xref: /openbmc/linux/drivers/nvmem/snvs_lpgpr.c (revision 5c816641)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2015 Pengutronix, Steffen Trumtrar <kernel@pengutronix.de>
4  * Copyright (c) 2017 Pengutronix, Oleksij Rempel <kernel@pengutronix.de>
5  */
6 
7 #include <linux/mfd/syscon.h>
8 #include <linux/module.h>
9 #include <linux/nvmem-provider.h>
10 #include <linux/of_device.h>
11 #include <linux/regmap.h>
12 
13 #define IMX6Q_SNVS_HPLR		0x00
14 #define IMX6Q_SNVS_LPLR		0x34
15 #define IMX6Q_SNVS_LPGPR	0x68
16 
17 #define IMX7D_SNVS_HPLR		0x00
18 #define IMX7D_SNVS_LPLR		0x34
19 #define IMX7D_SNVS_LPGPR	0x90
20 
21 #define IMX_GPR_SL		BIT(5)
22 #define IMX_GPR_HL		BIT(5)
23 
24 struct snvs_lpgpr_cfg {
25 	int offset;
26 	int offset_hplr;
27 	int offset_lplr;
28 	int size;
29 };
30 
31 struct snvs_lpgpr_priv {
32 	struct device_d			*dev;
33 	struct regmap			*regmap;
34 	struct nvmem_config		cfg;
35 	const struct snvs_lpgpr_cfg	*dcfg;
36 };
37 
38 static const struct snvs_lpgpr_cfg snvs_lpgpr_cfg_imx6q = {
39 	.offset		= IMX6Q_SNVS_LPGPR,
40 	.offset_hplr	= IMX6Q_SNVS_HPLR,
41 	.offset_lplr	= IMX6Q_SNVS_LPLR,
42 	.size		= 4,
43 };
44 
45 static const struct snvs_lpgpr_cfg snvs_lpgpr_cfg_imx7d = {
46 	.offset		= IMX7D_SNVS_LPGPR,
47 	.offset_hplr	= IMX7D_SNVS_HPLR,
48 	.offset_lplr	= IMX7D_SNVS_LPLR,
49 	.size		= 16,
50 };
51 
52 static int snvs_lpgpr_write(void *context, unsigned int offset, void *val,
53 			    size_t bytes)
54 {
55 	struct snvs_lpgpr_priv *priv = context;
56 	const struct snvs_lpgpr_cfg *dcfg = priv->dcfg;
57 	unsigned int lock_reg;
58 	int ret;
59 
60 	ret = regmap_read(priv->regmap, dcfg->offset_hplr, &lock_reg);
61 	if (ret < 0)
62 		return ret;
63 
64 	if (lock_reg & IMX_GPR_SL)
65 		return -EPERM;
66 
67 	ret = regmap_read(priv->regmap, dcfg->offset_lplr, &lock_reg);
68 	if (ret < 0)
69 		return ret;
70 
71 	if (lock_reg & IMX_GPR_HL)
72 		return -EPERM;
73 
74 	return regmap_bulk_write(priv->regmap, dcfg->offset + offset, val,
75 				bytes / 4);
76 }
77 
78 static int snvs_lpgpr_read(void *context, unsigned int offset, void *val,
79 			   size_t bytes)
80 {
81 	struct snvs_lpgpr_priv *priv = context;
82 	const struct snvs_lpgpr_cfg *dcfg = priv->dcfg;
83 
84 	return regmap_bulk_read(priv->regmap, dcfg->offset + offset,
85 			       val, bytes / 4);
86 }
87 
88 static int snvs_lpgpr_probe(struct platform_device *pdev)
89 {
90 	struct device *dev = &pdev->dev;
91 	struct device_node *node = dev->of_node;
92 	struct device_node *syscon_node;
93 	struct snvs_lpgpr_priv *priv;
94 	struct nvmem_config *cfg;
95 	struct nvmem_device *nvmem;
96 	const struct snvs_lpgpr_cfg *dcfg;
97 
98 	if (!node)
99 		return -ENOENT;
100 
101 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
102 	if (!priv)
103 		return -ENOMEM;
104 
105 	dcfg = of_device_get_match_data(dev);
106 	if (!dcfg)
107 		return -EINVAL;
108 
109 	syscon_node = of_get_parent(node);
110 	if (!syscon_node)
111 		return -ENODEV;
112 
113 	priv->regmap = syscon_node_to_regmap(syscon_node);
114 	of_node_put(syscon_node);
115 	if (IS_ERR(priv->regmap))
116 		return PTR_ERR(priv->regmap);
117 
118 	priv->dcfg = dcfg;
119 
120 	cfg = &priv->cfg;
121 	cfg->priv = priv;
122 	cfg->name = dev_name(dev);
123 	cfg->dev = dev;
124 	cfg->stride = 4;
125 	cfg->word_size = 4;
126 	cfg->size = dcfg->size;
127 	cfg->owner = THIS_MODULE;
128 	cfg->reg_read  = snvs_lpgpr_read;
129 	cfg->reg_write = snvs_lpgpr_write;
130 
131 	nvmem = devm_nvmem_register(dev, cfg);
132 
133 	return PTR_ERR_OR_ZERO(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 	{ .compatible = "fsl,imx7d-snvs-lpgpr",	.data = &snvs_lpgpr_cfg_imx7d },
141 	{ },
142 };
143 MODULE_DEVICE_TABLE(of, snvs_lpgpr_dt_ids);
144 
145 static struct platform_driver snvs_lpgpr_driver = {
146 	.probe	= snvs_lpgpr_probe,
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 and i.MX7 Secure Non-Volatile Storage");
156 MODULE_LICENSE("GPL v2");
157