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Message-ID: <YFQATabI/3V/aTfL@pendragon.ideasonboard.com>
Date: Fri, 19 Mar 2021 03:37:17 +0200
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: Manish Narani <manish.narani@...inx.com>
Cc: kishon@...com, vkoul@...nel.org, michal.simek@...inx.com,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
git@...inx.com
Subject: Re: [PATCH v2] phy: zynqmp: Handle the clock enable/disable properly
Hi Manish,
Thank you for the patch.
On Tue, Mar 09, 2021 at 04:47:44PM +0530, Manish Narani wrote:
> The current driver is not handling the clock enable/disable operations
> properly. The clocks need to be handled correctly by enabling or
> disabling at appropriate places. This patch adds code to handle the
> same.
>
> Signed-off-by: Manish Narani <manish.narani@...inx.com>
> ---
> drivers/phy/xilinx/phy-zynqmp.c | 57 ++++++++++++++++++++++++++++++++++++-----
> 1 file changed, 50 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/phy/xilinx/phy-zynqmp.c b/drivers/phy/xilinx/phy-zynqmp.c
> index 2b65f84..37fcecf 100644
> --- a/drivers/phy/xilinx/phy-zynqmp.c
> +++ b/drivers/phy/xilinx/phy-zynqmp.c
> @@ -219,6 +219,7 @@ struct xpsgtr_dev {
> struct mutex gtr_mutex; /* mutex for locking */
> struct xpsgtr_phy phys[NUM_LANES];
> const struct xpsgtr_ssc *refclk_sscs[NUM_LANES];
> + struct clk *clk[NUM_LANES];
> bool tx_term_fix;
> unsigned int saved_icm_cfg0;
> unsigned int saved_icm_cfg1;
> @@ -818,11 +819,15 @@ static struct phy *xpsgtr_xlate(struct device *dev,
> static int __maybe_unused xpsgtr_suspend(struct device *dev)
> {
> struct xpsgtr_dev *gtr_dev = dev_get_drvdata(dev);
> + unsigned int i;
>
> /* Save the snapshot ICM_CFG registers. */
> gtr_dev->saved_icm_cfg0 = xpsgtr_read(gtr_dev, ICM_CFG0);
> gtr_dev->saved_icm_cfg1 = xpsgtr_read(gtr_dev, ICM_CFG1);
>
> + for (i = 0; i < ARRAY_SIZE(gtr_dev->clk); i++)
> + clk_disable_unprepare(gtr_dev->clk[i]);
> +
> return 0;
> }
>
> @@ -832,6 +837,13 @@ static int __maybe_unused xpsgtr_resume(struct device *dev)
> unsigned int icm_cfg0, icm_cfg1;
> unsigned int i;
> bool skip_phy_init;
> + int err;
> +
> + for (i = 0; i < ARRAY_SIZE(gtr_dev->clk); i++) {
> + err = clk_prepare_enable(gtr_dev->clk[i]);
> + if (err)
> + goto err_clk_put;
> + }
>
> icm_cfg0 = xpsgtr_read(gtr_dev, ICM_CFG0);
> icm_cfg1 = xpsgtr_read(gtr_dev, ICM_CFG1);
> @@ -852,6 +864,12 @@ static int __maybe_unused xpsgtr_resume(struct device *dev)
> gtr_dev->phys[i].skip_phy_init = skip_phy_init;
>
> return 0;
> +
> +err_clk_put:
> + for (i = 0; i < ARRAY_SIZE(gtr_dev->clk); i++)
> + clk_disable_unprepare(gtr_dev->clk[i]);
You should only disable the clocks that have been successfully enabled.
