Re: [PATCH 2/2] mtd: spi-nor: Add support for flash reset

From: Michael Walle
Date: Tue Aug 30 2022 - 03:10:21 EST


Hi,

Am 2022-08-30 08:32, schrieb Potthuri, Sai Krishna:

> + if (ret)
> + return ret;
> +
> + /*
> + * Experimental Minimum Chip select high to Reset delay value
> + * based on the flash device spec.
> + */

Which flash device spec?
I referred some of the qspi, ospi flash vendors datasheets like Micron,
Macronix, ISSI, gigadevice, spansion.

Please mention here that you've looked at datasheets of different vendors.
And maybe instead of doing three comments, just one and then the reset
sequence.


> + usleep_range(1, 5);
> + gpiod_set_value(reset, 0);

Mh, is your logic inverted here? If I read the code correctly,
you should use a value of 1 to take the device into reset. The
device tree should then have a flag "active low", which will
Reset Sequence which I implemented here is high(1)->low(0)->high(1).
By doing this sequence (active low), flash device is getting reset,
this sequence
is tested using Octal SPI flash device.

How does the device tree property for your look like?
Has it the GPIO_ACTIVE_LOW flag set?

-michael