Re: [PATCH 1/2] mtd: rawnand: atmel: set pmecc data setup time

[Eugen Hristev <eugen.hristev@linaro.org>]

Hello Zixun, Alexander,

On 11/6/25 13:12, Zixun LI wrote:
> Setup the pmecc data setup time as 3 clock cycles for 133MHz as
> recommended by the datasheet.
> 
> Backported from Linux: f552a7c7 ("mtd: rawnand: atmel: set pmecc data
> setup time")

Maybe use 12 digits commit hash ? I cannot find this commit in Linux

> 
> Fixes: a490e1b7c017c ("nand: atmel: Add pmecc driver")
> 
> Signed-off-by: Zixun LI <admin@hifiphile.com>
> ---
>  drivers/mtd/nand/raw/atmel/pmecc.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/mtd/nand/raw/atmel/pmecc.c b/drivers/mtd/nand/raw/atmel/pmecc.c
> index e500a0fe3f8671ff08195c94c3383696a7731eb3..7c4e9bd5f9967b119239adf2b39e683ea62b71fd 100644
> --- a/drivers/mtd/nand/raw/atmel/pmecc.c
> +++ b/drivers/mtd/nand/raw/atmel/pmecc.c
> @@ -142,6 +142,7 @@ struct atmel_pmecc_caps {
>  	int nstrengths;
>  	int el_offset;
>  	bool correct_erased_chunks;
> +	bool clk_ctrl;
>  };
>  
>  struct atmel_pmecc_user_conf_cache {
> @@ -840,6 +841,10 @@ atmel_pmecc_create(struct udevice *dev,
>  
>  	pmecc->regs.timing = 0;
>  
> +	/* pmecc data setup time */
> +	if (caps->clk_ctrl)
> +		writel(PMECC_CLK_133MHZ, pmecc->regs.base + ATMEL_PMECC_CLK);
> +
>  	/* Disable all interrupts before registering the PMECC handler. */
>  	writel(0xffffffff, pmecc->regs.base + ATMEL_PMECC_IDR);
>  	atmel_pmecc_reset(pmecc);
> @@ -884,6 +889,7 @@ static struct atmel_pmecc_caps at91sam9g45_caps = {
>  	.strengths = atmel_pmecc_strengths,
>  	.nstrengths = 5,
>  	.el_offset = 0x8c,
> +	.clk_ctrl = true,

This appears to be done only for sam9g45.

So, Alexander, this should not impact sam9x60 .

I looked a bit in the Linux driver and this appears to be just as bad:
133 Mhz clock config hardcoded. I would expect this clock to be taken
from a clock input and not hardcoded. But oh well, if this clock is to
be changed in another device, it would be exposed somewhere...

Eugen

>  };
>  
>  static struct atmel_pmecc_caps sama5d4_caps = {
>