[PATCH v2 0/2] cpufreq: Add sunxi nvmem based CPU scaling driver

[PATCH v2 0/2] cpufreq: Add sunxi nvmem based CPU scaling driver

[Yangtao Li]

Add sunxi nvmem based CPU scaling driver, refers to qcom-cpufreq-kryo.

Yangtao Li (2):
  cpufreq: Add sunxi nvmem based CPU scaling driver
  dt-bindings: cpufreq: Document operating-points-v2-sunxi-cpu

 .../bindings/opp/sunxi-nvmem-cpufreq.txt      | 166 +++++++++++++
 MAINTAINERS                                   |   7 +
 drivers/cpufreq/Kconfig.arm                   |  10 +
 drivers/cpufreq/Makefile                      |   1 +
 drivers/cpufreq/cpufreq-dt-platdev.c          |   2 +
 drivers/cpufreq/sunxi-cpufreq-nvmem.c         | 234 ++++++++++++++++++
 6 files changed, 420 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/opp/sunxi-nvmem-cpufreq.txt
 create mode 100644 drivers/cpufreq/sunxi-cpufreq-nvmem.c

---
v2:
-update changelog
-convert to dev_pm_opp_set_prop_name use instead of dev_pm_opp_set_supported_hw
-some change in OPP Node 
---
2.17.0

[PATCH v2 1/2] cpufreq: Add sunxi nvmem based CPU scaling driver

[Yangtao Li]

For some SoCs, the CPU frequency subset and voltage value of each OPP
varies based on the silicon variant in use. The sunxi-cpufreq-nvmem
driver reads the efuse value from the SoC to provide the OPP framework
with required information.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
---
 MAINTAINERS                           |   7 +
 drivers/cpufreq/Kconfig.arm           |  10 ++
 drivers/cpufreq/Makefile              |   1 +
 drivers/cpufreq/cpufreq-dt-platdev.c  |   2 +
 drivers/cpufreq/sunxi-cpufreq-nvmem.c | 234 ++++++++++++++++++++++++++
 5 files changed, 254 insertions(+)
 create mode 100644 drivers/cpufreq/sunxi-cpufreq-nvmem.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 391405091c6b..bfd18ba6aa1a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -667,6 +667,13 @@ S:	Maintained
 F:	Documentation/i2c/busses/i2c-ali1563
 F:	drivers/i2c/busses/i2c-ali1563.c
 
+ALLWINNER CPUFREQ DRIVER
+M:	Yangtao Li <tiny.windzz@gmail.com>
+L:	linux-pm@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/opp/sunxi-nvmem-cpufreq.txt
+F:	drivers/cpufreq/sunxi-cpufreq-nvmem.c
+
 ALLWINNER SECURITY SYSTEM
 M:	Corentin Labbe <clabbe.montjoie@gmail.com>
 L:	linux-crypto@vger.kernel.org
diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index 179a1d302f48..25933c4321a7 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -18,6 +18,16 @@ config ACPI_CPPC_CPUFREQ
 
 	  If in doubt, say N.
 
+config ARM_ALLWINNER_CPUFREQ_NVMEM
+	tristate "Allwinner nvmem based CPUFreq"
+	depends on ARCH_SUNXI
+	depends on NVMEM_SUNXI_SID
+	select PM_OPP
+	help
+	  This adds the CPUFreq driver for Allwinner nvmem based SoC.
+
+	  If in doubt, say N.
+
 config ARM_ARMADA_37XX_CPUFREQ
 	tristate "Armada 37xx CPUFreq support"
 	depends on ARCH_MVEBU && CPUFREQ_DT
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index 689b26c6f949..da28de67613c 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -78,6 +78,7 @@ obj-$(CONFIG_ARM_SCMI_CPUFREQ)		+= scmi-cpufreq.o
 obj-$(CONFIG_ARM_SCPI_CPUFREQ)		+= scpi-cpufreq.o
 obj-$(CONFIG_ARM_SPEAR_CPUFREQ)		+= spear-cpufreq.o
 obj-$(CONFIG_ARM_STI_CPUFREQ)		+= sti-cpufreq.o
+obj-$(CONFIG_ARM_ALLWINNER_CPUFREQ_NVMEM) += sunxi-cpufreq-nvmem.o
 obj-$(CONFIG_ARM_TANGO_CPUFREQ)		+= tango-cpufreq.o
 obj-$(CONFIG_ARM_TEGRA20_CPUFREQ)	+= tegra20-cpufreq.o
 obj-$(CONFIG_ARM_TEGRA124_CPUFREQ)	+= tegra124-cpufreq.o
diff --git a/drivers/cpufreq/cpufreq-dt-platdev.c b/drivers/cpufreq/cpufreq-dt-platdev.c
index 47729a22c159..50e7810f3a28 100644
--- a/drivers/cpufreq/cpufreq-dt-platdev.c
+++ b/drivers/cpufreq/cpufreq-dt-platdev.c
@@ -105,6 +105,8 @@ static const struct of_device_id whitelist[] __initconst = {
  * platforms using "operating-points-v2" property.
  */
 static const struct of_device_id blacklist[] __initconst = {
+	{ .compatible = "allwinner,sun50i-h6", },
+
 	{ .compatible = "calxeda,highbank", },
 	{ .compatible = "calxeda,ecx-2000", },
 
