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 <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Andi Shyti <[e-mail]>

drivers/i2c/busses/Kconfig

···
 	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

···
 #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>
···
 	u16			syscstate;
 	u16			westate;
 	u16			errata;
+	struct mux_state	*mux_state;
 };
 
 static const u8 reg_map_ip_v1[] = {
···
 				       (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);
 
···
 	int ret;
 
 	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)