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SubjectRe: [PATCH v3 1/3] mtd: rawnand: denali_dt: add more clocks based on IP datasheet
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Am Freitag, 15. Juni 2018, 03:18:50 CEST schrieb Masahiro Yamada:
> According to the Denali User's Guide, this IP needs three clocks:
>
> - clk: controller core clock
>
> - clk_x: bus interface clock
>
> - ecc_clk: clock at which ECC circuitry is run
>
> Currently, denali_dt.c requires a single anonymous clock and its
> frequency. However, the driver needs to get the frequency of "clk_x"
> not "clk". This is confusing because people tend to assume the
> anonymous clock means the core clock. In fact, I got a report of
> SOCFPGA breakage because the timing parameters are calculated based
> on a wrong frequency.
>
> Instead of the cheesy implementation, the clocks in the real hardware
> should be represented in the driver and the DT-binding.
>
> However, adding new clocks would break the existing platforms. For the
> backward compatibility, the driver still accepts a single clock just as
> before. If clk_x is missing, clk_x_rate is set to a hardcoded value.
> This is fine for existing DT of Socionext UniPhier, and also fixes the
> issue of Altera (Intel) SOCFPGA because both platforms use 200 MHz for
> the bus interface clock.
>
> Fixes: 1bb88666775e ("mtd: nand: denali: handle timing parameters by setup_data_interface()")
> Cc: linux-stable <stable@vger.kernel.org> #4.14+
> Reported-by: Richard Weinberger <richard@nod.at>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Reviewed-by: Richard Weinberger <richard@nod.at>
Reported-by: Philipp Rosenberger <p.rosenberger@linutronix.de>

Thanks,
//richard

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