate is within the range that is configurable with existing input clock rate, else change input clock rate as required instead of modeling CCF clock nodes in the driver (more details in 12/12)

This makes use of Steffen Trumtrar's v17 of display timing DT support.

Testing has been done on AM335x SoC based boards like AM335x EVM. It has also been verified that display on DA850 EVM (non-DT boot) works as earlier.

This series is based on v3.8-rc3,
and is dependent on,
1. Series v17 "of: add display helper" by,
Steffen Trumtrar <[email protected]>
2. Patch "da8xx: Allow use by am33xx based devices" by, Pantelis Antoniou <[email protected]>
3. Series v3 "video: da8xx-fb: runtime timing configuration" by, me (Afzal Mohammed <[email protected]>)

To test this series on AM335x based boards,
1. Series "HWMOD fixes for AM33xx PWM submodules and device tree nodes" by, Philip, Avinash <[email protected]>
as well as following,
2. Series v2 "ARM: dts: AM33XX: lcdc support",
3. Patch v2 "ARM: OMAP2+: dpll: am335x - avoid freqsel",
4. Patch v2 "ARM: OMAP2+: clock: DEFINE_STRUCT_CLK_FLAGS helper",
5. Patch v2 "ARM: AM33XX: clock: SET_RATE_PARENT in lcd path" by, me (Afzal Mohammed <[email protected]>)
would be needed.

All above dependencies along with those required for testing is available @ git://gitorious.org/x0148406-public/linux-kernel.git tags/da8xx-fb-dt-v5

Regards
Afzal

v5: use v2 method of configuring pixel clock rate instead of modeling
CCF clock nodes in driver, i.e. set divider if rate is within the range that is configurable with existing input clock rate, else change input clock rate as required.
v4: use new registration for clock divider having minimum divider
requirement and have ifdef'ery in a better way
v3: model CCF clock divider with parent propogation if CCF selected
v2: 2 new patches - one to configure clock rate properly (12/12)and
other to make io operations safe (1/12)

Afzal Mohammed (11):
video: da8xx-fb: make io operations safe
video: da8xx-fb: enable sync lost intr for v2 ip
video: da8xx-fb: use devres
video: da8xx-fb: ensure non-null cfg in pdata
video: da8xx-fb: reorganize panel detection
video: da8xx-fb: minimal dt support
video: da8xx-fb: invoke platform callback safely
video: da8xx-fb: obtain fb_videomode info from dt
video: da8xx-fb: ensure pdata only for non-dt
video: da8xx-fb: setup struct lcd_ctrl_config for dt
video: da8xx-fb: set upstream clock rate (if reqd)

Manjunathappa, Prakash (1):
video: da8xx-fb: fix 24bpp raster configuration

 .../devicetree/bindings/video/fb-da8xx.txt         |  37 ++++
 drivers/video/da8xx-fb.c                           | 226 ++++++++++++++-------
 2 files changed, 194 insertions(+), 69 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/video/fb-da8xx.txt
Signature · 1 line
1.7.12
author
#1 lore raw

PATCH v5 1/12 video: da8xx-fb: make io operations safe

Replace __raw_readl/__raw_writel with readl/writel; this driver is reused on ARMv7 (AM335x SoC).

Signed-off-by Afzal Mohammed <[email protected]>

---

v2: new patch

 drivers/video/da8xx-fb.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
drivers/video/da8xx-fb.c +2 -2
index 720604c..35a33ca 100644
@@ -141,12 +141,12 @@ static int frame_done_flag;
 
 static inline unsigned int lcdc_read(unsigned int addr)
 {
-	return (unsigned int)__raw_readl(da8xx_fb_reg_base + (addr));
+	return (unsigned int)readl(da8xx_fb_reg_base + (addr));
 }
 
 static inline void lcdc_write(unsigned int val, unsigned int addr)
 {
-	__raw_writel(val, da8xx_fb_reg_base + (addr));
+	writel(val, da8xx_fb_reg_base + (addr));
 }
 
 struct da8xx_fb_par {
Signature · 1 line
1.7.12
author
#2 lore raw

PATCH v5 2/12 video: da8xx-fb: fix 24bpp raster configuration

In reply to Afzal Mohammed

From: "Manjunathappa, Prakash" <[email protected]>

Set only LCD_V2_TFT_24BPP_MODE bit for 24bpp and LCD_V2_TFT_24BPP_UNPACK bit along with LCD_V2_TFT_24BPP_MODE for 32bpp configuration.