diff --git a/drivers/cpufreq/sunxi-cpufreq-nvmem.c b/drivers/cpufreq/sunxi-cpufreq-nvmem.c
new file mode 100644
index 000000000000..a72caac572c4
--- /dev/null
+++ b/drivers/cpufreq/sunxi-cpufreq-nvmem.c
@@ -0,0 +1,234 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Allwinner CPUFreq nvmem based driver
+ *
+ * The sunxi-cpufreq-nvmem driver reads the efuse value from the SoC to
+ * provide the OPP framework with required information.
+ *
+ * Copyright (C) 2019 Yangtao Li <tiny.windzz@gmail.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_opp.h>
+#include <linux/slab.h>
+
+#define MAX_NAME_LEN      7
+
+struct sunxi_cpufreq_soc_data {
+	u32 (*efuse_xlate)(const struct sunxi_cpufreq_soc_data *soc_data,
+			   u32 efuse);
+	u32 nvmem_mask;
+	u32 nvmem_shift;
+};
+
+static struct platform_device *cpufreq_dt_pdev, *sunxi_cpufreq_pdev;
+
+static u32 sun50i_efuse_xlate(const struct sunxi_cpufreq_soc_data *soc_data,
+			      u32 efuse)
+{
+	return (efuse >> soc_data->nvmem_shift) & soc_data->nvmem_mask;
+}
+
+/**
+ * sunxi_cpufreq_get_efuse() - Parse and return efuse value present on SoC
+ * @soc_data: Pointer to sunxi_cpufreq_soc_data context
+ * @versions: Set to the value parsed from efuse
+ *
+ * Returns 0 if success.
+ */
+static int sunxi_cpufreq_get_efuse(const struct sunxi_cpufreq_soc_data *soc_data,
+				   u32 *versions)
+{
+	struct nvmem_cell *speedbin_nvmem;
+	struct device_node *np;
+	struct device *cpu_dev;
+	u32 *speedbin;
+	size_t len;
+	int ret;
+
+	cpu_dev = get_cpu_device(0);
+	if (!cpu_dev)
+		return -ENODEV;
+
+	np = dev_pm_opp_of_get_opp_desc_node(cpu_dev);
+	if (!np)
+		return -ENOENT;
+
+	ret = of_device_is_compatible(np, "operating-points-v2-sunxi-cpu");
+	if (!ret) {
+		of_node_put(np);
+		return -ENOENT;
+	}
+
+	speedbin_nvmem = of_nvmem_cell_get(np, NULL);
+	of_node_put(np);
+	if (IS_ERR(speedbin_nvmem)) {
+		if (PTR_ERR(speedbin_nvmem) != -EPROBE_DEFER)
+			pr_err("Could not get nvmem cell: %ld\n",
+			PTR_ERR(speedbin_nvmem));
+		return PTR_ERR(speedbin_nvmem);
+	}
+
+	speedbin = nvmem_cell_read(speedbin_nvmem, &len);
+	nvmem_cell_put(speedbin_nvmem);
+	if (IS_ERR(speedbin))
+		return PTR_ERR(speedbin);
+
+	*versions = soc_data->efuse_xlate(soc_data, *speedbin);
+
+	kfree(speedbin);
+	return 0;
+};
+
+static const struct sunxi_cpufreq_soc_data sun50i_h6_data = {
+	.efuse_xlate = sun50i_efuse_xlate,
+	.nvmem_mask = 0x7,
+	.nvmem_shift = 5,
+};
+
+static const struct of_device_id sunxi_cpufreq_match_list[] = {
+	{ .compatible = "allwinner,sun50i-h6", .data = &sun50i_h6_data },
+	{}
+};
+
+static const struct of_device_id *sunxi_cpufreq_match_node(void)
+{
+	struct device_node *np;
+	const struct of_device_id *match;
+
+	np = of_find_node_by_path("/");
+	match = of_match_node(sunxi_cpufreq_match_list, np);
+	of_node_put(np);
+
+	return match;
+}
+
+static int sunxi_cpufreq_nvmem_probe(struct platform_device *pdev)
+{
+	const struct sunxi_cpufreq_soc_data *soc_data;
+	struct opp_table **opp_tables;
+	const struct of_device_id *match;
+	char name[MAX_NAME_LEN];
+	unsigned int cpu;
+	u32 speed = 0;
+	int ret;
+
+	opp_tables = kcalloc(num_possible_cpus(), sizeof(*opp_tables),
+			     GFP_KERNEL);
+	if (!opp_tables)
+		return -ENOMEM;
+
+	match = sunxi_cpufreq_match_node();
+	soc_data = match->data;
+	if (!soc_data)
+		return -EINVAL;
+
+	ret = sunxi_cpufreq_get_efuse(soc_data, &speed);
+	if (ret)
+		return ret;
+
+	snprintf(name, MAX_NAME_LEN, "speed%d", speed);
+
+	for_each_possible_cpu(cpu) {
+		struct device *cpu_dev = get_cpu_device(cpu);
+
+		if (NULL == cpu_dev) {
+			ret = -ENODEV;
+			goto free_opp;
+		}
+
+		opp_tables[cpu] = dev_pm_opp_set_prop_name(cpu_dev, name);
+		if (IS_ERR(opp_tables[cpu])) {
+			ret = PTR_ERR(opp_tables[cpu]);
+			pr_err("Failed to set prop name\n");
+			goto free_opp;
+		}
+	}
+
+	cpufreq_dt_pdev = platform_device_register_simple("cpufreq-dt", -1,
+							  NULL, 0);
+	if (!IS_ERR(cpufreq_dt_pdev)) {
+		platform_set_drvdata(pdev, opp_tables);
+		return 0;
+	}
+
+	ret = PTR_ERR(cpufreq_dt_pdev);
+	pr_err("Failed to register platform device\n");
+
+free_opp:
+	for_each_possible_cpu(cpu) {
+		if (IS_ERR_OR_NULL(opp_tables[cpu]))
+			break;
+		dev_pm_opp_put_prop_name(opp_tables[cpu]);
+	}
+	kfree(opp_tables);
+
+	return ret;
+}
+
+static int sunxi_cpufreq_nvmem_remove(struct platform_device *pdev)
+{
+	struct opp_table **opp_tables = platform_get_drvdata(pdev);
+	unsigned int cpu;
+
+	platform_device_unregister(cpufreq_dt_pdev);
+
+	for_each_possible_cpu(cpu)
+		dev_pm_opp_put_prop_name(opp_tables[cpu]);
+
+	kfree(opp_tables);
+
+	return 0;
+}
+
+static struct platform_driver sunxi_cpufreq_driver = {
+	.probe = sunxi_cpufreq_nvmem_probe,
+	.remove = sunxi_cpufreq_nvmem_remove,
+	.driver = {
+		.name = "sunxi-cpufreq-nvmem",
+	},
+};
+
+/*
+ * Since the driver depends on nvmem drivers, which may return EPROBE_DEFER,
+ * all the real activity is done in the probe, which may be defered as well.
+ * The init here is only registering the driver and the platform device.
+ */
+static int __init sunxi_cpufreq_init(void)
+{
+	const struct of_device_id *match;
+	int ret;
+
+	match = sunxi_cpufreq_match_node();
+	if (!match)
+		return -ENODEV;
+
+	ret = platform_driver_register(&sunxi_cpufreq_driver);
+	if (unlikely(ret < 0))
+		return ret;
+
+	sunxi_cpufreq_pdev = platform_device_register_simple(
+		"sunxi-cpufreq-nvmem", -1, NULL, 0);
+	ret = PTR_ERR_OR_ZERO(sunxi_cpufreq_pdev);
+	if (0 == ret)
+		return 0;
+
+	platform_driver_unregister(&sunxi_cpufreq_driver);
+	return ret;
+}
+module_init(sunxi_cpufreq_init);
+
+static void __exit sunxi_cpufreq_exit(void)
+{
+	platform_device_unregister(sunxi_cpufreq_pdev);
+	platform_driver_unregister(&sunxi_cpufreq_driver);
+}
+module_exit(sunxi_cpufreq_exit);
+
+MODULE_DESCRIPTION("Sunxi cpufreq driver");
+MODULE_LICENSE("GPL v2");
-- 
2.17.0

