Re: [PATCH V5 1/2] video: exynos_dp: Add device tree support to DP driver

On Saturday, October 13, 2012 6:44 AM Sylwester Nawrocki wrote

On 10/12/2012 10:47 PM, Ajay Kumar wrote:

quoted

This patch enables device tree based discovery support for DP driver.
The driver is modified to handle platform data in both the cases:
with DT and non-DT.

Signed-off-by: Ajay Kumar<redacted>
Acked-by: Jingoo Han<redacted>
---
  drivers/video/exynos/exynos_dp_core.c |  161 ++++++++++++++++++++++++++++++---
  drivers/video/exynos/exynos_dp_core.h |    2 +
  2 files changed, 149 insertions(+), 14 deletions(-)

diff --git a/drivers/video/exynos/exynos_dp_core.c b/drivers/video/exynos/exynos_dp_core.c
index d55470e..62932ba 100644
--- a/drivers/video/exynos/exynos_dp_core.c
+++ b/drivers/video/exynos/exynos_dp_core.c

@@ -18,6 +18,7 @@
  #include<linux/io.h>
  #include<linux/interrupt.h>
  #include<linux/delay.h>
+#include<linux/of.h>

  #include<video/exynos_dp.h>

@@ -856,6 +857,99 @@ static irqreturn_t exynos_dp_irq_handler(int irq, void *arg)
  	return IRQ_HANDLED;
  }

+#ifdef CONFIG_OF
+struct exynos_dp_platdata *exynos_dp_dt_parse_pdata(struct device *dev)
+{
+	struct device_node *dp_node = dev->of_node;
+	struct exynos_dp_platdata *pd;
+	struct video_info *dp_video_config;
+
+	pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);
+	if (!pd) {
+		dev_err(dev, "memory allocation for pdata failed\n");
+		return ERR_PTR(-ENOMEM);
+	}
+	dp_video_config = devm_kzalloc(dev,
+				sizeof(*dp_video_config), GFP_KERNEL);
+
+	if (!dp_video_config) {
+		dev_err(dev, "memory allocation for video config failed\n");
+		return ERR_PTR(-ENOMEM);
+	}
+	pd->video_info = dp_video_config;
+
+	if (of_get_property(dp_node, "hsync-active-high", NULL))
+		dp_video_config->h_sync_polarity = 1;
+
+	if (of_get_property(dp_node, "vsync-active-high", NULL))
+		dp_video_config->v_sync_polarity = 1;
+
+	if (of_get_property(dp_node, "interlaced", NULL))
+		dp_video_config->interlaced = 1;

of_property_read_bool() could also be used here.

OK, right.
of_property_read_bool() would be better.

quoted

+
+	of_property_read_u32(dp_node, "samsung,color-space",
+				&dp_video_config->color_space);
+
+	of_property_read_u32(dp_node, "samsung,dynamic-range",
+				&dp_video_config->dynamic_range);
+
+	of_property_read_u32(dp_node, "samsung,ycbcr-coeff",
+				&dp_video_config->ycbcr_coeff);
+
+	of_property_read_u32(dp_node, "samsung,color-depth",
+				&dp_video_config->color_depth);
+
+	of_property_read_u32(dp_node, "samsung,link-rate",
+				&dp_video_config->link_rate);
+
+	of_property_read_u32(dp_node, "samsung,lane-count",
+				&dp_video_config->lane_count);

Shouldn't it be checked whether all these required properties are present ?
If someone forgets to specify any one the driver will silently ignore it,
not giving a clue what's wrong.

OK, right.

quoted

+	return pd;
+}
+
+void exynos_dp_dt_parse_phydata(struct exynos_dp_device *dp)
+{
+	struct device_node *dp_phy_node;
+	u32 phy_base;
+	void *virt_phy_base;
+
+	dp_phy_node = of_find_node_by_name(dp->dev->of_node, "dptx-phy");
+	if (!dp_phy_node) {
+		dp->dp_phy_addr = NULL;

Is this required ? You've allocated dp with kzalloc().

