On Tue, Jan 08, 2013 at 02:54:02PM +0800, Shawn Guo wrote:
> Add an imx6q-cpufreq 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 be instantiated on other
> platform, as IMX is built with multiplatform support.
>
> Signed-off-by: Shawn Guo <shawn.guo@xxxxxxxxxx>
> ---
> drivers/cpufreq/Kconfig.arm | 9 ++
> drivers/cpufreq/Makefile | 1 +
> drivers/cpufreq/imx6q-cpufreq.c | 325 +++++++++++++++++++++++++++++++++++++++
> 3 files changed, 335 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..8b3db8c
> --- /dev/null
> +++ b/drivers/cpufreq/imx6q-cpufreq.c
> @@ -0,0 +1,325 @@
> +/*
> + * 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.
> + */
> +
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +
> +#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) {
> + pr_err("failed to match target freqency %d: %d\n",
> + target_freq, ret);
> + return ret;
> + }
> +
> + freq_hz = freq_table[index].frequency * 1000;
> + freqs.new = freq_hz / 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)) {
> + pr_err("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);
> +
> + pr_debug("%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) {
> + pr_err("failed to scale voltage up: %d\n", ret);
> + freqs.new = freqs.old;
> + return ret;
> + }
So this regulator_set_voltage_tol can fail, ...
> +
> + /*
> + * 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);
... but these can't?
> + }
> + }
> +
> + /*
> + * The setpoints are selected per PLL/PDF frequencies, so we need to
> + * reprogram PLL for frequency scaling. The procedure of reprogramming
> + * PLL1 is as blow.
s/blow/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
> + */
[...]
> +
> +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;
> +
> + np = of_find_node_by_path("/cpus/cpu@0");
> + if (!np) {
> + pr_err("failed to find cpu0 node\n");
> + return -ENOENT;
> + }
> +
> + cpu_dev = get_cpu_device(0);
> + if (!cpu_dev) {
> + pr_err("failed to get cpu0 device\n");
Since you have a struct device * you should use it throughout the driver
to give the messages a bit more context.
> + ret = -ENODEV;
> + goto put_node;
> + }
> +
> + cpu_dev->of_node = np;
> +
> + arm_clk = clk_get(cpu_dev, "arm");
> + pll1_sys_clk = clk_get(cpu_dev, "pll1_sys");
> + pll1_sw_clk = clk_get(cpu_dev, "pll1_sw");
> + step_clk = clk_get(cpu_dev, "step");
> + pll2_pfd2_396m_clk = clk_get(cpu_dev, "pll2_pfd2_396m");
devm_*?
Sascha
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