Patch is tested on am335x-evm for 24bpp and da850-evm for 16bpp configurations.

Signed-off-by Manjunathappa, Prakash <[email protected]>
Signed-off-by Afzal Mohammed <[email protected]>
---
 drivers/video/da8xx-fb.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
drivers/video/da8xx-fb.c +2 -2
index 35a33ca..7f92f37 100644
@@ -550,10 +550,10 @@ static int lcd_cfg_frame_buffer(struct da8xx_fb_par *par, u32 width, u32 height,
 	case 4:
 	case 16:
 		break;
-	case 24:
-		reg |= LCD_V2_TFT_24BPP_MODE;
 	case 32:
 		reg |= LCD_V2_TFT_24BPP_UNPACK;
+	case 24:
+		reg |= LCD_V2_TFT_24BPP_MODE;
 		break;
 
 	case 8:
Signature · 1 line
1.7.12
author
#3 lore raw

PATCH v5 3/12 video: da8xx-fb: enable sync lost intr for v2 ip

In reply to Afzal Mohammed

interrupt handler is checking for sync lost interrupt, but it was not enabled, enable it.

Signed-off-by Afzal Mohammed <[email protected]>
---
 drivers/video/da8xx-fb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/video/da8xx-fb.c +1 -1
index 7f92f37..ca69e01 100644
@@ -318,7 +318,7 @@ static void lcd_blit(int load_mode, struct da8xx_fb_par *par)
 			reg_int = lcdc_read(LCD_INT_ENABLE_SET_REG) |
 				LCD_V2_END_OF_FRAME0_INT_ENA |
 				LCD_V2_END_OF_FRAME1_INT_ENA |
-				LCD_FRAME_DONE;
+				LCD_FRAME_DONE | LCD_SYNC_LOST;
 			lcdc_write(reg_int, LCD_INT_ENABLE_SET_REG);
 		}
 		reg_dma |= LCD_DUAL_FRAME_BUFFER_ENABLE;
Signature · 1 line
1.7.12
author
#4 lore raw

PATCH v5 4/12 video: da8xx-fb: use devres

In reply to Afzal Mohammed

Replace existing resource handling in the driver with managed device resource.

Signed-off-by Afzal Mohammed <[email protected]>
---
 drivers/video/da8xx-fb.c | 35 ++++++-----------------------------
 1 file changed, 6 insertions(+), 29 deletions(-)
drivers/video/da8xx-fb.c +6 -29
index ca69e01..7a32e83 100644
@@ -1036,12 +1036,9 @@ static int fb_remove(struct platform_device *dev)
 				  par->p_palette_base);
 		dma_free_coherent(NULL, par->vram_size, par->vram_virt,
 				  par->vram_phys);
-		free_irq(par->irq, par);
 		pm_runtime_put_sync(&dev->dev);
 		pm_runtime_disable(&dev->dev);
 		framebuffer_release(info);
-		iounmap(da8xx_fb_reg_base);
-		release_mem_region(lcdc_regs->start, resource_size(lcdc_regs));
 
 	}
 	return 0;

@@ -1265,7 +1262,6 @@ static int fb_probe(struct platform_device *device)
 	struct fb_info *da8xx_fb_info;
 	struct clk *fb_clk = NULL;
 	struct da8xx_fb_par *par;
-	resource_size_t len;
 	int ret, i;
 	unsigned long ulcm;
 

