i2c: qcom-geni: Add shutdown callback for i2c

If the hardware is still accessing memory after SMMU translation
is disabled (as part of smmu shutdown callback), then the
IOVAs (I/O virtual address) which it was using will go on the bus
as the physical addresses which will result in unknown crashes
like NoC/interconnect errors.

So, implement shutdown callback for i2c driver to suspend the bus
during system "reboot" or "shutdown".

Fixes: 37692de5 ("i2c: i2c-qcom-geni: Add bus driver for the Qualcomm GENI I2C controller")
Signed-off-by: Roja Rani Yarubandi <rojay@codeaurora.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

drivers/i2c/busses/i2c-qcom-geni.c

@@ -650,6 +650,14 @@ static int geni_i2c_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static void geni_i2c_shutdown(struct platform_device *pdev)
+{
+	struct geni_i2c_dev *gi2c = platform_get_drvdata(pdev);
+
+	/* Make client i2c transfers start failing */
+	i2c_mark_adapter_suspended(&gi2c->adap);
+}
+
 static int __maybe_unused geni_i2c_runtime_suspend(struct device *dev)
 {
 	int ret;
@@ -714,6 +722,7 @@ MODULE_DEVICE_TABLE(of, geni_i2c_dt_match);
 static struct platform_driver geni_i2c_driver = {
 	.probe  = geni_i2c_probe,
 	.remove = geni_i2c_remove,
+	.shutdown = geni_i2c_shutdown,
 	.driver = {
 		.name = "geni_i2c",
 		.pm = &geni_i2c_pm_ops,