[PATCH v4 08/12] clk: qcom: Add KPSS ACC/GCC driver

[Sricharan R <sricharan@codeaurora.org>]

From: Stephen Boyd <sboyd@codeaurora.org>

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.

Cc: <devicetree@vger.kernel.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---
 .../devicetree/bindings/arm/msm/qcom,kpss-acc.txt  |  7 ++
 .../devicetree/bindings/arm/msm/qcom,kpss-gcc.txt  | 28 +++++++
 drivers/clk/qcom/Kconfig                           |  8 ++
 drivers/clk/qcom/Makefile                          |  1 +
 drivers/clk/qcom/kpss-xcc.c                        | 96 ++++++++++++++++++++++
 5 files changed, 140 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/arm/msm/qcom,kpss-gcc.txt
 create mode 100644 drivers/clk/qcom/kpss-xcc.c

diff --git a/Documentation/devicetree/bindings/arm/msm/qcom,kpss-acc.txt b/Documentation/devicetree/bindings/arm/msm/qcom,kpss-acc.txt
index 1333db9..382a574 100644
--- a/Documentation/devicetree/bindings/arm/msm/qcom,kpss-acc.txt
+++ b/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";
 	};
diff --git a/Documentation/devicetree/bindings/arm/msm/qcom,kpss-gcc.txt b/Documentation/devicetree/bindings/arm/msm/qcom,kpss-gcc.txt
new file mode 100644
index 0000000..d1e12f1
--- /dev/null
+++ b/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";
+	};
diff --git a/drivers/clk/qcom/Kconfig b/drivers/clk/qcom/Kconfig
index 6592595..17dcb88 100644
--- a/drivers/clk/qcom/Kconfig
+++ b/drivers/clk/qcom/Kconfig
@@ -214,6 +214,14 @@ 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
diff --git a/drivers/clk/qcom/Makefile b/drivers/clk/qcom/Makefile
index b6741b0..7ad2302 100644
--- a/drivers/clk/qcom/Makefile
+++ b/drivers/clk/qcom/Makefile
@@ -37,4 +37,5 @@ obj-$(CONFIG_MSM_MMCC_8996) += mmcc-msm8996.o
 obj-$(CONFIG_QCOM_CLK_RPM) += clk-rpm.o
 obj-$(CONFIG_QCOM_CLK_SMD_RPM) += clk-smd-rpm.o
 obj-$(CONFIG_SPMI_PMIC_CLKDIV) += clk-spmi-pmic-div.o
+obj-$(CONFIG_KPSS_XCC) += kpss-xcc.o
 obj-$(CONFIG_QCOM_HFPLL) += hfpll.o
diff --git a/drivers/clk/qcom/kpss-xcc.c b/drivers/clk/qcom/kpss-xcc.c
new file mode 100644
index 0000000..bed51c6
--- /dev/null
+++ b/drivers/clk/qcom/kpss-xcc.c
@@ -0,0 +1,96 @@
+/* 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");
-- 
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