diff options
Diffstat (limited to 'drivers/cpufreq/imx6q-cpufreq.c')
| -rw-r--r-- | drivers/cpufreq/imx6q-cpufreq.c | 336 |
1 files changed, 336 insertions, 0 deletions
diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c new file mode 100644 index 00000000000..d6b6ef350cb --- /dev/null +++ b/drivers/cpufreq/imx6q-cpufreq.c @@ -0,0 +1,336 @@ +/* + * 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/cpufreq.h> +#include <linux/delay.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> + +#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); + } + + rcu_read_lock(); + opp = opp_find_freq_ceil(cpu_dev, &freq_hz); + if (IS_ERR(opp)) { + rcu_read_unlock(); + dev_err(cpu_dev, "failed to find OPP for %ld\n", freq_hz); + return PTR_ERR(opp); + } + + volt = opp_get_voltage(opp); + rcu_read_unlock(); + 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 vddarm 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 + * - Reprogram 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); + if (freq_hz > clk_get_rate(pll2_pfd2_396m_clk)) { + clk_set_rate(pll1_sys_clk, freqs.new * 1000); + /* + * If we are leaving 396 MHz set-point, we need to enable + * pll1_sys_clk and disable pll2_pfd2_396m_clk to keep + * their use count correct. + */ + if (freqs.old * 1000 <= clk_get_rate(pll2_pfd2_396m_clk)) { + clk_prepare_enable(pll1_sys_clk); + clk_disable_unprepare(pll2_pfd2_396m_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 vddarm 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; + 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; + struct opp *opp; + unsigned long min_volt, max_volt; + int num, ret; + + cpu_dev = &pdev->dev; + + np = of_find_node_by_path("/cpus/cpu@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 */ + num = opp_get_opp_count(cpu_dev); + if (num < 0) { + ret = num; + 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; + + /* + * OPP is maintained in order of increasing frequency, and + * freq_table initialised from OPP is therefore sorted in the + * same order. + */ + rcu_read_lock(); + opp = opp_find_freq_exact(cpu_dev, + freq_table[0].frequency * 1000, true); + min_volt = opp_get_voltage(opp); + opp = opp_find_freq_exact(cpu_dev, + freq_table[--num].frequency * 1000, true); + max_volt = opp_get_voltage(opp); + rcu_read_unlock(); + ret = regulator_set_voltage_time(arm_reg, min_volt, max_volt); + if (ret > 0) + transition_latency += ret * 1000; + + /* Count vddpu and vddsoc latency in for 1.2 GHz support */ + if (freq_table[num].frequency == FREQ_1P2_GHZ / 1000) { + ret = regulator_set_voltage_time(pu_reg, PU_SOC_VOLTAGE_NORMAL, + PU_SOC_VOLTAGE_HIGH); + if (ret > 0) + transition_latency += ret * 1000; + ret = regulator_set_voltage_time(soc_reg, PU_SOC_VOLTAGE_NORMAL, + PU_SOC_VOLTAGE_HIGH); + if (ret > 0) + transition_latency += ret * 1000; + } + + 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@linaro.org>"); +MODULE_DESCRIPTION("Freescale i.MX6Q cpufreq driver"); +MODULE_LICENSE("GPL"); |