clk: qcom: Add A7 PLL support

Add support for PLL found in Qualcomm SDX55 platforms which is used to
provide clock to the Cortex A7 CPU via a mux. This PLL can provide high
frequency clock to the CPU above 1GHz as compared to the other sources
like GPLL0.

In this driver, the power domain is attached to the cpudev. This is
required for CPUFreq functionality and there seems to be no better place
to do other than this driver (no dedicated CPUFreq driver).

Signed-off-by: Manivannan Sadhasivam <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Stephen Boyd <[e-mail]>

drivers/clk/qcom/Kconfig

···
 	  Say Y if you want to support higher CPU frequencies on MSM8916
 	  devices.
 
+config QCOM_A7PLL
+	tristate "SDX55 A7 PLL"
+	help
+	  Support for the A7 PLL on SDX55 devices. It provides the CPU with
+	  frequencies above 1GHz.
+	  Say Y if you want to support higher CPU frequencies on SDX55
+	  devices.
+
 config QCOM_CLK_APCS_MSM8916
 	tristate "MSM8916 APCS Clock Controller"
 	depends on QCOM_APCS_IPC || COMPILE_TEST

drivers/clk/qcom/Makefile

···
 obj-$(CONFIG_MSM_MMCC_8996) += mmcc-msm8996.o
 obj-$(CONFIG_MSM_MMCC_8998) += mmcc-msm8998.o
 obj-$(CONFIG_QCOM_A53PLL) += a53-pll.o
+obj-$(CONFIG_QCOM_A7PLL) += a7-pll.o
 obj-$(CONFIG_QCOM_CLK_APCS_MSM8916) += apcs-msm8916.o
 obj-$(CONFIG_QCOM_CLK_APCC_MSM8996) += clk-cpu-8996.o
 obj-$(CONFIG_QCOM_CLK_RPM) += clk-rpm.o

drivers/clk/qcom/a7-pll.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Qualcomm A7 PLL driver
+ *
+ * Copyright (c) 2020, Linaro Limited
+ * Author: Manivannan Sadhasivam <[e-mail]>
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#include "clk-alpha-pll.h"
+
+#define LUCID_PLL_OFF_L_VAL 0x04
+
+static const struct pll_vco lucid_vco[] = {
+	{ 249600000, 2000000000, 0 },
+};
+
+static struct clk_alpha_pll a7pll = {
+	.offset = 0x100,
+	.vco_table = lucid_vco,
+	.num_vco = ARRAY_SIZE(lucid_vco),
+	.regs = clk_alpha_pll_regs[CLK_ALPHA_PLL_TYPE_LUCID],
+	.clkr = {
+		.hw.init = &(struct clk_init_data){
+			.name = "a7pll",
+			.parent_data =  &(const struct clk_parent_data){
+				.fw_name = "bi_tcxo",
+			},
+			.num_parents = 1,
+			.ops = &clk_alpha_pll_lucid_ops,
+		},
+	},
+};
+
+static const struct alpha_pll_config a7pll_config = {
+	.l = 0x39,
+	.config_ctl_val = 0x20485699,
+	.config_ctl_hi_val = 0x2261,
+	.config_ctl_hi1_val = 0x029A699C,
+	.user_ctl_val = 0x1,
+	.user_ctl_hi_val = 0x805,
+};
+
+static const struct regmap_config a7pll_regmap_config = {
+	.reg_bits		= 32,
+	.reg_stride		= 4,
+	.val_bits		= 32,
+	.max_register		= 0x1000,
+	.fast_io		= true,
+};
+
+static int qcom_a7pll_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct regmap *regmap;
+	void __iomem *base;
+	u32 l_val;
+	int ret;
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	regmap = devm_regmap_init_mmio(dev, base, &a7pll_regmap_config);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	/* Configure PLL only if the l_val is zero */
+	regmap_read(regmap, a7pll.offset + LUCID_PLL_OFF_L_VAL, &l_val);
+	if (!l_val)
+		clk_lucid_pll_configure(&a7pll, regmap, &a7pll_config);
+
+	ret = devm_clk_register_regmap(dev, &a7pll.clkr);
+	if (ret)
+		return ret;
+
+	return devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get,
+					   &a7pll.clkr.hw);
+}
+
+static const struct of_device_id qcom_a7pll_match_table[] = {
+	{ .compatible = "qcom,sdx55-a7pll" },
+	{ }
+};
+
+static struct platform_driver qcom_a7pll_driver = {
+	.probe = qcom_a7pll_probe,
+	.driver = {
+		.name = "qcom-a7pll",
+		.of_match_table = qcom_a7pll_match_table,
+	},
+};
+module_platform_driver(qcom_a7pll_driver);
+
+MODULE_DESCRIPTION("Qualcomm A7 PLL Driver");
+MODULE_LICENSE("GPL v2");