@@ -1275,29 +1271,16 @@ static int fb_probe(struct platform_device *device)
 	}
 
 	lcdc_regs = platform_get_resource(device, IORESOURCE_MEM, 0);
-	if (!lcdc_regs) {
-		dev_err(&device->dev,
-			"Can not get memory resource for LCD controller\n");
-		return -ENOENT;
-	}
-
-	len = resource_size(lcdc_regs);
-
-	lcdc_regs = request_mem_region(lcdc_regs->start, len, lcdc_regs->name);
-	if (!lcdc_regs)
-		return -EBUSY;
-
-	da8xx_fb_reg_base = ioremap(lcdc_regs->start, len);
+	da8xx_fb_reg_base = devm_request_and_ioremap(&device->dev, lcdc_regs);
 	if (!da8xx_fb_reg_base) {
-		ret = -EBUSY;
-		goto err_request_mem;
+		dev_err(&device->dev, "memory resource setup failed\n");
+		return -EADDRNOTAVAIL;
 	}
 
-	fb_clk = clk_get(&device->dev, "fck");
+	fb_clk = devm_clk_get(&device->dev, "fck");
 	if (IS_ERR(fb_clk)) {
 		dev_err(&device->dev, "Can not get device clock\n");
-		ret = -ENODEV;
-		goto err_ioremap;
+		return -ENODEV;
 	}
 
 	pm_runtime_enable(&device->dev);

@@ -1458,7 +1441,7 @@ static int fb_probe(struct platform_device *device)
 		lcdc_irq_handler = lcdc_irq_handler_rev02;
 	}
 
-	ret = request_irq(par->irq, lcdc_irq_handler, 0,
+	ret = devm_request_irq(&device->dev, par->irq, lcdc_irq_handler, 0,
 			DRIVER_NAME, par);
 	if (ret)
 		goto irq_freq;

@@ -1488,12 +1471,6 @@ err_pm_runtime_disable:
 	pm_runtime_put_sync(&device->dev);
 	pm_runtime_disable(&device->dev);
 
-err_ioremap:
-	iounmap(da8xx_fb_reg_base);
-
-err_request_mem:
-	release_mem_region(lcdc_regs->start, len);
-
 	return ret;
 }
Signature · 1 line
1.7.12
author
#5 lore raw

PATCH v5 5/12 video: da8xx-fb: ensure non-null cfg in pdata

In reply to Afzal Mohammed

Ensure that platform data contains pointer for lcd_ctrl_config.

Signed-off-by Afzal Mohammed <[email protected]>
---
 drivers/video/da8xx-fb.c | 5 +++++
 1 file changed, 5 insertions(+)
drivers/video/da8xx-fb.c +5 -0
index 7a32e83..3b146bc 100644
@@ -1320,6 +1320,11 @@ static int fb_probe(struct platform_device *device)
 
 	lcd_cfg = (struct lcd_ctrl_config *)fb_pdata->controller_data;
 
+	if (!lcd_cfg) {
+		ret = -EINVAL;
+		goto err_pm_runtime_disable;
+	}
+
 	da8xx_fb_info = framebuffer_alloc(sizeof(struct da8xx_fb_par),
 					&device->dev);
 	if (!da8xx_fb_info) {
Signature · 1 line
1.7.12
author
#6 lore raw

PATCH v5 6/12 video: da8xx-fb: reorganize panel detection

In reply to Afzal Mohammed

Move panel detection to a separate function, this helps in readability as well as makes DT support cleaner.

