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ZhengShunQian03a69562015-09-30 13:56:44 +01001/*
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
Caesar Wangc37ff3f2015-12-14 09:43:39 +000017#include <linux/clk.h>
18#include <linux/delay.h>
ZhengShunQian03a69562015-09-30 13:56:44 +010019#include <linux/device.h>
20#include <linux/io.h>
21#include <linux/module.h>
Caesar Wangc37ff3f2015-12-14 09:43:39 +000022#include <linux/nvmem-provider.h>
23#include <linux/slab.h>
ZhengShunQian03a69562015-09-30 13:56:44 +010024#include <linux/of.h>
Caesar Wangc37ff3f2015-12-14 09:43:39 +000025#include <linux/platform_device.h>
ZhengShunQian03a69562015-09-30 13:56:44 +010026
27#define EFUSE_A_SHIFT 6
28#define EFUSE_A_MASK 0x3ff
29#define EFUSE_PGENB BIT(3)
30#define EFUSE_LOAD BIT(2)
31#define EFUSE_STROBE BIT(1)
32#define EFUSE_CSB BIT(0)
33
34#define REG_EFUSE_CTRL 0x0000
35#define REG_EFUSE_DOUT 0x0004
36
Caesar Wangc37ff3f2015-12-14 09:43:39 +000037struct rockchip_efuse_chip {
ZhengShunQian03a69562015-09-30 13:56:44 +010038 struct device *dev;
39 void __iomem *base;
Caesar Wangc37ff3f2015-12-14 09:43:39 +000040 struct clk *clk;
ZhengShunQian03a69562015-09-30 13:56:44 +010041};
42
Srinivas Kandagatlacc907552016-04-24 20:28:11 +010043static int rockchip_efuse_read(void *context, unsigned int offset,
44 void *val, size_t bytes)
ZhengShunQian03a69562015-09-30 13:56:44 +010045{
Caesar Wangc37ff3f2015-12-14 09:43:39 +000046 struct rockchip_efuse_chip *efuse = context;
ZhengShunQian03a69562015-09-30 13:56:44 +010047 u8 *buf = val;
48 int ret;
49
Caesar Wangc37ff3f2015-12-14 09:43:39 +000050 ret = clk_prepare_enable(efuse->clk);
ZhengShunQian03a69562015-09-30 13:56:44 +010051 if (ret < 0) {
Caesar Wangc37ff3f2015-12-14 09:43:39 +000052 dev_err(efuse->dev, "failed to prepare/enable efuse clk\n");
ZhengShunQian03a69562015-09-30 13:56:44 +010053 return ret;
54 }
55
Caesar Wangc37ff3f2015-12-14 09:43:39 +000056 writel(EFUSE_LOAD | EFUSE_PGENB, efuse->base + REG_EFUSE_CTRL);
ZhengShunQian03a69562015-09-30 13:56:44 +010057 udelay(1);
Srinivas Kandagatlacc907552016-04-24 20:28:11 +010058 while (bytes--) {
Caesar Wangc37ff3f2015-12-14 09:43:39 +000059 writel(readl(efuse->base + REG_EFUSE_CTRL) &
ZhengShunQian03a69562015-09-30 13:56:44 +010060 (~(EFUSE_A_MASK << EFUSE_A_SHIFT)),
Caesar Wangc37ff3f2015-12-14 09:43:39 +000061 efuse->base + REG_EFUSE_CTRL);
62 writel(readl(efuse->base + REG_EFUSE_CTRL) |
Srinivas Kandagatlacc907552016-04-24 20:28:11 +010063 ((offset++ & EFUSE_A_MASK) << EFUSE_A_SHIFT),
Caesar Wangc37ff3f2015-12-14 09:43:39 +000064 efuse->base + REG_EFUSE_CTRL);
ZhengShunQian03a69562015-09-30 13:56:44 +010065 udelay(1);
Caesar Wangc37ff3f2015-12-14 09:43:39 +000066 writel(readl(efuse->base + REG_EFUSE_CTRL) |
67 EFUSE_STROBE, efuse->base + REG_EFUSE_CTRL);
ZhengShunQian03a69562015-09-30 13:56:44 +010068 udelay(1);
Caesar Wangc37ff3f2015-12-14 09:43:39 +000069 *buf++ = readb(efuse->base + REG_EFUSE_DOUT);
70 writel(readl(efuse->base + REG_EFUSE_CTRL) &
71 (~EFUSE_STROBE), efuse->base + REG_EFUSE_CTRL);
ZhengShunQian03a69562015-09-30 13:56:44 +010072 udelay(1);
