Unverified Commit 33a2fde5 authored by Tudor Ambarus's avatar Tudor Ambarus Committed by Mark Brown
Browse files

spi: Introduce spi-cs-setup-ns property 



SPI NOR flashes have specific cs-setup time requirements without which
they can't work at frequencies close to their maximum supported frequency,
as they miss the first bits of the instruction command. Unrecognized
commands are ignored, thus the flash will be unresponsive. Introduce the
spi-cs-setup-ns property to allow spi devices to specify their cs setup
time.

Signed-off-by: default avatarTudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20221117105249.115649-3-tudor.ambarus@microchip.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent f6c911f3

drivers/spi/spi.c

+6 −0
Original line number Original line Diff line number Diff line
@@ -2224,6 +2224,7 @@ static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi, 
			   struct device_node *nc)

			   struct device_node *nc)

{

{

	u32 value;

	u32 value;

	u16 cs_setup;

	int rc;

	int rc;





	/* Mode (clock phase/polarity/etc.) */

	/* Mode (clock phase/polarity/etc.) */
@@ -2309,6 +2310,11 @@ static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi, 
	if (!of_property_read_u32(nc, "spi-max-frequency", &value))

	if (!of_property_read_u32(nc, "spi-max-frequency", &value))

		spi->max_speed_hz = value;

		spi->max_speed_hz = value;





	if (!of_property_read_u16(nc, "spi-cs-setup-ns", &cs_setup)) {

		spi->cs_setup.value = cs_setup;

		spi->cs_setup.unit = SPI_DELAY_UNIT_NSECS;

	}



	return 0;

	return 0;

}

}