diff mbox

[RFC,02/13] drm/tegra: Add helper functions for setting up DPAUX pads

Message ID 1466165027-17917-3-git-send-email-jonathanh@nvidia.com
State Superseded
Headers show

Commit Message

Jon Hunter June 17, 2016, 12:03 p.m. UTC
In preparation for adding pinctrl support for the DPAUX pads, add
helpers functions for configuring the pads and controlling the power
for the pads.

Please note that although a simple if-statement could be used instead
of a case statement for configuring the pads as there are only two
possible modes, a case statement is used because when integrating with
the pinctrl framework, we need to be able to handle invalid modes that
could be passed.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
---
 drivers/gpu/drm/tegra/dpaux.c | 75 ++++++++++++++++++++++++++-----------------
 1 file changed, 45 insertions(+), 30 deletions(-)

Comments

Thierry Reding June 17, 2016, 4:11 p.m. UTC | #1
On Fri, Jun 17, 2016 at 01:03:36PM +0100, Jon Hunter wrote:
> In preparation for adding pinctrl support for the DPAUX pads, add
> helpers functions for configuring the pads and controlling the power
> for the pads.
> 
> Please note that although a simple if-statement could be used instead
> of a case statement for configuring the pads as there are only two
> possible modes, a case statement is used because when integrating with
> the pinctrl framework, we need to be able to handle invalid modes that
> could be passed.
> 
> Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
> ---
>  drivers/gpu/drm/tegra/dpaux.c | 75 ++++++++++++++++++++++++++-----------------
>  1 file changed, 45 insertions(+), 30 deletions(-)
> 
> diff --git a/drivers/gpu/drm/tegra/dpaux.c b/drivers/gpu/drm/tegra/dpaux.c
> index 0874a7e5b37b..aa3a037fcd3b 100644
> --- a/drivers/gpu/drm/tegra/dpaux.c
> +++ b/drivers/gpu/drm/tegra/dpaux.c
> @@ -267,6 +267,45 @@ static irqreturn_t tegra_dpaux_irq(int irq, void *data)
>  	return ret;
>  }
>  
> +static void tegra_dpaux_powerdown(struct tegra_dpaux *dpaux, bool enable)
> +{
> +	u32 value = tegra_dpaux_readl(dpaux, DPAUX_HYBRID_SPARE);
> +
> +	if (enable)
> +		value |= DPAUX_HYBRID_SPARE_PAD_POWER_DOWN;
> +	else
> +		value &= ~DPAUX_HYBRID_SPARE_PAD_POWER_DOWN;
> +
> +	tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_SPARE);
> +}

I'd like for this to be two functions without the boolean parameter. The
reason is that without looking at the implementation there's no way to
understand what the meaning of true and false is. If instead you call
this:

	static void tegra_dpaux_pad_power_down(struct tegra_dpaux *dpaux)
	{
		...
	}

and

	static void tegra_dpaux_pad_power_up(struct tegra_dpaux *dpaux)
	{
		...
	}

you can easily deduce from the name what's going on.

> +static int tegra_dpaux_config(struct tegra_dpaux *dpaux, int function)

Can function not be unsigned?