ZhengShunQian03a69562015-09-30 13:56:44 +010073 }
74
75 /* Switch to standby mode */
Caesar Wangc37ff3f2015-12-14 09:43:39 +000076 writel(EFUSE_PGENB | EFUSE_CSB, efuse->base + REG_EFUSE_CTRL);
ZhengShunQian03a69562015-09-30 13:56:44 +010077
Caesar Wangc37ff3f2015-12-14 09:43:39 +000078 clk_disable_unprepare(efuse->clk);
ZhengShunQian03a69562015-09-30 13:56:44 +010079
80 return 0;
81}
82
ZhengShunQian03a69562015-09-30 13:56:44 +010083static struct nvmem_config econfig = {
84 .name = "rockchip-efuse",
85 .owner = THIS_MODULE,
Srinivas Kandagatlacc907552016-04-24 20:28:11 +010086 .stride = 1,
87 .word_size = 1,
ZhengShunQian03a69562015-09-30 13:56:44 +010088 .read_only = true,
89};
90
91static const struct of_device_id rockchip_efuse_match[] = {
Caesar Wangc37ff3f2015-12-14 09:43:39 +000092 { .compatible = "rockchip,rockchip-efuse", },
ZhengShunQian03a69562015-09-30 13:56:44 +010093 { /* sentinel */},
94};
95MODULE_DEVICE_TABLE(of, rockchip_efuse_match);
96
kbuild test robot7e532f72015-09-30 21:46:06 +080097static int rockchip_efuse_probe(struct platform_device *pdev)
ZhengShunQian03a69562015-09-30 13:56:44 +010098{
ZhengShunQian03a69562015-09-30 13:56:44 +010099 struct resource *res;
100 struct nvmem_device *nvmem;
Caesar Wangc37ff3f2015-12-14 09:43:39 +0000101 struct rockchip_efuse_chip *efuse;
102
103 efuse = devm_kzalloc(&pdev->dev, sizeof(struct rockchip_efuse_chip),
104 GFP_KERNEL);
105 if (!efuse)
106 return -ENOMEM;
ZhengShunQian03a69562015-09-30 13:56:44 +0100107
108 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
Caesar Wangc37ff3f2015-12-14 09:43:39 +0000109 efuse->base = devm_ioremap_resource(&pdev->dev, res);
110 if (IS_ERR(efuse->base))
111 return PTR_ERR(efuse->base);
ZhengShunQian03a69562015-09-30 13:56:44 +0100112
Caesar Wangc37ff3f2015-12-14 09:43:39 +0000113 efuse->clk = devm_clk_get(&pdev->dev, "pclk_efuse");
114 if (IS_ERR(efuse->clk))
115 return PTR_ERR(efuse->clk);
ZhengShunQian03a69562015-09-30 13:56:44 +0100116
Caesar Wangc37ff3f2015-12-14 09:43:39 +0000117 efuse->dev = &pdev->dev;
Srinivas Kandagatlacc907552016-04-24 20:28:11 +0100118 econfig.size = resource_size(res);
119 econfig.reg_read = rockchip_efuse_read;
120 econfig.priv = efuse;
Caesar Wangc37ff3f2015-12-14 09:43:39 +0000121 econfig.dev = efuse->dev;
ZhengShunQian03a69562015-09-30 13:56:44 +0100122 nvmem = nvmem_register(&econfig);
123 if (IS_ERR(nvmem))
124 return PTR_ERR(nvmem);
125
126 platform_set_drvdata(pdev, nvmem);
127
128 return 0;
129}
130
kbuild test robot7e532f72015-09-30 21:46:06 +0800131static int rockchip_efuse_remove(struct platform_device *pdev)
ZhengShunQian03a69562015-09-30 13:56:44 +0100132{
133 struct nvmem_device *nvmem = platform_get_drvdata(pdev);
134
135 return nvmem_unregister(nvmem);
136}
137
138static struct platform_driver rockchip_efuse_driver = {
139 .probe = rockchip_efuse_probe,
140 .remove = rockchip_efuse_remove,
141 .driver = {
142 .name = "rockchip-efuse",
143 .of_match_table = rockchip_efuse_match,
144 },
145};
146
147module_platform_driver(rockchip_efuse_driver);
148MODULE_DESCRIPTION("rockchip_efuse driver");
149MODULE_LICENSE("GPL v2");