1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2017, 2020-2021, 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/nvmem-provider.h>
10 #include <linux/platform_device.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 regmap			*regmap;
22 	struct nvmem_config		sdam_config;
23 	unsigned int			base;
24 	unsigned int			size;
25 };
26 
27 /* read only register offsets */
28 static const u8 sdam_ro_map[] = {
29 	REGISTER_MAP_ID,
30 	REGISTER_MAP_VERSION,
31 	SDAM_SIZE
32 };
33 
34 static bool sdam_is_valid(struct sdam_chip *sdam, unsigned int offset,
35 				size_t len)
36 {
37 	unsigned int sdam_mem_end = SDAM_MEM_START + sdam->size - 1;
38 
39 	if (!len)
40 		return false;
41 
42 	if (offset >= SDAM_MEM_START && offset <= sdam_mem_end
43 				&& (offset + len - 1) <= sdam_mem_end)
44 		return true;
45 	else if ((offset == SDAM_PBS_TRIG_SET || offset == SDAM_PBS_TRIG_CLR)
46 				&& (len == 1))
47 		return true;
48 
49 	return false;
50 }
51 
52 static bool sdam_is_ro(unsigned int offset, size_t len)
53 {
54 	int i;
55 
56 	for (i = 0; i < ARRAY_SIZE(sdam_ro_map); i++)
57 		if (offset <= sdam_ro_map[i] && (offset + len) > sdam_ro_map[i])
58 			return true;
59 
60 	return false;
61 }
62 
63 static int sdam_read(void *priv, unsigned int offset, void *val,
64 				size_t bytes)
65 {
66 	struct sdam_chip *sdam = priv;
67 	struct device *dev = sdam->sdam_config.dev;
68 	int rc;
69 
70 	if (!sdam_is_valid(sdam, offset, bytes)) {
71 		dev_err(dev, "Invalid SDAM offset %#x len=%zd\n",
72 			offset, bytes);
73 		return -EINVAL;
74 	}
75 
76 	rc = regmap_bulk_read(sdam->regmap, sdam->base + offset, val, bytes);
77 	if (rc < 0)
78 		dev_err(dev, "Failed to read SDAM offset %#x len=%zd, rc=%d\n",
79 						offset, bytes, rc);
80 
81 	return rc;
82 }
83 
84 static int sdam_write(void *priv, unsigned int offset, void *val,
85 				size_t bytes)
86 {
87 	struct sdam_chip *sdam = priv;
88 	struct device *dev = sdam->sdam_config.dev;
89 	int rc;
90 
91 	if (!sdam_is_valid(sdam, offset, bytes)) {
92 		dev_err(dev, "Invalid SDAM offset %#x len=%zd\n",
93 			offset, bytes);
94 		return -EINVAL;
95 	}
96 
97 	if (sdam_is_ro(offset, bytes)) {
98 		dev_err(dev, "Invalid write offset %#x len=%zd\n",
99 			offset, bytes);
100 		return -EINVAL;
101 	}
102 
103 	rc = regmap_bulk_write(sdam->regmap, sdam->base + offset, val, bytes);
104 	if (rc < 0)
105 		dev_err(dev, "Failed to write SDAM offset %#x len=%zd, rc=%d\n",
106 						offset, bytes, rc);
107 
108 	return rc;
109 }
110 
111 static int sdam_probe(struct platform_device *pdev)
112 {
113 	struct sdam_chip *sdam;
114 	struct nvmem_device *nvmem;
115 	unsigned int val;
116 	int rc;
117 
118 	sdam = devm_kzalloc(&pdev->dev, sizeof(*sdam), GFP_KERNEL);
119 	if (!sdam)
120 		return -ENOMEM;
121 
122 	sdam->regmap = dev_get_regmap(pdev->dev.parent, NULL);
123 	if (!sdam->regmap) {
124 		dev_err(&pdev->dev, "Failed to get regmap handle\n");
125 		return -ENXIO;
126 	}
127 
128 	rc = of_property_read_u32(pdev->dev.of_node, "reg", &sdam->base);
129 	if (rc < 0) {
130 		dev_err(&pdev->dev, "Failed to get SDAM base, rc=%d\n", rc);
131 		return -EINVAL;
132 	}
133 
134 	rc = regmap_read(sdam->regmap, sdam->base + SDAM_SIZE, &val);
135 	if (rc < 0) {
136 		dev_err(&pdev->dev, "Failed to read SDAM_SIZE rc=%d\n", rc);
137 		return -EINVAL;
138 	}
139 	sdam->size = val * 32;
140 
141 	sdam->sdam_config.dev = &pdev->dev;
142 	sdam->sdam_config.name = "spmi_sdam";
143 	sdam->sdam_config.id = NVMEM_DEVID_AUTO;
144 	sdam->sdam_config.owner = THIS_MODULE;
145 	sdam->sdam_config.add_legacy_fixed_of_cells = true;
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 MODULE_DEVICE_TABLE(of, sdam_match_table);
171 
172 static struct platform_driver sdam_driver = {
173 	.driver = {
174 		.name = "qcom,spmi-sdam",
175 		.of_match_table = sdam_match_table,
176 	},
177 	.probe		= sdam_probe,
178 };
179 module_platform_driver(sdam_driver);
180 
181 MODULE_DESCRIPTION("QCOM SPMI SDAM driver");
182 MODULE_LICENSE("GPL v2");
183