Something like this should do:
while (i-- > 0)
clk_disable_unprepare(gtr_dev->clk[i]);
> +
> + return err;
> }
>
> static const struct dev_pm_ops xpsgtr_pm_ops = {
> @@ -865,6 +883,7 @@ static const struct dev_pm_ops xpsgtr_pm_ops = {
> static int xpsgtr_get_ref_clocks(struct xpsgtr_dev *gtr_dev)
> {
> unsigned int refclk;
> + int ret;
>
> for (refclk = 0; refclk < ARRAY_SIZE(gtr_dev->refclk_sscs); ++refclk) {
> unsigned long rate;
> @@ -874,14 +893,22 @@ static int xpsgtr_get_ref_clocks(struct xpsgtr_dev *gtr_dev)
>
> snprintf(name, sizeof(name), "ref%u", refclk);
> clk = devm_clk_get_optional(gtr_dev->dev, name);
> - if (IS_ERR(clk))
> - return dev_err_probe(gtr_dev->dev, PTR_ERR(clk),
> - "Failed to get reference clock %u\n",
> - refclk);
> + if (IS_ERR(clk)) {
> + ret = dev_err_probe(gtr_dev->dev, PTR_ERR(clk),
> + "Failed to get reference clock %u\n",
> + refclk);
> + goto err_clk_put;
> + }
>
> if (!clk)
> continue;
>
> + gtr_dev->clk[refclk] = clk;
> +
> + ret = clk_prepare_enable(gtr_dev->clk[refclk]);
> + if (ret)
> + goto err_clk_put;
> +
> /*
> * Get the spread spectrum (SSC) settings for the reference
> * clock rate.
> @@ -899,11 +926,18 @@ static int xpsgtr_get_ref_clocks(struct xpsgtr_dev *gtr_dev)
> dev_err(gtr_dev->dev,
> "Invalid rate %lu for reference clock %u\n",
> rate, refclk);
> - return -EINVAL;
> + ret = -EINVAL;
> + goto err_clk_put;
> }
> }
>
> return 0;
> +
> +err_clk_put:
> + for (refclk = 0; refclk < ARRAY_SIZE(gtr_dev->clk); refclk++)
> + clk_disable_unprepare(gtr_dev->clk[refclk]);
Here too you will disable a clock that hasn't been enabled if
clk_prepare_enable() failed. Clocks that haven't been retrieved at all
are fine, as clk_disable_unprepare() can be safely called with a NULL
pointer. This could be fixed by replacing the code above with
ret = clk_prepare_enable(clk);
if (ret)
goto err_clk_put;
gtr_dev->clk[refclk] = clk;
> +
> + return ret;
> }
>
> static int xpsgtr_probe(struct platform_device *pdev)
> @@ -912,6 +946,7 @@ static int xpsgtr_probe(struct platform_device *pdev)
> struct xpsgtr_dev *gtr_dev;
> struct phy_provider *provider;
> unsigned int port;
> + unsigned int i;
> int ret;
>
> gtr_dev = devm_kzalloc(&pdev->dev, sizeof(*gtr_dev), GFP_KERNEL);
> @@ -951,7 +986,8 @@ static int xpsgtr_probe(struct platform_device *pdev)
> phy = devm_phy_create(&pdev->dev, np, &xpsgtr_phyops);
> if (IS_ERR(phy)) {
> dev_err(&pdev->dev, "failed to create PHY\n");
> - return PTR_ERR(phy);
> + ret = PTR_ERR(phy);
> + goto err_clk_put;
> }
>
> gtr_phy->phy = phy;
> @@ -962,9 +998,16 @@ static int xpsgtr_probe(struct platform_device *pdev)
> provider = devm_of_phy_provider_register(&pdev->dev, xpsgtr_xlate);
> if (IS_ERR(provider)) {
> dev_err(&pdev->dev, "registering provider failed\n");
> - return PTR_ERR(provider);
> + ret = PTR_ERR(provider);
> + goto err_clk_put;
> }
> return 0;
> +
> +err_clk_put:
> + for (i = 0; i < ARRAY_SIZE(gtr_dev->clk); i++)
> + clk_disable_unprepare(gtr_dev->clk[i]);
> +
> + return ret;
> }
>
> static const struct of_device_id xpsgtr_of_match[] = {
--
Regards,
Laurent Pinchart
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