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"); 157