linux-kernel - Re: [PATCH 2/2] mfd: madera: Add support for requesting the supply clocks

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Date:   Mon, 12 Aug 2019 11:38:53 +0100
From:   Lee Jones <lee.jones@...aro.org>
To:     Charles Keepax <ckeepax@...nsource.cirrus.com>
Cc:     robh+dt@...nel.org, mark.rutland@....com,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        patches@...nsource.cirrus.com
Subject: Re: [PATCH 2/2] mfd: madera: Add support for requesting the supply
 clocks

On Tue, 06 Aug 2019, Charles Keepax wrote:

> Add the ability to get the clock for each clock input pin of the chip
> and enable MCLK2 since that is expected to be a permanently enabled
> 32kHz clock.
> 
> Signed-off-by: Charles Keepax <ckeepax@...nsource.cirrus.com>
> ---
>  drivers/mfd/madera-core.c       | 24 +++++++++++++++++++++++-
>  include/linux/mfd/madera/core.h | 11 +++++++++++
>  2 files changed, 34 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mfd/madera-core.c b/drivers/mfd/madera-core.c
> index 29540cbf75934..8d7ab1c7bf9f7 100644
> --- a/drivers/mfd/madera-core.c
> +++ b/drivers/mfd/madera-core.c
> @@ -428,6 +428,7 @@ static void madera_set_micbias_info(struct madera *madera)
>  
>  int madera_dev_init(struct madera *madera)
>  {
> +	static const char * const mclk_name[] = { "mclk1", "mclk2", "mclk3" };
>  	struct device *dev = madera->dev;
>  	unsigned int hwid;
>  	int (*patch_fn)(struct madera *) = NULL;
> @@ -450,6 +451,17 @@ int madera_dev_init(struct madera *madera)
>  		       sizeof(madera->pdata));
>  	}
>  
> +	BUILD_BUG_ON(ARRAY_SIZE(madera->mclk) != ARRAY_SIZE(mclk_name));

Not sure how this could happen.  Surely we don't need it.

> +	for (i = 0; i < ARRAY_SIZE(madera->mclk); i++) {
> +		madera->mclk[i] = devm_clk_get_optional(madera->dev,
> +							mclk_name[i]);
> +		if (IS_ERR(madera->mclk[i])) {
> +			dev_warn(madera->dev, "Failed to get %s: %ld\n",
> +				 mclk_name[i], PTR_ERR(madera->mclk[i]));

Do we even want to warn on the non-acquisition of an optional clock?

Especially with a message that looks like something actually failed.

> +			madera->mclk[i] = NULL;
> +		}
> +	}
> +
>  	ret = madera_get_reset_gpio(madera);
>  	if (ret)
>  		return ret;
> @@ -660,13 +672,19 @@ int madera_dev_init(struct madera *madera)
>  	}
>  
>  	/* Init 32k clock sourced from MCLK2 */
> +	ret = clk_prepare_enable(madera->mclk[MADERA_MCLK2]);
> +	if (ret != 0) {
> +		dev_err(madera->dev, "Failed to enable 32k clock: %d\n", ret);
> +		goto err_reset;
> +	}

What happened to this being optional?

>  	ret = regmap_update_bits(madera->regmap,
>  			MADERA_CLOCK_32K_1,
>  			MADERA_CLK_32K_ENA_MASK | MADERA_CLK_32K_SRC_MASK,
>  			MADERA_CLK_32K_ENA | MADERA_32KZ_MCLK2);
>  	if (ret) {
>  		dev_err(madera->dev, "Failed to init 32k clock: %d\n", ret);
> -		goto err_reset;
> +		goto err_clock;
>  	}
>  
>  	pm_runtime_set_active(madera->dev);
> @@ -687,6 +705,8 @@ int madera_dev_init(struct madera *madera)
>  
>  err_pm_runtime:
>  	pm_runtime_disable(madera->dev);
> +err_clock:
> +	clk_disable_unprepare(madera->mclk[MADERA_MCLK2]);

Where are the other clocks consumed?

>  err_reset:
>  	madera_enable_hard_reset(madera);
>  	regulator_disable(madera->dcvdd);
> @@ -713,6 +733,8 @@ int madera_dev_exit(struct madera *madera)
>  	 */
>  	pm_runtime_disable(madera->dev);
>  
> +	clk_disable_unprepare(madera->mclk[MADERA_MCLK2]);
> +
>  	regulator_disable(madera->dcvdd);
>  	regulator_put(madera->dcvdd);
>  
> diff --git a/include/linux/mfd/madera/core.h b/include/linux/mfd/madera/core.h
> index 7ffa696cce7ca..2b6c83fe221dc 100644
> --- a/include/linux/mfd/madera/core.h
> +++ b/include/linux/mfd/madera/core.h
> @@ -8,6 +8,7 @@
>  #ifndef MADERA_CORE_H
>  #define MADERA_CORE_H
>  
> +#include <linux/clk.h>
>  #include <linux/gpio/consumer.h>
>  #include <linux/interrupt.h>
>  #include <linux/mfd/madera/pdata.h>
> @@ -29,6 +30,13 @@ enum madera_type {
>  	CS42L92 = 9,
>  };
>  
> +enum {
> +	MADERA_MCLK1,
> +	MADERA_MCLK2,
> +	MADERA_MCLK3,
> +	MADERA_NUM_MCLK
> +};
> +
>  #define MADERA_MAX_CORE_SUPPLIES	2
>  #define MADERA_MAX_GPIOS		40
>  
> @@ -155,6 +163,7 @@ struct snd_soc_dapm_context;
>   * @irq_dev:		the irqchip child driver device
>   * @irq_data:		pointer to irqchip data for the child irqchip driver
>   * @irq:		host irq number from SPI or I2C configuration
> + * @mclk:		pointers to clock supplies
>   * @out_clamp:		indicates output clamp state for each analogue output
>   * @out_shorted:	indicates short circuit state for each analogue output
>   * @hp_ena:		bitflags of enable state for the headphone outputs
> @@ -184,6 +193,8 @@ struct madera {
>  	struct regmap_irq_chip_data *irq_data;
>  	int irq;
>  
> +	struct clk *mclk[MADERA_NUM_MCLK];
> +
>  	unsigned int num_micbias;
>  	unsigned int num_childbias[MADERA_MAX_MICBIAS];
>  

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
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