drivers/nvmem/rockchip-efuse.c

   1 /*
   2  * Rockchip eFuse Driver
   3  *
   4  * Copyright (c) 2015 Rockchip Electronics Co. Ltd.
   5  * Author: Caesar Wang <wxt@rock-chips.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of version 2 of the GNU General Public License as
   9  * published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  14  * more details.
  15  */
  16
  17 #include <linux/clk.h>
  18 #include <linux/delay.h>
  19 #include <linux/device.h>
  20 #include <linux/io.h>
  21 #include <linux/module.h>
  22 #include <linux/nvmem-provider.h>
  23 #include <linux/slab.h>
  24 #include <linux/of.h>
  25 #include <linux/of_platform.h>
  26 #include <linux/platform_device.h>
  27
  28 #define RK3288_A_SHIFT          6
  29 #define RK3288_A_MASK           0x3ff
  30 #define RK3288_PGENB            BIT(3)
  31 #define RK3288_LOAD             BIT(2)
  32 #define RK3288_STROBE           BIT(1)
  33 #define RK3288_CSB              BIT(0)
  34
  35 #define RK3399_A_SHIFT          16
  36 #define RK3399_A_MASK           0x3ff
  37 #define RK3399_NBYTES           4
  38 #define RK3399_STROBSFTSEL      BIT(9)
  39 #define RK3399_RSB              BIT(7)
  40 #define RK3399_PD               BIT(5)
  41 #define RK3399_PGENB            BIT(3)
  42 #define RK3399_LOAD             BIT(2)
  43 #define RK3399_STROBE           BIT(1)
  44 #define RK3399_CSB              BIT(0)
  45
  46 #define REG_EFUSE_CTRL          0x0000
  47 #define REG_EFUSE_DOUT          0x0004
  48
  49 struct rockchip_efuse_chip {
  50         struct device *dev;
  51         void __iomem *base;
  52         struct clk *clk;
  53 };
  54
  55 static int rockchip_rk3288_efuse_read(void *context, unsigned int offset,
  56                                       void *val, size_t bytes)
  57 {
  58         struct rockchip_efuse_chip *efuse = context;
  59         u8 *buf = val;
  60         int ret;
  61
  62         ret = clk_prepare_enable(efuse->clk);
  63         if (ret < 0) {
  64                 dev_err(efuse->dev, "failed to prepare/enable efuse clk\n");
  65                 return ret;
  66         }
  67
  68         writel(RK3288_LOAD | RK3288_PGENB, efuse->base + REG_EFUSE_CTRL);
  69         udelay(1);
  70         while (bytes--) {
  71                 writel(readl(efuse->base + REG_EFUSE_CTRL) &
  72                              (~(RK3288_A_MASK << RK3288_A_SHIFT)),
  73                              efuse->base + REG_EFUSE_CTRL);
  74                 writel(readl(efuse->base + REG_EFUSE_CTRL) |
  75                              ((offset++ & RK3288_A_MASK) << RK3288_A_SHIFT),
  76                              efuse->base + REG_EFUSE_CTRL);
  77                 udelay(1);
  78                 writel(readl(efuse->base + REG_EFUSE_CTRL) |
  79                              RK3288_STROBE, efuse->base + REG_EFUSE_CTRL);
  80                 udelay(1);
  81                 *buf++ = readb(efuse->base + REG_EFUSE_DOUT);
  82                 writel(readl(efuse->base + REG_EFUSE_CTRL) &
  83                        (~RK3288_STROBE), efuse->base + REG_EFUSE_CTRL);
  84                 udelay(1);
  85         }
  86
  87         /* Switch to standby mode */
  88         writel(RK3288_PGENB | RK3288_CSB, efuse->base + REG_EFUSE_CTRL);
  89
  90         clk_disable_unprepare(efuse->clk);
  91
  92         return 0;
  93 }
  94
  95 static int rockchip_rk3399_efuse_read(void *context, unsigned int offset,
  96                                       void *val, size_t bytes)
  97 {
  98         struct rockchip_efuse_chip *efuse = context;
  99         unsigned int addr_start, addr_end, addr_offset, addr_len;
 100         u32 out_value;
 101         u8 *buf;
 102         int ret, i = 0;
 103
 104         ret = clk_prepare_enable(efuse->clk);
 105         if (ret < 0) {
 106                 dev_err(efuse->dev, "failed to prepare/enable efuse clk\n");
 107                 return ret;
 108         }
 109
 110         addr_start = rounddown(offset, RK3399_NBYTES) / RK3399_NBYTES;
 111         addr_end = roundup(offset + bytes, RK3399_NBYTES) / RK3399_NBYTES;
 112         addr_offset = offset % RK3399_NBYTES;
 113         addr_len = addr_end - addr_start;
 114
 115         buf = kzalloc(sizeof(*buf) * addr_len * RK3399_NBYTES, GFP_KERNEL);
 116         if (!buf) {
 117                 clk_disable_unprepare(efuse->clk);
 118                 return -ENOMEM;
 119         }
 120
 121         writel(RK3399_LOAD | RK3399_PGENB | RK3399_STROBSFTSEL | RK3399_RSB,