[PATCH v2 2/2] dt-bindings: cpufreq: Document operating-points-v2-sunxi-cpu

[Yangtao Li]

Allwinner Process Voltage Scaling Tables defines the voltage and
frequency value  based on the speedbin blown in the efuse combination.
The sunxi-cpufreq-nvmem driver reads the efuse value from the SoC to
provide the OPP framework with required information.
This is used to determine the voltage and frequency value for each
OPP of operating-points-v2 table when it is parsed by the OPP framework.

The "operating-points-v2-sunxi-cpu" DT extends the "operating-points-v2"
with following parameters:
- nvmem-cells (NVMEM area containig the speedbin information)
- opp-microvolt-<name>: voltage in micro Volts.
  At runtime, the platform can pick a <name> and matching
  opp-microvolt-<name> property

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
---
 .../bindings/opp/sunxi-nvmem-cpufreq.txt      | 166 ++++++++++++++++++
 1 file changed, 166 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/opp/sunxi-nvmem-cpufreq.txt

diff --git a/Documentation/devicetree/bindings/opp/sunxi-nvmem-cpufreq.txt b/Documentation/devicetree/bindings/opp/sunxi-nvmem-cpufreq.txt
new file mode 100644
index 000000000000..c81a2075b974
--- /dev/null
+++ b/Documentation/devicetree/bindings/opp/sunxi-nvmem-cpufreq.txt
@@ -0,0 +1,166 @@
+Allwinner Technologies, Inc. NVMEM CPUFreq and OPP bindings
+===================================
+
+For some SoCs, the CPU frequency subset and voltage value of each OPP
+varies based on the silicon variant in use. Allwinner Process Voltage
+Scaling Tables defines the voltage and frequency value  based on the
+speedbin blown in the efuse combination. The sunxi-cpufreq-nvmem driver
+reads the efuse value from the SoC to provide the OPP framework with
+required information.
+
+Required properties:
+--------------------
+In 'cpus' nodes:
+- operating-points-v2: Phandle to the operating-points-v2 table to use.
+
+In 'operating-points-v2' table:
+- compatible: Should be
+	- 'operating-points-v2-sunxi-cpu'.
+- nvmem-cells: A phandle pointing to a nvmem-cells node representing the
+		efuse registers that has information about the
+		speedbin that is used to select the right frequency/voltage
+		value pair.
+		Please refer the for nvmem-cells
+		bindings Documentation/devicetree/bindings/nvmem/nvmem.txt
+		and also examples below.
+
+In every OPP node:
+- opp-microvolt-<name>: Voltage in micro Volts.
+			At runtime, the platform can pick a <name> and
+			matching opp-microvolt-<name> property.
+			[See: opp.txt]
+
+Example 1:
+---------
+
+	cpus {
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		cpu0: cpu@0 {
+			compatible = "arm,cortex-a53";
+			device_type = "cpu";
+			reg = <0>;
+			enable-method = "psci";
+			clocks = <&ccu CLK_CPUX>;
+			clock-latency-ns = <244144>; /* 8 32k periods */
+			operating-points-v2 = <&cpu_opp_table>;
+			#cooling-cells = <2>;
+		};
+
+		cpu1: cpu@1 {
+			compatible = "arm,cortex-a53";
+			device_type = "cpu";
+			reg = <1>;
+			enable-method = "psci";
+			clocks = <&ccu CLK_CPUX>;
+			clock-latency-ns = <244144>; /* 8 32k periods */
+			operating-points-v2 = <&cpu_opp_table>;
+			#cooling-cells = <2>;
+		};
+
+		cpu2: cpu@2 {
+			compatible = "arm,cortex-a53";
+			device_type = "cpu";
+			reg = <2>;
+			enable-method = "psci";
+			clocks = <&ccu CLK_CPUX>;
+			clock-latency-ns = <244144>; /* 8 32k periods */
+			operating-points-v2 = <&cpu_opp_table>;
+			#cooling-cells = <2>;
+		};
+
+		cpu3: cpu@3 {
+			compatible = "arm,cortex-a53";
+			device_type = "cpu";
+			reg = <3>;
+			enable-method = "psci";
+			clocks = <&ccu CLK_CPUX>;
+			clock-latency-ns = <244144>; /* 8 32k periods */
+			operating-points-v2 = <&cpu_opp_table>;
+			#cooling-cells = <2>;
+		};
+        };
+
