clk: qcom: Add KPSS ACC/GCC driver

The ACC and GCC regions present in KPSSv1 contain registers to
control clocks and power to each Krait CPU and L2. For CPUfreq
purposes probe these devices and expose a mux clock that chooses
between PXO and PLL8.

Change-Id: Icaa1b68652eb4c836e8aacad80ff6cebe34cad4f
Cc: <devicetree@vger.kernel.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Taniya Das <tdas@codeaurora.org>

Documentation/devicetree/bindings/arm/msm/qcom,kpss-acc.txt

@@ -21,10 +21,17 @@ PROPERTIES
 		    the register region. An optional second element specifies
 		    the base address and size of the alias register region.
 
+- clock-output-names:
+	Usage: optional
+	Value type: <string>
+	Definition: Name of the output clock. Typically acpuX_aux where X is a
+		    CPU number starting at 0.
+
 Example:
 
 	clock-controller@2088000 {
 		compatible = "qcom,kpss-acc-v2";
 		reg = <0x02088000 0x1000>,
 		      <0x02008000 0x1000>;
+		clock-output-names = "acpu0_aux";
 	};

Documentation/devicetree/bindings/arm/msm/qcom,kpss-gcc.txt

@@ -0,0 +1,28 @@
+Krait Processor Sub-system (KPSS) Global Clock Controller (GCC)
+
+PROPERTIES
+
+- compatible:
+	Usage: required
+	Value type: <string>
+	Definition: should be one of:
+			"qcom,kpss-gcc"
+
+- reg:
+	Usage: required
+	Value type: <prop-encoded-array>
+	Definition: base address and size of the register region
+
+- clock-output-names:
+	Usage: required
+	Value type: <string>
+	Definition: Name of the output clock. Typically acpu_l2_aux indicating
+		    an L2 cache auxiliary clock.
+
+Example:
+
+	l2cc: clock-controller@2011000 {
+		compatible = "qcom,kpss-gcc";
+		reg = <0x2011000 0x1000>;
+		clock-output-names = "acpu_l2_aux";
+	};

drivers/clk/qcom/Kconfig

@@ -132,6 +132,14 @@ config QCOM_HFPLL
 	  Say Y if you want to support CPU frequency scaling on devices
 	  such as MSM8974, APQ8084, etc.
 
+config KPSS_XCC
+	tristate "KPSS Clock Controller"
+	depends on COMMON_CLK_QCOM
+	help
+	  Support for the Krait ACC and GCC clock controllers. Say Y
+	  if you want to support CPU frequency scaling on devices such
+	  as MSM8960, APQ8064, etc.
+
 config KRAIT_CLOCKS
 	bool
 	select KRAIT_L2_ACCESSORS

drivers/clk/qcom/Makefile

@@ -26,4 +26,5 @@ obj-$(CONFIG_MSM_GCC_8996) += gcc-msm8996.o
 obj-$(CONFIG_MSM_MMCC_8960) += mmcc-msm8960.o
 obj-$(CONFIG_MSM_MMCC_8974) += mmcc-msm8974.o
 obj-$(CONFIG_MSM_MMCC_8996) += mmcc-msm8996.o
+obj-$(CONFIG_KPSS_XCC) += kpss-xcc.o
 obj-$(CONFIG_QCOM_HFPLL) += hfpll.o

drivers/clk/qcom/kpss-xcc.c

@@ -0,0 +1,95 @@
+/* Copyright (c) 2014-2015, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+
+static const char *aux_parents[] = {
+	"pll8_vote",
+	"pxo",
+};
+
+static unsigned int aux_parent_map[] = {
+	3,
+	0,
+};
+
+static const struct of_device_id kpss_xcc_match_table[] = {
+	{ .compatible = "qcom,kpss-acc-v1", .data = (void *)1UL },
+	{ .compatible = "qcom,kpss-gcc" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, kpss_xcc_match_table);
+
+static int kpss_xcc_driver_probe(struct platform_device *pdev)
+{
+	const struct of_device_id *id;
+	struct clk *clk;
+	struct resource *res;
+	void __iomem *base;
+	const char *name;
+
+	id = of_match_device(kpss_xcc_match_table, &pdev->dev);
+	if (!id)
+		return -ENODEV;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	if (id->data) {
+		if (of_property_read_string_index(pdev->dev.of_node,
+					"clock-output-names", 0, &name))
+			return -ENODEV;
+		base += 0x14;
+	} else {
+		name = "acpu_l2_aux";
+		base += 0x28;
+	}
+
+	clk = clk_register_mux_table(&pdev->dev, name, aux_parents,
+				     ARRAY_SIZE(aux_parents), 0, base, 0, 0x3,
+				     0, aux_parent_map, NULL);
+
+	platform_set_drvdata(pdev, clk);
+
+	return PTR_ERR_OR_ZERO(clk);
+}
+
+static int kpss_xcc_driver_remove(struct platform_device *pdev)
+{
+	clk_unregister_mux(platform_get_drvdata(pdev));
+	return 0;
+}
+
+static struct platform_driver kpss_xcc_driver = {
+	.probe = kpss_xcc_driver_probe,
+	.remove = kpss_xcc_driver_remove,
+	.driver = {
+		.name = "kpss-xcc",
+		.of_match_table = kpss_xcc_match_table,
+	},
+};
+module_platform_driver(kpss_xcc_driver);
+
+MODULE_DESCRIPTION("Krait Processor Sub System (KPSS) Clock Driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:kpss-xcc");