linux-kernel - Re: [PATCH v3 1/2] phy: cadence: cdns-dphy: Fix PLL lock and O_CMN

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Message-ID: <218ba1a0-068d-4bb2-bba2-2739afa7f470@ideasonboard.com>
Date: Wed, 18 Jun 2025 13:01:48 +0300
From: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
To: Devarsh Thakkar <devarsht@...com>
Cc: sakari.ailus@...ux.intel.com, u.kleine-koenig@...libre.com,
 vigneshr@...com, aradhya.bhatia@...ux.dev, s-jain1@...com,
 r-donadkar@...com, vkoul@...nel.org, kishon@...nel.org, mripard@...nel.org,
 linux-phy@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 1/2] phy: cadence: cdns-dphy: Fix PLL lock and
 O_CMN_READY polling

Hi,

On 02/05/2025 06:34, Devarsh Thakkar wrote:
> PLL lockup and O_CMN_READY assertion can only happen after common state
> machine gets enabled (by programming DPHY_CMN_SSM register), but driver was
> polling them before the common state machine was enabled. To fix this :
> 
> - Add new function callbacks for polling on PLL lock and O_CMN_READY
>   assertion.
> - As state machine and clocks get enabled in power_on callback only, move
>   the clock related programming part from configure callback to power_on
>   callback and poll for the PLL lockup and O_CMN_READY assertion after
>   state machine gets enabled.
> - The configure callback only saves the PLL configuration received from the
>   client driver which will be applied later on in power_on callback.
> - Add checks to ensure configure is called before power_on and state
>   machine is in disabled state before power_on callback is called.
> - Disable state machine in power_off so that client driver can
>   re-configure the PLL by following up a power_off, configure, power_on
>   sequence.
> 
> Cc: stable@...r.kernel.org
> Fixes: 7a343c8bf4b5 ("phy: Add Cadence D-PHY support")
> Signed-off-by: Devarsh Thakkar <devarsht@...com>
> ---
> V3:
> - Move out clock programming logic to power_on as PLL polling and enable
>   can happen only after SSM enable
> - Disable state machine on power off
> 
> V2: 
> - Return error code on polling timeout
> - Moved out calibration logic to separate patch
> 
>  drivers/phy/cadence/cdns-dphy.c | 109 +++++++++++++++++++++++++-------
>  1 file changed, 85 insertions(+), 24 deletions(-)
> 
> diff --git a/drivers/phy/cadence/cdns-dphy.c b/drivers/phy/cadence/cdns-dphy.c
> index ed87a3970f83..a94109a63788 100644
> --- a/drivers/phy/cadence/cdns-dphy.c
> +++ b/drivers/phy/cadence/cdns-dphy.c
> @@ -79,6 +79,7 @@ struct cdns_dphy_cfg {
>  	u8 pll_ipdiv;
>  	u8 pll_opdiv;
>  	u16 pll_fbdiv;
> +	u64 hs_clk_rate;

This has a minor conflict with my cdns-dsi series, as I also add
hs_clk_rate but as u32. Also, applying both serieses,
cdns_dphy_config_from_opts() becomes odd as the hs_clk_rate will be
assigned back and forth between opts and cfg. Can you check this?

 Tomi