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SubjectRe: [PATCH v2 2/2] drivers: clk: zynqmp: Update fraction clock check from custom type flags
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Hi Stephan,

Thanks for the review.

> ------Original Message------
> From: Stephen Boyd <sboyd@kernel.org>
> Sent: Tuesday, May 26, 2020 6:08PM
> To: Jolly Shah <jolly.shah@xilinx.com>, Arm <arm@kernel.org>,
Linux-clk <linux-clk@vger.kernel.org>, Michal Simek
<michal.simek@xilinx.com>, Mturquette <mturquette@baylibre.com>, Olof
<olof@lixom.net>
> Cc: Rajan Vaja <rajanv@xilinx.com>,
Linux-arm-kernel@lists.infradead.org
<linux-arm-kernel@lists.infradead.org>, Linux-kernel@vger.kernel.org
<linux-kernel@vger.kernel.org>, Tejas Patel <tejas.patel@xilinx.com>,
Rajan Vaja <rajan.vaja@xilinx.com>, Jolly Shah <jolly.shah@xilinx.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@xilinx.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.
>

Yes firmware flags are using separate numberspace now. Firmware
maintains CCF and firmware specific flags separately but earlier
CLK_FRAC was mistakenly defined in ccf flagspace and hence handled here
for backward compatibility. Driver takes care of not registering same
with CCF. Let me know if I misunderstood.

Thanks,
Jolly Shah


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