 122                efuse->base + REG_EFUSE_CTRL);
 123         udelay(1);
 124         while (addr_len--) {
 125                 writel(readl(efuse->base + REG_EFUSE_CTRL) | RK3399_STROBE |
 126                        ((addr_start++ & RK3399_A_MASK) << RK3399_A_SHIFT),
 127                        efuse->base + REG_EFUSE_CTRL);
 128                 udelay(1);
 129                 out_value = readl(efuse->base + REG_EFUSE_DOUT);
 130                 writel(readl(efuse->base + REG_EFUSE_CTRL) & (~RK3399_STROBE),
 131                        efuse->base + REG_EFUSE_CTRL);
 132                 udelay(1);
 133
 134                 memcpy(&buf[i], &out_value, RK3399_NBYTES);
 135                 i += RK3399_NBYTES;
 136         }
 137
 138         /* Switch to standby mode */
 139         writel(RK3399_PD | RK3399_CSB, efuse->base + REG_EFUSE_CTRL);
 140
 141         memcpy(val, buf + addr_offset, bytes);
 142
 143         kfree(buf);
 144
 145         clk_disable_unprepare(efuse->clk);
 146
 147         return 0;
 148 }
 149
 150 static struct nvmem_config econfig = {
 151         .name = "rockchip-efuse",
 152         .owner = THIS_MODULE,
 153         .stride = 1,
 154         .word_size = 1,
 155         .read_only = true,
 156 };
 157
 158 static const struct of_device_id rockchip_efuse_match[] = {
 159         /* deprecated but kept around for dts binding compatibility */
 160         {
 161                 .compatible = "rockchip,rockchip-efuse",
 162                 .data = (void *)&rockchip_rk3288_efuse_read,
 163         },
 164         {
 165                 .compatible = "rockchip,rk3066a-efuse",
 166                 .data = (void *)&rockchip_rk3288_efuse_read,
 167         },
 168         {
 169                 .compatible = "rockchip,rk3188-efuse",
 170                 .data = (void *)&rockchip_rk3288_efuse_read,
 171         },
 172         {
 173                 .compatible = "rockchip,rk3288-efuse",
 174                 .data = (void *)&rockchip_rk3288_efuse_read,
 175         },
 176         {
 177                 .compatible = "rockchip,rk3399-efuse",
 178                 .data = (void *)&rockchip_rk3399_efuse_read,
 179         },
 180         { /* sentinel */},
 181 };
 182 MODULE_DEVICE_TABLE(of, rockchip_efuse_match);
 183
 184 static int rockchip_efuse_probe(struct platform_device *pdev)
 185 {
 186         struct resource *res;
 187         struct nvmem_device *nvmem;
 188         struct rockchip_efuse_chip *efuse;
 189         const struct of_device_id *match;
 190         struct device *dev = &pdev->dev;
 191
 192         match = of_match_device(dev->driver->of_match_table, dev);
 193         if (!match || !match->data) {
 194                 dev_err(dev, "failed to get match data\n");
 195                 return -EINVAL;
 196         }
 197
 198         efuse = devm_kzalloc(&pdev->dev, sizeof(struct rockchip_efuse_chip),
 199                              GFP_KERNEL);
 200         if (!efuse)
 201                 return -ENOMEM;
 202
 203         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 204         efuse->base = devm_ioremap_resource(&pdev->dev, res);
 205         if (IS_ERR(efuse->base))
 206                 return PTR_ERR(efuse->base);
 207
 208         efuse->clk = devm_clk_get(&pdev->dev, "pclk_efuse");
 209         if (IS_ERR(efuse->clk))
 210                 return PTR_ERR(efuse->clk);
 211
 212         efuse->dev = &pdev->dev;
 213         econfig.size = resource_size(res);
 214         econfig.reg_read = match->data;
 215         econfig.priv = efuse;
 216         econfig.dev = efuse->dev;
 217         nvmem = nvmem_register(&econfig);
 218         if (IS_ERR(nvmem))
 219                 return PTR_ERR(nvmem);
 220
 221         platform_set_drvdata(pdev, nvmem);
 222
 223         return 0;
 224 }
 225
 226 static int rockchip_efuse_remove(struct platform_device *pdev)
 227 {
 228         struct nvmem_device *nvmem = platform_get_drvdata(pdev);
 229
 230         return nvmem_unregister(nvmem);
 231 }
 232
 233 static struct platform_driver rockchip_efuse_driver = {
 234         .probe = rockchip_efuse_probe,
 235         .remove = rockchip_efuse_remove,
 236         .driver = {
 237                 .name = "rockchip-efuse",
 238                 .of_match_table = rockchip_efuse_match,
 239         },
 240 };
 241
 242 module_platform_driver(rockchip_efuse_driver);
 243 MODULE_DESCRIPTION("rockchip_efuse driver");
 244 MODULE_LICENSE("GPL v2");