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 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 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 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