+        cpu_opp_table: opp_table {
+                compatible = "operating-points-v2-sunxi-cpu";
+                nvmem-cells = <&speedbin_efuse>;
+                opp-shared;
+
+                opp@480000000 {
+                        clock-latency-ns = <244144>; /* 8 32k periods */
+                        opp-hz = /bits/ 64 <480000000>;
+
+                        opp-microvolt-speed0 = <880000>;
+                        opp-microvolt-speed1 = <820000>;
+                        opp-microvolt-speed2 = <800000>;
+                };
+
+                opp@720000000 {
+                        clock-latency-ns = <244144>; /* 8 32k periods */
+                        opp-hz = /bits/ 64 <720000000>;
+
+                        opp-microvolt-speed0 = <880000>;
+                        opp-microvolt-speed1 = <820000>;
+                        opp-microvolt-speed2 = <800000>;
+                };
+
+                opp@816000000 {
+                        clock-latency-ns = <244144>; /* 8 32k periods */
+                        opp-hz = /bits/ 64 <816000000>;
+
+                        opp-microvolt-speed0 = <880000>;
+                        opp-microvolt-speed1 = <820000>;
+                        opp-microvolt-speed2 = <800000>;
+                };
+
+                opp@888000000 {
+                        clock-latency-ns = <244144>; /* 8 32k periods */
+                        opp-hz = /bits/ 64 <888000000>;
+
+                        opp-microvolt-speed0 = <940000>;
+                        opp-microvolt-speed1 = <820000>;
+                        opp-microvolt-speed2 = <800000>;
+                };
+
+                opp@1080000000 {
+                        clock-latency-ns = <244144>; /* 8 32k periods */
+                        opp-hz = /bits/ 64 <1080000000>;
+
+                        opp-microvolt-speed0 = <1060000>;
+                        opp-microvolt-speed1 = <880000>;
+                        opp-microvolt-speed2 = <840000>;
+                };
+
+                opp@1320000000 {
+                        clock-latency-ns = <244144>; /* 8 32k periods */
+                        opp-hz = /bits/ 64 <1320000000>;
+
+                        opp-microvolt-speed0 = <1160000>;
+                        opp-microvolt-speed1 = <940000>;
+                        opp-microvolt-speed2 = <900000>;
+                };
+
+                opp@1488000000 {
+                        clock-latency-ns = <244144>; /* 8 32k periods */
+                        opp-hz = /bits/ 64 <1488000000>;
+
+                        opp-microvolt-speed0 = <1160000>;
+                        opp-microvolt-speed1 = <1000000>;
+                        opp-microvolt-speed2 = <960000>;
+                };
+        };
+....
+soc {
+....
+	sid: sid@3006000 {
+		compatible = "allwinner,sun50i-h6-sid";
+		reg = <0x03006000 0x400>;
+		#address-cells = <1>;
+		#size-cells = <1>;
+		....
+		speedbin_efuse: speed@1c {
+			reg = <0x1c 4>;
+		};
+        };
+};
-- 
2.17.0

Re: [PATCH v2 1/2] cpufreq: Add sunxi nvmem based CPU scaling driver

[Viresh Kumar]

On 09-04-19, 13:25, Yangtao Li wrote:
> +static const struct sunxi_cpufreq_soc_data sun50i_h6_data = {
> +	.efuse_xlate = sun50i_efuse_xlate,
> +	.nvmem_mask = 0x7,
> +	.nvmem_shift = 5,
> +};
> +
> +static const struct of_device_id sunxi_cpufreq_match_list[] = {
> +	{ .compatible = "allwinner,sun50i-h6", .data = &sun50i_h6_data },
> +	{}
> +};
> +
> +static const struct of_device_id *sunxi_cpufreq_match_node(void)
> +{
> +	struct device_node *np;
> +	const struct of_device_id *match;
> +
> +	np = of_find_node_by_path("/");
> +	match = of_match_node(sunxi_cpufreq_match_list, np);
> +	of_node_put(np);
> +
> +	return match;
> +}
> +

Above code can be placed just above sunxi_cpufreq_init(), if you ...

