linux-kernel - Re: [PATCH v2 2/2] drivers: clk: zynqmp: Update fraction clock check from custom type flags

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Message-ID: <159054169658.88029.371843532116000844@swboyd.mtv.corp.google.com>
Date:   Tue, 26 May 2020 18:08:16 -0700
From:   Stephen Boyd <sboyd@...nel.org>
To:     Jolly Shah <jolly.shah@...inx.com>, arm@...nel.org,
        linux-clk@...r.kernel.org, michal.simek@...inx.com,
        mturquette@...libre.com, olof@...om.net
Cc:     rajanv@...inx.com, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, Tejas Patel <tejas.patel@...inx.com>,
        Rajan Vaja <rajan.vaja@...inx.com>,
        Jolly Shah <jolly.shah@...inx.com>
Subject: Re: [PATCH v2 2/2] drivers: clk: zynqmp: Update fraction clock check from custom type flags

Quoting Jolly Shah (2020-03-12 14:31:39)
> From: Tejas Patel <tejas.patel@...inx.com>
> 
> Older firmware version sets BIT(13) in clkflag to mark a
> divider as fractional divider. Updated firmware version sets BIT(4)
> in type flags to mark a divider as fractional divider since
> BIT(13) is defined as CLK_DUTY_CYCLE_PARENT in the common clk
> framework flags.
> 
> To support both old and new firmware version, consider BIT(13) from
> clkflag and BIT(4) from type_flag to check if divider is fractional
> or not.
> 
> To maintain compatibility BIT(13) of clkflag in firmware will not be
> used in future for any purpose and will be marked as unused.

Why are we mixing the firmware flags with the ccf flags? They shouldn't
be the same. The firmware should have its own 'flag numberspace' that is
distinct from the common clk framework's 'flag numberspace'. Please fix
the code.