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spi: spi-sun6i: Fix chipselect/clock bug
[ Upstream commit0d7993b234
] The current sun6i SPI implementation initializes the transfer too early, resulting in SCK going high before the transfer. When using an additional (gpio) chipselect with sun6i, the chipselect is asserted at a time when clock is high, making the SPI transfer fail. This is due to SUN6I_GBL_CTL_BUS_ENABLE being written into SUN6I_GBL_CTL_REG at an early stage. Moving that to the transfer function, hence, right before the transfer starts, mitigates that problem. Fixes:3558fe900e
(spi: sunxi: Add Allwinner A31 SPI controller driver) Signed-off-by: Mirko Vogt <mirko-dev|linux@nanl.de> Signed-off-by: Ralf Schlatterbeck <rsc@runtux.com> Link: https://lore.kernel.org/r/20210614144507.y3udezjfbko7eavv@runtux.com Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
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1 changed files with 5 additions and 1 deletions
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@ -301,6 +301,10 @@ static int sun6i_spi_transfer_one(struct spi_master *master,
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}
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sun6i_spi_write(sspi, SUN6I_CLK_CTL_REG, reg);
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/* Finally enable the bus - doing so before might raise SCK to HIGH */
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reg = sun6i_spi_read(sspi, SUN6I_GBL_CTL_REG);
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reg |= SUN6I_GBL_CTL_BUS_ENABLE;
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sun6i_spi_write(sspi, SUN6I_GBL_CTL_REG, reg);
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/* Setup the transfer now... */
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if (sspi->tx_buf)
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@ -409,7 +413,7 @@ static int sun6i_spi_runtime_resume(struct device *dev)
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}
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sun6i_spi_write(sspi, SUN6I_GBL_CTL_REG,
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SUN6I_GBL_CTL_BUS_ENABLE | SUN6I_GBL_CTL_MASTER | SUN6I_GBL_CTL_TP);
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SUN6I_GBL_CTL_MASTER | SUN6I_GBL_CTL_TP);
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return 0;
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