> +static int sunxi_cpufreq_nvmem_probe(struct platform_device *pdev)
> +{
> +	const struct sunxi_cpufreq_soc_data *soc_data;
> +	struct opp_table **opp_tables;
> +	const struct of_device_id *match;
> +	char name[MAX_NAME_LEN];
> +	unsigned int cpu;
> +	u32 speed = 0;
> +	int ret;
> +
> +	opp_tables = kcalloc(num_possible_cpus(), sizeof(*opp_tables),
> +			     GFP_KERNEL);
> +	if (!opp_tables)
> +		return -ENOMEM;
> +
> +	match = sunxi_cpufreq_match_node();

... avoid this and ...

> +	soc_data = match->data;
> +	if (!soc_data)
> +		return -EINVAL;
> +
> +	ret = sunxi_cpufreq_get_efuse(soc_data, &speed);
> +	if (ret)
> +		return ret;
> +
> +	snprintf(name, MAX_NAME_LEN, "speed%d", speed);
> +
> +	for_each_possible_cpu(cpu) {
> +		struct device *cpu_dev = get_cpu_device(cpu);
> +
> +		if (NULL == cpu_dev) {
> +			ret = -ENODEV;
> +			goto free_opp;
> +		}
> +
> +		opp_tables[cpu] = dev_pm_opp_set_prop_name(cpu_dev, name);
> +		if (IS_ERR(opp_tables[cpu])) {
> +			ret = PTR_ERR(opp_tables[cpu]);
> +			pr_err("Failed to set prop name\n");
> +			goto free_opp;
> +		}
> +	}
> +
> +	cpufreq_dt_pdev = platform_device_register_simple("cpufreq-dt", -1,
> +							  NULL, 0);
> +	if (!IS_ERR(cpufreq_dt_pdev)) {
> +		platform_set_drvdata(pdev, opp_tables);
> +		return 0;
> +	}
> +
> +	ret = PTR_ERR(cpufreq_dt_pdev);
> +	pr_err("Failed to register platform device\n");
> +
> +free_opp:
> +	for_each_possible_cpu(cpu) {
> +		if (IS_ERR_OR_NULL(opp_tables[cpu]))
> +			break;
> +		dev_pm_opp_put_prop_name(opp_tables[cpu]);
> +	}
> +	kfree(opp_tables);
> +
> +	return ret;
> +}
> +
> +static int sunxi_cpufreq_nvmem_remove(struct platform_device *pdev)
> +{
> +	struct opp_table **opp_tables = platform_get_drvdata(pdev);
> +	unsigned int cpu;
> +
> +	platform_device_unregister(cpufreq_dt_pdev);
> +
> +	for_each_possible_cpu(cpu)
> +		dev_pm_opp_put_prop_name(opp_tables[cpu]);
> +
> +	kfree(opp_tables);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver sunxi_cpufreq_driver = {
> +	.probe = sunxi_cpufreq_nvmem_probe,
> +	.remove = sunxi_cpufreq_nvmem_remove,
> +	.driver = {
> +		.name = "sunxi-cpufreq-nvmem",
> +	},
> +};
> +
> +/*
> + * Since the driver depends on nvmem drivers, which may return EPROBE_DEFER,
> + * all the real activity is done in the probe, which may be defered as well.
> + * The init here is only registering the driver and the platform device.
> + */
> +static int __init sunxi_cpufreq_init(void)
> +{
> +	const struct of_device_id *match;
> +	int ret;
> +
> +	match = sunxi_cpufreq_match_node();
> +	if (!match)
> +		return -ENODEV;
> +
> +	ret = platform_driver_register(&sunxi_cpufreq_driver);
> +	if (unlikely(ret < 0))
> +		return ret;
> +
> +	sunxi_cpufreq_pdev = platform_device_register_simple(
> +		"sunxi-cpufreq-nvmem", -1, NULL, 0);

... pass match->data as platform device's data here..

> +	ret = PTR_ERR_OR_ZERO(sunxi_cpufreq_pdev);
> +	if (0 == ret)
> +		return 0;
> +
> +	platform_driver_unregister(&sunxi_cpufreq_driver);
> +	return ret;
> +}
> +module_init(sunxi_cpufreq_init);
> +
> +static void __exit sunxi_cpufreq_exit(void)
> +{
> +	platform_device_unregister(sunxi_cpufreq_pdev);
> +	platform_driver_unregister(&sunxi_cpufreq_driver);
> +}
> +module_exit(sunxi_cpufreq_exit);
> +
> +MODULE_DESCRIPTION("Sunxi cpufreq driver");
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.17.0

-- 
viresh

Re: [PATCH v2 2/2] dt-bindings: cpufreq: Document operating-points-v2-sunxi-cpu

[Viresh Kumar]

On 09-04-19, 13:25, Yangtao Li wrote:
> Allwinner Process Voltage Scaling Tables defines the voltage and
> frequency value  based on the speedbin blown in the efuse combination.
> The sunxi-cpufreq-nvmem driver reads the efuse value from the SoC to
> provide the OPP framework with required information.
> This is used to determine the voltage and frequency value for each
> OPP of operating-points-v2 table when it is parsed by the OPP framework.
> 
> The "operating-points-v2-sunxi-cpu" DT extends the "operating-points-v2"
> with following parameters:
> - nvmem-cells (NVMEM area containig the speedbin information)
> - opp-microvolt-<name>: voltage in micro Volts.
>   At runtime, the platform can pick a <name> and matching
>   opp-microvolt-<name> property
> 
> Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
> ---
>  .../bindings/opp/sunxi-nvmem-cpufreq.txt      | 166 ++++++++++++++++++
>  1 file changed, 166 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/opp/sunxi-nvmem-cpufreq.txt

LGTM.

