2020-07-23 23:49:45

by Sowjanya Komatineni

Subject: [RFC PATCH v4 04/14] i2c: tegra: Fix runtime resume to re-init VI I2C

VI I2C is on host1x bus and is part of VE power domain.

During suspend/resume VE power domain goes through power off/on.

So, controller reset followed by i2c re-initialization is required
after the domain power up.

This patch fixes it.

Signed-off-by: Sowjanya Komatineni <[email protected]>
---
drivers/i2c/busses/i2c-tegra.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 7b93c45..1bf3666 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -293,6 +293,8 @@ struct tegra_i2c_dev {
bool is_curr_atomic_xfer;
};

+static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev, bool clk_reinit);
+
static void dvc_writel(struct tegra_i2c_dev *i2c_dev, u32 val,
unsigned long reg)
{
@@ -675,8 +677,22 @@ static int __maybe_unused tegra_i2c_runtime_resume(struct device *dev)
goto disable_slow_clk;
}

+ /*
+ * VI I2C device is attached to VE power domain which goes through
+ * power ON/OFF during PM runtime resume/suspend. So, controller
+ * should go through reset and need to re-initialize after power
+ * domain ON.
+ */
+ if (i2c_dev->is_vi) {
+ ret = tegra_i2c_init(i2c_dev, true);
+ if (ret)
+ goto disable_div_clk;
+ }
+
return 0;

+disable_div_clk:
+ clk_disable(i2c_dev->div_clk);
disable_slow_clk:
clk_disable(i2c_dev->slow_clk);
disable_fast_clk:
--
2.7.4

2020-07-26 23:54:09

by Dmitry Osipenko

Subject: Re: [RFC PATCH v4 04/14] i2c: tegra: Fix runtime resume to re-init VI I2C

24.07.2020 02:51, Sowjanya Komatineni пишет:
> VI I2C is on host1x bus and is part of VE power domain.
>
> During suspend/resume VE power domain goes through power off/on.
>
> So, controller reset followed by i2c re-initialization is required
> after the domain power up.
>
> This patch fixes it.
>
> Signed-off-by: Sowjanya Komatineni <[email protected]>
> ---
> drivers/i2c/busses/i2c-tegra.c | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
>
> diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
> index 7b93c45..1bf3666 100644
> --- a/drivers/i2c/busses/i2c-tegra.c
> +++ b/drivers/i2c/busses/i2c-tegra.c
> @@ -293,6 +293,8 @@ struct tegra_i2c_dev {
> bool is_curr_atomic_xfer;
> };
>
> +static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev, bool clk_reinit);
> +
> static void dvc_writel(struct tegra_i2c_dev *i2c_dev, u32 val,
> unsigned long reg)
> {
> @@ -675,8 +677,22 @@ static int __maybe_unused tegra_i2c_runtime_resume(struct device *dev)
> goto disable_slow_clk;
> }
>
> + /*
> + * VI I2C device is attached to VE power domain which goes through
> + * power ON/OFF during PM runtime resume/suspend. So, controller
> + * should go through reset and need to re-initialize after power
> + * domain ON.
> + */
> + if (i2c_dev->is_vi) {
> + ret = tegra_i2c_init(i2c_dev, true);
> + if (ret)
> + goto disable_div_clk;
> + }
> +
> return 0;
>
> +disable_div_clk:
> + clk_disable(i2c_dev->div_clk);
> disable_slow_clk:
> clk_disable(i2c_dev->slow_clk);
> disable_fast_clk:
>

This look okay, but isn't RPM usage a bit too expensive for VI? Maybe
RPM autodelay needs to be set for the I2C driver?

Reviewed-by: Dmitry Osipenko <[email protected]>

2020-07-27 20:56:01

by Sowjanya Komatineni

Subject: Re: [RFC PATCH v4 04/14] i2c: tegra: Fix runtime resume to re-init VI I2C

On 7/26/20 4:53 PM, Dmitry Osipenko wrote:
> 24.07.2020 02:51, Sowjanya Komatineni пишет:
>> VI I2C is on host1x bus and is part of VE power domain.
>>
>> During suspend/resume VE power domain goes through power off/on.
>>
>> So, controller reset followed by i2c re-initialization is required
>> after the domain power up.
>>
>> This patch fixes it.
>>
>> Signed-off-by: Sowjanya Komatineni <[email protected]>
>> ---
>> drivers/i2c/busses/i2c-tegra.c | 16 ++++++++++++++++
>> 1 file changed, 16 insertions(+)
>>
>> diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
>> index 7b93c45..1bf3666 100644
>> --- a/drivers/i2c/busses/i2c-tegra.c
>> +++ b/drivers/i2c/busses/i2c-tegra.c
>> @@ -293,6 +293,8 @@ struct tegra_i2c_dev {
>> bool is_curr_atomic_xfer;
>> };
>>
>> +static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev, bool clk_reinit);
>> +
>> static void dvc_writel(struct tegra_i2c_dev *i2c_dev, u32 val,
>> unsigned long reg)
>> {
>> @@ -675,8 +677,22 @@ static int __maybe_unused tegra_i2c_runtime_resume(struct device *dev)
>> goto disable_slow_clk;
>> }
>>
>> + /*
>> + * VI I2C device is attached to VE power domain which goes through
>> + * power ON/OFF during PM runtime resume/suspend. So, controller
>> + * should go through reset and need to re-initialize after power
>> + * domain ON.
>> + */
>> + if (i2c_dev->is_vi) {
>> + ret = tegra_i2c_init(i2c_dev, true);
>> + if (ret)
>> + goto disable_div_clk;
>> + }
>> +
>> return 0;
>>
>> +disable_div_clk:
>> + clk_disable(i2c_dev->div_clk);
>> disable_slow_clk:
>> clk_disable(i2c_dev->slow_clk);
>> disable_fast_clk:
>>
> This look okay, but isn't RPM usage a bit too expensive for VI? Maybe
> RPM autodelay needs to be set for the I2C driver?
>
> Reviewed-by: Dmitry Osipenko <[email protected]>
>
Thanks Dmitry. Will look into and have separate patch for VI I2C RPM
auto-delay out of this series sometime next week.

Regards

Sowjanya