[PATCH v8 3/3] mailbox: qcom: Add support for APCS clock controller

@@ -21,6 +21,11 @@ platforms.
 	Value type: <u32>
 	Definition: as described in mailbox.txt, must be 1
 
+- #clock-cells:
+	Usage: required for msm8916 platforms
+	Value type: <u32>
+	Definition: as described in clock-bindings.txt, must be 0
+
 
 = EXAMPLE
 The following example describes the APCS HMSS found in MSM8996 and part of the

@@ -11,6 +11,8 @@
  * GNU General Public License for more details.
  */
 
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/io.h>

@@ -19,6 +21,34 @@
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/mailbox_controller.h>
+#include <linux/regmap.h>
+
+#include "../clk/qcom/clk-regmap.h"
+#include "../clk/qcom/clk-regmap-mux-div.h"
+
+enum {
+	P_GPLL0,
+	P_A53PLL,
+};
+
+static const struct parent_map gpll0_a53cc_map[] = {
+	{ P_GPLL0, 4 },
+	{ P_A53PLL, 5 },
+};
+
+static const char * const gpll0_a53cc[] = {
+	"gpll0_vote",
+	"a53pll",
+};
+
+static const struct regmap_config a53cc_regmap_config = {
+	.reg_bits		= 32,
+	.reg_stride		= 4,
+	.val_bits		= 32,
+	.max_register		= 0x1000,
+	.fast_io		= true,
+	.val_format_endian	= REGMAP_ENDIAN_LITTLE,
+};
 
 #define QCOM_APCS_IPC_BITS	32
 

@@ -45,8 +75,93 @@ static const struct mbox_chan_ops qcom_apcs_ipc_ops = {
 	.send_data = qcom_apcs_ipc_send_data,
 };
 
+/*
+ * We use the notifier function for switching to a temporary safe configuration
+ * (mux and divider), while the A53 PLL is reconfigured.
+ */
+static int a53cc_notifier_cb(struct notifier_block *nb, unsigned long event,
+			     void *data)
+{
+	int ret = 0;
+	struct clk_regmap_mux_div *md = container_of(nb,
+						     struct clk_regmap_mux_div,
+						     clk_nb);
+	if (event == PRE_RATE_CHANGE)
+		/* set the mux and divider to safe frequency (400mhz) */
+		ret = __mux_div_set_src_div(md, 4, 3);
+
+	return notifier_from_errno(ret);
+}
+
+static int msm8916_register_clk(struct device *dev, void __iomem *base)
+{
+	struct clk_regmap_mux_div *a53cc;
+	struct clk *pclk;
+	struct regmap *regmap;
+	struct clk_init_data init = { };
+	int ret;
+
+	a53cc = devm_kzalloc(dev, sizeof(*a53cc), GFP_KERNEL);
+	if (!a53cc)
+		return -ENOMEM;
+
+	a53cc->reg_offset = 0x50;
+	a53cc->hid_width = 5;
+	a53cc->hid_shift = 0;
+	a53cc->src_width = 3;
+	a53cc->src_shift = 8;
+	a53cc->parent_map = gpll0_a53cc_map;
+
+	init.name = "a53mux";
+	init.parent_names = gpll0_a53cc;
+	init.num_parents = 2;
+	init.ops = &clk_regmap_mux_div_ops;
+	init.flags = CLK_SET_RATE_PARENT;
+	a53cc->clkr.hw.init = &init;
+
+	pclk = __clk_lookup(gpll0_a53cc[1]);
+	if (!pclk)
+		return -EPROBE_DEFER;
+
+	a53cc->clk_nb.notifier_call = a53cc_notifier_cb;
+	ret = clk_notifier_register(pclk, &a53cc->clk_nb);
+	if (ret) {
+		dev_err(dev, "failed to register clock notifier: %d\n", ret);
+		return ret;
+	}
+
+	regmap = devm_regmap_init_mmio(dev, base, &a53cc_regmap_config);
+	if (IS_ERR(regmap)) {
+		ret = PTR_ERR(regmap);
+		dev_err(dev, "failed to init regmap mmio: %d\n", ret);
+		goto err;
+	}
+
+	a53cc->clkr.regmap = regmap;
+
+	ret = devm_clk_register_regmap(dev, &a53cc->clkr);
+	if (ret) {
+		dev_err(dev, "failed to register regmap clock: %d\n", ret);
+		goto err;
+	}
+
+	ret = of_clk_add_hw_provider(dev->of_node, of_clk_hw_simple_get,
+				     &a53cc->clkr.hw);
+	if (ret) {
+		dev_err(dev, "failed to add clock provider: %d\n", ret);
+		goto err;
+	}
+
+	return 0;
+
+err:
+	clk_notifier_unregister(pclk, &a53cc->clk_nb);
+	return ret;
+}
+
 static int qcom_apcs_ipc_probe(struct platform_device *pdev)
 {
+	struct device_node *np = pdev->dev.of_node;
 	struct qcom_apcs_ipc *apcs;
 	struct resource *res;
 	unsigned long offset;

@@ -63,6 +178,13 @@ static int qcom_apcs_ipc_probe(struct platform_device *pdev)
 	if (IS_ERR(base))
 		return PTR_ERR(base);
 
+	if (of_device_is_compatible(np, "qcom,msm8916-apcs-kpss-global")) {
+		/* register the APCS mux and divider clock */
+		ret = msm8916_register_clk(&pdev->dev, base);
+		if (ret)
+			return ret;
+	}
+
 	offset = (unsigned long)of_device_get_match_data(&pdev->dev);
 
 	apcs->reg = base + offset;
--