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1 | /* |
2 | * Copyright (c) 2015 Pengutronix, Steffen Trumtrar <kernel@pengutronix.de> | |
3 | * Copyright (c) 2017 Pengutronix, Oleksij Rempel <kernel@pengutronix.de> | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License version 2 | |
7 | * as published by the Free Software Foundation. | |
8 | */ | |
9 | ||
10 | #include <linux/mfd/syscon.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/nvmem-provider.h> | |
13 | #include <linux/of_device.h> | |
14 | #include <linux/regmap.h> | |
15 | ||
16 | #define IMX6Q_SNVS_HPLR 0x00 | |
17 | #define IMX6Q_GPR_SL BIT(5) | |
18 | #define IMX6Q_SNVS_LPLR 0x34 | |
19 | #define IMX6Q_GPR_HL BIT(5) | |
20 | #define IMX6Q_SNVS_LPGPR 0x68 | |
21 | ||
22 | struct snvs_lpgpr_cfg { | |
23 | int offset; | |
24 | int offset_hplr; | |
25 | int offset_lplr; | |
26 | }; | |
27 | ||
28 | struct snvs_lpgpr_priv { | |
29 | struct device_d *dev; | |
30 | struct regmap *regmap; | |
31 | struct nvmem_config cfg; | |
32 | const struct snvs_lpgpr_cfg *dcfg; | |
33 | }; | |
34 | ||
35 | static const struct snvs_lpgpr_cfg snvs_lpgpr_cfg_imx6q = { | |
36 | .offset = IMX6Q_SNVS_LPGPR, | |
37 | .offset_hplr = IMX6Q_SNVS_HPLR, | |
38 | .offset_lplr = IMX6Q_SNVS_LPLR, | |
39 | }; | |
40 | ||
41 | static int snvs_lpgpr_write(void *context, unsigned int offset, void *val, | |
42 | size_t bytes) | |
43 | { | |
44 | struct snvs_lpgpr_priv *priv = context; | |
45 | const struct snvs_lpgpr_cfg *dcfg = priv->dcfg; | |
46 | unsigned int lock_reg; | |
47 | int ret; | |
48 | ||
49 | ret = regmap_read(priv->regmap, dcfg->offset_hplr, &lock_reg); | |
50 | if (ret < 0) | |
51 | return ret; | |
52 | ||
53 | if (lock_reg & IMX6Q_GPR_SL) | |
54 | return -EPERM; | |
55 | ||
56 | ret = regmap_read(priv->regmap, dcfg->offset_lplr, &lock_reg); | |
57 | if (ret < 0) | |
58 | return ret; | |
59 | ||
60 | if (lock_reg & IMX6Q_GPR_HL) | |
61 | return -EPERM; | |
62 | ||
63 | return regmap_bulk_write(priv->regmap, dcfg->offset + offset, val, | |
64 | bytes / 4); | |
65 | } | |
66 | ||
67 | static int snvs_lpgpr_read(void *context, unsigned int offset, void *val, | |
68 | size_t bytes) | |
69 | { | |
70 | struct snvs_lpgpr_priv *priv = context; | |
71 | const struct snvs_lpgpr_cfg *dcfg = priv->dcfg; | |
72 | ||
73 | return regmap_bulk_read(priv->regmap, dcfg->offset + offset, | |
74 | val, bytes / 4); | |
75 | } | |
76 | ||
77 | static int snvs_lpgpr_probe(struct platform_device *pdev) | |
78 | { | |
79 | struct device *dev = &pdev->dev; | |
80 | struct device_node *node = dev->of_node; | |
81 | struct device_node *syscon_node; | |
82 | struct snvs_lpgpr_priv *priv; | |
83 | struct nvmem_config *cfg; | |
84 | struct nvmem_device *nvmem; | |
85 | const struct snvs_lpgpr_cfg *dcfg; | |
86 | ||
87 | if (!node) | |
88 | return -ENOENT; | |
89 | ||
90 | priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); | |
91 | if (!priv) | |
92 | return -ENOMEM; | |
93 | ||
94 | dcfg = of_device_get_match_data(dev); | |
95 | if (!dcfg) | |
96 | return -EINVAL; | |
97 | ||
98 | syscon_node = of_get_parent(node); | |
99 | if (!syscon_node) | |
100 | return -ENODEV; | |
101 | ||
102 | priv->regmap = syscon_node_to_regmap(syscon_node); | |
103 | of_node_put(syscon_node); | |
104 | if (IS_ERR(priv->regmap)) | |
105 | return PTR_ERR(priv->regmap); | |
106 | ||
107 | priv->dcfg = dcfg; | |
108 | ||
109 | cfg = &priv->cfg; | |
110 | cfg->priv = priv; | |
111 | cfg->name = dev_name(dev); | |
112 | cfg->dev = dev; | |
113 | cfg->stride = 4, | |
114 | cfg->word_size = 4, | |
115 | cfg->size = 4, | |
116 | cfg->owner = THIS_MODULE, | |
117 | cfg->reg_read = snvs_lpgpr_read, | |
118 | cfg->reg_write = snvs_lpgpr_write, | |
119 | ||
120 | nvmem = nvmem_register(cfg); | |
121 | if (IS_ERR(nvmem)) | |
122 | return PTR_ERR(nvmem); | |
123 | ||
124 | platform_set_drvdata(pdev, nvmem); | |
125 | ||
126 | return 0; | |
127 | } | |
128 | ||
129 | static int snvs_lpgpr_remove(struct platform_device *pdev) | |
130 | { | |
131 | struct nvmem_device *nvmem = platform_get_drvdata(pdev); | |
132 | ||
133 | return nvmem_unregister(nvmem); | |
134 | } | |
135 | ||
136 | static const struct of_device_id snvs_lpgpr_dt_ids[] = { | |
137 | { .compatible = "fsl,imx6q-snvs-lpgpr", .data = &snvs_lpgpr_cfg_imx6q }, | |
138 | { .compatible = "fsl,imx6ul-snvs-lpgpr", | |
139 | .data = &snvs_lpgpr_cfg_imx6q }, | |
140 | { }, | |
141 | }; | |
142 | MODULE_DEVICE_TABLE(of, snvs_lpgpr_dt_ids); | |
143 | ||
144 | static struct platform_driver snvs_lpgpr_driver = { | |
145 | .probe = snvs_lpgpr_probe, | |
146 | .remove = snvs_lpgpr_remove, | |
147 | .driver = { | |
148 | .name = "snvs_lpgpr", | |
149 | .of_match_table = snvs_lpgpr_dt_ids, | |
150 | }, | |
151 | }; | |
152 | module_platform_driver(snvs_lpgpr_driver); | |
153 | ||
154 | MODULE_AUTHOR("Oleksij Rempel <o.rempel@pengutronix.de>"); | |
155 | MODULE_DESCRIPTION("Low Power General Purpose Register in i.MX6 Secure Non-Volatile Storage"); | |
156 | MODULE_LICENSE("GPL v2"); |