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| author |   Marcus Weseloh <mweseloh42@gmail.com> | 2016-01-05 21:46:20 +0100 |
|---|---|---|
| committer |   Mark Brown <broonie@kernel.org> | 2016-01-07 15:41:25 +0000 |
| commit | 218e0b575ffe6de1c93249871b25bbf570fe1cb5 (patch) | |
| tree | 11a31b1449cb713465b52bc2d565a2539ae6b315 /drivers/spi/spi-sun4i.c | |
| parent | Linux 4.4-rc1 (diff) | |
| download | linux-dev-218e0b575ffe6de1c93249871b25bbf570fe1cb5.tar.xz linux-dev-218e0b575ffe6de1c93249871b25bbf570fe1cb5.zip | |
spi: sun4i: Prevent chip-select from being activated twice before a transfer
The SPI core calls set_cs before a transfer, but the SUN4I_CTL_CS_MANUAL
flag is only set in transfer_one. This leads to the following pattern on
the chip-select line (with runtime power-management on every transfer,
without it only on the first one):
activate, deactivate, activate, transfer, deactivate
Moving the configuration of the SUN4I_CTL_CS_MANUAL flag from transfer_one
to set_cs removes the double activation.
Signed-off-by: Marcus Weseloh <mweseloh42@gmail.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi/spi-sun4i.c')
| -rw-r--r-- | drivers/spi/spi-sun4i.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/spi/spi-sun4i.c b/drivers/spi/spi-sun4i.c index fbb0a4d74e91..a6d936c68674 100644 --- a/drivers/spi/spi-sun4i.c +++ b/drivers/spi/spi-sun4i.c @@ -140,6 +140,9 @@ static void sun4i_spi_set_cs(struct spi_device *spi, bool enable) reg &= ~SUN4I_CTL_CS_MASK; reg |= SUN4I_CTL_CS(spi->chip_select); + /* We want to control the chip select manually */ + reg |= SUN4I_CTL_CS_MANUAL; + if (enable) reg |= SUN4I_CTL_CS_LEVEL; else @@ -222,9 +225,6 @@ static int sun4i_spi_transfer_one(struct spi_master *master, else reg |= SUN4I_CTL_DHB; - /* We want to control the chip select manually */ - reg |= SUN4I_CTL_CS_MANUAL; - sun4i_spi_write(sspi, SUN4I_CTL_REG, reg); /* Ensure that we have a parent clock fast enough */ |