Add MediaTek MT7986 SPI NAND support

Merge series from Xiangsheng Hou <xiangsheng.hou@mediatek.com>:

This patch series split from bellow series which pick-up spi relevant patches
https://lore.kernel.org/all/20230130030656.12127-1-xiangsheng.hou@mediatek.com.
This series add MediaTek MT7986 SPI NAND controller support, add read latch
latency, smaple delay adjust and add optional nfi_hclk.

Documentation/devicetree/bindings/spi/mediatek,spi-mtk-snfi.yaml

@@ -18,14 +18,12 @@ description: |
   using the accompanying ECC engine. There should be only one spi
   slave device following generic spi bindings.
 
-allOf:
-  - $ref: /schemas/spi/spi-controller.yaml#
-
 properties:
   compatible:
     enum:
       - mediatek,mt7622-snand
       - mediatek,mt7629-snand
+      - mediatek,mt7986-snand
 
   reg:
     items:
@@ -36,19 +34,20 @@ properties:
       - description: NFI interrupt
 
   clocks:
-    items:
-      - description: clock used for the controller
-      - description: clock used for the SPI bus
+    minItems: 2
+    maxItems: 3
 
   clock-names:
-    items:
-      - const: nfi_clk
-      - const: pad_clk
+    minItems: 2
+    maxItems: 3
 
   nand-ecc-engine:
     description: device-tree node of the accompanying ECC engine.
     $ref: /schemas/types.yaml#/definitions/phandle
 
+  mediatek,rx-latch-latency-ns:
+    description: Data read latch latency, unit is nanoseconds.
+
 required:
   - compatible
   - reg
@@ -57,6 +56,43 @@ required:
   - clock-names
   - nand-ecc-engine
 
+allOf:
+  - $ref: /schemas/spi/spi-controller.yaml#
+  - if:
+      properties:
+        compatible:
+          enum:
+            - mediatek,mt7622-snand
+            - mediatek,mt7629-snand
+    then:
+      properties:
+        clocks:
+          items:
+            - description: clock used for the controller
+            - description: clock used for the SPI bus
+        clock-names:
+          items:
+            - const: nfi_clk
+            - const: pad_clk
+
+  - if:
+      properties:
+        compatible:
+          enum:
+            - mediatek,mt7986-snand
+    then:
+      properties:
+        clocks:
+          items:
+            - description: clock used for the controller
+            - description: clock used for the SPI bus
+            - description: clock used for the AHB bus
+        clock-names:
+          items:
+            - const: nfi_clk
+            - const: pad_clk
+            - const: nfi_hclk
+
 unevaluatedProperties: false
 
 examples:

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)
@@ -297,6 +302,7 @@ struct mtk_snand {
 	struct device *dev;
 	struct clk *nfi_clk;
 	struct clk *pad_clk;
+	struct clk *nfi_hclk;
 	void __iomem *nfi_base;
 	int irq;
 	struct completion op_done;
@@ -1339,7 +1345,16 @@ static int mtk_snand_enable_clk(struct mtk_snand *ms)
 		dev_err(ms->dev, "unable to enable pad clk\n");
 		goto err1;
 	}
+	ret = clk_prepare_enable(ms->nfi_hclk);
+	if (ret) {
+		dev_err(ms->dev, "unable to enable nfi hclk\n");
+		goto err2;
+	}
+
 	return 0;
+
+err2:
+	clk_disable_unprepare(ms->pad_clk);
 err1:
 	clk_disable_unprepare(ms->nfi_clk);
 	return ret;
@@ -1347,6 +1362,7 @@ static int mtk_snand_enable_clk(struct mtk_snand *ms)
 
 static void mtk_snand_disable_clk(struct mtk_snand *ms)
 {
+	clk_disable_unprepare(ms->nfi_hclk);
 	clk_disable_unprepare(ms->pad_clk);
 	clk_disable_unprepare(ms->nfi_clk);
 }
@@ -1357,6 +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);
@@ -1401,6 +1419,13 @@ static int mtk_snand_probe(struct platform_device *pdev)
 		goto release_ecc;
 	}
 
+	ms->nfi_hclk = devm_clk_get_optional(&pdev->dev, "nfi_hclk");
+	if (IS_ERR(ms->nfi_hclk)) {
+		ret = PTR_ERR(ms->nfi_hclk);
+		dev_err(&pdev->dev, "unable to get nfi_hclk, err = %d\n", ret);
+		goto release_ecc;
+	}
+
 	ret = mtk_snand_enable_clk(ms);
 	if (ret)
 		goto release_ecc;
@@ -1428,10 +1453,22 @@ 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, ms->caps->sector_size,
-				      ms->caps->spare_sizes[0]);
+	ret = mtk_snand_setup_pagefmt(ms, SZ_2K, SZ_64);
 	if (ret) {
 		dev_err(ms->dev, "failed to set initial page format\n");
 		goto disable_clk;