mirror of https://gitee.com/openkylin/linux.git
218 lines
4.6 KiB
C
218 lines
4.6 KiB
C
/*
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* Freescale MXS On-Chip OTP driver
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*
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* Copyright (C) 2015 Stefan Wahren <stefan.wahren@i2se.com>
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*
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* Based on the driver from Huang Shijie and Christoph G. Baumann
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include <linux/clk.h>
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#include <linux/delay.h>
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/io.h>
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#include <linux/module.h>
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#include <linux/nvmem-provider.h>
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#include <linux/of_device.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/stmp_device.h>
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/* OCOTP registers and bits */
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#define BM_OCOTP_CTRL_RD_BANK_OPEN BIT(12)
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#define BM_OCOTP_CTRL_ERROR BIT(9)
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#define BM_OCOTP_CTRL_BUSY BIT(8)
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#define OCOTP_TIMEOUT 10000
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#define OCOTP_DATA_OFFSET 0x20
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struct mxs_ocotp {
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struct clk *clk;
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void __iomem *base;
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struct nvmem_device *nvmem;
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};
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static int mxs_ocotp_wait(struct mxs_ocotp *otp)
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{
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int timeout = OCOTP_TIMEOUT;
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unsigned int status = 0;
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while (timeout--) {
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status = readl(otp->base);
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if (!(status & (BM_OCOTP_CTRL_BUSY | BM_OCOTP_CTRL_ERROR)))
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break;
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cpu_relax();
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}
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if (status & BM_OCOTP_CTRL_BUSY)
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return -EBUSY;
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else if (status & BM_OCOTP_CTRL_ERROR)
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return -EIO;
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return 0;
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}
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static int mxs_ocotp_read(void *context, unsigned int offset,
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void *val, size_t bytes)
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{
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struct mxs_ocotp *otp = context;
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u32 *buf = val;
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int ret;
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ret = clk_enable(otp->clk);
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if (ret)
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return ret;
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writel(BM_OCOTP_CTRL_ERROR, otp->base + STMP_OFFSET_REG_CLR);
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ret = mxs_ocotp_wait(otp);
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if (ret)
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goto disable_clk;
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/* open OCOTP banks for read */
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writel(BM_OCOTP_CTRL_RD_BANK_OPEN, otp->base + STMP_OFFSET_REG_SET);
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/* approximately wait 33 hclk cycles */
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udelay(1);
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ret = mxs_ocotp_wait(otp);
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if (ret)
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goto close_banks;
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while (bytes) {
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if ((offset < OCOTP_DATA_OFFSET) || (offset % 16)) {
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/* fill up non-data register */
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*buf++ = 0;
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} else {
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*buf++ = readl(otp->base + offset);
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}
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bytes -= 4;
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offset += 4;
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}
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close_banks:
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/* close banks for power saving */
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writel(BM_OCOTP_CTRL_RD_BANK_OPEN, otp->base + STMP_OFFSET_REG_CLR);
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disable_clk:
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clk_disable(otp->clk);
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return ret;
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}
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static struct nvmem_config ocotp_config = {
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.name = "mxs-ocotp",
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.stride = 16,
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.word_size = 4,
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.reg_read = mxs_ocotp_read,
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};
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struct mxs_data {
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int size;
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};
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static const struct mxs_data imx23_data = {
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.size = 0x220,
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};
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static const struct mxs_data imx28_data = {
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.size = 0x2a0,
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};
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static const struct of_device_id mxs_ocotp_match[] = {
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{ .compatible = "fsl,imx23-ocotp", .data = &imx23_data },
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{ .compatible = "fsl,imx28-ocotp", .data = &imx28_data },
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{ /* sentinel */},
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};
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MODULE_DEVICE_TABLE(of, mxs_ocotp_match);
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static int mxs_ocotp_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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const struct mxs_data *data;
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struct mxs_ocotp *otp;
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struct resource *res;
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const struct of_device_id *match;
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int ret;
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match = of_match_device(dev->driver->of_match_table, dev);
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if (!match || !match->data)
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return -EINVAL;
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otp = devm_kzalloc(dev, sizeof(*otp), GFP_KERNEL);
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if (!otp)
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return -ENOMEM;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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otp->base = devm_ioremap_resource(dev, res);
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if (IS_ERR(otp->base))
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return PTR_ERR(otp->base);
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otp->clk = devm_clk_get(&pdev->dev, NULL);
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if (IS_ERR(otp->clk))
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return PTR_ERR(otp->clk);
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ret = clk_prepare(otp->clk);
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if (ret < 0) {
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dev_err(dev, "failed to prepare clk: %d\n", ret);
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return ret;
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}
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data = match->data;
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ocotp_config.size = data->size;
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ocotp_config.priv = otp;
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ocotp_config.dev = dev;
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otp->nvmem = devm_nvmem_register(dev, &ocotp_config);
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if (IS_ERR(otp->nvmem)) {
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ret = PTR_ERR(otp->nvmem);
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goto err_clk;
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}
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platform_set_drvdata(pdev, otp);
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return 0;
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err_clk:
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clk_unprepare(otp->clk);
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return ret;
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}
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static int mxs_ocotp_remove(struct platform_device *pdev)
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{
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struct mxs_ocotp *otp = platform_get_drvdata(pdev);
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clk_unprepare(otp->clk);
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return 0;
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}
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static struct platform_driver mxs_ocotp_driver = {
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.probe = mxs_ocotp_probe,
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.remove = mxs_ocotp_remove,
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.driver = {
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.name = "mxs-ocotp",
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.of_match_table = mxs_ocotp_match,
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},
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};
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module_platform_driver(mxs_ocotp_driver);
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MODULE_AUTHOR("Stefan Wahren <stefan.wahren@i2se.com>");
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MODULE_DESCRIPTION("driver for OCOTP in i.MX23/i.MX28");
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MODULE_LICENSE("GPL v2");
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