Messages in this thread | | | Date | Mon, 16 Jun 2014 15:24:04 +0100 | From | Lee Jones <> | Subject | Re: [PATCH 1/2] mfd: cros_ec: spi: Fix end of transfer on devices with no spi-msg-delay |
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> cros_ec_spi makes the assumption that a 0-length message will put the > spi chip select back to normal (non cs_toggle mode). This used to be > the case back on kernel-3.8 on the spi-s3c64xx driver but doesn't > appear to be true anymore. It seems like it was a pretty questionable > assumption to begin with, so let's fix the code to be more robust. We > know that a message with a single 0-length segment _will_ put things > back in order. Change cros_ec_spi to handle this. > > This wasn't a problem on the main user of cros_ec_spi upstream (tegra) > because it specified 'google,cros-ec-spi-msg-delay'. > > Signed-off-by: Doug Anderson <dianders@chromium.org> > --- > drivers/mfd/cros_ec_spi.c | 18 +++++++----------- > 1 file changed, 7 insertions(+), 11 deletions(-)
Looks fine to me and I'm sure you've tested this on your platform.
Applied, thanks.
> diff --git a/drivers/mfd/cros_ec_spi.c b/drivers/mfd/cros_ec_spi.c > index 0b8d328..0cbc3db 100644 > --- a/drivers/mfd/cros_ec_spi.c > +++ b/drivers/mfd/cros_ec_spi.c > @@ -266,18 +266,14 @@ static int cros_ec_command_spi_xfer(struct cros_ec_device *ec_dev, > dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret); > } > > - /* turn off CS */ > + /* > + * Turn off CS, possibly adding a delay to ensure the rising edge > + * doesn't come too soon after the end of the data. > + */ > spi_message_init(&msg); > - > - if (ec_spi->end_of_msg_delay) { > - /* > - * Add delay for last transaction, to ensure the rising edge > - * doesn't come too soon after the end of the data. > - */ > - memset(&trans, 0, sizeof(trans)); > - trans.delay_usecs = ec_spi->end_of_msg_delay; > - spi_message_add_tail(&trans, &msg); > - } > + memset(&trans, 0, sizeof(trans)); > + trans.delay_usecs = ec_spi->end_of_msg_delay; > + spi_message_add_tail(&trans, &msg); > > final_ret = spi_sync(ec_spi->spi, &msg); > ktime_get_ts(&ts);
-- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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