linux-kernel - Re: [PATCH v4 4/4] drm/msm/dsi/phy: Define PHY_CMN_CLK

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Message-ID: <df4cfdb1-66be-4264-aed3-0d5567e721f7@linaro.org>
Date: Mon, 17 Feb 2025 14:37:31 +0100
From: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc: Rob Clark <robdclark@...il.com>, Abhinav Kumar
 <quic_abhinavk@...cinc.com>, Sean Paul <sean@...rly.run>,
 Marijn Suijten <marijn.suijten@...ainline.org>,
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
 Jonathan Marek <jonathan@...ek.ca>, linux-arm-msm@...r.kernel.org,
 dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org,
 linux-kernel@...r.kernel.org, Rob Clark <robdclark@...omium.org>
Subject: Re: [PATCH v4 4/4] drm/msm/dsi/phy: Define PHY_CMN_CLK_CFG[01]
 bitfields and simplify saving

On 17/02/2025 14:13, Dmitry Baryshkov wrote:
> On Mon, Feb 17, 2025 at 12:53:17PM +0100, Krzysztof Kozlowski wrote:
>> Add bitfields for PHY_CMN_CLK_CFG0 and PHY_CMN_CLK_CFG1 registers to
>> avoid hard-coding bit masks and shifts and make the code a bit more
>> readable.  While touching the lines in dsi_7nm_pll_save_state()
>> resulting cached->pix_clk_div assignment would be too big, so just
>> combine pix_clk_div and bit_clk_div into one cached state to make
>> everything simpler.
>>
>> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
>>
>> ---
>>
>> Changes in v4:
>> 1. Add mising bitfield.h include
>> 2. One more FIELD_GET and DSI_7nm_PHY_CMN_CLK_CFG1_DSICLK_SEL (Dmitry)
>>
>> Changes in v3:
>> 1. Use FIELD_GET
>> 2. Keep separate bit_clk_div and pix_clk_div
>> 3. Rebase (some things moved to previous patches)
>>
>> Changes in v2:
>> 1. New patch
>> ---
>>  drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c             | 13 ++++++++-----
>>  drivers/gpu/drm/msm/registers/display/dsi_phy_7nm.xml |  1 +
>>  2 files changed, 9 insertions(+), 5 deletions(-)
>>
>> @@ -739,7 +741,8 @@ static int pll_7nm_register(struct dsi_pll_7nm *pll_7nm, struct clk_hw **provide
>>  		u32 data;
>>  
>>  		data = readl(pll_7nm->phy->base + REG_DSI_7nm_PHY_CMN_CLK_CFG1);
>> -		writel(data | 3, pll_7nm->phy->base + REG_DSI_7nm_PHY_CMN_CLK_CFG1);
>> +		writel(data | DSI_7nm_PHY_CMN_CLK_CFG1_DSICLK_SEL(3),
>> +		       pll_7nm->phy->base + REG_DSI_7nm_PHY_CMN_CLK_CFG1);
> 
> Nit: should this also be using dsi_pll_cmn_clk_cfg1_update() ?


This is before clocks are registered so there is really no chance for
simultaneous access.

It is rather then question of code readability or obviousness.



Best regards,
Krzysztof