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