i2c: riic: Add RZ/G2L support

RZ/G2L i2c controller is compatible with RZ/A i2c controller.
By default IP is in reset state, so need to perform release
reset before accessing any register.
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

drivers/i2c/busses/i2c-riic.c

@@ -42,8 +42,10 @@
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/reset.h>
 
 #define RIIC_ICCR1	0x00
 #define RIIC_ICCR2	0x04
@@ -86,6 +88,11 @@
 
 #define RIIC_INIT_MSG	-1
 
+enum riic_type {
+	RIIC_RZ_A,
+	RIIC_RZ_G2L,
+};
+
 struct riic_dev {
 	void __iomem *base;
 	u8 *buf;
@@ -395,7 +402,9 @@ static int riic_i2c_probe(struct platform_device *pdev)
 	struct i2c_adapter *adap;
 	struct resource *res;
 	struct i2c_timings i2c_t;
+	struct reset_control *rstc;
 	int i, ret;
+	enum riic_type type;
 
 	riic = devm_kzalloc(&pdev->dev, sizeof(*riic), GFP_KERNEL);
 	if (!riic)
@@ -412,6 +421,17 @@ static int riic_i2c_probe(struct platform_device *pdev)
 		return PTR_ERR(riic->clk);
 	}
 
+	type = (enum riic_type)of_device_get_match_data(&pdev->dev);
+	if (type == RIIC_RZ_G2L) {
+		rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
+		if (IS_ERR(rstc)) {
+			dev_err(&pdev->dev, "Error: missing reset ctrl\n");
+			return PTR_ERR(rstc);
+		}
+
+		reset_control_deassert(rstc);
+	}
+
 	for (i = 0; i < ARRAY_SIZE(riic_irqs); i++) {
 		res = platform_get_resource(pdev, IORESOURCE_IRQ, riic_irqs[i].res_num);
 		if (!res)
@@ -472,7 +492,8 @@ static int riic_i2c_remove(struct platform_device *pdev)
 }
 
 static const struct of_device_id riic_i2c_dt_ids[] = {
-	{ .compatible = "renesas,riic-rz" },
+	{ .compatible = "renesas,riic-r9a07g044", .data = (void *)RIIC_RZ_G2L },
+	{ .compatible = "renesas,riic-rz", .data = (void *)RIIC_RZ_A },
 	{ /* Sentinel */ },
 };