1 // SPDX-License-Identifier: GPL-2.0
3 * Allwinner CPUFreq nvmem based driver
5 * The sun50i-cpufreq-nvmem driver reads the efuse value from the SoC to
6 * provide the OPP framework with required information.
8 * Copyright (C) 2019 Yangtao Li <tiny.windzz@gmail.com>
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 #include <linux/module.h>
14 #include <linux/nvmem-consumer.h>
15 #include <linux/of_device.h>
16 #include <linux/platform_device.h>
17 #include <linux/pm_opp.h>
18 #include <linux/slab.h>
20 #define MAX_NAME_LEN 7
22 #define NVMEM_MASK 0x7
25 static struct platform_device
*cpufreq_dt_pdev
, *sun50i_cpufreq_pdev
;
28 * sun50i_cpufreq_get_efuse() - Parse and return efuse value present on SoC
29 * @versions: Set to the value parsed from efuse
31 * Returns 0 if success.
33 static int sun50i_cpufreq_get_efuse(u32
*versions
)
35 struct nvmem_cell
*speedbin_nvmem
;
36 struct device_node
*np
;
37 struct device
*cpu_dev
;
38 u32
*speedbin
, efuse_value
;
42 cpu_dev
= get_cpu_device(0);
46 np
= dev_pm_opp_of_get_opp_desc_node(cpu_dev
);
50 ret
= of_device_is_compatible(np
,
51 "allwinner,sun50i-h6-operating-points");
57 speedbin_nvmem
= of_nvmem_cell_get(np
, NULL
);
59 if (IS_ERR(speedbin_nvmem
)) {
60 if (PTR_ERR(speedbin_nvmem
) != -EPROBE_DEFER
)
61 pr_err("Could not get nvmem cell: %ld\n",
62 PTR_ERR(speedbin_nvmem
));
63 return PTR_ERR(speedbin_nvmem
);
66 speedbin
= nvmem_cell_read(speedbin_nvmem
, &len
);
67 nvmem_cell_put(speedbin_nvmem
);
69 return PTR_ERR(speedbin
);
71 efuse_value
= (*speedbin
>> NVMEM_SHIFT
) & NVMEM_MASK
;
72 switch (efuse_value
) {
81 * For other situations, we treat it as bin0.
82 * This vf table can be run for any good cpu.
92 static int sun50i_cpufreq_nvmem_probe(struct platform_device
*pdev
)
94 struct opp_table
**opp_tables
;
95 char name
[MAX_NAME_LEN
];
100 opp_tables
= kcalloc(num_possible_cpus(), sizeof(*opp_tables
),
105 ret
= sun50i_cpufreq_get_efuse(&speed
);
109 snprintf(name
, MAX_NAME_LEN
, "speed%d", speed
);
111 for_each_possible_cpu(cpu
) {
112 struct device
*cpu_dev
= get_cpu_device(cpu
);
119 opp_tables
[cpu
] = dev_pm_opp_set_prop_name(cpu_dev
, name
);
120 if (IS_ERR(opp_tables
[cpu
])) {
121 ret
= PTR_ERR(opp_tables
[cpu
]);
122 pr_err("Failed to set prop name\n");
127 cpufreq_dt_pdev
= platform_device_register_simple("cpufreq-dt", -1,
129 if (!IS_ERR(cpufreq_dt_pdev
)) {
130 platform_set_drvdata(pdev
, opp_tables
);
134 ret
= PTR_ERR(cpufreq_dt_pdev
);
135 pr_err("Failed to register platform device\n");
138 for_each_possible_cpu(cpu
) {
139 if (IS_ERR_OR_NULL(opp_tables
[cpu
]))
141 dev_pm_opp_put_prop_name(opp_tables
[cpu
]);
148 static int sun50i_cpufreq_nvmem_remove(struct platform_device
*pdev
)
150 struct opp_table
**opp_tables
= platform_get_drvdata(pdev
);
153 platform_device_unregister(cpufreq_dt_pdev
);
155 for_each_possible_cpu(cpu
)
156 dev_pm_opp_put_prop_name(opp_tables
[cpu
]);
163 static struct platform_driver sun50i_cpufreq_driver
= {
164 .probe
= sun50i_cpufreq_nvmem_probe
,
165 .remove
= sun50i_cpufreq_nvmem_remove
,
167 .name
= "sun50i-cpufreq-nvmem",
171 static const struct of_device_id sun50i_cpufreq_match_list
[] = {
172 { .compatible
= "allwinner,sun50i-h6" },
176 static const struct of_device_id
*sun50i_cpufreq_match_node(void)
178 const struct of_device_id
*match
;
179 struct device_node
*np
;
181 np
= of_find_node_by_path("/");
182 match
= of_match_node(sun50i_cpufreq_match_list
, np
);
189 * Since the driver depends on nvmem drivers, which may return EPROBE_DEFER,
190 * all the real activity is done in the probe, which may be defered as well.
191 * The init here is only registering the driver and the platform device.
193 static int __init
sun50i_cpufreq_init(void)
195 const struct of_device_id
*match
;
198 match
= sun50i_cpufreq_match_node();
202 ret
= platform_driver_register(&sun50i_cpufreq_driver
);
203 if (unlikely(ret
< 0))
206 sun50i_cpufreq_pdev
=
207 platform_device_register_simple("sun50i-cpufreq-nvmem",
209 ret
= PTR_ERR_OR_ZERO(sun50i_cpufreq_pdev
);
213 platform_driver_unregister(&sun50i_cpufreq_driver
);
216 module_init(sun50i_cpufreq_init
);
218 static void __exit
sun50i_cpufreq_exit(void)
220 platform_device_unregister(sun50i_cpufreq_pdev
);
221 platform_driver_unregister(&sun50i_cpufreq_driver
);
223 module_exit(sun50i_cpufreq_exit
);
225 MODULE_DESCRIPTION("Sun50i-h6 cpufreq driver");
226 MODULE_LICENSE("GPL v2");