Thierry
Jon Hunter June 20, 2016, 7:59 a.m. UTC | #2
On 17/06/16 17:11, Thierry Reding wrote:
> * PGP Signed by an unknown key
> 
> On Fri, Jun 17, 2016 at 01:03:36PM +0100, Jon Hunter wrote:
>> In preparation for adding pinctrl support for the DPAUX pads, add
>> helpers functions for configuring the pads and controlling the power
>> for the pads.
>>
>> Please note that although a simple if-statement could be used instead
>> of a case statement for configuring the pads as there are only two
>> possible modes, a case statement is used because when integrating with
>> the pinctrl framework, we need to be able to handle invalid modes that
>> could be passed.
>>
>> Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
>> ---
>>  drivers/gpu/drm/tegra/dpaux.c | 75 ++++++++++++++++++++++++++-----------------
>>  1 file changed, 45 insertions(+), 30 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/tegra/dpaux.c b/drivers/gpu/drm/tegra/dpaux.c
>> index 0874a7e5b37b..aa3a037fcd3b 100644
>> --- a/drivers/gpu/drm/tegra/dpaux.c
>> +++ b/drivers/gpu/drm/tegra/dpaux.c
>> @@ -267,6 +267,45 @@ static irqreturn_t tegra_dpaux_irq(int irq, void *data)
>>  	return ret;
>>  }
>>  
>> +static void tegra_dpaux_powerdown(struct tegra_dpaux *dpaux, bool enable)
>> +{
>> +	u32 value = tegra_dpaux_readl(dpaux, DPAUX_HYBRID_SPARE);
>> +
>> +	if (enable)
>> +		value |= DPAUX_HYBRID_SPARE_PAD_POWER_DOWN;
>> +	else
>> +		value &= ~DPAUX_HYBRID_SPARE_PAD_POWER_DOWN;
>> +
>> +	tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_SPARE);
>> +}
> 
> I'd like for this to be two functions without the boolean parameter. The
> reason is that without looking at the implementation there's no way to
> understand what the meaning of true and false is. If instead you call
> this:
> 
> 	static void tegra_dpaux_pad_power_down(struct tegra_dpaux *dpaux)
> 	{
> 		...
> 	}
> 
> and
> 
> 	static void tegra_dpaux_pad_power_up(struct tegra_dpaux *dpaux)
> 	{
> 		...
> 	}
> 
> you can easily deduce from the name what's going on.

OK, fine with me. I was not sure if it was obvious or not.

>> +static int tegra_dpaux_config(struct tegra_dpaux *dpaux, int function)
> 
> Can function not be unsigned?

Yes it can and in fact should be. I had thought that it needed to be
signed to match with the pinctrl-ops but on closer inspection that is
not the case.

Jon
diff mbox

Patch

diff --git a/drivers/gpu/drm/tegra/dpaux.c b/drivers/gpu/drm/tegra/dpaux.c
index 0874a7e5b37b..aa3a037fcd3b 100644
--- a/drivers/gpu/drm/tegra/dpaux.c
+++ b/drivers/gpu/drm/tegra/dpaux.c
@@ -267,6 +267,45 @@  static irqreturn_t tegra_dpaux_irq(int irq, void *data)
 	return ret;
 }
 
