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Message-ID: <CAPDyKFpwgZSkE+TNehZ1Un=5CfjoEtfvELfrS6t-ZHZPscy3Yg@mail.gmail.com>
Date: Fri, 16 Oct 2015 14:35:00 +0200
From: Ulf Hansson <ulf.hansson@...aro.org>
To: Shawn Lin <shawn.lin@...k-chips.com>
Cc: Michal Simek <michal.simek@...inx.com>,
"S?ren Brinkmann" <soren.brinkmann@...inx.com>,
linux-mmc <linux-mmc@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"open list:ARM/Rockchip SoC..." <linux-rockchip@...ts.infradead.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: Re: [PATCH 1/2] mmc: sdhci-of-arasan: add phy support for sdhci-of-arasan
On 11 September 2015 at 10:54, Shawn Lin <shawn.lin@...k-chips.com> 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@...k-chips.com>
> ---
>
> 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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