1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * dptf_pch_fivr: DPTF PCH FIVR Participant driver
4 * Copyright (c) 2020, Intel Corporation.
5 */
6
7#include <linux/acpi.h>
8#include <linux/kernel.h>
9#include <linux/module.h>
10#include <linux/platform_device.h>
11
12struct pch_fivr_resp {
13 u64 status;
14 u64 result;
15};
16
17static int pch_fivr_read(acpi_handle handle, char *method, struct pch_fivr_resp *fivr_resp)
18{
19 struct acpi_buffer resp = { sizeof(struct pch_fivr_resp), fivr_resp};
20 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
21 struct acpi_buffer format = { sizeof("NN"), "NN" };
22 union acpi_object *obj;
23 acpi_status status;
24 int ret = -EFAULT;
25
26 status = acpi_evaluate_object(object: handle, pathname: method, NULL, return_object_buffer: &buffer);
27 if (ACPI_FAILURE(status))
28 return ret;
29
30 obj = buffer.pointer;
31 if (!obj || obj->type != ACPI_TYPE_PACKAGE)
32 goto release_buffer;
33
34 status = acpi_extract_package(package: obj, format: &format, buffer: &resp);
35 if (ACPI_FAILURE(status))
36 goto release_buffer;
37
38 if (fivr_resp->status)
39 goto release_buffer;
40
41 ret = 0;
42
43release_buffer:
44 kfree(objp: buffer.pointer);
45 return ret;
46}
47
48/*
49 * Presentation of attributes which are defined for INTC10xx
50 * They are:
51 * freq_mhz_low_clock : Set PCH FIVR switching freq for
52 * FIVR clock 19.2MHz and 24MHz
53 * freq_mhz_high_clock : Set PCH FIVR switching freq for
54 * FIVR clock 38.4MHz
55 */
56#define PCH_FIVR_SHOW(name, method) \
57static ssize_t name##_show(struct device *dev,\
58 struct device_attribute *attr,\
59 char *buf)\
60{\
61 struct acpi_device *acpi_dev = dev_get_drvdata(dev);\
62 struct pch_fivr_resp fivr_resp;\
63 int status;\
64\
65 status = pch_fivr_read(acpi_dev->handle, #method, &fivr_resp);\
66 if (status)\
67 return status;\
68\
69 return sprintf(buf, "%llu\n", fivr_resp.result);\
70}
71
72#define PCH_FIVR_STORE(name, method) \
73static ssize_t name##_store(struct device *dev,\
74 struct device_attribute *attr,\
75 const char *buf, size_t count)\
76{\
77 struct acpi_device *acpi_dev = dev_get_drvdata(dev);\
78 acpi_status status;\
79 u32 val;\
80\
81 if (kstrtouint(buf, 0, &val) < 0)\
82 return -EINVAL;\
83\
84 status = acpi_execute_simple_method(acpi_dev->handle, #method, val);\
85 if (ACPI_SUCCESS(status))\
86 return count;\
87\
88 return -EINVAL;\
89}
90
91PCH_FIVR_SHOW(freq_mhz_low_clock, GFC0)
92PCH_FIVR_SHOW(freq_mhz_high_clock, GFC1)
93PCH_FIVR_SHOW(ssc_clock_info, GEMI)
94PCH_FIVR_SHOW(fivr_switching_freq_mhz, GFCS)
95PCH_FIVR_SHOW(fivr_switching_fault_status, GFFS)
96PCH_FIVR_STORE(freq_mhz_low_clock, RFC0)
97PCH_FIVR_STORE(freq_mhz_high_clock, RFC1)
98
99static DEVICE_ATTR_RW(freq_mhz_low_clock);
100static DEVICE_ATTR_RW(freq_mhz_high_clock);
101static DEVICE_ATTR_RO(ssc_clock_info);
102static DEVICE_ATTR_RO(fivr_switching_freq_mhz);
103static DEVICE_ATTR_RO(fivr_switching_fault_status);
104
105static struct attribute *fivr_attrs[] = {
106 &dev_attr_freq_mhz_low_clock.attr,
107 &dev_attr_freq_mhz_high_clock.attr,
108 &dev_attr_ssc_clock_info.attr,
109 &dev_attr_fivr_switching_freq_mhz.attr,
110 &dev_attr_fivr_switching_fault_status.attr,
111 NULL
112};
113
114static const struct attribute_group pch_fivr_attribute_group = {
115 .attrs = fivr_attrs,
116 .name = "pch_fivr_switch_frequency"
117};
118
119static int pch_fivr_add(struct platform_device *pdev)
120{
121 struct acpi_device *acpi_dev;
122 unsigned long long ptype;
123 acpi_status status;
124 int result;
125
126 acpi_dev = ACPI_COMPANION(&(pdev->dev));
127 if (!acpi_dev)
128 return -ENODEV;
129
130 status = acpi_evaluate_integer(handle: acpi_dev->handle, pathname: "PTYP", NULL, data: &ptype);
131 if (ACPI_FAILURE(status) || ptype != 0x05)
132 return -ENODEV;
133
134 result = sysfs_create_group(kobj: &pdev->dev.kobj,
135 grp: &pch_fivr_attribute_group);
136 if (result)
137 return result;
138
139 platform_set_drvdata(pdev, data: acpi_dev);
140
141 return 0;
142}
143
144static void pch_fivr_remove(struct platform_device *pdev)
145{
146 sysfs_remove_group(kobj: &pdev->dev.kobj, grp: &pch_fivr_attribute_group);
147}
148
149static const struct acpi_device_id pch_fivr_device_ids[] = {
150 {"INTC1045", 0},
151 {"INTC1049", 0},
152 {"INTC1064", 0},
153 {"INTC10A3", 0},
154 {"", 0},
155};
156MODULE_DEVICE_TABLE(acpi, pch_fivr_device_ids);
157
158static struct platform_driver pch_fivr_driver = {
159 .probe = pch_fivr_add,
160 .remove_new = pch_fivr_remove,
161 .driver = {
162 .name = "dptf_pch_fivr",
163 .acpi_match_table = pch_fivr_device_ids,
164 },
165};
166
167module_platform_driver(pch_fivr_driver);
168
169MODULE_AUTHOR("Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>");
170MODULE_LICENSE("GPL v2");
171MODULE_DESCRIPTION("ACPI DPTF PCH FIVR driver");
172

source code of linux/drivers/acpi/dptf/dptf_pch_fivr.c