OK, right.

quoted

+		return;
+	}
+
+	of_property_read_u32(dp_phy_node, "reg",&phy_base);
+	of_property_read_u32(dp_phy_node, "samsung,enable-mask",
+							&dp->enable_mask);

I think you should check the return values, these are required properties.
Some error logs might be useful here.

OK, right.

quoted

+	virt_phy_base = ioremap(phy_base, SZ_4);

How about assigning to dp->dp_phy_addr directly and gettting rid of
virt_phy_base ?

OK, right.
There is no reason, virt_phy_base should be removed.

quoted

+	if (!virt_phy_base) {
+		dev_err(dp->dev, "failed to ioremap dp-phy\n");
+		dp->dp_phy_addr = NULL;
+		return;
+	}
+	dp->dp_phy_addr = virt_phy_base;
+}
+
+void exynos_dp_phy_init(struct exynos_dp_device *dp)
+{
+	u32 reg;
+
+	reg = __raw_readl(dp->dp_phy_addr);
+	reg |= dp->enable_mask;
+	__raw_writel(reg, dp->dp_phy_addr);
+}
+
+void exynos_dp_phy_exit(struct exynos_dp_device *dp)
+{
+	u32 reg;
+
+	reg = __raw_readl(dp->dp_phy_addr);
+	reg&= ~(dp->enable_mask);
+	__raw_writel(reg, dp->dp_phy_addr);
+}
+#endif /* CONFIG_OF */
+
  static int __devinit exynos_dp_probe(struct platform_device *pdev)
  {
  	struct resource *res;

@@ -864,12 +958,6 @@ static int __devinit exynos_dp_probe(struct platform_device *pdev)

  	int ret = 0;

-	pdata = pdev->dev.platform_data;
-	if (!pdata) {
-		dev_err(&pdev->dev, "no platform data\n");
-		return -EINVAL;
-	}
-
  	dp = devm_kzalloc(&pdev->dev, sizeof(struct exynos_dp_device),
  				GFP_KERNEL);
  	if (!dp) {

@@ -879,6 +967,21 @@ static int __devinit exynos_dp_probe(struct platform_device *pdev)

  	dp->dev =&pdev->dev;

+	if (pdev->dev.of_node) {
+		pdata = exynos_dp_dt_parse_pdata(&pdev->dev);
+		if (IS_ERR(pdata))
+			return PTR_ERR(pdata);
+
+		exynos_dp_dt_parse_phydata(dp);
+	} else {
+		pdata = pdev->dev.platform_data;
+	}
+
+	if (!pdata) {
+		dev_err(&pdev->dev, "no platform data\n");
+		return -EINVAL;
+	}
+

This check is only reqired for non-dt case, might be worth to move
it under else statement above.

OK, right.

quoted

  	dp->clock = devm_clk_get(&pdev->dev, "dp");
  	if (IS_ERR(dp->clock)) {
  		dev_err(&pdev->dev, "failed to get clock\n");

@@ -909,8 +1012,14 @@ static int __devinit exynos_dp_probe(struct platform_device *pdev)
  	}

  	dp->video_info = pdata->video_info;
-	if (pdata->phy_init)
-		pdata->phy_init();
+
+	if (pdev->dev.of_node) {
+		if (dp->dp_phy_addr)
+			exynos_dp_phy_init(dp);
+	} else {
+		if (pdata->phy_init)
+			pdata->phy_init();
+	}

  	exynos_dp_init_dp(dp);

@@ -953,8 +1062,13 @@ static int __devexit exynos_dp_remove(struct platform_device *pdev)
  	struct exynos_dp_platdata *pdata = pdev->dev.platform_data;
  	struct exynos_dp_device *dp = platform_get_drvdata(pdev);

This doesn't belong to your patch, but the above 2 lines could be written as:

  	struct exynos_dp_device *dp = dev_get_drvdata(&pdev->dev);

Same in functions exynos_dp_suspend() and exynos_dp_resume().