-- 
viresh

Re: [PATCH v2 2/2] dt-bindings: cpufreq: Document operating-points-v2-sunxi-cpu

[Maxime Ripard]

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On Tue, Apr 09, 2019 at 01:25:58PM -0400, Yangtao Li wrote:
> Allwinner Process Voltage Scaling Tables defines the voltage and
> frequency value  based on the speedbin blown in the efuse combination.
> The sunxi-cpufreq-nvmem driver reads the efuse value from the SoC to
> provide the OPP framework with required information.
> This is used to determine the voltage and frequency value for each
> OPP of operating-points-v2 table when it is parsed by the OPP framework.
>
> The "operating-points-v2-sunxi-cpu" DT extends the "operating-points-v2"
> with following parameters:
> - nvmem-cells (NVMEM area containig the speedbin information)
> - opp-microvolt-<name>: voltage in micro Volts.
>   At runtime, the platform can pick a <name> and matching
>   opp-microvolt-<name> property
>
> Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
> ---
>  .../bindings/opp/sunxi-nvmem-cpufreq.txt      | 166 ++++++++++++++++++
>  1 file changed, 166 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/opp/sunxi-nvmem-cpufreq.txt
>
> diff --git a/Documentation/devicetree/bindings/opp/sunxi-nvmem-cpufreq.txt b/Documentation/devicetree/bindings/opp/sunxi-nvmem-cpufreq.txt
> new file mode 100644
> index 000000000000..c81a2075b974
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/opp/sunxi-nvmem-cpufreq.txt
> @@ -0,0 +1,166 @@
> +Allwinner Technologies, Inc. NVMEM CPUFreq and OPP bindings
> +===================================
> +
> +For some SoCs, the CPU frequency subset and voltage value of each OPP
> +varies based on the silicon variant in use. Allwinner Process Voltage
> +Scaling Tables defines the voltage and frequency value  based on the
> +speedbin blown in the efuse combination. The sunxi-cpufreq-nvmem driver
> +reads the efuse value from the SoC to provide the OPP framework with
> +required information.
> +
> +Required properties:
> +--------------------
> +In 'cpus' nodes:
> +- operating-points-v2: Phandle to the operating-points-v2 table to use.
> +
> +In 'operating-points-v2' table:
> +- compatible: Should be
> +	- 'operating-points-v2-sunxi-cpu'.

Vendor-specific compatibles should have the vendor mentionned.

Also, even though the H6 is the only SoC so far that has needed this,
we can't really assume that it will be the only SoC to use it, or that
it will always behave like that.

So having something like allwinner,sun50i-h6-operating-points would be
great.

> +- nvmem-cells: A phandle pointing to a nvmem-cells node representing the
> +		efuse registers that has information about the
> +		speedbin that is used to select the right frequency/voltage
> +		value pair.
> +		Please refer the for nvmem-cells
> +		bindings Documentation/devicetree/bindings/nvmem/nvmem.txt
> +		and also examples below.
> +
> +In every OPP node:
> +- opp-microvolt-<name>: Voltage in micro Volts.
> +			At runtime, the platform can pick a <name> and
> +			matching opp-microvolt-<name> property.
> +			[See: opp.txt]

You need to document the valid names here.

Thanks!
Maxime

--
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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Re: [PATCH v2 1/2] cpufreq: Add sunxi nvmem based CPU scaling driver

[Frank Lee]

