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(handle, method, NULL, &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(obj, &format, &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(buffer.pointer);
45	return ret;
46}
47
48/*
49 * Presentation of attributes which are defined for INT1045
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_STORE(freq_mhz_low_clock, RFC0)
94PCH_FIVR_STORE(freq_mhz_high_clock, RFC1)
95
96static DEVICE_ATTR_RW(freq_mhz_low_clock);
97static DEVICE_ATTR_RW(freq_mhz_high_clock);
98
99static struct attribute *fivr_attrs[] = {
100	&dev_attr_freq_mhz_low_clock.attr,
101	&dev_attr_freq_mhz_high_clock.attr,
102	NULL
103};
104
105static const struct attribute_group pch_fivr_attribute_group = {
106	.attrs = fivr_attrs,
107	.name = "pch_fivr_switch_frequency"
108};
109
110static int pch_fivr_add(struct platform_device *pdev)
111{
112	struct acpi_device *acpi_dev;
113	unsigned long long ptype;
114	acpi_status status;
115	int result;
116
117	acpi_dev = ACPI_COMPANION(&(pdev->dev));
118	if (!acpi_dev)
119		return -ENODEV;
120
121	status = acpi_evaluate_integer(acpi_dev->handle, "PTYP", NULL, &ptype);
122	if (ACPI_FAILURE(status) || ptype != 0x05)
123		return -ENODEV;
124
125	result = sysfs_create_group(&pdev->dev.kobj,
126				    &pch_fivr_attribute_group);
127	if (result)
128		return result;
129
130	platform_set_drvdata(pdev, acpi_dev);
131
132	return 0;
133}
134
135static int pch_fivr_remove(struct platform_device *pdev)
136{
137	sysfs_remove_group(&pdev->dev.kobj, &pch_fivr_attribute_group);
138
139	return 0;
140}
141
142static const struct acpi_device_id pch_fivr_device_ids[] = {
143	{"INTC1045", 0},
144	{"INTC1049", 0},
145	{"", 0},
146};
147MODULE_DEVICE_TABLE(acpi, pch_fivr_device_ids);
148
149static struct platform_driver pch_fivr_driver = {
150	.probe = pch_fivr_add,
151	.remove = pch_fivr_remove,
152	.driver = {
153		.name = "dptf_pch_fivr",
154		.acpi_match_table = pch_fivr_device_ids,
155	},
156};
157
158module_platform_driver(pch_fivr_driver);
159
160MODULE_AUTHOR("Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>");
161MODULE_LICENSE("GPL v2");
162MODULE_DESCRIPTION("ACPI DPTF PCH FIVR driver");
163