Re: [PATCH v2 2/2] mtd: nand: raw: gpmi: improve power management handling

[Frank Li]

On Wed, Oct 02, 2024 at 10:39:44AM -0500, Han Xu wrote:
> The commit refactors the power management handling in the gpmi nand
> driver. It removes redundant pm_runtime calls in the probe function,
> handles the pad control in suspend and resume, and moves the calls to
> acquire and release DMA channels to the runtime suspend and resume
> functions.

Use  imperative mode

Refactor the power management. Remove redundate pm_runtime calls and pad
control in the probe function. Move acquire and release DMA channels to
the runtime suspend and resume because dma engine use DMA channel used/free
to do power saving.

>
> Signed-off-by: Han Xu <han.xu@xxxxxxx>
> ---
>  drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c | 66 ++++++++++++----------
>  1 file changed, 37 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c b/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
> index a7d79679248d..76e4b89e2451 100644
> --- a/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
> +++ b/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
> @@ -15,6 +15,7 @@
>  #include <linux/of.h>
>  #include <linux/platform_device.h>
>  #include <linux/pm_runtime.h>
> +#include <linux/pinctrl/consumer.h>

order by alphabet

>  #include <linux/dma/mxs-dma.h>
>  #include "gpmi-nand.h"
>  #include "gpmi-regs.h"
> @@ -737,9 +738,8 @@ static int bch_set_geometry(struct gpmi_nand_data *this)
>  	if (ret)
>  		return ret;
>
> -	ret = pm_runtime_get_sync(this->dev);
> +	ret = pm_runtime_resume_and_get(this->dev);
>  	if (ret < 0) {
> -		pm_runtime_put_autosuspend(this->dev);
>  		return ret;
>  	}
>
> @@ -1301,10 +1301,6 @@ static int acquire_resources(struct gpmi_nand_data *this)
>  	if (ret)
>  		goto exit_regs;
>
> -	ret = acquire_dma_channels(this);
> -	if (ret)
> -		goto exit_regs;
> -
>  	ret = gpmi_get_clks(this);
>  	if (ret)
>  		goto exit_clock;
> @@ -2761,15 +2757,9 @@ static int gpmi_nand_probe(struct platform_device *pdev)
>  	if (ret)
>  		goto exit_acquire_resources;
>
> -	ret = __gpmi_enable_clk(this, true);
> -	if (ret)
> -		goto exit_acquire_resources;
> -
> +	pm_runtime_enable(&pdev->dev);
>  	pm_runtime_set_autosuspend_delay(&pdev->dev, 500);
>  	pm_runtime_use_autosuspend(&pdev->dev);
> -	pm_runtime_set_active(&pdev->dev);
> -	pm_runtime_enable(&pdev->dev);
> -	pm_runtime_get_sync(&pdev->dev);
>
>  	ret = gpmi_init(this);
>  	if (ret)
> @@ -2779,15 +2769,12 @@ static int gpmi_nand_probe(struct platform_device *pdev)
>  	if (ret)
>  		goto exit_nfc_init;
>
> -	pm_runtime_mark_last_busy(&pdev->dev);
> -	pm_runtime_put_autosuspend(&pdev->dev);
> -
>  	dev_info(this->dev, "driver registered.\n");
>
>  	return 0;
>
>  exit_nfc_init:
> -	pm_runtime_put(&pdev->dev);
> +	pm_runtime_dont_use_autosuspend(&pdev->dev);
>  	pm_runtime_disable(&pdev->dev);
>  	release_resources(this);
>  exit_acquire_resources:
> @@ -2801,22 +2788,23 @@ static void gpmi_nand_remove(struct platform_device *pdev)
>  	struct nand_chip *chip = &this->nand;
>  	int ret;
>
> -	pm_runtime_put_sync(&pdev->dev);
> -	pm_runtime_disable(&pdev->dev);
> -
>  	ret = mtd_device_unregister(nand_to_mtd(chip));
>  	WARN_ON(ret);
>  	nand_cleanup(chip);
>  	gpmi_free_dma_buffer(this);
>  	release_resources(this);
> +	pm_runtime_dont_use_autosuspend(&pdev->dev);
> +	pm_runtime_disable(&pdev->dev);
>  }
>
>  static int gpmi_pm_suspend(struct device *dev)
>  {
> -	struct gpmi_nand_data *this = dev_get_drvdata(dev);
> +	int ret;
>
> -	release_dma_channels(this);
> -	return 0;
> +	pinctrl_pm_select_sleep_state(dev);
> +	ret = pm_runtime_force_suspend(dev);
> +
> +	return ret;

needn't define varible ret

return pm_runtime_force_suspend(dev);

>  }
>
>  static int gpmi_pm_resume(struct device *dev)
> @@ -2824,9 +2812,13 @@ static int gpmi_pm_resume(struct device *dev)
>  	struct gpmi_nand_data *this = dev_get_drvdata(dev);
>  	int ret;
>
> -	ret = acquire_dma_channels(this);
> -	if (ret < 0)
> +	ret = pm_runtime_force_resume(dev);
> +	if (ret) {
> +		dev_err(this->dev, "Error in resume %d\n", ret);
>  		return ret;
> +	}
> +
> +	pinctrl_pm_select_default_state(dev);
>
>  	/* re-init the GPMI registers */
>  	ret = gpmi_init(this);
> @@ -2849,18 +2841,34 @@ static int gpmi_pm_resume(struct device *dev)
>  	return 0;
>  }
>
> -static int __maybe_unused gpmi_runtime_suspend(struct device *dev)
> +#define gpmi_enable_clk(x)	__gpmi_enable_clk(x, true)
> +#define gpmi_disable_clk(x)	__gpmi_enable_clk(x, false)
> +
> +static int gpmi_runtime_suspend(struct device *dev)

remove __maybe should below previous patch.

>  {
>  	struct gpmi_nand_data *this = dev_get_drvdata(dev);
>
> -	return __gpmi_enable_clk(this, false);
> +	gpmi_disable_clk(this);
> +	release_dma_channels(this);
> +
> +	return 0;
>  }
>
> -static int __maybe_unused gpmi_runtime_resume(struct device *dev)
> +static int gpmi_runtime_resume(struct device *dev)
>  {
>  	struct gpmi_nand_data *this = dev_get_drvdata(dev);
> +	int ret;
> +
> +	ret = gpmi_enable_clk(this);
> +	if (ret)
> +		return ret;
> +
> +	ret = acquire_dma_channels(this);
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
>
> -	return __gpmi_enable_clk(this, true);

It will be simple if

	return acquire_dma_channels(this);
>  }
>
>  static const struct dev_pm_ops gpmi_pm_ops = {
> --
> 2.34.1
>