diff mbox series

[v3,04/15] phy: tegra: xusb: tegra210: Do not reset UPHY PLL

Message ID 20200909081041.3190157-5-jckuo@nvidia.com
State New
Headers show
Series Tegra XHCI controller ELPG support | expand

Commit Message

JC Kuo Sept. 9, 2020, 8:10 a.m. UTC
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(-)

Comments

Thierry Reding Sept. 28, 2020, 1:06 p.m. UTC | #1
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 mbox series

Patch

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: