firmware: arm_scmi: Simplify chan_available transport operation

SCMI transport operation .chan_available determines in a transport
specific way if an SCMI channel is still available and to be configured.
Such information is derived by analyzing bits of device node in a
transport specific way, all it needs is a device node to operate up on,
not necessarily a full blown device.

Simplify the helper to receive in input a reference to a device_node
instead of a device carrying a pointer to such device_node.
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20221222185049.737625-2-cristian.marussi@arm.comSigned-off-by: Sudeep Holla <sudeep.holla@arm.com>

drivers/firmware/arm_scmi/common.h

@@ -153,7 +153,7 @@ struct scmi_chan_info {
  */
 struct scmi_transport_ops {
 	int (*link_supplier)(struct device *dev);
-	bool (*chan_available)(struct device *dev, int idx);
+	bool (*chan_available)(struct device_node *of_node, int idx);
 	int (*chan_setup)(struct scmi_chan_info *cinfo, struct device *dev,
 			  bool tx);
 	int (*chan_free)(int id, void *p, void *data);

drivers/firmware/arm_scmi/driver.c

@@ -2003,7 +2003,7 @@ static int scmi_chan_setup(struct scmi_info *info, struct device *dev,
 	if (cinfo)
 		return 0;
 
-	if (!info->desc->ops->chan_available(dev, idx)) {
+	if (!info->desc->ops->chan_available(dev->of_node, idx)) {
 		cinfo = idr_find(idr, SCMI_PROTOCOL_BASE);
 		if (unlikely(!cinfo)) /* Possible only if platform has no Rx */
 			return -EINVAL;

drivers/firmware/arm_scmi/mailbox.c

@@ -46,9 +46,9 @@ static void rx_callback(struct mbox_client *cl, void *m)
 	scmi_rx_callback(smbox->cinfo, shmem_read_header(smbox->shmem), NULL);
 }
 
-static bool mailbox_chan_available(struct device *dev, int idx)
+static bool mailbox_chan_available(struct device_node *of_node, int idx)
 {
-	return !of_parse_phandle_with_args(dev->of_node, "mboxes",
+	return !of_parse_phandle_with_args(of_node, "mboxes",
 					   "#mbox-cells", idx, NULL);
 }
 

drivers/firmware/arm_scmi/optee.c

@@ -328,11 +328,11 @@ static int scmi_optee_link_supplier(struct device *dev)
 	return 0;
 }
 
-static bool scmi_optee_chan_available(struct device *dev, int idx)
+static bool scmi_optee_chan_available(struct device_node *of_node, int idx)
 {
 	u32 channel_id;
 
-	return !of_property_read_u32_index(dev->of_node, "linaro,optee-channel-id",
+	return !of_property_read_u32_index(of_node, "linaro,optee-channel-id",
 					   idx, &channel_id);
 }
 

drivers/firmware/arm_scmi/smc.c

@@ -52,9 +52,9 @@ static irqreturn_t smc_msg_done_isr(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
-static bool smc_chan_available(struct device *dev, int idx)
+static bool smc_chan_available(struct device_node *of_node, int idx)
 {
-	struct device_node *np = of_parse_phandle(dev->of_node, "shmem", 0);
+	struct device_node *np = of_parse_phandle(of_node, "shmem", 0);
 	if (!np)
 		return false;
 

drivers/firmware/arm_scmi/virtio.c

@@ -385,7 +385,7 @@ static int virtio_link_supplier(struct device *dev)
 	return 0;
 }
 
-static bool virtio_chan_available(struct device *dev, int idx)
+static bool virtio_chan_available(struct device_node *of_node, int idx)
 {
 	struct scmi_vio_channel *channels, *vioch = NULL;