fsi: occ: Support probing the hwmon child device from dts node

There is now a need for reading devicetree properties in the OCC
hwmon driver, which isn't current supported as the FSI driver just
instantiates a basic platform device. Add support for this use case
by checking for an "occ-hwmon" node and if present, creating an
OF device from it.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20220809200701.218059-3-eajames@linux.ibm.com
Signed-off-by: Joel Stanley <joel@jms.id.au>

diff --git a/drivers/fsi/fsi-occ.c b/drivers/fsi/fsi-occ.c
index 8f7f602..abdd37d 100644 (file)
--- a/drivers/fsi/fsi-occ.c
+++ b/drivers/fsi/fsi-occ.c
@@ -44,6 +44,7 @@ struct occ {
        struct device *sbefifo;
        char name[32];
        int idx;
+       bool platform_hwmon;
        u8 sequence_number;
        void *buffer;
        void *client_buffer;
@@ -598,7 +599,7 @@ int fsi_occ_submit(struct device *dev, const void *request, size_t req_len,
 }
 EXPORT_SYMBOL_GPL(fsi_occ_submit);
 
-static int occ_unregister_child(struct device *dev, void *data)
+static int occ_unregister_platform_child(struct device *dev, void *data)
 {
        struct platform_device *hwmon_dev = to_platform_device(dev);
 
@@ -607,12 +608,25 @@ static int occ_unregister_child(struct device *dev, void *data)
        return 0;
 }
 
+static int occ_unregister_of_child(struct device *dev, void *data)
+{
+       struct platform_device *hwmon_dev = to_platform_device(dev);
+
+       of_device_unregister(hwmon_dev);
+       if (dev->of_node)
+               of_node_clear_flag(dev->of_node, OF_POPULATED);
+
+       return 0;
+}
+
 static int occ_probe(struct platform_device *pdev)
 {
        int rc;
        u32 reg;
+       char child_name[32];
        struct occ *occ;
-       struct platform_device *hwmon_dev;
+       struct platform_device *hwmon_dev = NULL;
+       struct device_node *hwmon_node;
        struct device *dev = &pdev->dev;
        struct platform_device_info hwmon_dev_info = {
                .parent = dev,
@@ -671,10 +685,20 @@ static int occ_probe(struct platform_device *pdev)
                return rc;
        }
 
-       hwmon_dev_info.id = occ->idx;
-       hwmon_dev = platform_device_register_full(&hwmon_dev_info);
-       if (IS_ERR(hwmon_dev))
-               dev_warn(dev, "failed to create hwmon device\n");
+       hwmon_node = of_get_child_by_name(dev->of_node, hwmon_dev_info.name);
+       if (hwmon_node) {
+               snprintf(child_name, sizeof(child_name), "%s.%d", hwmon_dev_info.name, occ->idx);
+               hwmon_dev = of_platform_device_create(hwmon_node, child_name, dev);
+               of_node_put(hwmon_node);
+       }
+
+       if (!hwmon_dev) {
+               occ->platform_hwmon = true;
+               hwmon_dev_info.id = occ->idx;
+               hwmon_dev = platform_device_register_full(&hwmon_dev_info);
+               if (IS_ERR(hwmon_dev))
+                       dev_warn(dev, "failed to create hwmon device\n");
+       }
 
        return 0;
 }
@@ -690,7 +714,10 @@ static int occ_remove(struct platform_device *pdev)
        occ->buffer = NULL;
        mutex_unlock(&occ->occ_lock);
 
-       device_for_each_child(&pdev->dev, NULL, occ_unregister_child);
+       if (occ->platform_hwmon)
+               device_for_each_child(&pdev->dev, NULL, occ_unregister_platform_child);
+       else
+               device_for_each_child(&pdev->dev, NULL, occ_unregister_of_child);
 
        ida_simple_remove(&occ_ida, occ->idx);