linux-kernel - Re: [PATCH v5 2/6] spi: spi-geni-qcom: Use OPP API to set clk/perf state

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Message-ID: <20200513190752.GS2165@builder.lan>
Date:   Wed, 13 May 2020 12:07:52 -0700
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Rajendra Nayak <rnayak@...eaurora.org>
Cc:     viresh.kumar@...aro.org, sboyd@...nel.org, agross@...nel.org,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        mka@...omium.org, Mark Brown <broonie@...nel.org>,
        Alok Chauhan <alokc@...eaurora.org>,
        Akash Asthana <akashast@...eaurora.org>,
        linux-spi@...r.kernel.org
Subject: Re: [PATCH v5 2/6] spi: spi-geni-qcom: Use OPP API to set clk/perf
 state

On Wed 13 May 04:12 PDT 2020, Rajendra Nayak wrote:

> geni spi needs to express a perforamnce state requirement on CX
> depending on the frequency of the clock rates. Use OPP table from
> DT to register with OPP framework and use dev_pm_opp_set_rate() to
> set the clk/perf state.
> 
> Signed-off-by: Rajendra Nayak <rnayak@...eaurora.org>
> Reviewed-by: Matthias Kaehlcke <mka@...omium.org>
> Cc: Mark Brown <broonie@...nel.org>
> Cc: Alok Chauhan <alokc@...eaurora.org>
> Cc: Akash Asthana <akashast@...eaurora.org>
> Cc: linux-spi@...r.kernel.org
> ---
> This patch will need to land via the msm tree because of a dependency
> with another change.
> Change in v5: OPP cleanup done as the last thing in spi_geni_remove()
> 
>  drivers/spi/spi-geni-qcom.c | 26 +++++++++++++++++++++++---
>  1 file changed, 23 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/spi/spi-geni-qcom.c b/drivers/spi/spi-geni-qcom.c
> index c397242..0d7ead1 100644
> --- a/drivers/spi/spi-geni-qcom.c
> +++ b/drivers/spi/spi-geni-qcom.c
> @@ -7,6 +7,7 @@
>  #include <linux/log2.h>
>  #include <linux/module.h>
>  #include <linux/platform_device.h>
> +#include <linux/pm_opp.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/qcom-geni-se.h>
>  #include <linux/spi/spi.h>
> @@ -95,7 +96,6 @@ static int get_spi_clk_cfg(unsigned int speed_hz,
>  {
>  	unsigned long sclk_freq;
>  	unsigned int actual_hz;
> -	struct geni_se *se = &mas->se;
>  	int ret;
>  
>  	ret = geni_se_clk_freq_match(&mas->se,
> @@ -112,9 +112,9 @@ static int get_spi_clk_cfg(unsigned int speed_hz,
>  
>  	dev_dbg(mas->dev, "req %u=>%u sclk %lu, idx %d, div %d\n", speed_hz,
>  				actual_hz, sclk_freq, *clk_idx, *clk_div);
> -	ret = clk_set_rate(se->clk, sclk_freq);
> +	ret = dev_pm_opp_set_rate(mas->dev, sclk_freq);
>  	if (ret)
> -		dev_err(mas->dev, "clk_set_rate failed %d\n", ret);
> +		dev_err(mas->dev, "dev_pm_opp_set_rate failed %d\n", ret);
>  	return ret;
>  }
>  
> @@ -561,6 +561,17 @@ static int spi_geni_probe(struct platform_device *pdev)
>  	mas->se.wrapper = dev_get_drvdata(dev->parent);
>  	mas->se.base = base;
>  	mas->se.clk = clk;
> +	mas->se.opp_table = dev_pm_opp_set_clkname(&pdev->dev, "se");
> +	if (IS_ERR(mas->se.opp_table))
> +		return PTR_ERR(mas->se.opp_table);
> +	/* OPP table is optional */
> +	ret = dev_pm_opp_of_add_table(&pdev->dev);
> +	if (!ret) {
> +		mas->se.has_opp_table = true;
> +	} else if (ret != -ENODEV) {
> +		dev_err(&pdev->dev, "invalid OPP table in device tree\n");
> +		return ret;
> +	}
>  
>  	spi->bus_num = -1;
>  	spi->dev.of_node = dev->of_node;
> @@ -596,6 +607,9 @@ static int spi_geni_probe(struct platform_device *pdev)
>  spi_geni_probe_runtime_disable:
>  	pm_runtime_disable(dev);
>  	spi_master_put(spi);
> +	if (mas->se.has_opp_table)

Why do you need has_opp_table?

Afaict if dev_pm_opp_of_add_table() returns -ENODEV there's no attached
opp-table and dev_pm_opp_of_remove_table() is a nop.

Regards,
Bjorn

> +		dev_pm_opp_of_remove_table(&pdev->dev);
> +	dev_pm_opp_put_clkname(mas->se.opp_table);
>  	return ret;
>  }
>  
> @@ -609,6 +623,9 @@ static int spi_geni_remove(struct platform_device *pdev)
>  
>  	free_irq(mas->irq, spi);
>  	pm_runtime_disable(&pdev->dev);
> +	if (mas->se.has_opp_table)
> +		dev_pm_opp_of_remove_table(&pdev->dev);
> +	dev_pm_opp_put_clkname(mas->se.opp_table);
>  	return 0;
>  }
>  
> @@ -617,6 +634,9 @@ static int __maybe_unused spi_geni_runtime_suspend(struct device *dev)
>  	struct spi_master *spi = dev_get_drvdata(dev);
>  	struct spi_geni_master *mas = spi_master_get_devdata(spi);
>  
> +	/* Drop the performance state vote */
> +	dev_pm_opp_set_rate(dev, 0);
> +
>  	return geni_se_resources_off(&mas->se);
>  }
>  
> -- 
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
> of Code Aurora Forum, hosted by The Linux Foundation