xref: /linux/drivers/nvmem/snvs_lpgpr.c (revision a1c613ae4c322ddd58d5a8539dbfba2a0380a8c0)
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.h>
11 #include <linux/platform_device.h>
12 #include <linux/regmap.h>
13 
14 #define IMX6Q_SNVS_HPLR		0x00
15 #define IMX6Q_SNVS_LPLR		0x34
16 #define IMX6Q_SNVS_LPGPR	0x68
17 
18 #define IMX7D_SNVS_HPLR		0x00
19 #define IMX7D_SNVS_LPLR		0x34
20 #define IMX7D_SNVS_LPGPR	0x90
21 
22 #define IMX_GPR_SL		BIT(5)
23 #define IMX_GPR_HL		BIT(5)
24 
25 struct snvs_lpgpr_cfg {
26 	int offset;
27 	int offset_hplr;
28 	int offset_lplr;
29 	int size;
30 };
31 
32 struct snvs_lpgpr_priv {
33 	struct device_d			*dev;
34 	struct regmap			*regmap;
35 	struct nvmem_config		cfg;
36 	const struct snvs_lpgpr_cfg	*dcfg;
37 };
38 
39 static const struct snvs_lpgpr_cfg snvs_lpgpr_cfg_imx6q = {
40 	.offset		= IMX6Q_SNVS_LPGPR,
41 	.offset_hplr	= IMX6Q_SNVS_HPLR,
42 	.offset_lplr	= IMX6Q_SNVS_LPLR,
43 	.size		= 4,
44 };
45 
46 static const struct snvs_lpgpr_cfg snvs_lpgpr_cfg_imx7d = {
47 	.offset		= IMX7D_SNVS_LPGPR,
48 	.offset_hplr	= IMX7D_SNVS_HPLR,
49 	.offset_lplr	= IMX7D_SNVS_LPLR,
50 	.size		= 16,
51 };
52 
snvs_lpgpr_write(void * context,unsigned int offset,void * val,size_t bytes)53 static int snvs_lpgpr_write(void *context, unsigned int offset, void *val,
54 			    size_t bytes)
55 {
56 	struct snvs_lpgpr_priv *priv = context;
57 	const struct snvs_lpgpr_cfg *dcfg = priv->dcfg;
58 	unsigned int lock_reg;
59 	int ret;
60 
61 	ret = regmap_read(priv->regmap, dcfg->offset_hplr, &lock_reg);
62 	if (ret < 0)
63 		return ret;
64 
65 	if (lock_reg & IMX_GPR_SL)
66 		return -EPERM;
67 
68 	ret = regmap_read(priv->regmap, dcfg->offset_lplr, &lock_reg);
69 	if (ret < 0)
70 		return ret;
71 
72 	if (lock_reg & IMX_GPR_HL)
73 		return -EPERM;
74 
75 	return regmap_bulk_write(priv->regmap, dcfg->offset + offset, val,
76 				bytes / 4);
77 }
78 
snvs_lpgpr_read(void * context,unsigned int offset,void * val,size_t bytes)79 static int snvs_lpgpr_read(void *context, unsigned int offset, void *val,
80 			   size_t bytes)
81 {
82 	struct snvs_lpgpr_priv *priv = context;
83 	const struct snvs_lpgpr_cfg *dcfg = priv->dcfg;
84 
85 	return regmap_bulk_read(priv->regmap, dcfg->offset + offset,
86 			       val, bytes / 4);
87 }
88 
snvs_lpgpr_probe(struct platform_device * pdev)89 static int snvs_lpgpr_probe(struct platform_device *pdev)
90 {
91 	struct device *dev = &pdev->dev;
92 	struct device_node *node = dev->of_node;
93 	struct device_node *syscon_node;
94 	struct snvs_lpgpr_priv *priv;
95 	struct nvmem_config *cfg;
96 	struct nvmem_device *nvmem;
97 	const struct snvs_lpgpr_cfg *dcfg;
98 
99 	if (!node)
100 		return -ENOENT;
101 
102 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
103 	if (!priv)
104 		return -ENOMEM;
105 
106 	dcfg = of_device_get_match_data(dev);
107 	if (!dcfg)
108 		return -EINVAL;
109 
110 	syscon_node = of_get_parent(node);
111 	if (!syscon_node)
112 		return -ENODEV;
113 
114 	priv->regmap = syscon_node_to_regmap(syscon_node);
115 	of_node_put(syscon_node);
116 	if (IS_ERR(priv->regmap))
117 		return PTR_ERR(priv->regmap);
118 
119 	priv->dcfg = dcfg;
120 
121 	cfg = &priv->cfg;
122 	cfg->priv = priv;
123 	cfg->name = dev_name(dev);
124 	cfg->dev = dev;
125 	cfg->stride = 4;
126 	cfg->word_size = 4;
127 	cfg->size = dcfg->size;
128 	cfg->owner = THIS_MODULE;
129 	cfg->reg_read  = snvs_lpgpr_read;
130 	cfg->reg_write = snvs_lpgpr_write;
131 
132 	nvmem = devm_nvmem_register(dev, cfg);
133 
134 	return PTR_ERR_OR_ZERO(nvmem);
135 }
136 
137 static const struct of_device_id snvs_lpgpr_dt_ids[] = {
138 	{ .compatible = "fsl,imx6q-snvs-lpgpr", .data = &snvs_lpgpr_cfg_imx6q },
139 	{ .compatible = "fsl,imx6ul-snvs-lpgpr",
140 	  .data = &snvs_lpgpr_cfg_imx6q },
141 	{ .compatible = "fsl,imx7d-snvs-lpgpr",	.data = &snvs_lpgpr_cfg_imx7d },
142 	{ },
143 };
144 MODULE_DEVICE_TABLE(of, snvs_lpgpr_dt_ids);
145 
146 static struct platform_driver snvs_lpgpr_driver = {
147 	.probe	= snvs_lpgpr_probe,
148 	.driver = {
149 		.name	= "snvs_lpgpr",
150 		.of_match_table = snvs_lpgpr_dt_ids,
151 	},
152 };
153 module_platform_driver(snvs_lpgpr_driver);
154 
155 MODULE_AUTHOR("Oleksij Rempel <o.rempel@pengutronix.de>");
156 MODULE_DESCRIPTION("Low Power General Purpose Register in i.MX6 and i.MX7 Secure Non-Volatile Storage");
157 MODULE_LICENSE("GPL v2");
158