| Message ID | 20200909081041.3190157-5-jckuo@nvidia.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Tegra XHCI controller ELPG support | expand |
On Wed, Sep 09, 2020 at 04:10:30PM +0800, JC Kuo wrote: > Once UPHY PLL hardware power sequencer is enabled, do not assert > reset to PEX/SATA PLLs, otherwise UPHY PLL operation will be broken. > This commit removes reset_control_assert(pcie->rst) and > reset_control_assert(sata->rst) from PEX/SATA UPHY disable procedure. > > Signed-off-by: JC Kuo <jckuo@nvidia.com> > --- > v3: > new, was a part of "phy: tegra: xusb: Rearrange UPHY init on Tegra210" > > drivers/phy/tegra/xusb-tegra210.c | 2 -- > 1 file changed, 2 deletions(-) > > diff --git a/drivers/phy/tegra/xusb-tegra210.c b/drivers/phy/tegra/xusb-tegra210.c > index f06e7bc7a51b..ef4bbcbed60b 100644 > --- a/drivers/phy/tegra/xusb-tegra210.c > +++ b/drivers/phy/tegra/xusb-tegra210.c > @@ -504,7 +504,6 @@ static void tegra210_pex_uphy_disable(struct tegra_xusb_padctl *padctl) > if (--pcie->enable > 0) > goto unlock; > > - reset_control_assert(pcie->rst); > clk_disable_unprepare(pcie->pll); > > unlock: > @@ -746,7 +745,6 @@ static void tegra210_sata_uphy_disable(struct tegra_xusb_padctl *padctl) > if (--sata->enable > 0) > goto unlock; > > - reset_control_assert(sata->rst); > clk_disable_unprepare(sata->pll); > > unlock: Does this mean that we can no longer reset these PLLs anymore? Is that safe? Would we ever need to reset them for recovery or similar? For power saving, is disabling the clock enough, or could we save some extra power by putting the PLLs into reset? Thierry
Asserting reset to a PLL when it's managed by hardware power sequencer would break sequencer's state machine. Putting PLL in reset doesn't save some extra power. Thanks for review. JC On 9/28/20 9:06 PM, Thierry Reding wrote: > On Wed, Sep 09, 2020 at 04:10:30PM +0800, JC Kuo wrote: >> Once UPHY PLL hardware power sequencer is enabled, do not assert >> reset to PEX/SATA PLLs, otherwise UPHY PLL operation will be broken. >> This commit removes reset_control_assert(pcie->rst) and >> reset_control_assert(sata->rst) from PEX/SATA UPHY disable procedure. >> >> Signed-off-by: JC Kuo <jckuo@nvidia.com> >> --- >> v3: >> new, was a part of "phy: tegra: xusb: Rearrange UPHY init on Tegra210" >> >> drivers/phy/tegra/xusb-tegra210.c | 2 -- >> 1 file changed, 2 deletions(-) >> >> diff --git a/drivers/phy/tegra/xusb-tegra210.c b/drivers/phy/tegra/xusb-tegra210.c >> index f06e7bc7a51b..ef4bbcbed60b 100644 >> --- a/drivers/phy/tegra/xusb-tegra210.c >> +++ b/drivers/phy/tegra/xusb-tegra210.c >> @@ -504,7 +504,6 @@ static void tegra210_pex_uphy_disable(struct tegra_xusb_padctl *padctl) >> if (--pcie->enable > 0) >> goto unlock; >> >> - reset_control_assert(pcie->rst); >> clk_disable_unprepare(pcie->pll); >> >> unlock: >> @@ -746,7 +745,6 @@ static void tegra210_sata_uphy_disable(struct tegra_xusb_padctl *padctl) >> if (--sata->enable > 0) >> goto unlock; >> >> - reset_control_assert(sata->rst); >> clk_disable_unprepare(sata->pll); >> >> unlock: > > Does this mean that we can no longer reset these PLLs anymore? Is that > safe? Would we ever need to reset them for recovery or similar? For > power saving, is disabling the clock enough, or could we save some extra > power by putting the PLLs into reset? > > Thierry >
diff --git a/drivers/phy/tegra/xusb-tegra210.c b/drivers/phy/tegra/xusb-tegra210.c index f06e7bc7a51b..ef4bbcbed60b 100644 --- a/drivers/phy/tegra/xusb-tegra210.c +++ b/drivers/phy/tegra/xusb-tegra210.c @@ -504,7 +504,6 @@ static void tegra210_pex_uphy_disable(struct tegra_xusb_padctl *padctl) if (--pcie->enable > 0) goto unlock; - reset_control_assert(pcie->rst); clk_disable_unprepare(pcie->pll); unlock: @@ -746,7 +745,6 @@ static void tegra210_sata_uphy_disable(struct tegra_xusb_padctl *padctl) if (--sata->enable > 0) goto unlock; - reset_control_assert(sata->rst); clk_disable_unprepare(sata->pll); unlock:
Once UPHY PLL hardware power sequencer is enabled, do not assert reset to PEX/SATA PLLs, otherwise UPHY PLL operation will be broken. This commit removes reset_control_assert(pcie->rst) and reset_control_assert(sata->rst) from PEX/SATA UPHY disable procedure. Signed-off-by: JC Kuo <jckuo@nvidia.com> --- v3: new, was a part of "phy: tegra: xusb: Rearrange UPHY init on Tegra210" drivers/phy/tegra/xusb-tegra210.c | 2 -- 1 file changed, 2 deletions(-)