| Message ID | 20240422114150.84426-1-heikki.keranen@bittium.com (mailing list archive) |
|---|---|
| State | Superseded |
| Commit | 856d9e8e9d42759b7fe6c6e13a2d6ff325b65f91 |
| Headers | show |
| Series | spi: mux: Fix master controller settings after mux select | expand |
On Mon, 22 Apr 2024 14:41:50 +0300, Heikki Keranen wrote: > In some cases SPI child devices behind spi-mux require different > settings like: max_speed_hz, mode and bits_per_word. > > Typically the slave device driver puts the settings in place and calls > spi_setup() once during probe and assumes they stay in place for all > following spi transfers. > > [...] Applied to https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next Thanks! [1/1] spi: mux: Fix master controller settings after mux select commit: 856d9e8e9d42759b7fe6c6e13a2d6ff325b65f91 All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted. You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed. If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced. Please add any relevant lists and maintainers to the CCs when replying to this mail. Thanks, Mark
Mon, Apr 22, 2024 at 02:41:50PM +0300, Heikki Keranen kirjoitti: > In some cases SPI child devices behind spi-mux require different > settings like: max_speed_hz, mode and bits_per_word. > > Typically the slave device driver puts the settings in place and calls > spi_setup() once during probe and assumes they stay in place for all > following spi transfers. > > However spi-mux forwarded spi_setup() -call to SPI master driver only > when slave driver calls spi_setup(). If second slave device was > accessed meanwhile and that driver called spi_setup(), the > settings did not change back to the first spi device. > In case of wrong max_speed_hz this caused spi trasfers to fail. > > This commit adds spi_setup() call after mux is changed. This way > the right device specific parameters are set to the master driver. > > The fix has been tested by using custom hardware and debugging > spi master driver speed settings. > Co-authored-by: Petri Tauriainen <petri.tauriainen@bittium.com> Since it's already applied for the future please note, the correct tag is Co-developed-by and in accordance with Submitting Patches it must followed by the respective Signed-off-by. In this case it had to be Co-developed-by: Petri Tauriainen <petri.tauriainen@bittium.com> Signed-off-by: Petri Tauriainen <petri.tauriainen@bittium.com>
diff --git a/drivers/spi/spi-mux.c b/drivers/spi/spi-mux.c index bd988f53753e..5d72e3d59df8 100644 --- a/drivers/spi/spi-mux.c +++ b/drivers/spi/spi-mux.c @@ -68,6 +68,8 @@ static int spi_mux_select(struct spi_device *spi) priv->current_cs = spi_get_chipselect(spi, 0); + spi_setup(priv->spi); + return 0; }
In some cases SPI child devices behind spi-mux require different settings like: max_speed_hz, mode and bits_per_word. Typically the slave device driver puts the settings in place and calls spi_setup() once during probe and assumes they stay in place for all following spi transfers. However spi-mux forwarded spi_setup() -call to SPI master driver only when slave driver calls spi_setup(). If second slave device was accessed meanwhile and that driver called spi_setup(), the settings did not change back to the first spi device. In case of wrong max_speed_hz this caused spi trasfers to fail. This commit adds spi_setup() call after mux is changed. This way the right device specific parameters are set to the master driver. The fix has been tested by using custom hardware and debugging spi master driver speed settings. Co-authored-by: Petri Tauriainen <petri.tauriainen@bittium.com> Signed-off-by: Heikki Keranen <heikki.keranen@bittium.com> --- drivers/spi/spi-mux.c | 2 ++ 1 file changed, 2 insertions(+)