[PATCH v3 1/2] cpufreq: add imx6q-cpufreq driver
Shawn Guo
shawn.guo at linaro.org
Mon Jan 14 10:02:12 EST 2013
Add an imx6q-cpufreq driver for Freescale i.MX6Q SoC to handle the
hardware specific frequency and voltage scaling requirements.
The driver supports module build and is instantiated by the platform
device/driver mechanism, so that it will not be instantiated on other
platforms, as IMX is built with multiplatform support.
Signed-off-by: Shawn Guo <shawn.guo at linaro.org>
Reviewed-by: Viresh Kumar <viresh.kumar at linaro.org>
Acked-by: Rafael J. Wysocki <rjw at sisk.pl>
---
drivers/cpufreq/Kconfig.arm | 9 ++
drivers/cpufreq/Makefile | 1 +
drivers/cpufreq/imx6q-cpufreq.c | 296 +++++++++++++++++++++++++++++++++++++++
3 files changed, 306 insertions(+)
create mode 100644 drivers/cpufreq/imx6q-cpufreq.c
diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index a0b3661..9e628ba 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -77,6 +77,15 @@ config ARM_EXYNOS5250_CPUFREQ
This adds the CPUFreq driver for Samsung EXYNOS5250
SoC.
+config ARM_IMX6Q_CPUFREQ
+ tristate "Freescale i.MX6Q cpufreq support"
+ depends on SOC_IMX6Q
+ depends on REGULATOR_ANATOP
+ help
+ This adds cpufreq driver support for Freescale i.MX6Q SOC.
+
+ If in doubt, say N.
+
config ARM_SPEAR_CPUFREQ
bool "SPEAr CPUFreq support"
depends on PLAT_SPEAR
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index 1f254ec0..31699a0 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -49,6 +49,7 @@ obj-$(CONFIG_ARM_EXYNOS_CPUFREQ) += exynos-cpufreq.o
obj-$(CONFIG_ARM_EXYNOS4210_CPUFREQ) += exynos4210-cpufreq.o
obj-$(CONFIG_ARM_EXYNOS4X12_CPUFREQ) += exynos4x12-cpufreq.o
obj-$(CONFIG_ARM_EXYNOS5250_CPUFREQ) += exynos5250-cpufreq.o
+obj-$(CONFIG_ARM_IMX6Q_CPUFREQ) += imx6q-cpufreq.o
obj-$(CONFIG_ARM_OMAP2PLUS_CPUFREQ) += omap-cpufreq.o
obj-$(CONFIG_ARM_SPEAR_CPUFREQ) += spear-cpufreq.o
diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c
new file mode 100644
index 0000000..218d8f1
--- /dev/null
+++ b/drivers/cpufreq/imx6q-cpufreq.c
@@ -0,0 +1,296 @@
+/*
+ * Copyright (C) 2013 Freescale Semiconductor, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/clk.h>
+#include <linux/cpu.h>
+#include <linux/cpufreq.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/opp.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+
+#define PU_SOC_VOLTAGE_NORMAL 1250000
+#define PU_SOC_VOLTAGE_HIGH 1275000
+#define FREQ_1P2_GHZ 1200000000
+
+static struct regulator *arm_reg;
+static struct regulator *pu_reg;
+static struct regulator *soc_reg;
+
+static struct clk *arm_clk;
+static struct clk *pll1_sys_clk;
+static struct clk *pll1_sw_clk;
+static struct clk *step_clk;
+static struct clk *pll2_pfd2_396m_clk;
+
+static struct device *cpu_dev;
+static struct cpufreq_frequency_table *freq_table;
+static unsigned int transition_latency;
+
+static int imx6q_verify_speed(struct cpufreq_policy *policy)
+{
+ return cpufreq_frequency_table_verify(policy, freq_table);
+}
+
+static unsigned int imx6q_get_speed(unsigned int cpu)
+{
+ return clk_get_rate(arm_clk) / 1000;
+}
+
+static int imx6q_set_target(struct cpufreq_policy *policy,
+ unsigned int target_freq, unsigned int relation)
+{
+ struct cpufreq_freqs freqs;
+ struct opp *opp;
+ unsigned long freq_hz, volt, volt_old;
