1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2017 The Linux Foundation. All rights reserved.
4  */
5 
6 #include <linux/device.h>
7 #include <linux/module.h>
8 #include <linux/of.h>
9 #include <linux/of_platform.h>
10 #include <linux/nvmem-provider.h>
11 #include <linux/regmap.h>
12 
13 #define SDAM_MEM_START			0x40
14 #define REGISTER_MAP_ID			0x40
15 #define REGISTER_MAP_VERSION		0x41
16 #define SDAM_SIZE			0x44
17 #define SDAM_PBS_TRIG_SET		0xE5
18 #define SDAM_PBS_TRIG_CLR		0xE6
19 
20 struct sdam_chip {
21 	struct platform_device		*pdev;
22 	struct regmap			*regmap;
23 	struct nvmem_config		sdam_config;
24 	unsigned int			base;
25 	unsigned int			size;
26 };
27 
28 /* read only register offsets */
29 static const u8 sdam_ro_map[] = {
30 	REGISTER_MAP_ID,
31 	REGISTER_MAP_VERSION,
32 	SDAM_SIZE
33 };
34 
35 static bool sdam_is_valid(struct sdam_chip *sdam, unsigned int offset,
36 				size_t len)
37 {
38 	unsigned int sdam_mem_end = SDAM_MEM_START + sdam->size - 1;
39 
40 	if (!len)
41 		return false;
42 
43 	if (offset >= SDAM_MEM_START && offset <= sdam_mem_end
44 				&& (offset + len - 1) <= sdam_mem_end)
45 		return true;
46 	else if ((offset == SDAM_PBS_TRIG_SET || offset == SDAM_PBS_TRIG_CLR)
47 				&& (len == 1))
48 		return true;
49 
50 	return false;
51 }
52 
53 static bool sdam_is_ro(unsigned int offset, size_t len)
54 {
55 	int i;
56 
57 	for (i = 0; i < ARRAY_SIZE(sdam_ro_map); i++)
58 		if (offset <= sdam_ro_map[i] && (offset + len) > sdam_ro_map[i])
59 			return true;
60 
61 	return false;
62 }
63 
64 static int sdam_read(void *priv, unsigned int offset, void *val,
65 				size_t bytes)
66 {
67 	struct sdam_chip *sdam = priv;
68 	struct device *dev = &sdam->pdev->dev;
69 	int rc;
70 
71 	if (!sdam_is_valid(sdam, offset, bytes)) {
72 		dev_err(dev, "Invalid SDAM offset %#x len=%zd\n",
73 			offset, bytes);
74 		return -EINVAL;
75 	}
76 
77 	rc = regmap_bulk_read(sdam->regmap, sdam->base + offset, val, bytes);
78 	if (rc < 0)
79 		dev_err(dev, "Failed to read SDAM offset %#x len=%zd, rc=%d\n",
80 						offset, bytes, rc);
81 
82 	return rc;
83 }
84 
85 static int sdam_write(void *priv, unsigned int offset, void *val,
86 				size_t bytes)
87 {
88 	struct sdam_chip *sdam = priv;
89 	struct device *dev = &sdam->pdev->dev;
90 	int rc;
91 
92 	if (!sdam_is_valid(sdam, offset, bytes)) {
93 		dev_err(dev, "Invalid SDAM offset %#x len=%zd\n",
94 			offset, bytes);
95 		return -EINVAL;
96 	}
97 
98 	if (sdam_is_ro(offset, bytes)) {
99 		dev_err(dev, "Invalid write offset %#x len=%zd\n",
100 			offset, bytes);
101 		return -EINVAL;
102 	}
103 
104 	rc = regmap_bulk_write(sdam->regmap, sdam->base + offset, val, bytes);
105 	if (rc < 0)
106 		dev_err(dev, "Failed to write SDAM offset %#x len=%zd, rc=%d\n",
107 						offset, bytes, rc);
108 
109 	return rc;
110 }
111 
112 static int sdam_probe(struct platform_device *pdev)
113 {
114 	struct sdam_chip *sdam;
115 	struct nvmem_device *nvmem;
116 	unsigned int val;
117 	int rc;
118 
119 	sdam = devm_kzalloc(&pdev->dev, sizeof(*sdam), GFP_KERNEL);
120 	if (!sdam)
121 		return -ENOMEM;
122 
123 	sdam->regmap = dev_get_regmap(pdev->dev.parent, NULL);
124 	if (!sdam->regmap) {
125 		dev_err(&pdev->dev, "Failed to get regmap handle\n");
126 		return -ENXIO;
127 	}
128 
129 	rc = of_property_read_u32(pdev->dev.of_node, "reg", &sdam->base);
130 	if (rc < 0) {
131 		dev_err(&pdev->dev, "Failed to get SDAM base, rc=%d\n", rc);
132 		return -EINVAL;
133 	}
134 
135 	rc = regmap_read(sdam->regmap, sdam->base + SDAM_SIZE, &val);
136 	if (rc < 0) {
137 		dev_err(&pdev->dev, "Failed to read SDAM_SIZE rc=%d\n", rc);
138 		return -EINVAL;
139 	}
140 	sdam->size = val * 32;
141 
142 	sdam->sdam_config.dev = &pdev->dev;
143 	sdam->sdam_config.name = "spmi_sdam";
144 	sdam->sdam_config.id = pdev->id;
145 	sdam->sdam_config.owner = THIS_MODULE,
146 	sdam->sdam_config.stride = 1;
147 	sdam->sdam_config.word_size = 1;
148 	sdam->sdam_config.reg_read = sdam_read;
149 	sdam->sdam_config.reg_write = sdam_write;
150 	sdam->sdam_config.priv = sdam;
151 
152 	nvmem = devm_nvmem_register(&pdev->dev, &sdam->sdam_config);
153 	if (IS_ERR(nvmem)) {
154 		dev_err(&pdev->dev,
155 			"Failed to register SDAM nvmem device rc=%ld\n",
156 			PTR_ERR(nvmem));
157 		return -ENXIO;
158 	}
159 	dev_dbg(&pdev->dev,
160 		"SDAM base=%#x size=%u registered successfully\n",
161 		sdam->base, sdam->size);
162 
163 	return 0;
164 }
165 
166 static const struct of_device_id sdam_match_table[] = {
167 	{ .compatible = "qcom,spmi-sdam" },
168 	{},
169 };
170 
171 static struct platform_driver sdam_driver = {
172 	.driver = {
173 		.name = "qcom,spmi-sdam",
174 		.of_match_table = sdam_match_table,
175 	},
176 	.probe		= sdam_probe,
177 };
178 
179 static int __init sdam_init(void)
180 {
181 	return platform_driver_register(&sdam_driver);
182 }
183 subsys_initcall(sdam_init);
184 
185 static void __exit sdam_exit(void)
186 {
187 	return platform_driver_unregister(&sdam_driver);
188 }
189 module_exit(sdam_exit);
190 
191 MODULE_DESCRIPTION("QCOM SPMI SDAM driver");
192 MODULE_LICENSE("GPL v2");
193