Re: [PATCH 1/2] mmc: sdhci-of-arasan: add phy support for sdhci-of-arasan

[Ulf Hansson]

On 11 September 2015 at 10:54, Shawn Lin <shawn.lin@xxxxxxxxxxxxxx> wrote:
> This patch adds Generic PHY access for sdhci-of-arasan. Driver
> can get PHY handler from dt-binding, and power-on/init the PHY.
> Also we add pm ops for PHY here if CONFIG_PM_SLEEP is enabled.
>
> Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
> ---
>
>  drivers/mmc/host/sdhci-of-arasan.c | 90 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 90 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
> index 621c3f4..fdd71c7 100644
> --- a/drivers/mmc/host/sdhci-of-arasan.c
> +++ b/drivers/mmc/host/sdhci-of-arasan.c
> @@ -21,6 +21,7 @@
>
>  #include <linux/module.h>
>  #include <linux/of_device.h>
> +#include <linux/phy/phy.h>
>  #include "sdhci-pltfm.h"
>
>  #define SDHCI_ARASAN_CLK_CTRL_OFFSET   0x2c
> @@ -35,6 +36,7 @@
>   */
>  struct sdhci_arasan_data {
>         struct clk      *clk_ahb;
> +       struct phy      *phy;
>  };
>
>  static unsigned int sdhci_arasan_get_timeout_clock(struct sdhci_host *host)
> @@ -67,6 +69,62 @@ static struct sdhci_pltfm_data sdhci_arasan_pdata = {
>
>  #ifdef CONFIG_PM_SLEEP
>  /**
> +  * sdhci_arasan_suspend_phy - Suspend phy method for the driver
> +  * @phy:        Handler of phy structure
> +  * Returns 0 on success and error value on error
> +  *
> +  * Put the phy in a deactive state.
> +  */
> +static int sdhci_arasan_suspend_phy(struct phy *phy)
> +{
> +       int ret;
> +
> +       ret = phy_exit(phy);
> +       if (ret < 0)
> +               goto err_phy_exit;

This odd to me. First you do phy_exit() then phy_power_off(). It seems
like it should be in the opposite order.

Moreover I wonder why phy_exit() is needed, I expected that to be
called at ->remove() only!?

> +
> +       ret = phy_power_off(phy);
> +       if (ret < 0)
> +               goto err_phy_pwr_off;
> +
> +       return 0;
> +
> +err_phy_pwr_off:
> +       phy_power_on(phy);
> +err_phy_exit:
> +       phy_init(phy);
> +       return ret;
> +}
> +
> +/**
> +  * sdhci_arasan_resume_phy - Resume phy method for the driver
> +  * @phy:        Handler of phy structure
> +  * Returns 0 on success and error value on error
> +  *
> +  * Put the phy in a active state.
> +  */
> +static int sdhci_arasan_resume_phy(struct phy *phy)
> +{
> +       int ret;
> +
> +       ret = phy_power_on(phy);
> +       if (ret < 0)
> +               goto err_phy_pwr_on;
> +
> +       ret = phy_init(phy);
> +       if (ret < 0)
> +               goto err_phy_init;
> +

Similar comment as above.

> +       return 0;
> +
> +err_phy_init:
> +       phy_exit(phy);
> +err_phy_pwr_on:
> +       phy_power_off(phy);
> +       return ret;
> +}
> +
> +/**
>   * sdhci_arasan_suspend - Suspend method for the driver
>   * @dev:       Address of the device structure
>   * Returns 0 on success and error value on error
> @@ -88,6 +146,12 @@ static int sdhci_arasan_suspend(struct device *dev)
>         clk_disable(pltfm_host->clk);
>         clk_disable(sdhci_arasan->clk_ahb);
>
> +       if (sdhci_arasan->phy) {
> +               ret = sdhci_arasan_suspend_phy(sdhci_arasan->phy);
> +               if (ret < 0)
> +                       return ret;
> +       }

This means you will suspend the phy after you have disabled the
clocks. Of course I can't tell whether that okay, but it doesn't
follow the same sequence as in ->probe(). To me that indicates that
either probe or suspend/resume could be broken.

> +
>         return 0;
>  }
>
> @@ -119,6 +183,12 @@ static int sdhci_arasan_resume(struct device *dev)
>                 return ret;
>         }
>
> +       if (sdhci_arasan->phy) {
> +               ret = sdhci_arasan_resume_phy(sdhci_arasan->phy);
> +               if (ret < 0)
> +                       return ret;
> +       }
> +
>         return sdhci_resume_host(host);
>  }
>  #endif /* ! CONFIG_PM_SLEEP */
> @@ -163,6 +233,26 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
>                 goto clk_dis_ahb;
>         }
>
> +       sdhci_arasan->phy = devm_phy_get(&pdev->dev, "phy_arasan");
> +       if (!IS_ERR(sdhci_arasan->phy)) {

I understand the phy is optional, but you still need to handle the
EPROBE_DEFER case.

Perhaps you should also use devm_phy_optional_get() instead!?

> +               ret = phy_power_on(sdhci_arasan->phy);

This looks a bit weird. Shouldn't you do phy_init() prior phy_power_on()?

Similar comment applies to phy_exit() and phy_power_off().

> +               if (ret < 0) {
> +                       dev_err(&pdev->dev, "phy_power_on err.\n");
> +                       phy_power_off(sdhci_arasan->phy);
> +                       goto clk_dis_ahb;
> +               }
> +
> +               ret = phy_init(sdhci_arasan->phy);
> +               if (ret < 0) {
> +                       dev_err(&pdev->dev, "phy_init err.\n");
> +                       phy_exit(sdhci_arasan->phy);
> +                       phy_power_off(sdhci_arasan->phy);
> +                       goto clk_dis_ahb;
> +               }
> +       } else {

This else isn't needed. When you are about to access the phy you can
check the cookie of it by "!IS_ERR(sdhci_arasan->phy)".

> +               sdhci_arasan->phy = NULL;
> +       }
> +
>         host = sdhci_pltfm_init(pdev, &sdhci_arasan_pdata, 0);
>         if (IS_ERR(host)) {
>                 ret = PTR_ERR(host);
> --
> 2.3.7
>
>

Kind regards
Uffe
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