On Fri, 15 Jun 2018 10:18:50 +0900, Masahiro Yamada yamada.masahiro@socionext.com wrote:
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: Miquel Raynal miquel.raynal@bootlin.com
Thanks, Miquèl