[PATCH v6 4/5] spi: mtk-snfi: Add snfi sample delay and read latency adjustment

[Xiangsheng Hou <xiangsheng.hou@mediatek.com>]

Add snfi sample delay and read latency adjustment which can get
from dts property.

Signed-off-by: Xiangsheng Hou <xiangsheng.hou@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
 drivers/spi/spi-mtk-snfi.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/spi/spi-mtk-snfi.c b/drivers/spi/spi-mtk-snfi.c
index 85644308df23..f3f95eb37365 100644
--- a/drivers/spi/spi-mtk-snfi.c
+++ b/drivers/spi/spi-mtk-snfi.c
@@ -195,6 +195,8 @@
 #define DATA_READ_MODE_X4 2
 #define DATA_READ_MODE_DUAL 5
 #define DATA_READ_MODE_QUAD 6
+#define DATA_READ_LATCH_LAT GENMASK(9, 8)
+#define DATA_READ_LATCH_LAT_S 8
 #define PG_LOAD_CUSTOM_EN BIT(7)
 #define DATARD_CUSTOM_EN BIT(6)
 #define CS_DESELECT_CYC_S 0
@@ -205,6 +207,9 @@
 
 #define SNF_DLY_CTL3 0x548
 #define SFCK_SAM_DLY_S 0
+#define SFCK_SAM_DLY GENMASK(5, 0)
+#define SFCK_SAM_DLY_TOTAL 9
+#define SFCK_SAM_DLY_RANGE 47
 
 #define SNF_STA_CTL1 0x550
 #define CUS_PG_DONE BIT(28)
@@ -1368,6 +1373,8 @@ static int mtk_snand_probe(struct platform_device *pdev)
 	const struct of_device_id *dev_id;
 	struct spi_controller *ctlr;
 	struct mtk_snand *ms;
+	unsigned long spi_freq;
+	u32 val = 0;
 	int ret;
 
 	dev_id = of_match_node(mtk_snand_ids, np);
@@ -1446,6 +1453,19 @@ static int mtk_snand_probe(struct platform_device *pdev)
 	// switch to SNFI mode
 	nfi_write32(ms, SNF_CFG, SPI_MODE);
 
+	ret = of_property_read_u32(np, "rx-sample-delay-ns", &val);
+	if (!ret)
+		nfi_rmw32(ms, SNF_DLY_CTL3, SFCK_SAM_DLY,
+			  val * SFCK_SAM_DLY_RANGE / SFCK_SAM_DLY_TOTAL);
+
+	ret = of_property_read_u32(np, "mediatek,rx-latch-latency-ns", &val);
+	if (!ret) {
+		spi_freq = clk_get_rate(ms->pad_clk);
+		val = DIV_ROUND_CLOSEST(val, NSEC_PER_SEC / spi_freq);
+		nfi_rmw32(ms, SNF_MISC_CTL, DATA_READ_LATCH_LAT,
+			  val << DATA_READ_LATCH_LAT_S);
+	}
+
 	// setup an initial page format for ops matching page_cache_op template
 	// before ECC is called.
 	ret = mtk_snand_setup_pagefmt(ms, SZ_2K, SZ_64);
-- 
2.25.1