? 2016/6/14 7:04, Douglas Anderson ??:
> In commit 802ac39a5566 ("mmc: sdhci-of-arasan: fix set_clock when a phy
> is supported") we added code to power the PHY off and on whenever the
> clock was changed but we avoided doing the power cycle code when the
> clock was low speed. Let's now do it always.
>
> Although there may be other reasons for power cycling the PHY when the
> clock changes, one of the main reasons is that we need to give the DLL a
> chance to re-lock with the new clock.
>
> One of the things that the DLL is for is tuning the Receive Clock in
> HS200 mode and STRB in HS400 mode. Thus it is clear that we should make
> sure we power cycle the PHY (and wait for the DLL to lock) when we know
> we'll be in one of these two speed modes. That's what the original code
> did, though it used the clock rate rather than the speed mode. However,
> even in speed modes other than HS200,/HS400 the DLL is used for
> something since it can be clearly observed that the PHY doesn't function
> properly if you leave the DLL off.
>
> Although it appears less important to power cycle the PHY and wait for
> the DLL to lock when not in HS200/HS400 modes (no bugs were reported),
> it still seems wise to let the locking always happen nevertheless.
>
> Note: as part of this, we make sure that we never try to turn the PHY on
> when the clock is off (when the clock rate is 0). The PHY cannot work
> when the clock is off since its DLL can't lock.
>
> This change requires ("phy: rockchip-emmc: Increase lock time
> allowance") and will cause problems if picked without that change.
Thanks for doint it.
Reviewed-by: Shawn Lin <shawn.lin at rock-chips.com>
>
> Signed-off-by: Douglas Anderson <dianders at chromium.org>
> ---
> Changes in v2: None
>
> drivers/mmc/host/sdhci-of-arasan.c | 23 ++++++++---------------
> 1 file changed, 8 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
> index 533e2bcb10bc..3ff1711077c2 100644
> --- a/drivers/mmc/host/sdhci-of-arasan.c
> +++ b/drivers/mmc/host/sdhci-of-arasan.c
> @@ -35,11 +35,13 @@
> /**
> * struct sdhci_arasan_data
> * @clk_ahb: Pointer to the AHB clock
> - * @phy: Pointer to the generic phy
> + * @phy: Pointer to the generic phy
> + * @phy_on: True if the PHY is turned on.
> */
> struct sdhci_arasan_data {
> struct clk *clk_ahb;
> struct phy *phy;
> + bool phy_on;
> };
>
> static unsigned int sdhci_arasan_get_timeout_clock(struct sdhci_host *host)
> @@ -61,12 +63,10 @@ static void sdhci_arasan_set_clock(struct sdhci_host *host, unsigned int clock)
> {
> struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
> - bool ctrl_phy = false;
>
> - if (clock > MMC_HIGH_52_MAX_DTR && (!IS_ERR(sdhci_arasan->phy)))
> - ctrl_phy = true;
> + if (sdhci_arasan->phy_on && !IS_ERR(sdhci_arasan->phy)) {
> + sdhci_arasan->phy_on = false;
>
> - if (ctrl_phy) {
> spin_unlock_irq(&host->lock);
> phy_power_off(sdhci_arasan->phy);
> spin_lock_irq(&host->lock);
> @@ -74,7 +74,9 @@ static void sdhci_arasan_set_clock(struct sdhci_host *host, unsigned int clock)
>
> sdhci_set_clock(host, clock);
>
> - if (ctrl_phy) {
> + if (host->mmc->actual_clock && !IS_ERR(sdhci_arasan->phy)) {
> + sdhci_arasan->phy_on = true;
> +
> spin_unlock_irq(&host->lock);
> phy_power_on(sdhci_arasan->phy);
> spin_lock_irq(&host->lock);
> @@ -257,12 +259,6 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
> goto clk_disable_all;
> }
>
> - ret = phy_power_on(sdhci_arasan->phy);
> - if (ret < 0) {
> - dev_err(&pdev->dev, "phy_power_on err.\n");
> - goto err_phy_power;
> - }
> -
> host->mmc_host_ops.hs400_enhanced_strobe =
> sdhci_arasan_hs400_enhanced_strobe;
> }
> @@ -275,9 +271,6 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
>
> err_add_host:
> if (!IS_ERR(sdhci_arasan->phy))
> - phy_power_off(sdhci_arasan->phy);
> -err_phy_power:
> - if (!IS_ERR(sdhci_arasan->phy))
> phy_exit(sdhci_arasan->phy);
> clk_disable_all:
> clk_disable_unprepare(clk_xin);
>
--
Best Regards
Shawn Lin
