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 
12 struct pch_fivr_resp {
13 	u64 status;
14 	u64 result;
15 };
16 
pch_fivr_read(acpi_handle handle,char * method,struct pch_fivr_resp * fivr_resp)17 static 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 
43 release_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) \
57 static 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) \
73 static 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 
91 PCH_FIVR_SHOW(freq_mhz_low_clock, GFC0)
92 PCH_FIVR_SHOW(freq_mhz_high_clock, GFC1)
93 PCH_FIVR_SHOW(ssc_clock_info, GEMI)
94 PCH_FIVR_SHOW(fivr_switching_freq_mhz, GFCS)
95 PCH_FIVR_SHOW(fivr_switching_fault_status, GFFS)
96 PCH_FIVR_STORE(freq_mhz_low_clock, RFC0)
97 PCH_FIVR_STORE(freq_mhz_high_clock, RFC1)
98 
99 static DEVICE_ATTR_RW(freq_mhz_low_clock);
100 static DEVICE_ATTR_RW(freq_mhz_high_clock);
101 static DEVICE_ATTR_RO(ssc_clock_info);
102 static DEVICE_ATTR_RO(fivr_switching_freq_mhz);
103 static DEVICE_ATTR_RO(fivr_switching_fault_status);
104 
105 static 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 
114 static const struct attribute_group pch_fivr_attribute_group = {
115 	.attrs = fivr_attrs,
116 	.name = "pch_fivr_switch_frequency"
117 };
118 
pch_fivr_add(struct platform_device * pdev)119 static 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(acpi_dev->handle, "PTYP", NULL, &ptype);
131 	if (ACPI_FAILURE(status) || ptype != 0x05)
132 		return -ENODEV;
133 
134 	result = sysfs_create_group(&pdev->dev.kobj,
135 				    &pch_fivr_attribute_group);
136 	if (result)
137 		return result;
138 
139 	platform_set_drvdata(pdev, acpi_dev);
140 
141 	return 0;
142 }
143 
pch_fivr_remove(struct platform_device * pdev)144 static int pch_fivr_remove(struct platform_device *pdev)
145 {
146 	sysfs_remove_group(&pdev->dev.kobj, &pch_fivr_attribute_group);
147 
148 	return 0;
149 }
150 
151 static const struct acpi_device_id pch_fivr_device_ids[] = {
152 	{"INTC1045", 0},
153 	{"INTC1049", 0},
154 	{"", 0},
155 };
156 MODULE_DEVICE_TABLE(acpi, pch_fivr_device_ids);
157 
158 static struct platform_driver pch_fivr_driver = {
159 	.probe = pch_fivr_add,
160 	.remove = pch_fivr_remove,
161 	.driver = {
162 		.name = "dptf_pch_fivr",
163 		.acpi_match_table = pch_fivr_device_ids,
164 	},
165 };
166 
167 module_platform_driver(pch_fivr_driver);
168 
169 MODULE_AUTHOR("Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>");
170 MODULE_LICENSE("GPL v2");
171 MODULE_DESCRIPTION("ACPI DPTF PCH FIVR driver");
172