On 6.06.2023 16:35, Adrien Thierry wrote: > Thanks for your feedback Konrad and Andrew! > > On Tue, Jun 06, 2023 at 08:55:16AM -0500, Andrew Halaney wrote: >> On Tue, Jun 06, 2023 at 01:14:00AM +0200, Konrad Dybcio wrote: >>> >>> >>> On 5.06.2023 20:44, Adrien Thierry wrote: >>>> The driver is not enabling the ref clock, which thus gets disabled by >>>> the clk_disable_unused initcall. This leads to the dwc3 controller >>>> failing to initialize if probed after clk_disable_unused is called, for >>>> instance when the driver is built as a module. >>>> >>>> To fix this, switch to the clk_bulk API to handle both cfg_ahb and ref >>>> clocks at the proper places. >>>> >>>> Note that the cfg_ahb clock is currently not used by any device tree >>>> instantiation of the PHY. Work needs to be done separately to fix this. >>>> >>>> Link: https://lore.kernel.org/linux-arm-msm/ZEqvy+khHeTkC2hf@fedora/ >>>> Fixes: 51e8114f80d0 ("phy: qcom-snps: Add SNPS USB PHY driver for QCOM based SOCs") >>>> Signed-off-by: Adrien Thierry <athierry@xxxxxxxxxx> >>>> --- >>>> drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c | 67 ++++++++++++++----- >>>> 1 file changed, 49 insertions(+), 18 deletions(-) >>>> >>>> diff --git a/drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c b/drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c >>>> index 6c237f3cc66d..ce1d2f8b568a 100644 >>>> --- a/drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c >>>> +++ b/drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c >>>> @@ -110,11 +110,13 @@ struct phy_override_seq { >>>> /** >>>> * struct qcom_snps_hsphy - snps hs phy attributes >>>> * >>>> + * @dev: device structure >>>> + * >>>> * @phy: generic phy >>>> * @base: iomapped memory space for snps hs phy >>>> * >>>> - * @cfg_ahb_clk: AHB2PHY interface clock >>>> - * @ref_clk: phy reference clock >>>> + * @num_clks: number of clocks >>>> + * @clks: array of clocks >>>> * @phy_reset: phy reset control >>>> * @vregs: regulator supplies bulk data >>>> * @phy_initialized: if PHY has been initialized correctly >>>> @@ -122,11 +124,13 @@ struct phy_override_seq { >>>> * @update_seq_cfg: tuning parameters for phy init >>>> */ >>>> struct qcom_snps_hsphy { >>>> + struct device *dev; >>>> + >>>> struct phy *phy; >>>> void __iomem *base; >>>> >>>> - struct clk *cfg_ahb_clk; >>>> - struct clk *ref_clk; >>>> + int num_clks; >>>> + struct clk_bulk_data *clks; >>>> struct reset_control *phy_reset; >>>> struct regulator_bulk_data vregs[SNPS_HS_NUM_VREGS]; >>>> >>>> @@ -135,6 +139,32 @@ struct qcom_snps_hsphy { >>>> struct phy_override_seq update_seq_cfg[NUM_HSPHY_TUNING_PARAMS]; >>>> }; >>>> >>>> +static int qcom_snps_hsphy_clk_init(struct qcom_snps_hsphy *hsphy) >>>> +{ >>>> + struct device *dev = hsphy->dev; >>>> + >>>> + hsphy->num_clks = 2; >>>> + hsphy->clks = devm_kcalloc(dev, hsphy->num_clks, sizeof(*hsphy->clks), GFP_KERNEL); >>>> + if (!hsphy->clks) >>>> + return -ENOMEM; >>>> + >>>> + /* >>>> + * HACK: For cfg_ahb clock, use devm_clk_get_optional() because currently no device >>>> + * tree instantiation of the PHY is using the clock. This needs to be fixed in order >>>> + * for this code to be able to use devm_clk_bulk_get(). >>>> + */ >>>> + hsphy->clks[0].id = "cfg_ahb"; >>>> + hsphy->clks[0].clk = devm_clk_get_optional(dev, "cfg_ahb"); >>> Hm, maybe you could first check if we can get this clock >>> properly (!IS_ERR_OR_NULL) and then allocate the second >>> slot.. >>> >> >> The bulk clk api handles NULL clks without issue if I am reading right, >> so personally if we're going to use the bulk api I say we carry the extra >> slot unconditionally. No expert on this stuff but that seems more >> straightforward. Honestly I wouldn't mind using the bulk optional API, >> then checking the "non optional ref clock" manually. That's closer to >> the ideal flow to me. Super opinionated though, don't take my word as >> right. >> > > Agree with Andrew. Since cfg_ahb is always NULL, I'm certainly "wasting" > an array cell here but I think it also better highlights the fact that > it's a hack and that cfg_ahb needs to be properly wired in the DTs. As for > using the bulk optional API, I'm fine with both! Hm right, let's keep it as-is so that the other clock which is actually necessary never gets skipped accidentally.. Konrad > >>>> + >>>> + hsphy->clks[1].id = "ref"; >>>> + hsphy->clks[1].clk = devm_clk_get(dev, "ref"); >>>> + if (IS_ERR(hsphy->clks[1].clk)) >>>> + return dev_err_probe(dev, PTR_ERR(hsphy->clks[1].clk), >>>> + "failed to get ref clk\n"); >>>> + >>>> + return 0; >>>> +} >>>> + >>>> static inline void qcom_snps_hsphy_write_mask(void __iomem *base, u32 offset, >>>> u32 mask, u32 val) >>>> { >>>> @@ -165,7 +195,7 @@ static int qcom_snps_hsphy_suspend(struct qcom_snps_hsphy *hsphy) >>>> 0, USB2_AUTO_RESUME); >>>> } >>>> >>>> - clk_disable_unprepare(hsphy->cfg_ahb_clk); >>>> + clk_bulk_disable_unprepare(hsphy->num_clks, hsphy->clks); >>>> return 0; >>>> } >>>> >>>> @@ -175,9 +205,9 @@ static int qcom_snps_hsphy_resume(struct qcom_snps_hsphy *hsphy) >>>> >>>> dev_dbg(&hsphy->phy->dev, "Resume QCOM SNPS PHY, mode\n"); >>>> >>>> - ret = clk_prepare_enable(hsphy->cfg_ahb_clk); >>>> + ret = clk_bulk_prepare_enable(hsphy->num_clks, hsphy->clks); >>> Aren't you dereferencing NULL if the optional clock is absent? >>> >> >> Similar to above, the bulk api seems to handle NULL clks gracefully. >> > > devm_clk_get_optional() will return NULL for cfg_ahb, but AFAIU NULL > serves as a dummy clock [1] with which the clock API deals gracefully. The > various functions like clk_prepare(), clk_enable() check if the clock is > NULL and return 0 immediately if that's the case (see for instance [2]). > > [1] https://elixir.bootlin.com/linux/v6.4-rc5/source/include/linux/clk.h#L514 > [2] https://elixir.bootlin.com/linux/v6.4-rc5/source/drivers/clk/clk.c#L1045 > > Best, > Adrien > >> Thanks, >> Andrew >> >
