linux-kernel - Re: [PATCH v1 2/3] clk: qcom: rcg2: Add support for hardware control mode

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Date:   Tue, 16 Jul 2019 09:49:02 +0530
From:   Taniya Das <tdas@...eaurora.org>
To:     Stephen Boyd <sboyd@...nel.org>,
        Michael Turquette <mturquette@...libre.com>
Cc:     Andy Gross <andy.gross@...aro.org>,
        David Brown <david.brown@...aro.org>,
        Rajendra Nayak <rnayak@...eaurora.org>,
        linux-arm-msm@...r.kernel.org, linux-soc@...r.kernel.org,
        linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 2/3] clk: qcom: rcg2: Add support for hardware control
 mode

Hello Stephen,

Thanks for your review.

On 7/16/2019 4:22 AM, Stephen Boyd wrote:
> Quoting Taniya Das (2019-05-08 11:24:54)
>> diff --git a/drivers/clk/qcom/clk-rcg2.c b/drivers/clk/qcom/clk-rcg2.c
>> index 57dbac9..5bb6d45 100644
>> --- a/drivers/clk/qcom/clk-rcg2.c
>> +++ b/drivers/clk/qcom/clk-rcg2.c
>> @@ -289,6 +289,9 @@ static int __clk_rcg2_configure(struct clk_rcg2 *rcg, const struct freq_tbl *f)
>>          cfg |= rcg->parent_map[index].cfg << CFG_SRC_SEL_SHIFT;
>>          if (rcg->mnd_width && f->n && (f->m != f->n))
>>                  cfg |= CFG_MODE_DUAL_EDGE;
>> +       if (rcg->flags & HW_CLK_CTRL_MODE)
>> +               cfg |= CFG_HW_CLK_CTRL_MASK;
>> +
> 
> Above this we have commit bdc3bbdd40ba ("clk: qcom: Clear hardware clock
> control bit of RCG") that clears this bit. Is it possible to always set
> this bit and then have an override flag used in sdm845 that says to
> _not_ set this bit? Presumably on earlier platforms writing the bit is a
> no-op so it's safe to write the bit on those platforms.
> 
> This way, if it's going to be the default we can avoid setting the flag
> and only set the flag on older platforms where it shouldn't be done for
> some reason.
> 

Not all the subsystem clock controllers might have this hardware control
bit set from design. Thus we want to set them based on the flag.

>>          return regmap_update_bits(rcg->clkr.regmap, RCG_CFG_OFFSET(rcg),
>>                                          mask, cfg);
>>   }
>> --
>> Qualcomm INDIA, on behalf of Qualcomm Innovation Center, Inc.is a member
>> of the Code Aurora Forum, hosted by the  Linux Foundation.
>>

-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation.

--