SSBI: Convert SSBI to device tree

The SSBI bus is exclusive to the Qualcomm MSM targets, and all SoCs
using it will be using device tree.  Convert this driver to indentify
with device tree.

This makes the bus probing a good bit simpler, since the attaching of
child nodes can be represented directly in the devicetree, rather than
having to be inferred by name.
Signed-off-by: David Brown <davidb@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/arm/msm/ssbi.txt

+* Qualcomm SSBI
+
+Some Qualcomm MSM devices contain a point-to-point serial bus used to
+communicate with a limited range of devices (mostly power management
+chips).
+
+These require the following properties:
+
+- compatible: "qcom,ssbi"
+
+- qcom,controller-type
+  indicates the SSBI bus variant the controller should use to talk
+  with the slave device.  This should be one of "ssbi", "ssbi2", or
+  "pmic-arbiter".  The type chosen is determined by the attached
+  slave.
+
+The slave device should be the single child node of the ssbi device
+with a compatible field.

arch/arm/boot/dts/msm8660-surf.dts

@@ -38,4 +38,10 @@ serial@19c400000 {
 		      <0x19c00000 0x1000>;
 		interrupts = <0 195 0x0>;
 	};
+
+	qcom,ssbi@500000 {
+		compatible = "qcom,ssbi";
+		reg = <0x500000 0x1000>;
+		qcom,controller-type = "pmic-arbiter";
+	};
 };

arch/arm/boot/dts/msm8960-cdp.dts

@@ -38,4 +38,10 @@ serial@19c400000 {
 		      <0x16400000 0x1000>;
 		interrupts = <0 154 0x0>;
 	};
+
+	qcom,ssbi@500000 {
+		compatible = "qcom,ssbi";
+		reg = <0x500000 0x1000>;
+		qcom,controller-type = "pmic-arbiter";
+	};
 };

drivers/ssbi/ssbi.c

@@ -26,6 +26,8 @@
 #include <linux/slab.h>
 #include <linux/msm_ssbi.h>
 #include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
 
 /* SSBI 2.0 controller registers */
 #define SSBI2_CMD			0x0008
@@ -261,56 +263,13 @@ int msm_ssbi_write(struct device *dev, u16 addr, u8 *buf, int len)
 }
 EXPORT_SYMBOL_GPL(msm_ssbi_write);
 
-static int msm_ssbi_add_slave(struct msm_ssbi *ssbi,
-				const struct msm_ssbi_slave_info *slave)
-{
-	struct platform_device *slave_pdev;
-	int ret;
-
-	if (ssbi->slave) {
-		pr_err("slave already attached??\n");
-		return -EBUSY;
-	}
-
-	slave_pdev = platform_device_alloc(slave->name, -1);
-	if (!slave_pdev) {
-		pr_err("cannot allocate pdev for slave '%s'", slave->name);
-		ret = -ENOMEM;
-		goto err;
-	}
-
-	slave_pdev->dev.parent = ssbi->dev;
-	slave_pdev->dev.platform_data = slave->platform_data;
-
-	ret = platform_device_add(slave_pdev);
-	if (ret) {
-		pr_err("cannot add slave platform device for '%s'\n",
-				slave->name);
-		goto err;
-	}
-
-	ssbi->slave = &slave_pdev->dev;
-	return 0;
-
-err:
-	if (slave_pdev)
-		platform_device_put(slave_pdev);
-	return ret;
-}
-
 static int msm_ssbi_probe(struct platform_device *pdev)
 {
-	const struct msm_ssbi_platform_data *pdata = pdev->dev.platform_data;
+	struct device_node *np = pdev->dev.of_node;
 	struct resource *mem_res;
 	struct msm_ssbi *ssbi;
 	int ret = 0;
-
-	if (!pdata) {
-		pr_err("missing platform data\n");
-		return -EINVAL;
-	}
-
-	pr_debug("%s\n", pdata->slave.name);
+	const char *type;
 
 	ssbi = kzalloc(sizeof(struct msm_ssbi), GFP_KERNEL);
 	if (!ssbi) {
@@ -334,7 +293,25 @@ static int msm_ssbi_probe(struct platform_device *pdev)
 	ssbi->dev = &pdev->dev;
 	platform_set_drvdata(pdev, ssbi);
 
-	ssbi->controller_type = pdata->controller_type;
+	type = of_get_property(np, "qcom,controller-type", NULL);
+	if (type == NULL) {
+		pr_err("Missing qcom,controller-type property\n");
+		ret = -EINVAL;
+		goto err_ssbi_controller;
+	}
+	dev_info(&pdev->dev, "SSBI controller type: '%s'\n", type);
+	if (strcmp(type, "ssbi") == 0)
+		ssbi->controller_type = MSM_SBI_CTRL_SSBI;
+	else if (strcmp(type, "ssbi2") == 0)
+		ssbi->controller_type = MSM_SBI_CTRL_SSBI2;
+	else if (strcmp(type, "pmic-arbiter") == 0)
+		ssbi->controller_type = MSM_SBI_CTRL_PMIC_ARBITER;
+	else {
+		pr_err("Unknown qcom,controller-type\n");
+		ret = -EINVAL;
+		goto err_ssbi_controller;
+	}
+
 	if (ssbi->controller_type == MSM_SBI_CTRL_PMIC_ARBITER) {
 		ssbi->read = msm_ssbi_pa_read_bytes;
 		ssbi->write = msm_ssbi_pa_write_bytes;
@@ -345,13 +322,13 @@ static int msm_ssbi_probe(struct platform_device *pdev)
 
 	spin_lock_init(&ssbi->lock);
 
-	ret = msm_ssbi_add_slave(ssbi, &pdata->slave);
+	ret = of_platform_populate(np, NULL, NULL, &pdev->dev);
 	if (ret)
-		goto err_ssbi_add_slave;
+		goto err_ssbi_controller;
 
 	return 0;
 
-err_ssbi_add_slave:
+err_ssbi_controller:
 	platform_set_drvdata(pdev, NULL);
 	iounmap(ssbi->base);
 err_ioremap:
@@ -370,12 +347,18 @@ static int msm_ssbi_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static struct of_device_id ssbi_match_table[] = {
+	{ .compatible = "qcom,ssbi" },
+	{}
+};
+
 static struct platform_driver msm_ssbi_driver = {
 	.probe		= msm_ssbi_probe,
 	.remove		= msm_ssbi_remove,
 	.driver		= {
 		.name	= "msm_ssbi",
 		.owner	= THIS_MODULE,
+		.of_match_table = ssbi_match_table,
 	},
 };