On Wed, Apr 10, 2019 at 11:24 AM Viresh Kumar <viresh.kumar@linaro.org> wrote:
>
> On 09-04-19, 13:25, Yangtao Li wrote:
> > +static const struct sunxi_cpufreq_soc_data sun50i_h6_data = {
> > +     .efuse_xlate = sun50i_efuse_xlate,
> > +     .nvmem_mask = 0x7,
> > +     .nvmem_shift = 5,
> > +};
> > +
> > +static const struct of_device_id sunxi_cpufreq_match_list[] = {
> > +     { .compatible = "allwinner,sun50i-h6", .data = &sun50i_h6_data },
> > +     {}
> > +};
> > +
> > +static const struct of_device_id *sunxi_cpufreq_match_node(void)
> > +{
> > +     struct device_node *np;
> > +     const struct of_device_id *match;
> > +
> > +     np = of_find_node_by_path("/");
> > +     match = of_match_node(sunxi_cpufreq_match_list, np);
> > +     of_node_put(np);
> > +
> > +     return match;
> > +}
> > +
>
> Above code can be placed just above sunxi_cpufreq_init(), if you ...
>
> > +static int sunxi_cpufreq_nvmem_probe(struct platform_device *pdev)
> > +{
> > +     const struct sunxi_cpufreq_soc_data *soc_data;
> > +     struct opp_table **opp_tables;
> > +     const struct of_device_id *match;
> > +     char name[MAX_NAME_LEN];
> > +     unsigned int cpu;
> > +     u32 speed = 0;
> > +     int ret;
> > +
> > +     opp_tables = kcalloc(num_possible_cpus(), sizeof(*opp_tables),
> > +                          GFP_KERNEL);
> > +     if (!opp_tables)
> > +             return -ENOMEM;
> > +
> > +     match = sunxi_cpufreq_match_node();
>
> ... avoid this and ...
>
> > +     soc_data = match->data;
> > +     if (!soc_data)
> > +             return -EINVAL;
> > +
> > +     ret = sunxi_cpufreq_get_efuse(soc_data, &speed);
> > +     if (ret)
> > +             return ret;
> > +
> > +     snprintf(name, MAX_NAME_LEN, "speed%d", speed);
> > +
> > +     for_each_possible_cpu(cpu) {
> > +             struct device *cpu_dev = get_cpu_device(cpu);
> > +
> > +             if (NULL == cpu_dev) {
> > +                     ret = -ENODEV;
> > +                     goto free_opp;
> > +             }
> > +
> > +             opp_tables[cpu] = dev_pm_opp_set_prop_name(cpu_dev, name);
> > +             if (IS_ERR(opp_tables[cpu])) {
> > +                     ret = PTR_ERR(opp_tables[cpu]);
> > +                     pr_err("Failed to set prop name\n");
> > +                     goto free_opp;
> > +             }
> > +     }
> > +
> > +     cpufreq_dt_pdev = platform_device_register_simple("cpufreq-dt", -1,
> > +                                                       NULL, 0);
> > +     if (!IS_ERR(cpufreq_dt_pdev)) {
> > +             platform_set_drvdata(pdev, opp_tables);
> > +             return 0;
> > +     }
> > +
> > +     ret = PTR_ERR(cpufreq_dt_pdev);
> > +     pr_err("Failed to register platform device\n");
> > +
> > +free_opp:
> > +     for_each_possible_cpu(cpu) {
> > +             if (IS_ERR_OR_NULL(opp_tables[cpu]))
> > +                     break;
> > +             dev_pm_opp_put_prop_name(opp_tables[cpu]);
> > +     }
> > +     kfree(opp_tables);
> > +
> > +     return ret;
> > +}
> > +
> > +static int sunxi_cpufreq_nvmem_remove(struct platform_device *pdev)
> > +{
> > +     struct opp_table **opp_tables = platform_get_drvdata(pdev);
> > +     unsigned int cpu;
> > +
> > +     platform_device_unregister(cpufreq_dt_pdev);
> > +
> > +     for_each_possible_cpu(cpu)
> > +             dev_pm_opp_put_prop_name(opp_tables[cpu]);
> > +
> > +     kfree(opp_tables);
> > +
> > +     return 0;
> > +}
> > +
> > +static struct platform_driver sunxi_cpufreq_driver = {
> > +     .probe = sunxi_cpufreq_nvmem_probe,
> > +     .remove = sunxi_cpufreq_nvmem_remove,
> > +     .driver = {
> > +             .name = "sunxi-cpufreq-nvmem",
> > +     },
> > +};
> > +
> > +/*
> > + * Since the driver depends on nvmem drivers, which may return EPROBE_DEFER,
> > + * all the real activity is done in the probe, which may be defered as well.
> > + * The init here is only registering the driver and the platform device.
> > + */
> > +static int __init sunxi_cpufreq_init(void)
> > +{
> > +     const struct of_device_id *match;
> > +     int ret;
> > +
> > +     match = sunxi_cpufreq_match_node();
> > +     if (!match)
> > +             return -ENODEV;
> > +
> > +     ret = platform_driver_register(&sunxi_cpufreq_driver);
> > +     if (unlikely(ret < 0))
> > +             return ret;
> > +
> > +     sunxi_cpufreq_pdev = platform_device_register_simple(
> > +             "sunxi-cpufreq-nvmem", -1, NULL, 0);
>
> ... pass match->data as platform device's data here..
Yead, it is.

Thanks,
Yangtao
>
> > +     ret = PTR_ERR_OR_ZERO(sunxi_cpufreq_pdev);
> > +     if (0 == ret)
> > +             return 0;
> > +
> > +     platform_driver_unregister(&sunxi_cpufreq_driver);
> > +     return ret;
> > +}
> > +module_init(sunxi_cpufreq_init);
> > +
> > +static void __exit sunxi_cpufreq_exit(void)
> > +{
> > +     platform_device_unregister(sunxi_cpufreq_pdev);
> > +     platform_driver_unregister(&sunxi_cpufreq_driver);
> > +}
> > +module_exit(sunxi_cpufreq_exit);
> > +
> > +MODULE_DESCRIPTION("Sunxi cpufreq driver");
> > +MODULE_LICENSE("GPL v2");
> > --
> > 2.17.0
>
> --
> viresh

Re: [PATCH v2 2/2] dt-bindings: cpufreq: Document operating-points-v2-sunxi-cpu

[Frank Lee]

