soc: qcom: smd-rpm: Match rpmsg channel instead of compatible

There is an ever growing list of compatibles in the smd-rpm.c driver.
A fallback compatible would help here but would still require keeping
the current list around for backwards compatibility.

As an alternative, let's switch the driver to match the rpmsg_device_id
instead, which is always "rpm_requests" on all platforms. Add a check
to ensure that there is a device tree node defined for the device since
otherwise the of_platform_populate() call will operate on the root node (/).

Similar approaches with matching rpmsg_device_id are already used in
qcom_sysmon, qcom_glink_ssr, qrtr, and rpmsg_wwan_ctrl.

Tested-by: Konrad Dybcio <konrad.dybcio@linaro.org> # SM6375 (G-Link)
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Link: https://lore.kernel.org/r/20230531-rpm-rproc-v3-4-a07dcdefd918@gerhold.netSigned-off-by: Bjorn Andersson <andersson@kernel.org>

drivers/soc/qcom/smd-rpm.c

@@ -199,6 +199,9 @@ static int qcom_smd_rpm_probe(struct rpmsg_device *rpdev)
 	struct qcom_smd_rpm *rpm;
 	int ret;
 
+	if (!rpdev->dev.of_node)
+		return -EINVAL;
+
 	rpm = devm_kzalloc(&rpdev->dev, sizeof(*rpm), GFP_KERNEL);
 	if (!rpm)
 		return -ENOMEM;
@@ -230,38 +233,18 @@ static void qcom_smd_rpm_remove(struct rpmsg_device *rpdev)
 	of_platform_depopulate(&rpdev->dev);
 }
 
-static const struct of_device_id qcom_smd_rpm_of_match[] = {
-	{ .compatible = "qcom,rpm-apq8084" },
-	{ .compatible = "qcom,rpm-ipq6018" },
-	{ .compatible = "qcom,rpm-ipq9574" },
-	{ .compatible = "qcom,rpm-msm8226" },
-	{ .compatible = "qcom,rpm-msm8909" },
-	{ .compatible = "qcom,rpm-msm8916" },
-	{ .compatible = "qcom,rpm-msm8936" },
-	{ .compatible = "qcom,rpm-msm8953" },
-	{ .compatible = "qcom,rpm-msm8974" },
-	{ .compatible = "qcom,rpm-msm8976" },
-	{ .compatible = "qcom,rpm-msm8994" },
-	{ .compatible = "qcom,rpm-msm8996" },
-	{ .compatible = "qcom,rpm-msm8998" },
-	{ .compatible = "qcom,rpm-sdm660" },
-	{ .compatible = "qcom,rpm-sm6115" },
-	{ .compatible = "qcom,rpm-sm6125" },
-	{ .compatible = "qcom,rpm-sm6375" },
-	{ .compatible = "qcom,rpm-qcm2290" },
-	{ .compatible = "qcom,rpm-qcs404" },
-	{}
+static const struct rpmsg_device_id qcom_smd_rpm_id_table[] = {
+	{ .name = "rpm_requests", },
+	{ /* sentinel */ }
 };
-MODULE_DEVICE_TABLE(of, qcom_smd_rpm_of_match);
+MODULE_DEVICE_TABLE(rpmsg, qcom_smd_rpm_id_table);
 
 static struct rpmsg_driver qcom_smd_rpm_driver = {
 	.probe = qcom_smd_rpm_probe,
 	.remove = qcom_smd_rpm_remove,
 	.callback = qcom_smd_rpm_callback,
-	.drv  = {
-		.name  = "qcom_smd_rpm",
-		.of_match_table = qcom_smd_rpm_of_match,
-	},
+	.id_table = qcom_smd_rpm_id_table,
+	.drv.name = "qcom_smd_rpm",
 };
 
 static int __init qcom_smd_rpm_init(void)