clk: rs9: Support device specific dif bit calculation

The calculation DIFx is BIT(n) +1 is only true for 9FGV0241. With
additional devices this is getting more complicated.
Support a base bit for the DIF calculation, currently only devices
with consecutive bits are supported, e.g. the 6-channel device needs
additional logic.

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Link: https://lore.kernel.org/r/20230310075535.3476580-3-alexander.stein@ew.tq-group.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

Author: tq-steina

drivers/clk/clk-renesas-pcie.c

@@ -18,7 +18,6 @@
 #include <linux/regmap.h>
 
 #define RS9_REG_OE				0x0
-#define RS9_REG_OE_DIF_OE(n)			BIT((n) + 1)
 #define RS9_REG_SS				0x1
 #define RS9_REG_SS_AMP_0V6			0x0
 #define RS9_REG_SS_AMP_0V7			0x1
@@ -31,9 +30,6 @@
 #define RS9_REG_SS_SSC_MASK			(3 << 3)
 #define RS9_REG_SS_SSC_LOCK			BIT(5)
 #define RS9_REG_SR				0x2
-#define RS9_REG_SR_2V0_DIF(n)			0
-#define RS9_REG_SR_3V0_DIF(n)			BIT((n) + 1)
-#define RS9_REG_SR_DIF_MASK(n)		BIT((n) + 1)
 #define RS9_REG_REF				0x3
 #define RS9_REG_REF_OE				BIT(4)
 #define RS9_REG_REF_OD				BIT(5)
@@ -159,17 +155,27 @@ static const struct regmap_config rs9_regmap_config = {
 	.reg_read = rs9_regmap_i2c_read,
 };
 
+static u8 rs9_calc_dif(const struct rs9_driver_data *rs9, int idx)
+{
+	enum rs9_model model = rs9->chip_info->model;
+
+	if (model == RENESAS_9FGV0241)
+		return BIT(idx) + 1;
+
+	return 0;
+}
+
 static int rs9_get_output_config(struct rs9_driver_data *rs9, int idx)
 {
 	struct i2c_client *client = rs9->client;
+	u8 dif = rs9_calc_dif(rs9, idx);
 	unsigned char name[5] = "DIF0";
 	struct device_node *np;
 	int ret;
 	u32 sr;
 
 	/* Set defaults */
-	rs9->clk_dif_sr &= ~RS9_REG_SR_DIF_MASK(idx);
-	rs9->clk_dif_sr |= RS9_REG_SR_3V0_DIF(idx);
+	rs9->clk_dif_sr |= dif;
 
 	snprintf(name, 5, "DIF%d", idx);
 	np = of_get_child_by_name(client->dev.of_node, name);
@@ -181,11 +187,9 @@ static int rs9_get_output_config(struct rs9_driver_data *rs9, int idx)
 	of_node_put(np);
 	if (!ret) {
 		if (sr == 2000000) {		/* 2V/ns */
-			rs9->clk_dif_sr &= ~RS9_REG_SR_DIF_MASK(idx);
-			rs9->clk_dif_sr |= RS9_REG_SR_2V0_DIF(idx);
+			rs9->clk_dif_sr &= ~dif;
 		} else if (sr == 3000000) {	/* 3V/ns (default) */
-			rs9->clk_dif_sr &= ~RS9_REG_SR_DIF_MASK(idx);
-			rs9->clk_dif_sr |= RS9_REG_SR_3V0_DIF(idx);
+			rs9->clk_dif_sr |= dif;
 		} else
 			ret = dev_err_probe(&client->dev, -EINVAL,
 					    "Invalid renesas,slew-rate value\n");
@@ -256,11 +260,13 @@ static void rs9_update_config(struct rs9_driver_data *rs9)
 	}
 
 	for (i = 0; i < rs9->chip_info->num_clks; i++) {
-		if (rs9->clk_dif_sr & RS9_REG_SR_3V0_DIF(i))
+		u8 dif = rs9_calc_dif(rs9, i);
+
+		if (rs9->clk_dif_sr & dif)
 			continue;
 
-		regmap_update_bits(rs9->regmap, RS9_REG_SR, RS9_REG_SR_3V0_DIF(i),
-				   rs9->clk_dif_sr & RS9_REG_SR_3V0_DIF(i));
+		regmap_update_bits(rs9->regmap, RS9_REG_SR, dif,
+				   rs9->clk_dif_sr & dif);
 	}
 }