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197 lines
4.0 KiB
197 lines
4.0 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Freescale MXS On-Chip OTP driver |
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* |
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* Copyright (C) 2015 Stefan Wahren <[email protected]> |
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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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#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 void mxs_ocotp_action(void *data) |
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{ |
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clk_unprepare(data); |
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} |
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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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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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otp->base = devm_platform_ioremap_resource(pdev, 0); |
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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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ret = devm_add_action_or_reset(&pdev->dev, mxs_ocotp_action, otp->clk); |
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if (ret) |
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return ret; |
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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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return PTR_ERR(otp->nvmem); |
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platform_set_drvdata(pdev, otp); |
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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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.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 <[email protected]"); |
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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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