clk: qcom: Add A53 PLL support

The CPUs on Qualcomm MSM8916-based platforms are clocked by two PLLs,
a primary (A53) CPU PLL and a secondary fixed-rate GPLL0. These sources
are connected to a mux and half-integer divider, which is feeding the
CPU cores.

This patch adds support for the primary CPU PLL which generates the
higher range of frequencies above 1GHz.

Signed-off-by: Georgi Djakov <[e-mail]>
Acked-by: Bjorn Andersson <[e-mail]>
Tested-by: Amit Kucheria <[e-mail]>
[[e-mail]: Move to devm provider registration,
NUL terminate frequency table, made tristate/modular]
Signed-off-by: Stephen Boyd <[e-mail]>

Documentation/devicetree/bindings/clock/qcom,a53pll.txt

···
+Qualcomm MSM8916 A53 PLL Binding
+--------------------------------
+The A53 PLL on MSM8916 platforms is the main CPU PLL used used for frequencies
+above 1GHz.
+
+Required properties :
+- compatible : Shall contain only one of the following:
+
+		"qcom,msm8916-a53pll"
+
+- reg : shall contain base register location and length
+
+- #clock-cells : must be set to <0>
+
+Example:
+
+	a53pll: clock@b016000 {
+		compatible = "qcom,msm8916-a53pll";
+		reg = <0xb016000 0x40>;
+		#clock-cells = <0>;
+	};
+

drivers/clk/qcom/Kconfig

···
 	select REGMAP_MMIO
 	select RESET_CONTROLLER
 
+config QCOM_A53PLL
+	tristate "MSM8916 A53 PLL"
+	depends on COMMON_CLK_QCOM
+	default ARCH_QCOM
+	help
+	  Support for the A53 PLL on MSM8916 devices. It provides
+	  the CPU with frequencies above 1GHz.
+	  Say Y if you want to support higher CPU frequencies on MSM8916
+	  devices.
+
 config QCOM_CLK_RPM
 	tristate "RPM based Clock Controller"
 	depends on COMMON_CLK_QCOM && MFD_QCOM_RPM

drivers/clk/qcom/Makefile

···
 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_QCOM_A53PLL) += a53-pll.o
 obj-$(CONFIG_QCOM_CLK_RPM) += clk-rpm.o
 obj-$(CONFIG_QCOM_CLK_SMD_RPM) += clk-smd-rpm.o

drivers/clk/qcom/a53-pll.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Qualcomm A53 PLL driver
+ *
+ * Copyright (c) 2017, Linaro Limited
+ * Author: Georgi Djakov <[e-mail]>
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/module.h>
+
+#include "clk-pll.h"
+#include "clk-regmap.h"
+
+static const struct pll_freq_tbl a53pll_freq[] = {
+	{  998400000, 52, 0x0, 0x1, 0 },
+	{ 1094400000, 57, 0x0, 0x1, 0 },
+	{ 1152000000, 62, 0x0, 0x1, 0 },
+	{ 1209600000, 63, 0x0, 0x1, 0 },
+	{ 1248000000, 65, 0x0, 0x1, 0 },
+	{ 1363200000, 71, 0x0, 0x1, 0 },
+	{ 1401600000, 73, 0x0, 0x1, 0 },
+	{ }
+};
+
+static const struct regmap_config a53pll_regmap_config = {
+	.reg_bits		= 32,
+	.reg_stride		= 4,
+	.val_bits		= 32,
+	.max_register		= 0x40,
+	.fast_io		= true,
+};
+
+static int qcom_a53pll_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct regmap *regmap;
+	struct resource *res;
+	struct clk_pll *pll;
+	void __iomem *base;
+	struct clk_init_data init = { };
+	int ret;
+
+	pll = devm_kzalloc(dev, sizeof(*pll), GFP_KERNEL);
+	if (!pll)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	regmap = devm_regmap_init_mmio(dev, base, &a53pll_regmap_config);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	pll->l_reg = 0x04;
+	pll->m_reg = 0x08;
+	pll->n_reg = 0x0c;
+	pll->config_reg = 0x14;
+	pll->mode_reg = 0x00;
+	pll->status_reg = 0x1c;
+	pll->status_bit = 16;
+	pll->freq_tbl = a53pll_freq;
+
+	init.name = "a53pll";
+	init.parent_names = (const char *[]){ "xo" };
+	init.num_parents = 1;
+	init.ops = &clk_pll_sr2_ops;
+	init.flags = CLK_IS_CRITICAL;
+	pll->clkr.hw.init = &init;
+
+	ret = devm_clk_register_regmap(dev, &pll->clkr);
+	if (ret) {
+		dev_err(dev, "failed to register regmap clock: %d\n", ret);
+		return ret;
+	}
+
+	ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get,
+					  &pll->clkr.hw);
+	if (ret) {
+		dev_err(dev, "failed to add clock provider: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id qcom_a53pll_match_table[] = {
+	{ .compatible = "qcom,msm8916-a53pll" },
+	{ }
+};
+
+static struct platform_driver qcom_a53pll_driver = {
+	.probe = qcom_a53pll_probe,
+	.driver = {
+		.name = "qcom-a53pll",
+		.of_match_table = qcom_a53pll_match_table,
+	},
+};
+module_platform_driver(qcom_a53pll_driver);
+
+MODULE_DESCRIPTION("Qualcomm A53 PLL Driver");
+MODULE_LICENSE("GPL v2");