From 5cdd4f17f1375a228c4b33e57912ccc057395f68 Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Mon, 9 Mar 2009 21:02:13 +0000 Subject: S3C64XX: Add DVFS support to the S3C64XX cpufreq driver Use the regulator framework to provide optional support for DVFS in the S3C64XX cpufreq driver. When a software controllable regulator is configured the driver will use it to lower the supply voltage when running at a lower frequency, giving improved power saving. When regulator support is disabled or no regulator can be obtained for VDDARM the driver will fall back to scaling only the frequency. Signed-off-by: Mark Brown --- arch/arm/plat-s3c64xx/cpufreq.c | 109 +++++++++++++++++++++++++++++++++------- 1 file changed, 91 insertions(+), 18 deletions(-) (limited to 'arch') diff --git a/arch/arm/plat-s3c64xx/cpufreq.c b/arch/arm/plat-s3c64xx/cpufreq.c index 4179cab3dfb..97617e54bd5 100644 --- a/arch/arm/plat-s3c64xx/cpufreq.c +++ b/arch/arm/plat-s3c64xx/cpufreq.c @@ -15,26 +15,42 @@ #include #include #include +#include #include static struct clk *armclk; +static struct regulator *vddarm; + +struct s3c64xx_dvfs { + unsigned int vddarm_min; + unsigned int vddarm_max; +}; + +static struct s3c64xx_dvfs s3c6410_dvfs_table[] = { + [0] = { 1000000, 1000000 }, + [1] = { 1000000, 1050000 }, + [2] = { 1050000, 1100000 }, + [3] = { 1050000, 1150000 }, + [4] = { 1250000, 1350000 }, +}; static struct cpufreq_frequency_table s3c6410_freq_table[] = { { 0, 66000 }, - { 1, 133000 }, - { 2, 222000 }, - { 3, 266000 }, - { 4, 333000 }, - { 5, 400000 }, - { 6, 532000 }, - { 7, 533000 }, - { 8, 667000 }, + { 0, 133000 }, + { 1, 222000 }, + { 1, 266000 }, + { 2, 333000 }, + { 2, 400000 }, + { 3, 532000 }, + { 3, 533000 }, + { 4, 667000 }, { 0, CPUFREQ_TABLE_END }, }; /* Data tables for current CPU and maximum index into it */ static struct cpufreq_frequency_table *s3c64xx_freq_table; +static struct s3c64xx_dvfs *s3c64xx_dvfs_table; static int s3c64xx_cpufreq_verify_speed(struct cpufreq_policy *policy) { @@ -56,19 +72,21 @@ static int s3c64xx_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation) { - int ret; - unsigned int index; + int ret = 0; + unsigned int i; struct cpufreq_freqs freqs; + struct s3c64xx_dvfs *dvfs; ret = cpufreq_frequency_table_target(policy, s3c64xx_freq_table, - target_freq, relation, &index); + target_freq, relation, &i); if (ret != 0) return ret; freqs.cpu = 0; freqs.old = clk_get_rate(armclk) / 1000; - freqs.new = s3c64xx_freq_table[index].frequency; + freqs.new = s3c64xx_freq_table[i].frequency; freqs.flags = 0; + dvfs = &s3c64xx_dvfs_table[s3c64xx_freq_table[i].index]; if (freqs.old == freqs.new) return 0; @@ -77,31 +95,68 @@ static int s3c64xx_cpufreq_set_target(struct cpufreq_policy *policy, cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); - ret = clk_set_rate(armclk, freqs.new * 1000); - - cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); +#ifdef CONFIG_REGULATOR + if (vddarm && freqs.new > freqs.old) { + ret = regulator_set_voltage(vddarm, + dvfs->vddarm_min, + dvfs->vddarm_max); + if (ret != 0) { + pr_err("cpufreq: Failed to set VDDARM for %dkHz: %d\n", + freqs.new, ret); + goto err; + } + } +#endif + ret = clk_set_rate(armclk, freqs.new * 1000); if (ret < 0) { pr_err("cpufreq: Failed to set rate %dkHz: %d\n", freqs.new, ret); - return ret; + goto err; + } + +#ifdef CONFIG_REGULATOR + if (vddarm && freqs.new < freqs.old) { + ret = regulator_set_voltage(vddarm, + dvfs->vddarm_min, + dvfs->vddarm_max); + if (ret != 0) { + pr_err("cpufreq: Failed to set VDDARM for %dkHz: %d\n", + freqs.new, ret); + goto err_clk; + } } +#endif + + cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); pr_debug("cpufreq: Set actual frequency %lukHz\n", clk_get_rate(armclk) / 1000); return 0; + +err_clk: + if (clk_set_rate(armclk, freqs.old * 1000) < 0) + pr_err("Failed to restore original clock rate\n"); +err: + cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); + + return ret; } + static int __init s3c64xx_cpufreq_driver_init(struct cpufreq_policy *policy) { + int ret; struct cpufreq_frequency_table *freq;; if (policy->cpu != 0) return -EINVAL; - if (cpu_is_s3c6410()) + if (cpu_is_s3c6410()) { s3c64xx_freq_table = s3c6410_freq_table; + s3c64xx_dvfs_table = s3c6410_dvfs_table; + } if (s3c64xx_freq_table == NULL) { pr_err("cpufreq: No frequency information for this CPU\n"); @@ -115,6 +170,16 @@ static int __init s3c64xx_cpufreq_driver_init(struct cpufreq_policy *policy) return PTR_ERR(armclk); } +#ifdef CONFIG_REGULATOR + vddarm = regulator_get(NULL, "vddarm"); + if (IS_ERR(vddarm)) { + ret = PTR_ERR(vddarm); + pr_err("cpufreq: Failed to obtain VDDARM: %d\n", ret); + pr_err("cpufreq: Only frequency scaling available\n"); + vddarm = NULL; + } +#endif + /* Check for frequencies we can generate */ freq = s3c64xx_freq_table; while (freq->frequency != CPUFREQ_TABLE_END) { @@ -132,7 +197,15 @@ static int __init s3c64xx_cpufreq_driver_init(struct cpufreq_policy *policy) policy->cur = clk_get_rate(armclk) / 1000; policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; - return cpufreq_frequency_table_cpuinfo(policy, s3c64xx_freq_table); + ret = cpufreq_frequency_table_cpuinfo(policy, s3c64xx_freq_table); + if (ret == 0) + return ret; + + pr_err("cpufreq: Failed to configure frequency table: %d\n", ret); + + regulator_put(vddarm); + clk_put(armclk); + return ret; } static struct cpufreq_driver s3c64xx_cpufreq_driver = { -- cgit v1.2.3