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Release 4.14 drivers/nvmem/mxs-ocotp.c

Directory: drivers/nvmem
/*
 * Freescale MXS On-Chip OTP driver
 *
 * Copyright (C) 2015 Stefan Wahren <stefan.wahren@i2se.com>
 *
 * Based on the driver from Huang Shijie and Christoph G. Baumann
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/nvmem-provider.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/stmp_device.h>

/* OCOTP registers and bits */


#define BM_OCOTP_CTRL_RD_BANK_OPEN	BIT(12)

#define BM_OCOTP_CTRL_ERROR		BIT(9)

#define BM_OCOTP_CTRL_BUSY		BIT(8)


#define OCOTP_TIMEOUT		10000

#define OCOTP_DATA_OFFSET	0x20


struct mxs_ocotp {
	
struct clk *clk;
	
void __iomem *base;
	
struct nvmem_device *nvmem;
};


static int mxs_ocotp_wait(struct mxs_ocotp *otp) { int timeout = OCOTP_TIMEOUT; unsigned int status = 0; while (timeout--) { status = readl(otp->base); if (!(status & (BM_OCOTP_CTRL_BUSY | BM_OCOTP_CTRL_ERROR))) break; cpu_relax(); } if (status & BM_OCOTP_CTRL_BUSY) return -EBUSY; else if (status & BM_OCOTP_CTRL_ERROR) return -EIO; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Stefan Wahren79100.00%1100.00%
Total79100.00%1100.00%


static int mxs_ocotp_read(void *context, unsigned int offset, void *val, size_t bytes) { struct mxs_ocotp *otp = context; u32 *buf = val; int ret; ret = clk_enable(otp->clk); if (ret) return ret; writel(BM_OCOTP_CTRL_ERROR, otp->base + STMP_OFFSET_REG_CLR); ret = mxs_ocotp_wait(otp); if (ret) goto disable_clk; /* open OCOTP banks for read */ writel(BM_OCOTP_CTRL_RD_BANK_OPEN, otp->base + STMP_OFFSET_REG_SET); /* approximately wait 33 hclk cycles */ udelay(1); ret = mxs_ocotp_wait(otp); if (ret) goto close_banks; while (bytes) { if ((offset < OCOTP_DATA_OFFSET) || (offset % 16)) { /* fill up non-data register */ *buf++ = 0; } else { *buf++ = readl(otp->base + offset); } bytes -= 4; offset += 4; } close_banks: /* close banks for power saving */ writel(BM_OCOTP_CTRL_RD_BANK_OPEN, otp->base + STMP_OFFSET_REG_CLR); disable_clk: clk_disable(otp->clk); return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Stefan Wahren17894.18%133.33%
Srinivas Kandagatla105.29%133.33%
Stanislav Meduna10.53%133.33%
Total189100.00%3100.00%

static struct nvmem_config ocotp_config = { .name = "mxs-ocotp", .stride = 16, .word_size = 4, .owner = THIS_MODULE, .reg_read = mxs_ocotp_read, }; struct mxs_data { int size; }; static const struct mxs_data imx23_data = { .size = 0x220, }; static const struct mxs_data imx28_data = { .size = 0x2a0, }; static const struct of_device_id mxs_ocotp_match[] = { { .compatible = "fsl,imx23-ocotp", .data = &imx23_data }, { .compatible = "fsl,imx28-ocotp", .data = &imx28_data }, { /* sentinel */}, }; MODULE_DEVICE_TABLE(of, mxs_ocotp_match);
static int mxs_ocotp_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; const struct mxs_data *data; struct mxs_ocotp *otp; struct resource *res; const struct of_device_id *match; int ret; match = of_match_device(dev->driver->of_match_table, dev); if (!match || !match->data) return -EINVAL; otp = devm_kzalloc(dev, sizeof(*otp), GFP_KERNEL); if (!otp) return -ENOMEM; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); otp->base = devm_ioremap_resource(dev, res); if (IS_ERR(otp->base)) return PTR_ERR(otp->base); otp->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(otp->clk)) return PTR_ERR(otp->clk); ret = clk_prepare(otp->clk); if (ret < 0) { dev_err(dev, "failed to prepare clk: %d\n", ret); return ret; } data = match->data; ocotp_config.size = data->size; ocotp_config.priv = otp; ocotp_config.dev = dev; otp->nvmem = nvmem_register(&ocotp_config); if (IS_ERR(otp->nvmem)) { ret = PTR_ERR(otp->nvmem); goto err_clk; } platform_set_drvdata(pdev, otp); return 0; err_clk: clk_unprepare(otp->clk); return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Stefan Wahren26394.95%150.00%
Srinivas Kandagatla145.05%150.00%
Total277100.00%2100.00%


static int mxs_ocotp_remove(struct platform_device *pdev) { struct mxs_ocotp *otp = platform_get_drvdata(pdev); clk_unprepare(otp->clk); return nvmem_unregister(otp->nvmem); }

Contributors

PersonTokensPropCommitsCommitProp
Stefan Wahren36100.00%1100.00%
Total36100.00%1100.00%

static struct platform_driver mxs_ocotp_driver = { .probe = mxs_ocotp_probe, .remove = mxs_ocotp_remove, .driver = { .name = "mxs-ocotp", .of_match_table = mxs_ocotp_match, }, }; module_platform_driver(mxs_ocotp_driver); MODULE_AUTHOR("Stefan Wahren <stefan.wahren@i2se.com>"); MODULE_DESCRIPTION("driver for OCOTP in i.MX23/i.MX28"); MODULE_LICENSE("GPL v2");

Overall Contributors

PersonTokensPropCommitsCommitProp
Stefan Wahren76693.41%133.33%
Srinivas Kandagatla536.46%133.33%
Stanislav Meduna10.12%133.33%
Total820100.00%3100.00%
Directory: drivers/nvmem
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