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.

Cc: <devicetree@vger.kernel.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Sricharan R <sricharan@codeaurora.org>
Tested-by: Craig Tatlor <ctatlor97@gmail.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/qcom/Kconfig

@@ -284,3 +284,11 @@ config QCOM_HFPLL
 	  Support for the high-frequency PLLs present on Qualcomm devices.
 	  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.

drivers/clk/qcom/Makefile

@@ -45,4 +45,5 @@ obj-$(CONFIG_SDM_DISPCC_845) += dispcc-sdm845.o
 obj-$(CONFIG_SDM_GCC_845) += gcc-sdm845.o
 obj-$(CONFIG_SDM_VIDEOCC_845) += videocc-sdm845.o
 obj-$(CONFIG_SPMI_PMIC_CLKDIV) += clk-spmi-pmic-div.o
+obj-$(CONFIG_KPSS_XCC) += kpss-xcc.o
 obj-$(CONFIG_QCOM_HFPLL) += hfpll.o

drivers/clk/qcom/kpss-xcc.c

+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2018, The Linux Foundation. All rights reserved.
+
+#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");