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spi: s3c64xx: support loopback mode 

Modern exynos SoCs can support self loopback mode via setting BIT(3) of
MODE_CFG register. Previous SoCs don't have the bit so we need to add
has_loopback field in the s3c64xx_spi_port_config. Exynos Auto v9 SoC
has the bit and it will define the field to "true".
When it is set, SPI_LOOP mode will be marked.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Andi Shyti <andi@etezian.org>
Signed-off-by: Chanho Park <chanho61.park@samsung.com>
Link: https://lore.kernel.org/r/20220629102304.65712-2-chanho61.park@samsung.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Chanho Park 2022-06-29 19:23:01 +09:00 committed by Mark Brown
parent 152f2494ac
commit ffb7bcd3b2
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1 changed files with 8 additions and 0 deletions
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8
drivers/spi/spi-s3c64xx.c
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@ -59,6 +59,7 @@
#define S3C64XX_SPI_MODE_BUS_TSZ_HALFWORD (1<<17)
#define S3C64XX_SPI_MODE_BUS_TSZ_WORD (2<<17)
#define S3C64XX_SPI_MODE_BUS_TSZ_MASK (3<<17)
#define S3C64XX_SPI_MODE_SELF_LOOPBACK (1<<3)
#define S3C64XX_SPI_MODE_RXDMA_ON (1<<2)
#define S3C64XX_SPI_MODE_TXDMA_ON (1<<1)
#define S3C64XX_SPI_MODE_4BURST (1<<0)
@ -135,6 +136,7 @@ struct s3c64xx_spi_dma_data {
* @clk_from_cmu: True, if the controller does not include a clock mux and
* prescaler unit.
* @clk_ioclk: True if clock is present on this device
* @has_loopback: True if loopback mode can be supported
*
* The Samsung s3c64xx SPI controller are used on various Samsung SoC's but
* differ in some aspects such as the size of the fifo and spi bus clock
@ -149,6 +151,7 @@ struct s3c64xx_spi_port_config {
bool high_speed;
bool clk_from_cmu;
bool clk_ioclk;
bool has_loopback;
};
/**
@ -659,6 +662,9 @@ static int s3c64xx_spi_config(struct s3c64xx_spi_driver_data *sdd)
break;
}
if ((sdd->cur_mode & SPI_LOOP) && sdd->port_conf->has_loopback)
val |= S3C64XX_SPI_MODE_SELF_LOOPBACK;
writel(val, regs + S3C64XX_SPI_MODE_CFG);
if (sdd->port_conf->clk_from_cmu) {
@ -1148,6 +1154,8 @@ static int s3c64xx_spi_probe(struct platform_device *pdev)
SPI_BPW_MASK(8);
/* the spi->mode bits understood by this driver: */
master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
if (sdd->port_conf->has_loopback)
master->mode_bits |= SPI_LOOP;
master->auto_runtime_pm = true;
if (!is_polling(sdd))
master->can_dma = s3c64xx_spi_can_dma;