Re: [PATCH v8 04/13] phy: tegra: xusb: Rearrange UPHY init on Tegra210

Vinod Koul
2021-03-30T14:21:31Z

On 25-03-21, 17:40, Thierry Reding wrote:
> From: JC Kuo <jckuo@nvidia.com>
>
> This commit is a preparation for enabling XUSB SC7 support.
> It rearranges Tegra210 XUSB PADCTL UPHY initialization sequence,
> for the following reasons:
>
> 1. PLLE hardware power sequencer has to be enabled only after both
> PEX UPHY PLL and SATA UPHY PLL are initialized.
> tegra210_uphy_init() -> tegra210_pex_uphy_enable()
> -> tegra210_sata_uphy_enable()
> -> tegra210_plle_hw_sequence_start()
> -> tegra210_aux_mux_lp0_clamp_disable()
>
> 2. At cold boot and SC7 exit, the following bits must be cleared after
> PEX/SATA lanes are out of IDDQ (IDDQ_DISABLE=1).
> a. XUSB_PADCTL_ELPG_PROGRAM1_AUX_MUX_LP0_CLAMP_EN,
> b. XUSB_PADCTL_ELPG_PROGRAM1_AUX_MUX_LP0_CLAMP_EN_EARLY
> c. XUSB_PADCTL_ELPG_PROGRAM1_AUX_MUX_LP0_VCORE_DOWN
>
> tegra210_pex_uphy_enable() and tegra210_sata_uphy_enable() are in
> charge of bringing lanes out of IDDQ, and then AUX_MUX_LP0_* bits
> will be cleared by tegra210_aux_mux_lp0_clamp_disable().
>
> 3. Once UPHY PLL hardware power sequencer is enabled, do not assert
> reset to PEX/SATA PLLs, otherwise UPHY PLL operation will be broken.

Acked-By: Vinod Koul <vkoul@kernel.org>

--
~Vinod