mailbox: qcom: Convert APCS IPC driver to use regmap

This hardware block provides more functionalities that just IPC. Convert
it to regmap to allow other child platform devices to use the same regmap.
Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

drivers/mailbox/qcom-apcs-ipc-mailbox.c

@@ -18,6 +18,7 @@
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
+#include <linux/regmap.h>
 #include <linux/mailbox_controller.h>
 
 #define QCOM_APCS_IPC_BITS	32
@@ -26,19 +27,25 @@ struct qcom_apcs_ipc {
 	struct mbox_controller mbox;
 	struct mbox_chan mbox_chans[QCOM_APCS_IPC_BITS];
 
-	void __iomem *reg;
+	struct regmap *regmap;
 	unsigned long offset;
 };
 
+static const struct regmap_config apcs_regmap_config = {
+	.reg_bits = 32,
+	.reg_stride = 4,
+	.val_bits = 32,
+	.max_register = 0x1000,
+	.fast_io = true,
+};
+
 static int qcom_apcs_ipc_send_data(struct mbox_chan *chan, void *data)
 {
 	struct qcom_apcs_ipc *apcs = container_of(chan->mbox,
 						  struct qcom_apcs_ipc, mbox);
 	unsigned long idx = (unsigned long)chan->con_priv;
 
-	writel(BIT(idx), apcs->reg);
-
-	return 0;
+	return regmap_write(apcs->regmap, apcs->offset, BIT(idx));
 }
 
 static const struct mbox_chan_ops qcom_apcs_ipc_ops = {
@@ -47,7 +54,9 @@ static const struct mbox_chan_ops qcom_apcs_ipc_ops = {
 
 static int qcom_apcs_ipc_probe(struct platform_device *pdev)
 {
+	struct device_node *np = pdev->dev.of_node;
 	struct qcom_apcs_ipc *apcs;
+	struct regmap *regmap;
 	struct resource *res;
 	unsigned long offset;
 	void __iomem *base;
@@ -63,9 +72,14 @@ static int qcom_apcs_ipc_probe(struct platform_device *pdev)
 	if (IS_ERR(base))
 		return PTR_ERR(base);
 
+	regmap = devm_regmap_init_mmio(&pdev->dev, base, &apcs_regmap_config);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
 	offset = (unsigned long)of_device_get_match_data(&pdev->dev);
 
-	apcs->reg = base + offset;
+	apcs->regmap = regmap;
+	apcs->offset = offset;
 
 	/* Initialize channel identifiers */
 	for (i = 0; i < ARRAY_SIZE(apcs->mbox_chans); i++)