[4/5] clk: qcom: Add A7 PLL support

Commit Message

Manivannan Sadhasivam Jan. 4, 2021, 8:11 a.m. UTC

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]>
---
 drivers/clk/qcom/Kconfig  |   8 +++
 drivers/clk/qcom/Makefile |   1 +
 drivers/clk/qcom/a7-pll.c | 100 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 109 insertions(+)
 create mode 100644 drivers/clk/qcom/a7-pll.c

Comments

Konrad Dybcio Jan. 4, 2021, 3:30 p.m. UTC | #1

Hi,

could you explicitly state in the probe function (or just in the driver in general, as there's not much more?) and the config structs that the target SoC is X55?

A few more SoCs (MDM9607, MSM8x26 and some others) also use what's known as "A7PLL" downstream, but all of them have a separate configuration for their specific PLLs, which aren't compatible with each other.


Konrad

Manivannan Sadhasivam Jan. 8, 2021, 11:14 a.m. UTC | #2

On Mon, Jan 04, 2021 at 04:30:11PM +0100, Konrad Dybcio wrote:
> Hi,
> 
> could you explicitly state in the probe function (or just in the driver in general, as there's not much more?) and the config structs that the target SoC is X55?
> 

The compatible says it...

> A few more SoCs (MDM9607, MSM8x26 and some others) also use what's known as "A7PLL" downstream, but all of them have a separate configuration for their specific PLLs, which aren't compatible with each other.
> 

Yes, but that difference can be factored using the SoC specific compatibles in
future. The idea here is to have a generic A7 PLL driver much like A53 one and
use SoC specific PLL settings.

Thanks,
Mani

> 
> Konrad
>

Patch

diff --git a/drivers/clk/qcom/Kconfig b/drivers/clk/qcom/Kconfig
index d32bb12cd8d0..d6f4aee4427a 100644
--- a/drivers/clk/qcom/Kconfig
+++ b/drivers/clk/qcom/Kconfig
@@ -28,6 +28,14 @@  config QCOM_A53PLL
 	  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
diff --git a/drivers/clk/qcom/Makefile b/drivers/clk/qcom/Makefile
index 9e5e0e3cb7b4..e7e0ac382176 100644
--- a/drivers/clk/qcom/Makefile
+++ b/drivers/clk/qcom/Makefile
@@ -44,6 +44,7 @@  obj-$(CONFIG_MSM_MMCC_8974) += mmcc-msm8974.o
 obj-$(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
diff --git a/drivers/clk/qcom/a7-pll.c b/drivers/clk/qcom/a7-pll.c
new file mode 100644
index 000000000000..e171d3caf2cf
--- /dev/null
+++ b/drivers/clk/qcom/a7-pll.c
@@ -0,0 +1,100 @@ 
+// 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");