Signed-off-by Afzal Mohammed <[email protected]>
---
 drivers/video/da8xx-fb.c | 42 ++++++++++++++++++++++++++----------------
 1 file changed, 26 insertions(+), 16 deletions(-)
drivers/video/da8xx-fb.c +26 -16
index 3b146bc..b6ea5e9 100644
@@ -1253,6 +1253,27 @@ static struct fb_ops da8xx_fb_ops = {
 	.fb_blank = cfb_blank,
 };
 
+static struct fb_videomode *da8xx_fb_get_videomode(struct platform_device *dev)
+{
+	struct da8xx_lcdc_platform_data *fb_pdata = dev->dev.platform_data;
+	struct fb_videomode *lcdc_info;
+	int i;
+
+	for (i = 0, lcdc_info = known_lcd_panels;
+		i < ARRAY_SIZE(known_lcd_panels); i++, lcdc_info++) {
+		if (strcmp(fb_pdata->type, lcdc_info->name) == 0)
+			break;
+	}
+
+	if (i == ARRAY_SIZE(known_lcd_panels)) {
+		dev_err(&dev->dev, "no panel found\n");
+		return NULL;
+	}
+	dev_info(&dev->dev, "found %s panel\n", lcdc_info->name);
+
+	return lcdc_info;
+}
+
 static int fb_probe(struct platform_device *device)
 {
 	struct da8xx_lcdc_platform_data *fb_pdata =

@@ -1262,7 +1283,7 @@ static int fb_probe(struct platform_device *device)
 	struct fb_info *da8xx_fb_info;
 	struct clk *fb_clk = NULL;
 	struct da8xx_fb_par *par;
-	int ret, i;
+	int ret;
 	unsigned long ulcm;
 
 	if (fb_pdata == NULL) {

@@ -1270,6 +1291,10 @@ static int fb_probe(struct platform_device *device)
 		return -ENOENT;
 	}
 
+	lcdc_info = da8xx_fb_get_videomode(device);
+	if (lcdc_info == NULL)
+		return -ENODEV;
+
 	lcdc_regs = platform_get_resource(device, IORESOURCE_MEM, 0);
 	da8xx_fb_reg_base = devm_request_and_ioremap(&device->dev, lcdc_regs);
 	if (!da8xx_fb_reg_base) {

@@ -1303,21 +1328,6 @@ static int fb_probe(struct platform_device *device)
 		break;
 	}
 
-	for (i = 0, lcdc_info = known_lcd_panels;
-		i < ARRAY_SIZE(known_lcd_panels);
-		i++, lcdc_info++) {
-		if (strcmp(fb_pdata->type, lcdc_info->name) == 0)
-			break;
-	}
-
-	if (i == ARRAY_SIZE(known_lcd_panels)) {
-		dev_err(&device->dev, "GLCD: No valid panel found\n");
-		ret = -ENODEV;
-		goto err_pm_runtime_disable;
-	} else
-		dev_info(&device->dev, "GLCD: Found %s panel\n",
-					fb_pdata->type);
-
 	lcd_cfg = (struct lcd_ctrl_config *)fb_pdata->controller_data;
 
 	if (!lcd_cfg) {
Signature · 1 line
1.7.12
author
#7 lore raw

PATCH v5 7/12 video: da8xx-fb: minimal dt support

In reply to Afzal Mohammed

Driver is provided a means to have the probe triggered by DT.

Signed-off-by Afzal Mohammed <[email protected]>
---
 Documentation/devicetree/bindings/video/fb-da8xx.txt | 16 ++++++++++++++++
 drivers/video/da8xx-fb.c                             |  7 +++++++
 2 files changed, 23 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/video/fb-da8xx.txt
Documentation/devicetree/bindings/video/fb-da8xx.txt new file +16 -0
new file mode 100644
index 0000000..581e014
@@ -0,0 +1,16 @@
+TI LCD Controller on DA830/DA850/AM335x SoC's
+
+Required properties:
+- compatible:
+	DA830 - "ti,da830-lcdc"
+	AM335x SoC's - "ti,am3352-lcdc", "ti,da830-lcdc"
+- reg: Address range of lcdc register set
+- interrupts: lcdc interrupt
+
+Example:
+
+lcdc@4830e000 {
+	compatible = "ti,am3352-lcdc", "ti,da830-lcdc";
+	reg =  <0x4830e000 0x1000>;
+	interrupts = <36>;
+};
drivers/video/da8xx-fb.c +7 -0
index b6ea5e9..08ee8eb 100644
@@ -1595,6 +1595,12 @@ static int fb_resume(struct platform_device *dev)
 #define fb_resume NULL
 #endif
 
