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() - Determine speed grade from efuse value
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
;
74 * We treat unexpected efuse values as if the SoC was from
75 * the slowest bin. Expected efuse values are 1-3, slowest
78 if (efuse_value
>= 1 && efuse_value
<= 3)
79 *versions
= efuse_value
- 1;
87 static int sun50i_cpufreq_nvmem_probe(struct platform_device
*pdev
)
89 struct opp_table
**opp_tables
;
90 char name
[MAX_NAME_LEN
];
95 opp_tables
= kcalloc(num_possible_cpus(), sizeof(*opp_tables
),
100 ret
= sun50i_cpufreq_get_efuse(&speed
);
104 snprintf(name
, MAX_NAME_LEN
, "speed%d", speed
);
106 for_each_possible_cpu(cpu
) {
107 struct device
*cpu_dev
= get_cpu_device(cpu
);
114 opp_tables
[cpu
] = dev_pm_opp_set_prop_name(cpu_dev
, name
);
115 if (IS_ERR(opp_tables
[cpu
])) {
116 ret
= PTR_ERR(opp_tables
[cpu
]);
117 pr_err("Failed to set prop name\n");
122 cpufreq_dt_pdev
= platform_device_register_simple("cpufreq-dt", -1,
124 if (!IS_ERR(cpufreq_dt_pdev
)) {
125 platform_set_drvdata(pdev
, opp_tables
);
129 ret
= PTR_ERR(cpufreq_dt_pdev
);
130 pr_err("Failed to register platform device\n");
133 for_each_possible_cpu(cpu
) {
134 if (IS_ERR_OR_NULL(opp_tables
[cpu
]))
136 dev_pm_opp_put_prop_name(opp_tables
[cpu
]);
143 static int sun50i_cpufreq_nvmem_remove(struct platform_device
*pdev
)
145 struct opp_table
**opp_tables
= platform_get_drvdata(pdev
);
148 platform_device_unregister(cpufreq_dt_pdev
);
150 for_each_possible_cpu(cpu
)
151 dev_pm_opp_put_prop_name(opp_tables
[cpu
]);
158 static struct platform_driver sun50i_cpufreq_driver
= {
159 .probe
= sun50i_cpufreq_nvmem_probe
,
160 .remove
= sun50i_cpufreq_nvmem_remove
,
162 .name
= "sun50i-cpufreq-nvmem",
166 static const struct of_device_id sun50i_cpufreq_match_list
[] = {
167 { .compatible
= "allwinner,sun50i-h6" },
170 MODULE_DEVICE_TABLE(of
, sun50i_cpufreq_match_list
);
172 static const struct of_device_id
*sun50i_cpufreq_match_node(void)
174 const struct of_device_id
*match
;
175 struct device_node
*np
;
177 np
= of_find_node_by_path("/");
178 match
= of_match_node(sun50i_cpufreq_match_list
, np
);
185 * Since the driver depends on nvmem drivers, which may return EPROBE_DEFER,
186 * all the real activity is done in the probe, which may be defered as well.
187 * The init here is only registering the driver and the platform device.
189 static int __init
sun50i_cpufreq_init(void)
191 const struct of_device_id
*match
;
194 match
= sun50i_cpufreq_match_node();
198 ret
= platform_driver_register(&sun50i_cpufreq_driver
);
199 if (unlikely(ret
< 0))
202 sun50i_cpufreq_pdev
=
203 platform_device_register_simple("sun50i-cpufreq-nvmem",
205 ret
= PTR_ERR_OR_ZERO(sun50i_cpufreq_pdev
);
209 platform_driver_unregister(&sun50i_cpufreq_driver
);
212 module_init(sun50i_cpufreq_init
);
214 static void __exit
sun50i_cpufreq_exit(void)
216 platform_device_unregister(sun50i_cpufreq_pdev
);
217 platform_driver_unregister(&sun50i_cpufreq_driver
);
219 module_exit(sun50i_cpufreq_exit
);
221 MODULE_DESCRIPTION("Sun50i-h6 cpufreq driver");
222 MODULE_LICENSE("GPL v2");