i2c: omap: Add support for setting mux

Some SoCs require muxes in the routing for SDA and SCL lines.
Therefore, add support for setting the mux by reading the mux-states
property from the dt-node.

Signed-off-by: Jayesh Choudhary <j-choudhary@ti.com>
Link: https://lore.kernel.org/r/20250318103622.29979-3-j-choudhary@ti.com
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>

Author: jayesh-ti

drivers/i2c/busses/Kconfig

@@ -940,6 +940,7 @@ config I2C_OMAP
 	tristate "OMAP I2C adapter"
 	depends on ARCH_OMAP || ARCH_K3 || COMPILE_TEST
 	default MACH_OMAP_OSK
+	select MULTIPLEXER
 	help
 	  If you say yes to this option, support will be included for the
 	  I2C interface on the Texas Instruments OMAP1/2 family of processors.

drivers/i2c/busses/i2c-omap.c

@@ -24,6 +24,7 @@
 #include <linux/platform_device.h>
 #include <linux/clk.h>
 #include <linux/io.h>
+#include <linux/mux/consumer.h>
 #include <linux/of.h>
 #include <linux/slab.h>
 #include <linux/platform_data/i2c-omap.h>
@@ -211,6 +212,7 @@ struct omap_i2c_dev {
 	u16			syscstate;
 	u16			westate;
 	u16			errata;
+	struct mux_state	*mux_state;
 };
 
 static const u8 reg_map_ip_v1[] = {
@@ -1452,6 +1454,23 @@ omap_i2c_probe(struct platform_device *pdev)
 				       (1000 * omap->speed / 8);
 	}
 
+	if (of_property_read_bool(node, "mux-states")) {
+		struct mux_state *mux_state;
+
+		mux_state = devm_mux_state_get(&pdev->dev, NULL);
+		if (IS_ERR(mux_state)) {
+			r = PTR_ERR(mux_state);
+			dev_dbg(&pdev->dev, "failed to get I2C mux: %d\n", r);
+			goto err_disable_pm;
+		}
+		omap->mux_state = mux_state;
+		r = mux_state_select(omap->mux_state);
+		if (r) {
+			dev_err(&pdev->dev, "failed to select I2C mux: %d\n", r);
+			goto err_disable_pm;
+		}
+	}
+
 	/* reset ASAP, clearing any IRQs */
 	omap_i2c_init(omap);
 
@@ -1511,6 +1530,9 @@ static void omap_i2c_remove(struct platform_device *pdev)
 
 	i2c_del_adapter(&omap->adapter);
 
+	if (omap->mux_state)
+		mux_state_deselect(omap->mux_state);
+
 	ret = pm_runtime_get_sync(&pdev->dev);
 	if (ret < 0)
 		dev_err(omap->dev, "Failed to resume hardware, skip disable\n");