Re: [RFC PATCH 04/13] drm/tegra: Add sor-safe clock for DPAUX on Tegra210

[Jon Hunter <jonathanh@nvidia.com>]

On 17/06/16 17:18, Thierry Reding wrote:
> * PGP Signed by an unknown key
> 
> On Fri, Jun 17, 2016 at 01:03:38PM +0100, Jon Hunter wrote:
>> For Tegra210 the 'sor-safe' clock needs to be enabled when using DPAUX.
>> Add support to the DPAUX driver for enabling this clock on Tegra210.
>>
>> Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
>> ---
>>  drivers/gpu/drm/tegra/dpaux.c | 29 +++++++++++++++++++++++++++--
>>  1 file changed, 27 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/tegra/dpaux.c b/drivers/gpu/drm/tegra/dpaux.c
>> index aa3a037fcd3b..d696a7e45935 100644
>> --- a/drivers/gpu/drm/tegra/dpaux.c
>> +++ b/drivers/gpu/drm/tegra/dpaux.c
>> @@ -37,6 +37,7 @@ struct tegra_dpaux {
>>  
>>  	struct reset_control *rst;
>>  	struct clk *clk_parent;
>> +	struct clk *clk_sor;
> 
> Can we call this "clk_safe", please? On one hand that mirrors the name
> of the clock in the binding and on the other hand it avoids confusion
> with the real SOR clock.

OK.

>>  	struct clk *clk;
>>  
>>  	struct regulator *vdd;
>> @@ -340,18 +341,37 @@ static int tegra_dpaux_probe(struct platform_device *pdev)
>>  		return PTR_ERR(dpaux->rst);
>>  	}
>>  
>> +	if (of_device_is_compatible(pdev->dev.of_node,
>> +				    "nvidia,tegra210-dpaux")) {
>> +		dpaux->clk_sor = devm_clk_get(&pdev->dev, "sor-safe");
>> +		if (IS_ERR(dpaux->clk_sor)) {
>> +			dev_err(&pdev->dev,
>> +				"failed to get sor-safe clock: %ld\n",
>> +				PTR_ERR(dpaux->clk_sor));
>> +			return PTR_ERR(dpaux->clk_sor);
>> +		}
>> +
>> +		err = clk_prepare_enable(dpaux->clk_sor);
>> +		if (err < 0) {
>> +			dev_err(&pdev->dev,
>> +				"failed to enable sor-safe clock: %d\n", err);
>> +			return err;
>> +		}
>> +	}
> 
> Please make this part of a struct tegra_dpaux_soc, so that we don't have
> to check the compatible string again here. This could look like:
> 
> 	struct tegra_dpaux_soc {
> 		bool needs_safe_clock;
> 	};
> 
> 	static const struct tegra_dpaux_soc tegra124_dpaux_soc = {
> 		.needs_safe_clock = false,
> 	};
> 
> 	static const struct tegra_dpaux_soc tegra210_dpaux_soc = {
> 		.needs_safe_clock = true,
> 	};
> 
> 	...
> 
> 	static const struct of_device_id tegra_dpaux_of_match[] = {
> 		{ .compatible = "nvidia,tegra210-dpaux", .data = &tegra210_dpaux_soc },
> 		{ .compatible = "nvidia,tegra124-dpaux", .data = &tegra124_dpaux_soc },
> 		{ },
> 	};

OK. I wonder if we should call it 'has_safe_clock' because this clock
does not exist for tegra124 AFAICT. #bikeshed ;-)

>> @@ -434,6 +454,9 @@ disable_parent_clk:
>>  assert_reset:
>>  	reset_control_assert(dpaux->rst);
>>  	clk_disable_unprepare(dpaux->clk);
>> +disable_sor_clk:
>> +	if (dpaux->clk_sor)
>> +		clk_disable_unprepare(dpaux->clk_sor);
> 
> You can drop the extra check here, since the common clock framework
> ignores NULL or ERR_PTR() pointers.

OK.

>>  
>>  	return err;
>>  }
>> @@ -456,6 +479,8 @@ static int tegra_dpaux_remove(struct platform_device *pdev)
>>  	clk_disable_unprepare(dpaux->clk_parent);
>>  	reset_control_assert(dpaux->rst);
>>  	clk_disable_unprepare(dpaux->clk);
>> +	if (dpaux->clk_sor)
>> +		clk_disable_unprepare(dpaux->clk_sor);
> 
> Same here.

OK.

Cheers
Jon

-- 
nvpublic
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