diff options
Diffstat (limited to 'drivers/nvmem/rockchip-efuse.c')
| -rw-r--r-- | drivers/nvmem/rockchip-efuse.c | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/drivers/nvmem/rockchip-efuse.c b/drivers/nvmem/rockchip-efuse.c new file mode 100644 index 000000000000..7887070da02d --- /dev/null +++ b/drivers/nvmem/rockchip-efuse.c @@ -0,0 +1,186 @@ +/* + * Rockchip eFuse Driver + * + * Copyright (c) 2015 Rockchip Electronics Co. Ltd. + * Author: Caesar Wang <wxt@rock-chips.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of version 2 of the GNU General Public License as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ + +#include <linux/platform_device.h> +#include <linux/nvmem-provider.h> +#include <linux/slab.h> +#include <linux/regmap.h> +#include <linux/device.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/delay.h> +#include <linux/of.h> +#include <linux/clk.h> + +#define EFUSE_A_SHIFT 6 +#define EFUSE_A_MASK 0x3ff +#define EFUSE_PGENB BIT(3) +#define EFUSE_LOAD BIT(2) +#define EFUSE_STROBE BIT(1) +#define EFUSE_CSB BIT(0) + +#define REG_EFUSE_CTRL 0x0000 +#define REG_EFUSE_DOUT 0x0004 + +struct rockchip_efuse_context { + struct device *dev; + void __iomem *base; + struct clk *efuse_clk; +}; + +static int rockchip_efuse_write(void *context, const void *data, size_t count) +{ + /* Nothing TBD, Read-Only */ + return 0; +} + +static int rockchip_efuse_read(void *context, + const void *reg, size_t reg_size, + void *val, size_t val_size) +{ + unsigned int offset = *(u32 *)reg; + struct rockchip_efuse_context *_context = context; + void __iomem *base = _context->base; + struct clk *clk = _context->efuse_clk; + u8 *buf = val; + int ret; + + ret = clk_prepare_enable(clk); + if (ret < 0) { + dev_err(_context->dev, "failed to prepare/enable efuse clk\n"); + return ret; + } + + writel(EFUSE_LOAD | EFUSE_PGENB, base + REG_EFUSE_CTRL); + udelay(1); + while (val_size) { + writel(readl(base + REG_EFUSE_CTRL) & + (~(EFUSE_A_MASK << EFUSE_A_SHIFT)), + base + REG_EFUSE_CTRL); + writel(readl(base + REG_EFUSE_CTRL) | + ((offset & EFUSE_A_MASK) << EFUSE_A_SHIFT), + base + REG_EFUSE_CTRL); + udelay(1); + writel(readl(base + REG_EFUSE_CTRL) | + EFUSE_STROBE, base + REG_EFUSE_CTRL); + udelay(1); + *buf++ = readb(base + REG_EFUSE_DOUT); + writel(readl(base + REG_EFUSE_CTRL) & + (~EFUSE_STROBE), base + REG_EFUSE_CTRL); + udelay(1); + + val_size -= 1; + offset += 1; + } + + /* Switch to standby mode */ + writel(EFUSE_PGENB | EFUSE_CSB, base + REG_EFUSE_CTRL); + + clk_disable_unprepare(clk); + + return 0; +} + +static struct regmap_bus rockchip_efuse_bus = { + .read = rockchip_efuse_read, + .write = rockchip_efuse_write, + .reg_format_endian_default = REGMAP_ENDIAN_NATIVE, + .val_format_endian_default = REGMAP_ENDIAN_NATIVE, +}; + +struct regmap_config rockchip_efuse_regmap_config = { + .reg_bits = 32, + .reg_stride = 1, + .val_bits = 8, +}; + +static struct nvmem_config econfig = { + .name = "rockchip-efuse", + .owner = THIS_MODULE, + .read_only = true, +}; + +static const struct of_device_id rockchip_efuse_match[] = { + { .compatible = "rockchip,rockchip-efuse",}, + { /* sentinel */}, +}; +MODULE_DEVICE_TABLE(of, rockchip_efuse_match); + +int rockchip_efuse_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct resource *res; + struct nvmem_device *nvmem; + struct regmap *regmap; + void __iomem *base; + struct clk *clk; + struct rockchip_efuse_context *context; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + base = devm_ioremap_resource(dev, res); + if (IS_ERR(base)) + return PTR_ERR(base); + + context = devm_kzalloc(dev, sizeof(struct rockchip_efuse_context), + GFP_KERNEL); + if (IS_ERR(context)) + return PTR_ERR(context); + + clk = devm_clk_get(dev, "pclk_efuse"); + if (IS_ERR(clk)) + return PTR_ERR(clk); + + context->dev = dev; + context->base = base; + context->efuse_clk = clk; + + rockchip_efuse_regmap_config.max_register = resource_size(res) - 1; + + regmap = devm_regmap_init(dev, &rockchip_efuse_bus, + context, &rockchip_efuse_regmap_config); + if (IS_ERR(regmap)) { + dev_err(dev, "regmap init failed\n"); + return PTR_ERR(regmap); + } + econfig.dev = dev; + nvmem = nvmem_register(&econfig); + if (IS_ERR(nvmem)) + return PTR_ERR(nvmem); + + platform_set_drvdata(pdev, nvmem); + + return 0; +} + +int rockchip_efuse_remove(struct platform_device *pdev) +{ + struct nvmem_device *nvmem = platform_get_drvdata(pdev); + + return nvmem_unregister(nvmem); +} + +static struct platform_driver rockchip_efuse_driver = { + .probe = rockchip_efuse_probe, + .remove = rockchip_efuse_remove, + .driver = { + .name = "rockchip-efuse", + .of_match_table = rockchip_efuse_match, + }, +}; + +module_platform_driver(rockchip_efuse_driver); +MODULE_DESCRIPTION("rockchip_efuse driver"); +MODULE_LICENSE("GPL v2"); |