+static const struct of_device_id da8xx_fb_of_match[] = {
+	{.compatible = "ti,da830-lcdc", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, da8xx_fb_of_match);
+
 static struct platform_driver da8xx_fb_driver = {
 	.probe = fb_probe,
 	.remove = fb_remove,

@@ -1603,6 +1609,7 @@ static struct platform_driver da8xx_fb_driver = {
 	.driver = {
 		   .name = DRIVER_NAME,
 		   .owner = THIS_MODULE,
+		   .of_match_table = of_match_ptr(da8xx_fb_of_match),
 		   },
 };
Signature · 1 line
1.7.12
author
#8 lore raw

PATCH v5 8/12 video: da8xx-fb: invoke platform callback safely

In reply to Afzal Mohammed

Ensure that platform data is present before checking whether platform callback is present (the one used to control backlight). So far this was not an issue as driver was purely non-DT triggered, but now DT support has been added.

Signed-off-by Afzal Mohammed <[email protected]>
---
 drivers/video/da8xx-fb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/video/da8xx-fb.c +1 -1
index 08ee8eb..0beed20 100644
@@ -1347,7 +1347,7 @@ static int fb_probe(struct platform_device *device)
 	par->dev = &device->dev;
 	par->lcdc_clk = fb_clk;
 	par->lcd_fck_rate = clk_get_rate(fb_clk);
-	if (fb_pdata->panel_power_ctrl) {
+	if (fb_pdata && fb_pdata->panel_power_ctrl) {
 		par->panel_power_ctrl = fb_pdata->panel_power_ctrl;
 		par->panel_power_ctrl(1);
 	}
Signature · 1 line
1.7.12
author
#9 lore raw

PATCH v5 9/12 video: da8xx-fb: obtain fb_videomode info from dt

In reply to Afzal Mohammed

Obtain fb_videomode details for the connected lcd panel using the display timing details present in DT.

Signed-off-by Afzal Mohammed <[email protected]>
---
 .../devicetree/bindings/video/fb-da8xx.txt          | 21 +++++++++++++++++++++
 drivers/video/da8xx-fb.c                            | 17 +++++++++++++++++
 2 files changed, 38 insertions(+)
Documentation/devicetree/bindings/video/fb-da8xx.txt +21 -0
index 581e014..0741f78 100644
@@ -6,6 +6,12 @@ Required properties:
 	AM335x SoC's - "ti,am3352-lcdc", "ti,da830-lcdc"
 - reg: Address range of lcdc register set
 - interrupts: lcdc interrupt
+- display-timings: typical videomode of lcd panel, represented as child.
+  Refer Documentation/devicetree/bindings/video/display-timing.txt for
+  display timing binding details. If multiple videomodes are mentioned
+  in display timings node, typical videomode has to be mentioned as the
+  native mode or it has to be first child (driver cares only for native
+  videomode).
 
 Example:
 

@@ -13,4 +19,19 @@ lcdc@4830e000 {
 	compatible = "ti,am3352-lcdc", "ti,da830-lcdc";
 	reg =  <0x4830e000 0x1000>;
 	interrupts = <36>;
+	display-timings {
+		800x480p62 {
+			clock-frequency = <30000000>;
+			hactive = <800>;
+			vactive = <480>;
+			hfront-porch = <39>;
+			hback-porch = <39>;
+			hsync-len = <47>;
+			vback-porch = <29>;
+			vfront-porch = <13>;
+			vsync-len = <2>;
+			hsync-active = <1>;
+			vsync-active = <1>;
+		};
+	};
 };
drivers/video/da8xx-fb.c +17 -0
index 0beed20..0c68712 100644
@@ -36,6 +36,7 @@
 #include <linux/slab.h>
 #include <linux/delay.h>
 #include <linux/lcm.h>
+#include <video/of_display_timing.h>
 #include <video/da8xx-fb.h>
 #include <asm/div64.h>
 

