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spi: a3700: Set frequency limits at startup

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Armada 3700 SPI controller has an internal clock divider which can
divide the parent clock frequency by up to 30.

This patch sets the limits in the spi_controller fields so that we can
detect when a non-supported frequency is requested by a device for a
transfer.

Signed-off-by: Maxime Chevallier <maxime.chevallier@smile.fr>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Maxime Chevallier 2018-01-17 17:15:26 +01:00 committed by Mark Brown
parent 44a5f423e7
commit abf3a49e50
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GPG key ID: 24D68B725D5487D0
1 changed files with 7 additions and 0 deletions
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7
drivers/spi/spi-armada-3700.c
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@ -27,6 +27,8 @@
#define DRIVER_NAME "armada_3700_spi"
#define A3700_SPI_MAX_SPEED_HZ 100000000
#define A3700_SPI_MAX_PRESCALE 30
#define A3700_SPI_TIMEOUT 10
/* SPI Register Offest */
@ -815,6 +817,11 @@ static int a3700_spi_probe(struct platform_device *pdev)
goto error;
}
master->max_speed_hz = min_t(unsigned long, A3700_SPI_MAX_SPEED_HZ,
clk_get_rate(spi->clk));
master->min_speed_hz = DIV_ROUND_UP(clk_get_rate(spi->clk),
A3700_SPI_MAX_PRESCALE);
ret = a3700_spi_init(spi);
if (ret)
goto error_clk;