+ unsigned int index, cpu;
+ int ret;
+
+ ret = cpufreq_frequency_table_target(policy, freq_table, target_freq,
+ relation, &index);
+ if (ret) {
+ dev_err(cpu_dev, "failed to match target frequency %d: %d\n",
+ target_freq, ret);
+ return ret;
+ }
+
+ freqs.new = freq_table[index].frequency;
+ freq_hz = freqs.new * 1000;
+ freqs.old = clk_get_rate(arm_clk) / 1000;
+
+ if (freqs.old == freqs.new)
+ return 0;
+
+ for_each_online_cpu(cpu) {
+ freqs.cpu = cpu;
+ cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+ }
+
+ opp = opp_find_freq_ceil(cpu_dev, &freq_hz);
+ if (IS_ERR(opp)) {
+ dev_err(cpu_dev, "failed to find OPP for %ld\n", freq_hz);
+ return PTR_ERR(opp);
+ }
+
+ volt = opp_get_voltage(opp);
+ volt_old = regulator_get_voltage(arm_reg);
+
+ dev_dbg(cpu_dev, "%u MHz, %ld mV --> %u MHz, %ld mV\n",
+ freqs.old / 1000, volt_old / 1000,
+ freqs.new / 1000, volt / 1000);
+
+ /* scaling up? scale voltage before frequency */
+ if (freqs.new > freqs.old) {
+ ret = regulator_set_voltage_tol(arm_reg, volt, 0);
+ if (ret) {
+ dev_err(cpu_dev, "failed to scale voltage up: %d\n", ret);
+ return ret;
+ }
+
+ /*
+ * Need to increase vddpu and vddsoc for safety
+ * if we are about to run at 1.2 GHz.
+ */
+ if (freqs.new == FREQ_1P2_GHZ / 1000) {
+ regulator_set_voltage_tol(pu_reg,
+ PU_SOC_VOLTAGE_HIGH, 0);
+ regulator_set_voltage_tol(soc_reg,
+ PU_SOC_VOLTAGE_HIGH, 0);
+ }
+ }
+
+ /*
+ * The setpoints are selected per PLL/PDF frequencies, so we need to
+ * reprogram PLL for frequency scaling. The procedure of reprogramming
+ * PLL1 is as below.
+ *
+ * - Enable pll2_pfd2_396m_clk and reparent pll1_sw_clk to it
+ * - Disable pll1_sys_clk and reprogram it
+ * - Enable pll1_sys_clk and reparent pll1_sw_clk back to it
+ * - Disable pll2_pfd2_396m_clk
+ */
+ clk_prepare_enable(pll2_pfd2_396m_clk);
+ clk_set_parent(step_clk, pll2_pfd2_396m_clk);
+ clk_set_parent(pll1_sw_clk, step_clk);
+ clk_prepare_enable(pll1_sys_clk);
+ if (freq_hz > clk_get_rate(pll2_pfd2_396m_clk)) {
+ clk_disable_unprepare(pll1_sys_clk);
+ clk_set_rate(pll1_sys_clk, freqs.new * 1000);
+ clk_prepare_enable(pll1_sys_clk);
+ clk_set_parent(pll1_sw_clk, pll1_sys_clk);
+ clk_disable_unprepare(pll2_pfd2_396m_clk);
+ } else {
+ /*
+ * Disable pll1_sys_clk if pll2_pfd2_396m_clk is sufficient
+ * to provide the frequency.
+ */
+ clk_disable_unprepare(pll1_sys_clk);
+ }
+
+ /* Ensure the arm clock divider is what we expect */
+ ret = clk_set_rate(arm_clk, freqs.new * 1000);
+ if (ret) {
+ dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
+ regulator_set_voltage_tol(arm_reg, volt_old, 0);
+ return ret;
+ }
+
+ /* scaling down? scale voltage after frequency */
+ if (freqs.new < freqs.old) {
+ ret = regulator_set_voltage_tol(arm_reg, volt, 0);
+ if (ret)
+ dev_warn(cpu_dev, "failed to scale voltage down: %d\n", ret);
+
+ if (freqs.old == FREQ_1P2_GHZ / 1000) {
+ regulator_set_voltage_tol(pu_reg,
+ PU_SOC_VOLTAGE_NORMAL, 0);
+ regulator_set_voltage_tol(soc_reg,
+ PU_SOC_VOLTAGE_NORMAL, 0);
+ }
+ }
+
+ for_each_online_cpu(cpu) {
+ freqs.cpu = cpu;
+ cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+ }
+
+ return 0;
+}
+
+static int imx6q_cpufreq_init(struct cpufreq_policy *policy)
+{
+ int ret;
+
+ ret = cpufreq_frequency_table_cpuinfo(policy, freq_table);
