Hi Patrice,
On Wed, 12 Jan 2022 at 03:59, Patrice Chotard patrice.chotard@foss.st.com wrote:
Add spi_flash_probe_bus_cs() and spi_get_bus_and_cs() new "use_dt" param which allows to select SPI speed and mode from DT or from default value passed in parameters.
Since commit e2e95e5e2542 ("spi: Update speed/mode on change") when calling "sf probe" or "env save" on SPI flash, spi_set_speed_mode() is called twice.
spi_get_bus_and_cs() |--> spi_claim_bus() | |--> spi_set_speed_mode(speed and mode from DT) ... |--> spi_set_speed_mode(default speed and mode value)
The first spi_set_speed_mode() call is done with speed and mode values from DT, whereas the second call is done with speed and mode set to default value (speed is set to CONFIG_SF_DEFAULT_SPEED)
This is an issue because SPI flash performance are impacted by using default speed which can be lower than the one defined in DT.
One solution is to set CONFIG_SF_DEFAULT_SPEED to the speed defined in DT, but we loose flexibility offered by DT.
Another issue can be encountered with 2 SPI flashes using 2 different speeds. In this specific case usage of CONFIG_SF_DEFAULT_SPEED is not flexible compared to get the 2 different speeds from DT.
By adding new parameter "use_dt" to spi_flash_probe_bus_cs() and to spi_get_bus_and_cs(), this allows to force usage of either speed and mode from DT (use_dt = true) or to use speed and mode parameter value.
Signed-off-by: Patrice Chotard patrice.chotard@foss.st.com Cc: Marek Behun marek.behun@nic.cz Cc: Jagan Teki jagan@amarulasolutions.com Cc: Vignesh R vigneshr@ti.com Cc: Joe Hershberger joe.hershberger@ni.com Cc: Ramon Fried rfried.dev@gmail.com Cc: Lukasz Majewski lukma@denx.de Cc: Marek Vasut marex@denx.de Cc: Wolfgang Denk wd@denx.de Cc: Simon Glass sjg@chromium.org Cc: Stefan Roese sr@denx.de Cc: "Pali Rohár" pali@kernel.org Cc: Konstantin Porotchkin kostap@marvell.com Cc: Igal Liberman igall@marvell.com Cc: Bin Meng bmeng.cn@gmail.com Cc: Pratyush Yadav p.yadav@ti.com Cc: Sean Anderson seanga2@gmail.com Cc: Anji J anji.jagarlmudi@nxp.com Cc: Biwen Li biwen.li@nxp.com Cc: Priyanka Jain priyanka.jain@nxp.com Cc: Chaitanya Sakinam chaitanya.sakinam@nxp.com
board/CZ.NIC/turris_mox/turris_mox.c | 2 +- cmd/sf.c | 5 ++++- cmd/spi.c | 2 +- drivers/mtd/spi/sf-uclass.c | 8 ++++---- drivers/net/fm/fm.c | 5 +++-- drivers/net/pfe_eth/pfe_firmware.c | 2 +- drivers/net/sni_netsec.c | 3 ++- drivers/spi/spi-uclass.c | 8 ++++---- drivers/usb/gadget/max3420_udc.c | 2 +- env/sf.c | 2 +- include/spi.h | 9 +++++---- include/spi_flash.h | 2 +- test/dm/spi.c | 15 ++++++++------- 13 files changed, 36 insertions(+), 29 deletions(-)
I think this is a good idea, but should use a separate function name instead of adding an argument, since it doesn't make sense to pass parameters that are ignored.
Also we should probably have devicetree as the default (the base function name).
Regards, Simon