Re: [PATCH v1] phy: qcom-qmp: Raise qcom_qmp_phy_enable() polling delay

[Vivek Gautam]

Hi Marc,

On 6/13/2019 5:02 PM, Marc Gonzalez wrote:
readl_poll_timeout() calls usleep_range() to sleep between reads.
usleep_range() doesn't work efficiently for tiny values.
Raise the polling delay in qcom_qmp_phy_enable() to bring it in line
with the delay in qcom_qmp_phy_com_init().

Signed-off-by: Marc Gonzalez <marc.w.gonza...@free.fr>
---
Vivek, do you remember why you didn't use the same delay value in
qcom_qmp_phy_enable) and qcom_qmp_phy_com_init() ?

phy_qcom_init() thingy came from the PCIE phy driver from downstream 
msm-3.18
PCIE did something as below:

-----
do {
        if (pcie_phy_is_ready(dev))
                break;
        retries++;
        usleep_range(REFCLK_STABILIZATION_DELAY_US_MIN,
                                 REFCLK_STABILIZATION_DELAY_US_MAX);
} while (retries < PHY_READY_TIMEOUT_COUNT);

REFCLK_STABILIZATION_DELAY_US_MIN/MAX ==> 1000/1005
PHY_READY_TIMEOUT_COUNT ==> 10
-----


phy_enable() from the usb phy driver from downstream.
 /* Wait for PHY initialization to be done */
 do {
         if (readl_relaxed(phy->base +
                 phy->phy_reg[USB3_PHY_PCS_STATUS]) & PHYSTATUS)
                 usleep_range(1, 2);
else
break;
 } while (--init_timeout_usec);

init_timeout_usec ==> 1000
-----
USB never had a COM_PHY status bit.

So clearly the resolutions were different.

Does this change solves an issue at hand?

---
  drivers/phy/qualcomm/phy-qcom-qmp.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/phy/qualcomm/phy-qcom-qmp.c 
b/drivers/phy/qualcomm/phy-qcom-qmp.c
index bb522b915fa9..34ff6434da8f 100644
--- a/drivers/phy/qualcomm/phy-qcom-qmp.c
+++ b/drivers/phy/qualcomm/phy-qcom-qmp.c
@@ -1548,7 +1548,7 @@ static int qcom_qmp_phy_enable(struct phy *phy)
        status = pcs + cfg->regs[QPHY_PCS_READY_STATUS];
        mask = cfg->mask_pcs_ready;
  
-	ret = readl_poll_timeout(status, val, val & mask, 1,
+       ret = readl_poll_timeout(status, val, val & mask, 10,
                                 PHY_INIT_COMPLETE_TIMEOUT);
        if (ret) {
                dev_err(qmp->dev, "phy initialization timed-out\n");