@@ -1257,8 +1258,24 @@ static struct fb_videomode *da8xx_fb_get_videomode(struct platform_device *dev)
 {
 	struct da8xx_lcdc_platform_data *fb_pdata = dev->dev.platform_data;
 	struct fb_videomode *lcdc_info;
+	struct device_node *np = dev->dev.of_node;
 	int i;
 
+	if (np) {
+		lcdc_info = devm_kzalloc(&dev->dev,
+					 sizeof(struct fb_videomode),
+					 GFP_KERNEL);
+		if (!lcdc_info) {
+			dev_err(&dev->dev, "memory allocation failed\n");
+			return NULL;
+		}
+		if (of_get_fb_videomode(np, lcdc_info, OF_USE_NATIVE_MODE)) {
+			dev_err(&dev->dev, "timings not available in DT\n");
+			return NULL;
+		}
+		return lcdc_info;
+	}
+
 	for (i = 0, lcdc_info = known_lcd_panels;
 		i < ARRAY_SIZE(known_lcd_panels); i++, lcdc_info++) {
 		if (strcmp(fb_pdata->type, lcdc_info->name) == 0)
Signature · 1 line
1.7.12
author
#10 lore raw

PATCH v5 10/12 video: da8xx-fb: ensure pdata only for non-dt

In reply to Afzal Mohammed

This driver is DT probe-able, hence ensure presence of platform data only for non-DT boot.

Signed-off-by Afzal Mohammed <[email protected]>
---
 drivers/video/da8xx-fb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/video/da8xx-fb.c +1 -1
index 0c68712..1c1a616 100644
@@ -1303,7 +1303,7 @@ static int fb_probe(struct platform_device *device)
 	int ret;
 	unsigned long ulcm;
 
-	if (fb_pdata == NULL) {
+	if (fb_pdata == NULL && !device->dev.of_node) {
 		dev_err(&device->dev, "Can not get platform data\n");
 		return -ENOENT;
 	}
Signature · 1 line
1.7.12
author
#11 lore raw

PATCH v5 11/12 video: da8xx-fb: setup struct lcd_ctrl_config for dt

In reply to Afzal Mohammed

strcut lcd_ctrl_config information required for driver is currently obtained via platform data. To handle DT probing, create lcd_ctrl_config and populate it with default values, these values are sufficient for the panels so far used with this controller to work.

Signed-off-by Afzal Mohammed <[email protected]>
---
 drivers/video/da8xx-fb.c | 34 +++++++++++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)
drivers/video/da8xx-fb.c +33 -1
index 1c1a616..5455682 100644
@@ -1254,6 +1254,35 @@ static struct fb_ops da8xx_fb_ops = {
 	.fb_blank = cfb_blank,
 };
 
+static struct lcd_ctrl_config *da8xx_fb_create_cfg(struct platform_device *dev)
+{
+	struct lcd_ctrl_config *cfg;
+
+	cfg = devm_kzalloc(&dev->dev, sizeof(struct fb_videomode), GFP_KERNEL);
+	if (!cfg) {
+		dev_err(&dev->dev, "memory allocation failed\n");
+		return NULL;
+	}
+
+	/* default values */
+
+	if (lcd_revision == LCD_VERSION_1)
+		cfg->bpp = 16;
+	else
+		cfg->bpp = 32;
+
+	/*
+	 * For panels so far used with this LCDC, below statement is sufficient.
+	 * For new panels, if required, struct lcd_ctrl_cfg fields to be updated
+	 * with additional/modified values. Those values would have to be then
+	 * obtained from dt(requiring new dt bindings).
+	 */
+
+	cfg->panel_shade = COLOR_ACTIVE;
+
+	return cfg;
+}
+
 static struct fb_videomode *da8xx_fb_get_videomode(struct platform_device *dev)
 {
 	struct da8xx_lcdc_platform_data *fb_pdata = dev->dev.platform_data;

