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// SPDX-License-Identifier: GPL-2.0
/*
* Allwinner CPUFreq nvmem based driver
*
* The sun50i-cpufreq-nvmem driver reads the efuse value from the SoC to
* provide the OPP framework with required information.
*
* Copyright (C) 2019 Yangtao Li <tiny.windzz@gmail.com>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/nvmem-consumer.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pm_opp.h>
#include <linux/slab.h>
#define MAX_NAME_LEN 7
#define NVMEM_MASK 0x7
#define NVMEM_SHIFT 5
static struct platform_device *cpufreq_dt_pdev, *sun50i_cpufreq_pdev;
/**
* sun50i_cpufreq_get_efuse() - Determine speed grade from efuse value
* @versions: Set to the value parsed from efuse
*
* Returns 0 if success.
*/
static int sun50i_cpufreq_get_efuse(u32 *versions)
{
struct nvmem_cell *speedbin_nvmem;
struct device_node *np;
struct device *cpu_dev;
u32 *speedbin, efuse_value;
size_t len;
int ret;
cpu_dev = get_cpu_device(0);
if (!cpu_dev)
return -ENODEV;
np = dev_pm_opp_of_get_opp_desc_node(cpu_dev);
if (!np)
return -ENOENT;
ret = of_device_is_compatible(np,
"allwinner,sun50i-h6-operating-points");
if (!ret) {
of_node_put(np);
return -ENOENT;
}
speedbin_nvmem = of_nvmem_cell_get(np, NULL);
of_node_put(np);
if (IS_ERR(speedbin_nvmem)) {
if (PTR_ERR(speedbin_nvmem) != -EPROBE_DEFER)
pr_err("Could not get nvmem cell: %ld\n",
PTR_ERR(speedbin_nvmem));
return PTR_ERR(speedbin_nvmem);
}
speedbin = nvmem_cell_read(speedbin_nvmem, &len);
nvmem_cell_put(speedbin_nvmem);
if (IS_ERR(speedbin))
return PTR_ERR(speedbin);
efuse_value = (*speedbin >> NVMEM_SHIFT) & NVMEM_MASK;
/*
* We treat unexpected efuse values as if the SoC was from
* the slowest bin. Expected efuse values are 1-3, slowest
* to fastest.
*/
if (efuse_value >= 1 && efuse_value <= 3)
*versions = efuse_value - 1;
else
*versions = 0;
kfree(speedbin);
return 0;
};
static int sun50i_cpufreq_nvmem_probe(struct platform_device *pdev)
{
int *opp_tokens;
char name[MAX_NAME_LEN];
unsigned int cpu;
u32 speed = 0;
int ret;
opp_tokens = kcalloc(num_possible_cpus(), sizeof(*opp_tokens),
GFP_KERNEL);
if (!opp_tokens)
return -ENOMEM;
ret = sun50i_cpufreq_get_efuse(&speed);
if (ret) {
kfree(opp_tokens);
return ret;
}
snprintf(name, MAX_NAME_LEN, "speed%d", speed);
for_each_possible_cpu(cpu) {
struct device *cpu_dev = get_cpu_device(cpu);
if (!cpu_dev) {
ret = -ENODEV;
goto free_opp;
}
opp_tokens[cpu] = dev_pm_opp_set_prop_name(cpu_dev, name);
if (opp_tokens[cpu] < 0) {
ret = opp_tokens[cpu];
pr_err("Failed to set prop name\n");
goto free_opp;
}
}
cpufreq_dt_pdev = platform_device_register_simple("cpufreq-dt", -1,
NULL, 0);
if (!IS_ERR(cpufreq_dt_pdev)) {
platform_set_drvdata(pdev, opp_tokens);
return 0;
}
ret = PTR_ERR(cpufreq_dt_pdev);
pr_err("Failed to register platform device\n");
free_opp:
for_each_possible_cpu(cpu)
dev_pm_opp_put_prop_name(opp_tokens[cpu]);
kfree(opp_tokens);
return ret;
}
static int sun50i_cpufreq_nvmem_remove(struct platform_device *pdev)
{
int *opp_tokens = platform_get_drvdata(pdev);
unsigned int cpu;
platform_device_unregister(cpufreq_dt_pdev);
for_each_possible_cpu(cpu)
dev_pm_opp_put_prop_name(opp_tokens[cpu]);
kfree(opp_tokens);
return 0;
}
static struct platform_driver sun50i_cpufreq_driver = {
.probe = sun50i_cpufreq_nvmem_probe,
.remove = sun50i_cpufreq_nvmem_remove,
.driver = {
.name = "sun50i-cpufreq-nvmem",
},
};
static const struct of_device_id sun50i_cpufreq_match_list[] = {
{ .compatible = "allwinner,sun50i-h6" },
{}
};
MODULE_DEVICE_TABLE(of, sun50i_cpufreq_match_list);
static const struct of_device_id *sun50i_cpufreq_match_node(void)
{
const struct of_device_id *match;
struct device_node *np;
np = of_find_node_by_path("/");
match = of_match_node(sun50i_cpufreq_match_list, np);
of_node_put(np);
return match;
}
/*
* Since the driver depends on nvmem drivers, which may return EPROBE_DEFER,
* all the real activity is done in the probe, which may be defered as well.
* The init here is only registering the driver and the platform device.
*/
static int __init sun50i_cpufreq_init(void)
{
const struct of_device_id *match;
int ret;
match = sun50i_cpufreq_match_node();
if (!match)
return -ENODEV;
ret = platform_driver_register(&sun50i_cpufreq_driver);
if (unlikely(ret < 0))
return ret;
sun50i_cpufreq_pdev =
platform_device_register_simple("sun50i-cpufreq-nvmem",
-1, NULL, 0);
ret = PTR_ERR_OR_ZERO(sun50i_cpufreq_pdev);
if (ret == 0)
return 0;
platform_driver_unregister(&sun50i_cpufreq_driver);
return ret;
}
module_init(sun50i_cpufreq_init);
static void __exit sun50i_cpufreq_exit(void)
{
platform_device_unregister(sun50i_cpufreq_pdev);
platform_driver_unregister(&sun50i_cpufreq_driver);
}
module_exit(sun50i_cpufreq_exit);
MODULE_DESCRIPTION("Sun50i-h6 cpufreq driver");
MODULE_LICENSE("GPL v2");
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