On Wed, Apr 10, 2019 at 10:57 PM Maxime Ripard
<maxime.ripard@bootlin.com> wrote:
>
> On Tue, Apr 09, 2019 at 01:25:58PM -0400, Yangtao Li wrote:
> > Allwinner Process Voltage Scaling Tables defines the voltage and
> > frequency value  based on the speedbin blown in the efuse combination.
> > The sunxi-cpufreq-nvmem driver reads the efuse value from the SoC to
> > provide the OPP framework with required information.
> > This is used to determine the voltage and frequency value for each
> > OPP of operating-points-v2 table when it is parsed by the OPP framework.
> >
> > The "operating-points-v2-sunxi-cpu" DT extends the "operating-points-v2"
> > with following parameters:
> > - nvmem-cells (NVMEM area containig the speedbin information)
> > - opp-microvolt-<name>: voltage in micro Volts.
> >   At runtime, the platform can pick a <name> and matching
> >   opp-microvolt-<name> property
> >
> > Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
> > ---
> >  .../bindings/opp/sunxi-nvmem-cpufreq.txt      | 166 ++++++++++++++++++
> >  1 file changed, 166 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/opp/sunxi-nvmem-cpufreq.txt
> >
> > diff --git a/Documentation/devicetree/bindings/opp/sunxi-nvmem-cpufreq.txt b/Documentation/devicetree/bindings/opp/sunxi-nvmem-cpufreq.txt
> > new file mode 100644
> > index 000000000000..c81a2075b974
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/opp/sunxi-nvmem-cpufreq.txt
> > @@ -0,0 +1,166 @@
> > +Allwinner Technologies, Inc. NVMEM CPUFreq and OPP bindings
> > +===================================
> > +
> > +For some SoCs, the CPU frequency subset and voltage value of each OPP
> > +varies based on the silicon variant in use. Allwinner Process Voltage
> > +Scaling Tables defines the voltage and frequency value  based on the
> > +speedbin blown in the efuse combination. The sunxi-cpufreq-nvmem driver
> > +reads the efuse value from the SoC to provide the OPP framework with
> > +required information.
> > +
> > +Required properties:
> > +--------------------
> > +In 'cpus' nodes:
> > +- operating-points-v2: Phandle to the operating-points-v2 table to use.
> > +
> > +In 'operating-points-v2' table:
> > +- compatible: Should be
> > +     - 'operating-points-v2-sunxi-cpu'.
>
> Vendor-specific compatibles should have the vendor mentionned.
>
> Also, even though the H6 is the only SoC so far that has needed this,
> we can't really assume that it will be the only SoC to use it, or that
> it will always behave like that.
There is no doubt that many platforms need this.
>
> So having something like allwinner,sun50i-h6-operating-points would be
> great.
allwinner,cpu-operating-points-v2 Maybe better?
>
> > +- nvmem-cells: A phandle pointing to a nvmem-cells node representing the
> > +             efuse registers that has information about the
> > +             speedbin that is used to select the right frequency/voltage
> > +             value pair.
> > +             Please refer the for nvmem-cells
> > +             bindings Documentation/devicetree/bindings/nvmem/nvmem.txt
> > +             and also examples below.
> > +
> > +In every OPP node:
> > +- opp-microvolt-<name>: Voltage in micro Volts.
> > +                     At runtime, the platform can pick a <name> and
> > +                     matching opp-microvolt-<name> property.
> > +                     [See: opp.txt]
>
> You need to document the valid names here.
OK.

Cheers,
Yangtao

Re: [PATCH v2 2/2] dt-bindings: cpufreq: Document operating-points-v2-sunxi-cpu

[Maxime Ripard]

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On Thu, Apr 11, 2019 at 01:49:39AM +0800, Frank Lee wrote:
> On Wed, Apr 10, 2019 at 10:57 PM Maxime Ripard
> <maxime.ripard@bootlin.com> wrote:
> >
> > On Tue, Apr 09, 2019 at 01:25:58PM -0400, Yangtao Li wrote:
> > > Allwinner Process Voltage Scaling Tables defines the voltage and
> > > frequency value  based on the speedbin blown in the efuse combination.
> > > The sunxi-cpufreq-nvmem driver reads the efuse value from the SoC to
> > > provide the OPP framework with required information.
> > > This is used to determine the voltage and frequency value for each
> > > OPP of operating-points-v2 table when it is parsed by the OPP framework.
> > >
> > > The "operating-points-v2-sunxi-cpu" DT extends the "operating-points-v2"
> > > with following parameters:
> > > - nvmem-cells (NVMEM area containig the speedbin information)
> > > - opp-microvolt-<name>: voltage in micro Volts.
> > >   At runtime, the platform can pick a <name> and matching
> > >   opp-microvolt-<name> property
> > >
> > > Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
> > > ---
> > >  .../bindings/opp/sunxi-nvmem-cpufreq.txt      | 166 ++++++++++++++++++
> > >  1 file changed, 166 insertions(+)
> > >  create mode 100644 Documentation/devicetree/bindings/opp/sunxi-nvmem-cpufreq.txt
> > >
> > > diff --git a/Documentation/devicetree/bindings/opp/sunxi-nvmem-cpufreq.txt b/Documentation/devicetree/bindings/opp/sunxi-nvmem-cpufreq.txt
> > > new file mode 100644
> > > index 000000000000..c81a2075b974
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/opp/sunxi-nvmem-cpufreq.txt
> > > @@ -0,0 +1,166 @@
> > > +Allwinner Technologies, Inc. NVMEM CPUFreq and OPP bindings
> > > +===================================
> > > +
> > > +For some SoCs, the CPU frequency subset and voltage value of each OPP
> > > +varies based on the silicon variant in use. Allwinner Process Voltage
> > > +Scaling Tables defines the voltage and frequency value  based on the
> > > +speedbin blown in the efuse combination. The sunxi-cpufreq-nvmem driver
> > > +reads the efuse value from the SoC to provide the OPP framework with
> > > +required information.
> > > +
> > > +Required properties:
> > > +--------------------
> > > +In 'cpus' nodes:
> > > +- operating-points-v2: Phandle to the operating-points-v2 table to use.
> > > +
> > > +In 'operating-points-v2' table:
> > > +- compatible: Should be
> > > +     - 'operating-points-v2-sunxi-cpu'.
> >
> > Vendor-specific compatibles should have the vendor mentionned.
> >
> > Also, even though the H6 is the only SoC so far that has needed this,
> > we can't really assume that it will be the only SoC to use it, or that
> > it will always behave like that.
>
> There is no doubt that many platforms need this.

That many platform *may* need this, yeah, sure. We can probably even
share the same driver for them.

That all of those theretical platform will have the exact same
behaviour, down to how the data is stored in the nvmem, and how many
bins you have? I seriously doubt so.

> > So having something like allwinner,sun50i-h6-operating-points would be
> > great.
> allwinner,cpu-operating-points-v2 Maybe better?

No. You need to have the SoC name in there, and you can drop the
v2. There's never been a v1.

Maxime

--
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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