+ if (ret) {
+ dev_err(cpu_dev, "invalid frequency table: %d\n", ret);
+ return ret;
+ }
+
+ policy->cpuinfo.transition_latency = transition_latency;
+ policy->cur = clk_get_rate(arm_clk) / 1000;
+ policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
+ cpumask_setall(policy->cpus);
+ cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
+
+ return 0;
+}
+
+static int imx6q_cpufreq_exit(struct cpufreq_policy *policy)
+{
+ cpufreq_frequency_table_put_attr(policy->cpu);
+ return 0;
+}
+
+static struct freq_attr *imx6q_cpufreq_attr[] = {
+ &cpufreq_freq_attr_scaling_available_freqs,
+ NULL,
+};
+
+static struct cpufreq_driver imx6q_cpufreq_driver = {
+ .verify = imx6q_verify_speed,
+ .target = imx6q_set_target,
+ .get = imx6q_get_speed,
+ .init = imx6q_cpufreq_init,
+ .exit = imx6q_cpufreq_exit,
+ .name = "imx6q-cpufreq",
+ .attr = imx6q_cpufreq_attr,
+};
+
+static int imx6q_cpufreq_probe(struct platform_device *pdev)
+{
+ struct device_node *np;
+ int ret;
+
+ cpu_dev = &pdev->dev;
+
+ np = of_find_node_by_path("/cpus/cpu at 0");
+ if (!np) {
+ dev_err(cpu_dev, "failed to find cpu0 node\n");
+ return -ENOENT;
+ }
+
+ cpu_dev->of_node = np;
+
+ arm_clk = devm_clk_get(cpu_dev, "arm");
+ pll1_sys_clk = devm_clk_get(cpu_dev, "pll1_sys");
+ pll1_sw_clk = devm_clk_get(cpu_dev, "pll1_sw");
+ step_clk = devm_clk_get(cpu_dev, "step");
+ pll2_pfd2_396m_clk = devm_clk_get(cpu_dev, "pll2_pfd2_396m");
+ if (IS_ERR(arm_clk) || IS_ERR(pll1_sys_clk) || IS_ERR(pll1_sw_clk) ||
+ IS_ERR(step_clk) || IS_ERR(pll2_pfd2_396m_clk)) {
+ dev_err(cpu_dev, "failed to get clocks\n");
+ ret = -ENOENT;
+ goto put_node;
+ }
+
+ arm_reg = devm_regulator_get(cpu_dev, "arm");
+ pu_reg = devm_regulator_get(cpu_dev, "pu");
+ soc_reg = devm_regulator_get(cpu_dev, "soc");
+ if (!arm_reg || !pu_reg || !soc_reg) {
+ dev_err(cpu_dev, "failed to get regulators\n");
+ ret = -ENOENT;
+ goto put_node;
+ }
+
+ /* We expect an OPP table supplied by platform */
+ ret = opp_get_opp_count(cpu_dev);
+ if (ret < 0) {
+ dev_err(cpu_dev, "no OPP table is found: %d\n", ret);
+ goto put_node;
+ }
+
+ ret = opp_init_cpufreq_table(cpu_dev, &freq_table);
+ if (ret) {
+ dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
+ goto put_node;
+ }
+
+ if (of_property_read_u32(np, "clock-latency", &transition_latency))
+ transition_latency = CPUFREQ_ETERNAL;
+
+ ret = cpufreq_register_driver(&imx6q_cpufreq_driver);
+ if (ret) {
+ dev_err(cpu_dev, "failed register driver: %d\n", ret);
+ goto free_freq_table;
+ }
+
+ of_node_put(np);
+ return 0;
+
+free_freq_table:
+ opp_free_cpufreq_table(cpu_dev, &freq_table);
+put_node:
+ of_node_put(np);
+ return ret;
+}
+
+static int imx6q_cpufreq_remove(struct platform_device *pdev)
+{
+ cpufreq_unregister_driver(&imx6q_cpufreq_driver);
+ opp_free_cpufreq_table(cpu_dev, &freq_table);
+
+ return 0;
+}
+
+static struct platform_driver imx6q_cpufreq_platdrv = {
+ .driver = {
+ .name = "imx6q-cpufreq",
+ .owner = THIS_MODULE,
+ },
+ .probe = imx6q_cpufreq_probe,
+ .remove = imx6q_cpufreq_remove,
+};
+module_platform_driver(imx6q_cpufreq_platdrv);
+
+MODULE_AUTHOR("Shawn Guo <shawn.guo at linaro.org>");
+MODULE_DESCRIPTION("Freescale i.MX6Q cpufreq driver");
+MODULE_LICENSE("GPL");
--
1.7.9.5
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