spi: s3c64xx: constify driver/match data

The match data (struct s3c64xx_spi_port_config) stored in of_device_id
and platform_device_id tables is not modified by the driver and can be
handled entirely in a const-way to increase the code safety.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Reviewed-by: Sylwester Nawrocki <snawrocki@kernel.org>
Link: https://lore.kernel.org/r/20210414203343.203119-3-krzysztof.kozlowski@canonical.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-s3c64xx.c

@@ -190,7 +190,7 @@ struct s3c64xx_spi_driver_data {
 	unsigned                        cur_speed;
 	struct s3c64xx_spi_dma_data	rx_dma;
 	struct s3c64xx_spi_dma_data	tx_dma;
-	struct s3c64xx_spi_port_config	*port_conf;
+	const struct s3c64xx_spi_port_config	*port_conf;
 	unsigned int			port_id;
 };
 
@@ -1049,15 +1049,14 @@ static struct s3c64xx_spi_info *s3c64xx_spi_parse_dt(struct device *dev)
 }
 #endif
 
-static inline struct s3c64xx_spi_port_config *s3c64xx_spi_get_port_config(
+static inline const struct s3c64xx_spi_port_config *s3c64xx_spi_get_port_config(
 						struct platform_device *pdev)
 {
 #ifdef CONFIG_OF
 	if (pdev->dev.of_node)
-		return (struct s3c64xx_spi_port_config *)of_device_get_match_data(&pdev->dev);
+		return of_device_get_match_data(&pdev->dev);
 #endif
-	return (struct s3c64xx_spi_port_config *)
-			 platform_get_device_id(pdev)->driver_data;
+	return (const struct s3c64xx_spi_port_config *)platform_get_device_id(pdev)->driver_data;
 }
 
 static int s3c64xx_spi_probe(struct platform_device *pdev)
@@ -1395,27 +1394,27 @@ static const struct dev_pm_ops s3c64xx_spi_pm = {
 			   s3c64xx_spi_runtime_resume, NULL)
 };
 
-static struct s3c64xx_spi_port_config s3c2443_spi_port_config = {
+static const struct s3c64xx_spi_port_config s3c2443_spi_port_config = {
 	.fifo_lvl_mask	= { 0x7f },
 	.rx_lvl_offset	= 13,
 	.tx_st_done	= 21,
 	.high_speed	= true,
 };
 
-static struct s3c64xx_spi_port_config s3c6410_spi_port_config = {
+static const struct s3c64xx_spi_port_config s3c6410_spi_port_config = {
 	.fifo_lvl_mask	= { 0x7f, 0x7F },
 	.rx_lvl_offset	= 13,
 	.tx_st_done	= 21,
 };
 
-static struct s3c64xx_spi_port_config s5pv210_spi_port_config = {
+static const struct s3c64xx_spi_port_config s5pv210_spi_port_config = {
 	.fifo_lvl_mask	= { 0x1ff, 0x7F },
 	.rx_lvl_offset	= 15,
 	.tx_st_done	= 25,
 	.high_speed	= true,
 };
 
-static struct s3c64xx_spi_port_config exynos4_spi_port_config = {
+static const struct s3c64xx_spi_port_config exynos4_spi_port_config = {
 	.fifo_lvl_mask	= { 0x1ff, 0x7F, 0x7F },
 	.rx_lvl_offset	= 15,
 	.tx_st_done	= 25,
@@ -1424,7 +1423,7 @@ static struct s3c64xx_spi_port_config exynos4_spi_port_config = {
 	.quirks		= S3C64XX_SPI_QUIRK_CS_AUTO,
 };
 
-static struct s3c64xx_spi_port_config exynos7_spi_port_config = {
+static const struct s3c64xx_spi_port_config exynos7_spi_port_config = {
 	.fifo_lvl_mask	= { 0x1ff, 0x7F, 0x7F, 0x7F, 0x7F, 0x1ff},
 	.rx_lvl_offset	= 15,
 	.tx_st_done	= 25,
@@ -1433,7 +1432,7 @@ static struct s3c64xx_spi_port_config exynos7_spi_port_config = {
 	.quirks		= S3C64XX_SPI_QUIRK_CS_AUTO,
 };
 
-static struct s3c64xx_spi_port_config exynos5433_spi_port_config = {
+static const struct s3c64xx_spi_port_config exynos5433_spi_port_config = {
 	.fifo_lvl_mask	= { 0x1ff, 0x7f, 0x7f, 0x7f, 0x7f, 0x1ff},
 	.rx_lvl_offset	= 15,
 	.tx_st_done	= 25,