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

Frank Li
2024-10-02T16:23:50Z

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@nxp.com>
> ---
> 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