[RFC PATCH 03/11] mailbox: mpfs: support fixed binding (TODO: always use regmap)

[Conor Dooley <conor@kernel.org>]

From: Conor Dooley <conor.dooley@microchip.com>

The two previous bindings for this hardware were incorrect, as the
control/status and interrupt register regions should have been described
as syscons and dealt with via regmap in the driver. Add support for
accessing these registers using that method now, so that the hwmon
driver can be supported without using auxdev or hacks with io_remap().

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
 drivers/mailbox/mailbox-mpfs.c | 45 +++++++++++++++++++++++++++++++---
 1 file changed, 41 insertions(+), 4 deletions(-)

diff --git a/drivers/mailbox/mailbox-mpfs.c b/drivers/mailbox/mailbox-mpfs.c
index 0fd83bdd4cee..65aa466ffe8b 100644
--- a/drivers/mailbox/mailbox-mpfs.c
+++ b/drivers/mailbox/mailbox-mpfs.c
@@ -13,12 +13,15 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
+#include <linux/regmap.h>
 #include <linux/interrupt.h>
+#include <linux/mfd/syscon.h>
 #include <linux/mod_devicetable.h>
 #include <linux/platform_device.h>
 #include <linux/mailbox_controller.h>
 #include <soc/microchip/mpfs.h>
 
+#define MESSAGE_INT_OFFSET		0x18cu
 #define SERVICES_CR_OFFSET		0x50u
 #define SERVICES_SR_OFFSET		0x54u
 #define MAILBOX_REG_OFFSET		0x800u
@@ -68,6 +71,7 @@ struct mpfs_mbox {
 	void __iomem *int_reg;
 	struct mbox_chan chans[1];
 	struct mpfs_mss_response *response;
+	struct regmap *sysreg_scb, *control_scb;
 	u16 resp_offset;
 };
 
@@ -75,7 +79,10 @@ static bool mpfs_mbox_busy(struct mpfs_mbox *mbox)
 {
 	u32 status;
 
-	status = readl_relaxed(mbox->ctrl_base + SERVICES_SR_OFFSET);
+	if (mbox->control_scb)
+		regmap_read(mbox->control_scb, SERVICES_SR_OFFSET, &status);
+	else
+		status = readl_relaxed(mbox->ctrl_base + SERVICES_SR_OFFSET);
 
 	return status & SCB_STATUS_BUSY_MASK;
 }
@@ -95,7 +102,11 @@ static bool mpfs_mbox_last_tx_done(struct mbox_chan *chan)
 	 * Failed services are intended to generated interrupts, but in reality
 	 * this does not happen, so the status must be checked here.
 	 */
-	val = readl_relaxed(mbox->ctrl_base + SERVICES_SR_OFFSET);
+	if (mbox->control_scb)
+		regmap_read(mbox->control_scb, SERVICES_SR_OFFSET, &val);
+	else
+		val = readl_relaxed(mbox->ctrl_base + SERVICES_SR_OFFSET);
+
 	response->resp_status = (val & SCB_STATUS_MASK) >> SCB_STATUS_POS;
 
 	return true;
@@ -143,7 +154,12 @@ static int mpfs_mbox_send_data(struct mbox_chan *chan, void *data)
 
 	tx_trigger = (opt_sel << SCB_CTRL_POS) & SCB_CTRL_MASK;
 	tx_trigger |= SCB_CTRL_REQ_MASK | SCB_STATUS_NOTIFY_MASK;
-	writel_relaxed(tx_trigger, mbox->ctrl_base + SERVICES_CR_OFFSET);
+
+	if (mbox->control_scb)
+		regmap_write(mbox->control_scb, SERVICES_CR_OFFSET, tx_trigger);
+	else
+		writel_relaxed(tx_trigger, mbox->ctrl_base + SERVICES_CR_OFFSET);
+
 
 	return 0;
 }
@@ -185,7 +201,10 @@ static irqreturn_t mpfs_mbox_inbox_isr(int irq, void *data)
 	struct mbox_chan *chan = data;
 	struct mpfs_mbox *mbox = (struct mpfs_mbox *)chan->con_priv;
 
-	writel_relaxed(0, mbox->int_reg);
+	if (mbox->control_scb)
+		regmap_write(mbox->sysreg_scb, MESSAGE_INT_OFFSET, 0);
+	else
+		writel_relaxed(0, mbox->int_reg);
 
 	mpfs_mbox_rx_data(chan);
 
@@ -231,6 +250,23 @@ static int mpfs_mbox_probe(struct platform_device *pdev)
 	if (!mbox)
 		return -ENOMEM;
 
+	mbox->control_scb = syscon_regmap_lookup_by_compatible("microchip,mpfs-control-scb");
+	if (IS_ERR(mbox->control_scb)) {
+		mbox->control_scb = NULL;
+		goto old_format;
+	}
+
+	mbox->sysreg_scb = syscon_regmap_lookup_by_compatible("microchip,mpfs-sysreg-scb");
+	if (IS_ERR(mbox->sysreg_scb))
+		return -1;
+
+	mbox->mbox_base = devm_platform_get_and_ioremap_resource(pdev, 0, &regs);
+	if (IS_ERR(mbox->ctrl_base))
+		return PTR_ERR(mbox->mbox_base);
+
+	goto done;
+
+old_format:
 	mbox->ctrl_base = devm_platform_get_and_ioremap_resource(pdev, 0, &regs);
 	if (IS_ERR(mbox->ctrl_base))
 		return PTR_ERR(mbox->ctrl_base);
@@ -243,6 +279,7 @@ static int mpfs_mbox_probe(struct platform_device *pdev)
 	if (IS_ERR(mbox->mbox_base)) // account for the old dt-binding w/ 2 regs
 		mbox->mbox_base = mbox->ctrl_base + MAILBOX_REG_OFFSET;
 
+done:
 	mbox->irq = platform_get_irq(pdev, 0);
 	if (mbox->irq < 0)
 		return mbox->irq;
-- 
2.43.0