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

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Date:   Mon, 15 Jul 2019 15:52:18 -0700
From:   Stephen Boyd <sboyd@...nel.org>
To:     Michael Turquette <mturquette@...libre.com>,
        Taniya Das <tdas@...eaurora.org>
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,
        Taniya Das <tdas@...eaurora.org>
Subject: Re: [PATCH v1 2/3] clk: qcom: rcg2: Add support for hardware control mode

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.

>         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.
>