diff options
Diffstat (limited to 'drivers/cpufreq')
| -rw-r--r-- | drivers/cpufreq/Kconfig | 13 | ||||
| -rw-r--r-- | drivers/cpufreq/Makefile | 4 | ||||
| -rw-r--r-- | drivers/cpufreq/at32ap-cpufreq.c | 123 |
3 files changed, 140 insertions, 0 deletions
diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig index cbcb21e32771..d7ce6ccf5c91 100644 --- a/drivers/cpufreq/Kconfig +++ b/drivers/cpufreq/Kconfig @@ -205,6 +205,19 @@ depends on ARM source "drivers/cpufreq/Kconfig.arm" endmenu +menu "AVR32 CPU frequency scaling drivers" +depends on AVR32 + +config AVR32_AT32AP_CPUFREQ + bool "CPU frequency driver for AT32AP" + depends on PLATFORM_AT32AP + default n + help + This enables the CPU frequency driver for AT32AP processors. + If in doubt, say N. + +endmenu + menu "PowerPC CPU frequency scaling drivers" depends on PPC32 || PPC64 source "drivers/cpufreq/Kconfig.powerpc" diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile index 8b21016ac157..2701acafd65b 100644 --- a/drivers/cpufreq/Makefile +++ b/drivers/cpufreq/Makefile @@ -74,3 +74,7 @@ obj-$(CONFIG_ARCH_TEGRA) += tegra-cpufreq.o ################################################################################## # PowerPC platform drivers obj-$(CONFIG_CPU_FREQ_MAPLE) += maple-cpufreq.o + +################################################################################## +# Other platform drivers +obj-$(CONFIG_AVR32_AT32AP_CPUFREQ) += at32ap-cpufreq.o diff --git a/drivers/cpufreq/at32ap-cpufreq.c b/drivers/cpufreq/at32ap-cpufreq.c new file mode 100644 index 000000000000..654488723cb5 --- /dev/null +++ b/drivers/cpufreq/at32ap-cpufreq.c @@ -0,0 +1,123 @@ +/* + * Copyright (C) 2004-2007 Atmel Corporation + * + * Based on MIPS implementation arch/mips/kernel/time.c + * Copyright 2001 MontaVista Software 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 DEBUG*/ + +#include <linux/kernel.h> +#include <linux/types.h> +#include <linux/init.h> +#include <linux/cpufreq.h> +#include <linux/io.h> +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/export.h> + +static struct clk *cpuclk; + +static int at32_verify_speed(struct cpufreq_policy *policy) +{ + if (policy->cpu != 0) + return -EINVAL; + + cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, + policy->cpuinfo.max_freq); + return 0; +} + +static unsigned int at32_get_speed(unsigned int cpu) +{ + /* No SMP support */ + if (cpu) + return 0; + return (unsigned int)((clk_get_rate(cpuclk) + 500) / 1000); +} + +static unsigned int ref_freq; +static unsigned long loops_per_jiffy_ref; + +static int at32_set_target(struct cpufreq_policy *policy, + unsigned int target_freq, + unsigned int relation) +{ + struct cpufreq_freqs freqs; + long freq; + + /* Convert target_freq from kHz to Hz */ + freq = clk_round_rate(cpuclk, target_freq * 1000); + + /* Check if policy->min <= new_freq <= policy->max */ + if(freq < (policy->min * 1000) || freq > (policy->max * 1000)) + return -EINVAL; + + pr_debug("cpufreq: requested frequency %u Hz\n", target_freq * 1000); + + freqs.old = at32_get_speed(0); + freqs.new = (freq + 500) / 1000; + freqs.flags = 0; + + if (!ref_freq) { + ref_freq = freqs.old; + loops_per_jiffy_ref = boot_cpu_data.loops_per_jiffy; + } + + cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE); + if (freqs.old < freqs.new) + boot_cpu_data.loops_per_jiffy = cpufreq_scale( + loops_per_jiffy_ref, ref_freq, freqs.new); + clk_set_rate(cpuclk, freq); + if (freqs.new < freqs.old) + boot_cpu_data.loops_per_jiffy = cpufreq_scale( + loops_per_jiffy_ref, ref_freq, freqs.new); + cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE); + + pr_debug("cpufreq: set frequency %lu Hz\n", freq); + + return 0; +} + +static int __init at32_cpufreq_driver_init(struct cpufreq_policy *policy) +{ + if (policy->cpu != 0) + return -EINVAL; + + cpuclk = clk_get(NULL, "cpu"); + if (IS_ERR(cpuclk)) { + pr_debug("cpufreq: could not get CPU clk\n"); + return PTR_ERR(cpuclk); + } + + policy->cpuinfo.min_freq = (clk_round_rate(cpuclk, 1) + 500) / 1000; + policy->cpuinfo.max_freq = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000; + policy->cpuinfo.transition_latency = 0; + policy->cur = at32_get_speed(0); + policy->min = policy->cpuinfo.min_freq; + policy->max = policy->cpuinfo.max_freq; + + printk("cpufreq: AT32AP CPU frequency driver\n"); + + return 0; +} + +static struct cpufreq_driver at32_driver = { + .name = "at32ap", + .owner = THIS_MODULE, + .init = at32_cpufreq_driver_init, + .verify = at32_verify_speed, + .target = at32_set_target, + .get = at32_get_speed, + .flags = CPUFREQ_STICKY, +}; + +static int __init at32_cpufreq_init(void) +{ + return cpufreq_register_driver(&at32_driver); +} +late_initcall(at32_cpufreq_init); |