linux/drivers/cpufreq/omap-cpufreq.c
Yangtao Li fd459406b9 cpufreq: omap: Convert to platform remove callback returning void
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Yangtao Li <frank.li@vivo.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
2023-07-20 16:02:14 +05:30

201 lines
4.8 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* CPU frequency scaling for OMAP using OPP information
*
* Copyright (C) 2005 Nokia Corporation
* Written by Tony Lindgren <tony@atomide.com>
*
* Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
*
* Copyright (C) 2007-2011 Texas Instruments, Inc.
* - OMAP3/4 support by Rajendra Nayak, Santosh Shilimkar
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/cpufreq.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/pm_opp.h>
#include <linux/cpu.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>
#include <asm/smp_plat.h>
#include <asm/cpu.h>
/* OPP tolerance in percentage */
#define OPP_TOLERANCE 4
static struct cpufreq_frequency_table *freq_table;
static atomic_t freq_table_users = ATOMIC_INIT(0);
static struct device *mpu_dev;
static struct regulator *mpu_reg;
static int omap_target(struct cpufreq_policy *policy, unsigned int index)
{
int r, ret;
struct dev_pm_opp *opp;
unsigned long freq, volt = 0, volt_old = 0, tol = 0;
unsigned int old_freq, new_freq;
old_freq = policy->cur;
new_freq = freq_table[index].frequency;
freq = new_freq * 1000;
ret = clk_round_rate(policy->clk, freq);
if (ret < 0) {
dev_warn(mpu_dev,
"CPUfreq: Cannot find matching frequency for %lu\n",
freq);
return ret;
}
freq = ret;
if (mpu_reg) {
opp = dev_pm_opp_find_freq_ceil(mpu_dev, &freq);
if (IS_ERR(opp)) {
dev_err(mpu_dev, "%s: unable to find MPU OPP for %d\n",
__func__, new_freq);
return -EINVAL;
}
volt = dev_pm_opp_get_voltage(opp);
dev_pm_opp_put(opp);
tol = volt * OPP_TOLERANCE / 100;
volt_old = regulator_get_voltage(mpu_reg);
}
dev_dbg(mpu_dev, "cpufreq-omap: %u MHz, %ld mV --> %u MHz, %ld mV\n",
old_freq / 1000, volt_old ? volt_old / 1000 : -1,
new_freq / 1000, volt ? volt / 1000 : -1);
/* scaling up? scale voltage before frequency */
if (mpu_reg && (new_freq > old_freq)) {
r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
if (r < 0) {
dev_warn(mpu_dev, "%s: unable to scale voltage up.\n",
__func__);
return r;
}
}
ret = clk_set_rate(policy->clk, new_freq * 1000);
/* scaling down? scale voltage after frequency */
if (mpu_reg && (new_freq < old_freq)) {
r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
if (r < 0) {
dev_warn(mpu_dev, "%s: unable to scale voltage down.\n",
__func__);
clk_set_rate(policy->clk, old_freq * 1000);
return r;
}
}
return ret;
}
static inline void freq_table_free(void)
{
if (atomic_dec_and_test(&freq_table_users))
dev_pm_opp_free_cpufreq_table(mpu_dev, &freq_table);
}
static int omap_cpu_init(struct cpufreq_policy *policy)
{
int result;
policy->clk = clk_get(NULL, "cpufreq_ck");
if (IS_ERR(policy->clk))
return PTR_ERR(policy->clk);
if (!freq_table) {
result = dev_pm_opp_init_cpufreq_table(mpu_dev, &freq_table);
if (result) {
dev_err(mpu_dev,
"%s: cpu%d: failed creating freq table[%d]\n",
__func__, policy->cpu, result);
clk_put(policy->clk);
return result;
}
}
atomic_inc_return(&freq_table_users);
/* FIXME: what's the actual transition time? */
cpufreq_generic_init(policy, freq_table, 300 * 1000);
return 0;
}
static int omap_cpu_exit(struct cpufreq_policy *policy)
{
freq_table_free();
clk_put(policy->clk);
return 0;
}
static struct cpufreq_driver omap_driver = {
.flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
.verify = cpufreq_generic_frequency_table_verify,
.target_index = omap_target,
.get = cpufreq_generic_get,
.init = omap_cpu_init,
.exit = omap_cpu_exit,
.register_em = cpufreq_register_em_with_opp,
.name = "omap",
.attr = cpufreq_generic_attr,
};
static int omap_cpufreq_probe(struct platform_device *pdev)
{
mpu_dev = get_cpu_device(0);
if (!mpu_dev) {
pr_warn("%s: unable to get the MPU device\n", __func__);
return -EINVAL;
}
mpu_reg = regulator_get(mpu_dev, "vcc");
if (IS_ERR(mpu_reg)) {
pr_warn("%s: unable to get MPU regulator\n", __func__);
mpu_reg = NULL;
} else {
/*
* Ensure physical regulator is present.
* (e.g. could be dummy regulator.)
*/
if (regulator_get_voltage(mpu_reg) < 0) {
pr_warn("%s: physical regulator not present for MPU\n",
__func__);
regulator_put(mpu_reg);
mpu_reg = NULL;
}
}
return cpufreq_register_driver(&omap_driver);
}
static void omap_cpufreq_remove(struct platform_device *pdev)
{
cpufreq_unregister_driver(&omap_driver);
}
static struct platform_driver omap_cpufreq_platdrv = {
.driver = {
.name = "omap-cpufreq",
},
.probe = omap_cpufreq_probe,
.remove_new = omap_cpufreq_remove,
};
module_platform_driver(omap_cpufreq_platdrv);
MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
MODULE_LICENSE("GPL");