i2c: riic: Pass register offsets and chip details as OF data

With an increasing number of SoCs reusing this driver, each with slight
variations in the RIIC IP, it becomes necessary to support passing these
details as OF data. This approach simplifies the extension of the driver
for other SoCs.

This patch lays the groundwork for adding support for the Renesas RZ/V2H
SoC.
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>

drivers/i2c/busses/i2c-riic.c

@@ -46,18 +46,6 @@
 #include <linux/pm_runtime.h>
 #include <linux/reset.h>
 
-#define RIIC_ICCR1	0x00
-#define RIIC_ICCR2	0x04
-#define RIIC_ICMR1	0x08
-#define RIIC_ICMR3	0x10
-#define RIIC_ICSER	0x18
-#define RIIC_ICIER	0x1c
-#define RIIC_ICSR2	0x24
-#define RIIC_ICBRL	0x34
-#define RIIC_ICBRH	0x38
-#define RIIC_ICDRT	0x3c
-#define RIIC_ICDRR	0x40
-
 #define ICCR1_ICE	0x80
 #define ICCR1_IICRST	0x40
 #define ICCR1_SOWP	0x10
@@ -87,6 +75,25 @@
 
 #define RIIC_INIT_MSG	-1
 
+enum riic_reg_list {
+	RIIC_ICCR1 = 0,
+	RIIC_ICCR2,
+	RIIC_ICMR1,
+	RIIC_ICMR3,
+	RIIC_ICSER,
+	RIIC_ICIER,
+	RIIC_ICSR2,
+	RIIC_ICBRL,
+	RIIC_ICBRH,
+	RIIC_ICDRT,
+	RIIC_ICDRR,
+	RIIC_REG_END,
+};
+
+struct riic_of_data {
+	u8 regs[RIIC_REG_END];
+};
+
 struct riic_dev {
 	void __iomem *base;
 	u8 *buf;
@@ -94,6 +101,7 @@ struct riic_dev {
 	int bytes_left;
 	int err;
 	int is_last;
+	const struct riic_of_data *info;
 	struct completion msg_done;
 	struct i2c_adapter adapter;
 	struct clk *clk;
@@ -107,12 +115,12 @@ struct riic_irq_desc {
 
 static inline void riic_writeb(struct riic_dev *riic, u8 val, u8 offset)
 {
-	writeb(val, riic->base + offset);
+	writeb(val, riic->base + riic->info->regs[offset]);
 }
 
 static inline u8 riic_readb(struct riic_dev *riic, u8 offset)
 {
-	return readb(riic->base + offset);
+	return readb(riic->base + riic->info->regs[offset]);
 }
 
 static inline void riic_clear_set_bit(struct riic_dev *riic, u8 clear, u8 set, u8 reg)
@@ -453,6 +461,8 @@ static int riic_i2c_probe(struct platform_device *pdev)
 		}
 	}
 
+	riic->info = of_device_get_match_data(&pdev->dev);
+
 	adap = &riic->adapter;
 	i2c_set_adapdata(adap, riic);
 	strscpy(adap->name, "Renesas RIIC adapter", sizeof(adap->name));
@@ -497,8 +507,24 @@ static void riic_i2c_remove(struct platform_device *pdev)
 	pm_runtime_disable(&pdev->dev);
 }
 
+static const struct riic_of_data riic_rz_a_info = {
+	.regs = {
+		[RIIC_ICCR1] = 0x00,
+		[RIIC_ICCR2] = 0x04,
+		[RIIC_ICMR1] = 0x08,
+		[RIIC_ICMR3] = 0x10,
+		[RIIC_ICSER] = 0x18,
+		[RIIC_ICIER] = 0x1c,
+		[RIIC_ICSR2] = 0x24,
+		[RIIC_ICBRL] = 0x34,
+		[RIIC_ICBRH] = 0x38,
+		[RIIC_ICDRT] = 0x3c,
+		[RIIC_ICDRR] = 0x40,
+	},
+};
+
 static const struct of_device_id riic_i2c_dt_ids[] = {
-	{ .compatible = "renesas,riic-rz", },
+	{ .compatible = "renesas,riic-rz", .data = &riic_rz_a_info },
 	{ /* Sentinel */ },
 };