On Thu, Nov 21, 2024 at 04:09:27PM +0800, Song Xue wrote:
> Set the current load before enable regulator supplies at QUSB phy.
>
> Encountered one issue where the board powered down instantly once the UVC
> camera was attached to USB port while adding host mode on usb port and
> testing a UVC camera with the driver on QCS615 platform. The extensible
> boot loader mentioned that OCP(Over Current Protection) occurred at LDO12
> from regulators-0 upon powered on board again. That indicates that the
> current load set for QUSB phy, which use the regulator supply, is lower
> than expected.
>
> As per QUSB spec, set the maximum current load at 30mA to avoid overcurrent
> load when attach a device to the USB port.
>
> Fixes: 937e17f36a32 ("phy: qcom-qusb2: Power-on PHY before initialization")
> Signed-off-by: Song Xue <quic_songxue@xxxxxxxxxxx>
The patch looks good. But if we describe the regulator(s) with
regulator-allow-set-load; and not all the consumers vote for load, the
sum of the load when USB phy is disabled goes to 0 and we will enter
LPM.
For this reason we're not doing any load requests today. Can you confirm
that this works fine with a dtb where only HPM is permitted (as well as
LPM and HPM)? If so I'd be in favor of us merging this change, but
keeping the dts HPM-only until someone confirms that all consumers of
these regulators specify load-votes.
Regards,
Bjorn
> ---
> Changes in v2:
> - Removed "---" above the Fixes.
> - Link to v1: https://lore.kernel.org/r/20241121-add_set_load_to_qusb_phy-v1-1-0f44f3a3290e@xxxxxxxxxxx
> ---
> drivers/phy/qualcomm/phy-qcom-qusb2.c | 13 ++++++++++++-
> 1 file changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/phy/qualcomm/phy-qcom-qusb2.c b/drivers/phy/qualcomm/phy-qcom-qusb2.c
> index c52655a383cef008552ed4533b9f31d1cbf34a13..80f0d17c42717e843937255a9a780bbae5998535 100644
> --- a/drivers/phy/qualcomm/phy-qcom-qusb2.c
> +++ b/drivers/phy/qualcomm/phy-qcom-qusb2.c
> @@ -722,16 +722,27 @@ static int __maybe_unused qusb2_phy_runtime_resume(struct device *dev)
> return ret;
> }
>
> +#define QUSB2PHY_HPM_LOAD 30000 /*uA*/
> +
> static int qusb2_phy_init(struct phy *phy)
> {
> struct qusb2_phy *qphy = phy_get_drvdata(phy);
> const struct qusb2_phy_cfg *cfg = qphy->cfg;
> unsigned int val = 0;
> unsigned int clk_scheme;
> - int ret;
> + int ret, i;
>
> dev_vdbg(&phy->dev, "%s(): Initializing QUSB2 phy\n", __func__);
>
> + /* set the current load */
> + for (i = 0; i < ARRAY_SIZE(qphy->vregs); i++) {
> + ret = regulator_set_load(qphy->vregs[i].consumer, QUSB2PHY_HPM_LOAD);
> + if (ret) {
> + dev_err(&phy->dev, "failed to set load at %s\n", qphy->vregs[i].supply);
> + return ret;
> + }
> + }
> +
> /* turn on regulator supplies */
> ret = regulator_bulk_enable(ARRAY_SIZE(qphy->vregs), qphy->vregs);
> if (ret)
>
> ---
> base-commit: decc701f41d07481893fdea942c0ac6b226e84cd
> change-id: 20241121-add_set_load_to_qusb_phy-d1327c797ffe
>
> Best regards,
> --
> Song Xue <quic_songxue@xxxxxxxxxxx>
>
>