No, above 2 lines cannot be reduced to 1 line, as you mentioned.
This is because it makes build error.

quoted

-	if (pdata&&  pdata->phy_exit)
-		pdata->phy_exit();
+	if (pdev->dev.of_node) {
+		if (dp->dp_phy_addr)
+			exynos_dp_phy_exit(dp);
+	} else {
+		if (pdata&&  pdata->phy_exit)
+			pdata->phy_exit();
+	}

It is not possible to have valid dp->dp_phy_addr pointer without
valid pdev->dev.of_node, is it ?

Right, however, I prefer coding style as bellow:

if (pdev->dev.of_node)
	DT
else
	non-DT

Can't this (and all similar occurrences) be simplified to:

	if (dp->dp_phy_addr)
		exynos_dp_phy_exit(dp);
	else if (pdata->phy_exit)
		pdata->phy_exit();
?

It just requires dp->dp_phy_addr being NULL for non-dt case.
pdata is never NULL, otherwise probe() would have already failed.

OK, right.
pdata can be removed.

quoted

  	clk_disable_unprepare(dp->clock);

@@ -968,8 +1082,13 @@ static int exynos_dp_suspend(struct device *dev)
  	struct exynos_dp_platdata *pdata = pdev->dev.platform_data;
  	struct exynos_dp_device *dp = platform_get_drvdata(pdev);

-	if (pdata&&  pdata->phy_exit)
-		pdata->phy_exit();
+	if (dev->of_node) {
+		if (dp->dp_phy_addr)
+			exynos_dp_phy_exit(dp);
+	} else {
+		if (pdata&&  pdata->phy_exit)
+			pdata->phy_exit();
+	}

  	clk_disable_unprepare(dp->clock);

@@ -982,8 +1101,13 @@ static int exynos_dp_resume(struct device *dev)
  	struct exynos_dp_platdata *pdata = pdev->dev.platform_data;
  	struct exynos_dp_device *dp = platform_get_drvdata(pdev);

-	if (pdata&&  pdata->phy_init)
-		pdata->phy_init();
+	if (dev->of_node) {
+		if (dp->dp_phy_addr)
+			exynos_dp_phy_init(dp);
+	} else {
+		if (pdata&&  pdata->phy_init)
+			pdata->phy_init();
+	}

  	clk_prepare_enable(dp->clock);

@@ -1013,6 +1137,14 @@ static const struct dev_pm_ops exynos_dp_pm_ops = {
  	SET_SYSTEM_SLEEP_PM_OPS(exynos_dp_suspend, exynos_dp_resume)
  };

+#ifdef CONFIG_OF
+static const struct of_device_id exynos_dp_match[] = {
+	{ .compatible = "samsung,exynos5-dp" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, exynos_dp_match);
+#endif
+

How about just dropping this #ifdef, since you're using of_match_ptr() ?

OK, right.

quoted

  static struct platform_driver exynos_dp_driver = {
  	.probe		= exynos_dp_probe,
  	.remove		= __devexit_p(exynos_dp_remove),

@@ -1020,6 +1152,7 @@ static struct platform_driver exynos_dp_driver = {
  		.name	= "exynos-dp",
  		.owner	= THIS_MODULE,
  		.pm	=&exynos_dp_pm_ops,
+		.of_match_table = of_match_ptr(exynos_dp_match),
  	},
  };

diff --git a/drivers/video/exynos/exynos_dp_core.h b/drivers/video/exynos/exynos_dp_core.h
index 57b8a65..569858b 100644
--- a/drivers/video/exynos/exynos_dp_core.h
+++ b/drivers/video/exynos/exynos_dp_core.h

@@ -29,6 +29,8 @@ struct exynos_dp_device {
  	struct clk		*clock;
  	unsigned int		irq;
  	void __iomem		*reg_base;
+	void __iomem		*dp_phy_addr;

Nit: "dp" is already within the structure name. How about just
     naming it phy_addr ? dp->phy_addr might look better than
     dp->dp_phy_addr ;)

OK, right.

quoted

+	unsigned int		enable_mask;

  	struct video_info	*video_info;
  	struct link_train	link_train;

Ajay,

When CONFIG_OF is not enabled, it makes build errors.
In addition, exynos_dp_dt_parse_phydata needs return value,
instead of returning void.


Best regards,
Jingoo Han

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