+static void tegra_dpaux_powerdown(struct tegra_dpaux *dpaux, bool enable)
+{
+	u32 value = tegra_dpaux_readl(dpaux, DPAUX_HYBRID_SPARE);
+
+	if (enable)
+		value |= DPAUX_HYBRID_SPARE_PAD_POWER_DOWN;
+	else
+		value &= ~DPAUX_HYBRID_SPARE_PAD_POWER_DOWN;
+
+	tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_SPARE);
+}
+
+static int tegra_dpaux_config(struct tegra_dpaux *dpaux, int function)
+{
+	u32 value;
+
+	switch (function) {
+	case DPAUX_HYBRID_PADCTL_MODE_AUX:
+		value = DPAUX_HYBRID_PADCTL_AUX_CMH(2) |
+			DPAUX_HYBRID_PADCTL_AUX_DRVZ(4) |
+			DPAUX_HYBRID_PADCTL_AUX_DRVI(0x18) |
+			DPAUX_HYBRID_PADCTL_AUX_INPUT_RCV |
+			DPAUX_HYBRID_PADCTL_MODE_AUX;
+		break;
+	case DPAUX_HYBRID_PADCTL_MODE_I2C:
+		value = DPAUX_HYBRID_PADCTL_I2C_SDA_INPUT_RCV |
+			DPAUX_HYBRID_PADCTL_I2C_SCL_INPUT_RCV |
+			DPAUX_HYBRID_PADCTL_MODE_I2C;
+		break;
+	default:
+		return -ENOTSUPP;
+	}
+
+	tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_PADCTL);
+	tegra_dpaux_powerdown(dpaux, false);
+
+	return 0;
+}
+
 static int tegra_dpaux_probe(struct platform_device *pdev)
 {
 	struct tegra_dpaux *dpaux;
@@ -372,15 +411,9 @@  static int tegra_dpaux_probe(struct platform_device *pdev)
 	 * is no possibility to perform the I2C mode configuration in the
 	 * HDMI path.
 	 */
-	value = tegra_dpaux_readl(dpaux, DPAUX_HYBRID_SPARE);
-	value &= ~DPAUX_HYBRID_SPARE_PAD_POWER_DOWN;
-	tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_SPARE);
-
-	value = tegra_dpaux_readl(dpaux, DPAUX_HYBRID_PADCTL);
-	value = DPAUX_HYBRID_PADCTL_I2C_SDA_INPUT_RCV |
-		DPAUX_HYBRID_PADCTL_I2C_SCL_INPUT_RCV |
-		DPAUX_HYBRID_PADCTL_MODE_I2C;
-	tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_PADCTL);
+	err = tegra_dpaux_config(dpaux, DPAUX_HYBRID_PADCTL_MODE_I2C);
+	if (err < 0)
+		return err;
 
 	/* enable and clear all interrupts */
 	value = DPAUX_INTR_AUX_DONE | DPAUX_INTR_IRQ_EVENT |
@@ -408,12 +441,9 @@  assert_reset:
 static int tegra_dpaux_remove(struct platform_device *pdev)
 {
 	struct tegra_dpaux *dpaux = platform_get_drvdata(pdev);
-	u32 value;
 
 	/* make sure pads are powered down when not in use */
-	value = tegra_dpaux_readl(dpaux, DPAUX_HYBRID_SPARE);
-	value |= DPAUX_HYBRID_SPARE_PAD_POWER_DOWN;
-	tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_SPARE);
+	tegra_dpaux_powerdown(dpaux, true);
 
 	drm_dp_aux_unregister(&dpaux->aux);
 
@@ -538,30 +568,15 @@  enum drm_connector_status drm_dp_aux_detect(struct drm_dp_aux *aux)
 int drm_dp_aux_enable(struct drm_dp_aux *aux)
 {
 	struct tegra_dpaux *dpaux = to_dpaux(aux);
-	u32 value;
-
-	value = DPAUX_HYBRID_PADCTL_AUX_CMH(2) |
-		DPAUX_HYBRID_PADCTL_AUX_DRVZ(4) |
-		DPAUX_HYBRID_PADCTL_AUX_DRVI(0x18) |
-		DPAUX_HYBRID_PADCTL_AUX_INPUT_RCV |
-		DPAUX_HYBRID_PADCTL_MODE_AUX;
-	tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_PADCTL);
-
-	value = tegra_dpaux_readl(dpaux, DPAUX_HYBRID_SPARE);
-	value &= ~DPAUX_HYBRID_SPARE_PAD_POWER_DOWN;
-	tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_SPARE);
 
-	return 0;
+	return tegra_dpaux_config(dpaux, DPAUX_HYBRID_PADCTL_MODE_AUX);
 }
 
 int drm_dp_aux_disable(struct drm_dp_aux *aux)
 {
 	struct tegra_dpaux *dpaux = to_dpaux(aux);
-	u32 value;
 
-	value = tegra_dpaux_readl(dpaux, DPAUX_HYBRID_SPARE);
-	value |= DPAUX_HYBRID_SPARE_PAD_POWER_DOWN;
-	tegra_dpaux_writel(dpaux, value, DPAUX_HYBRID_SPARE);
+	tegra_dpaux_powerdown(dpaux, true);
 
 	return 0;
 }