@@ -1345,7 +1374,10 @@ static int fb_probe(struct platform_device *device)
 		break;
 	}
 
-	lcd_cfg = (struct lcd_ctrl_config *)fb_pdata->controller_data;
+	if (device->dev.of_node)
+		lcd_cfg = da8xx_fb_create_cfg(device);
+	else
+		lcd_cfg = (struct lcd_ctrl_config *)fb_pdata->controller_data;
 
 	if (!lcd_cfg) {
 		ret = -EINVAL;
Signature · 1 line
1.7.12
author
#12 lore raw

PATCH v5 12/12 video: da8xx-fb: set upstream clock rate (if reqd)

In reply to Afzal Mohammed

LCDC IP has a clock divider to adjust pixel clock, this limits pixel clock range to fck/255 - fck/2(fck - rate of input clock to LCDC IP). In the case of AM335x, where this IP is present, default fck is not sufficient to provide normal pixel clock rates, hence rendering this driver unusable on AM335x.

If input clock too is configurable, allowable range of pixel clock would increase. Here initially it is checked whether with present fck, divider in IP could be configured to obtain required rate, if not, fck is adjusted. This makes it usable on AM335x.

Note:
Another solution would be to model an inherited basic clock divider of CCF, an advantage would be a better possible resolution for pixel clk. And trying to instantiate a CCF clock would mean that to be consistent, 3 bits being turned on to enable clocks of LCDC IP would have to be modeled as gate clocks. Now that would bring in a total of 4 clocks, including necessity to create a new inherited divider clock, and that mean a branch of clock tree would be present in LCDC driver. This would add complexity to LCDC driver bringing in considerable amount of clock handling code, and this would not bring in much advantage for existing use cases other than providing a higher resolution of pixel clock. And existing use cases work without relying on clock modeling. Another fact is that out of the two platform's using this driver DaVinci is not yet converted to CCF. In future if higher resolution of pixel clock is required, and probably after DaVinci is CCF'ed, modeling clock nodes inside driver may be considered.

Signed-off-by Afzal Mohammed <[email protected]>

---

v5: use v2 method of configuring pixel clock rate instead of modeling
CCF clock nodes in driver, i.e. set divider if rate is within the range that is configurable with existing input clock rate, else change input clock rate as required.
v4: use new registration for clock divider having minimum divider
requirement and have ifdef'ery in a better way
v3: model CCF clock divider with parent propogation if CCF selected
v2: new patch

 drivers/video/da8xx-fb.c | 76 ++++++++++++++++++++++++++++++++++++------------
 1 file changed, 58 insertions(+), 18 deletions(-)
drivers/video/da8xx-fb.c +58 -18
index 5455682..09dfa12 100644
@@ -133,6 +133,9 @@
 #define WSI_TIMEOUT	50
 #define PALETTE_SIZE	256
 
+#define	CLK_MIN_DIV	2
+#define	CLK_MAX_DIV	255
+
 static void __iomem *da8xx_fb_reg_base;
 static struct resource *lcdc_regs;
 static unsigned int lcd_revision;

@@ -683,23 +686,21 @@ static void da8xx_fb_lcd_reset(void)
 	}
 }
 
-static inline unsigned da8xx_fb_calc_clk_divider(struct da8xx_fb_par *par,
-						 unsigned pixclock)
-{
-	return par->lcd_fck_rate / (PICOS2KHZ(pixclock) * 1000);
-}
-
-static inline unsigned da8xx_fb_round_clk(struct da8xx_fb_par *par,
-					  unsigned pixclock)
+static int da8xx_fb_config_clk_divider(struct da8xx_fb_par *par,
+					      unsigned div, unsigned rate)
 {
-	unsigned div;
+	int ret;
 
