linux-kernel - [PATCH v2 1/4] spi: s3c64xx: changed to PIO mode if there is no DMA

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Date:   Wed, 19 Apr 2023 15:06:36 +0900
From:   Jaewon Kim <jaewon02.kim@...sung.com>
To:     Mark Brown <broonie@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Andi Shyti <andi@...zian.org>,
        Alim Akhtar <alim.akhtar@...sung.com>
Cc:     linux-spi@...r.kernel.org, linux-samsung-soc@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Chanho Park <chanho61.park@...sung.com>,
        Jaewon Kim <jaewon02.kim@...sung.com>
Subject: [PATCH v2 1/4] spi: s3c64xx: changed to PIO mode if there is no DMA

Polling mode supported with qurik if there was no DMA in the SOC.
However, there are cased where we cannot or do not want to use DMA.
To support this case, if DMA is not set, it is switched to polling mode.

Signed-off-by: Jaewon Kim <jaewon02.kim@...sung.com>
---
 drivers/spi/spi-s3c64xx.c                 | 8 ++++++--
 include/linux/platform_data/spi-s3c64xx.h | 1 +
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
index 71d324ec9a70..273aa02322d9 100644
--- a/drivers/spi/spi-s3c64xx.c
+++ b/drivers/spi/spi-s3c64xx.c
@@ -19,7 +19,6 @@
 #include <linux/platform_data/spi-s3c64xx.h>
 
 #define MAX_SPI_PORTS		12
-#define S3C64XX_SPI_QUIRK_POLL		(1 << 0)
 #define S3C64XX_SPI_QUIRK_CS_AUTO	(1 << 1)
 #define AUTOSUSPEND_TIMEOUT	2000
 
@@ -116,7 +115,7 @@
 #define S3C64XX_SPI_TRAILCNT		S3C64XX_SPI_MAX_TRAILCNT
 
 #define msecs_to_loops(t) (loops_per_jiffy / 1000 * HZ * t)
-#define is_polling(x)	(x->port_conf->quirks & S3C64XX_SPI_QUIRK_POLL)
+#define is_polling(x)	(x->cntrlr_info->polling)
 
 #define RXBUSY    (1<<2)
 #define TXBUSY    (1<<3)
@@ -1067,6 +1066,11 @@ static struct s3c64xx_spi_info *s3c64xx_spi_parse_dt(struct device *dev)
 		sci->num_cs = temp;
 	}
 
+	if (!of_find_property(dev->of_node, "dmas", NULL)) {
+		dev_warn(dev, "cannot find DMA, changed to PIO mode\n");
+		sci->polling = 1;
+	}
+
 	sci->no_cs = of_property_read_bool(dev->of_node, "no-cs-readback");
 
 	return sci;
diff --git a/include/linux/platform_data/spi-s3c64xx.h b/include/linux/platform_data/spi-s3c64xx.h
index 5df1ace6d2c9..cb7b8ddc899f 100644
--- a/include/linux/platform_data/spi-s3c64xx.h
+++ b/include/linux/platform_data/spi-s3c64xx.h
@@ -35,6 +35,7 @@ struct s3c64xx_spi_info {
 	int src_clk_nr;
 	int num_cs;
 	bool no_cs;
+	bool polling;
 	int (*cfg_gpio)(void);
 };
 
-- 
2.17.1