-	div = da8xx_fb_calc_clk_divider(par, pixclock);
-	return KHZ2PICOS(par->lcd_fck_rate / (1000 * div));
-}
+	if (par->lcd_fck_rate != rate) {
+		ret = clk_set_rate(par->lcdc_clk, rate);
+		if (IS_ERR_VALUE(ret)) {
+			dev_err(par->dev,
+				"unable to set clock rate at %u\n", rate);
+			return ret;
+		}
+		par->lcd_fck_rate = clk_get_rate(par->lcdc_clk);
+	}
 
-static inline void da8xx_fb_config_clk_divider(unsigned div)
-{
 	/* Configure the LCD clock divisor. */
 	lcdc_write(LCD_CLK_DIVISOR(div) |
 			(LCD_RASTER_MODE & 0x1), LCD_CTRL_REG);

@@ -707,14 +708,49 @@ static inline void da8xx_fb_config_clk_divider(unsigned div)
 	if (lcd_revision == LCD_VERSION_2)
 		lcdc_write(LCD_V2_DMA_CLK_EN | LCD_V2_LIDD_CLK_EN |
 				LCD_V2_CORE_CLK_EN, LCD_CLK_ENABLE_REG);
+
+	return 0;
+}
+
+static unsigned int da8xx_fb_calc_clk_divider(struct da8xx_fb_par *par,
+					      unsigned pixclock,
+					      unsigned *rate)
+{
+	unsigned div;
+
+	pixclock = PICOS2KHZ(pixclock) * 1000;
+
+	*rate = par->lcd_fck_rate;
+
+	if (pixclock < (*rate / CLK_MAX_DIV)) {
+		*rate = clk_round_rate(par->lcdc_clk, pixclock * CLK_MAX_DIV);
+		div = CLK_MAX_DIV;
+	} else if (pixclock > (*rate / CLK_MIN_DIV)) {
+		*rate = clk_round_rate(par->lcdc_clk, pixclock * CLK_MIN_DIV);
+		div = CLK_MIN_DIV;
+	} else {
+		div = *rate / pixclock;
+	}
+
+	return div;
 }
 
-static inline void da8xx_fb_calc_config_clk_divider(struct da8xx_fb_par *par,
+static inline int da8xx_fb_calc_config_clk_divider(struct da8xx_fb_par *par,
 						    struct fb_videomode *mode)
 {
-	unsigned div = da8xx_fb_calc_clk_divider(par, mode->pixclock);
+	unsigned rate;
+	unsigned div = da8xx_fb_calc_clk_divider(par, mode->pixclock, &rate);
 
-	da8xx_fb_config_clk_divider(div);
+	return da8xx_fb_config_clk_divider(par, div, rate);
+}
+
+static inline unsigned da8xx_fb_round_clk(struct da8xx_fb_par *par,
+					  unsigned pixclock)
+{
+	unsigned div, rate;
+
+	div = da8xx_fb_calc_clk_divider(par, pixclock, &rate);
+	return KHZ2PICOS(rate / (1000 * div));
 }
 
 static int lcd_init(struct da8xx_fb_par *par, const struct lcd_ctrl_config *cfg,

@@ -723,7 +759,11 @@ static int lcd_init(struct da8xx_fb_par *par, const struct lcd_ctrl_config *cfg,
 	u32 bpp;
 	int ret = 0;
 
-	da8xx_fb_calc_config_clk_divider(par, panel);
+	ret = da8xx_fb_calc_config_clk_divider(par, panel);
+	if (IS_ERR_VALUE(ret)) {
+		dev_err(par->dev, "unable to configure clock\n");
+		return ret;
+	}
 
 	if (panel->sync & FB_SYNC_CLK_INVERT)
 		lcdc_write((lcdc_read(LCD_RASTER_TIMING_2_REG) |
Signature · 1 line
1.7.12