[linux-2.6-block.git] / drivers / nvmem / mxs-ocotp.c

/*
 * 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;
}

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;
}

static struct nvmem_config ocotp_config = {
	.name = "mxs-ocotp",
	.stride = 16,
	.word_size = 4,
	.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;
	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;

	otp->base = devm_platform_ioremap_resource(pdev, 0);
	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 = devm_nvmem_register(dev, &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;
}

static int mxs_ocotp_remove(struct platform_device *pdev)
{
	struct mxs_ocotp *otp = platform_get_drvdata(pdev);

	clk_unprepare(otp->clk);

	return 0;
}

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");
Commit	Line	Data
c01e9a11 SW	1	/*
	2	* Freescale MXS On-Chip OTP driver
	3	*
	4	* Copyright (C) 2015 Stefan Wahren <stefan.wahren@i2se.com>
	5	*
	6	* Based on the driver from Huang Shijie and Christoph G. Baumann
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License as published by
	10	* the Free Software Foundation; either version 2 of the License, or
	11	* (at your option) any later version.
	12	*
	13	* This program is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	* GNU General Public License for more details.
	17	*
	18	*/
	19	#include <linux/clk.h>
	20	#include <linux/delay.h>
	21	#include <linux/device.h>
	22	#include <linux/err.h>
	23	#include <linux/io.h>
	24	#include <linux/module.h>
	25	#include <linux/nvmem-provider.h>
	26	#include <linux/of_device.h>
	27	#include <linux/platform_device.h>
c01e9a11 SW	28	#include <linux/slab.h>
	29	#include <linux/stmp_device.h>
	30
	31	/* OCOTP registers and bits */
	32
	33	#define BM_OCOTP_CTRL_RD_BANK_OPEN BIT(12)
	34	#define BM_OCOTP_CTRL_ERROR BIT(9)
	35	#define BM_OCOTP_CTRL_BUSY BIT(8)
	36
	37	#define OCOTP_TIMEOUT 10000
	38	#define OCOTP_DATA_OFFSET 0x20
	39
	40	struct mxs_ocotp {
	41	struct clk *clk;
	42	void __iomem *base;
	43	struct nvmem_device *nvmem;
	44	};
	45
	46	static int mxs_ocotp_wait(struct mxs_ocotp *otp)
	47	{
	48	int timeout = OCOTP_TIMEOUT;
	49	unsigned int status = 0;
	50
	51	while (timeout--) {
	52	status = readl(otp->base);
	53
	54	if (!(status & (BM_OCOTP_CTRL_BUSY \| BM_OCOTP_CTRL_ERROR)))
	55	break;
	56
	57	cpu_relax();
	58	}
	59
	60	if (status & BM_OCOTP_CTRL_BUSY)
	61	return -EBUSY;
	62	else if (status & BM_OCOTP_CTRL_ERROR)
	63	return -EIO;
	64
	65	return 0;
	66	}
	67
7d8867d7 SK	68	static int mxs_ocotp_read(void *context, unsigned int offset,
7d8867d7 SK	69	void *val, size_t bytes)
c01e9a11 SW	70	{
c01e9a11 SW	71	struct mxs_ocotp *otp = context;
c01e9a11 SW	72	u32 *buf = val;
	73	int ret;
	74
	75	ret = clk_enable(otp->clk);
	76	if (ret)
	77	return ret;
	78
	79	writel(BM_OCOTP_CTRL_ERROR, otp->base + STMP_OFFSET_REG_CLR);
	80
	81	ret = mxs_ocotp_wait(otp);
	82	if (ret)
	83	goto disable_clk;
	84
	85	/* open OCOTP banks for read */
	86	writel(BM_OCOTP_CTRL_RD_BANK_OPEN, otp->base + STMP_OFFSET_REG_SET);
	87
	88	/* approximately wait 33 hclk cycles */
	89	udelay(1);
	90
	91	ret = mxs_ocotp_wait(otp);
	92	if (ret)
	93	goto close_banks;
	94
7d8867d7	95	while (bytes) {
c01e9a11 SW	96	if ((offset < OCOTP_DATA_OFFSET) \|\| (offset % 16)) {
c01e9a11 SW	97	/* fill up non-data register */
7d8867d7	98	*buf++ = 0;
c01e9a11	99	} else {
7d8867d7	100	*buf++ = readl(otp->base + offset);
c01e9a11 SW	101	}
c01e9a11 SW	102
7d8867d7 SK	103	bytes -= 4;
7d8867d7 SK	104	offset += 4;
c01e9a11 SW	105	}
	106
	107	close_banks:
	108	/* close banks for power saving */
	109	writel(BM_OCOTP_CTRL_RD_BANK_OPEN, otp->base + STMP_OFFSET_REG_CLR);
	110
	111	disable_clk:
	112	clk_disable(otp->clk);
	113
	114	return ret;
	115	}
	116
c01e9a11 SW	117	static struct nvmem_config ocotp_config = {
c01e9a11 SW	118	.name = "mxs-ocotp",
7d8867d7 SK	119	.stride = 16,
7d8867d7 SK	120	.word_size = 4,
7d8867d7	121	.reg_read = mxs_ocotp_read,
c01e9a11 SW	122	};
c01e9a11 SW	123
7d8867d7 SK	124	struct mxs_data {
7d8867d7 SK	125	int size;
c01e9a11 SW	126	};
c01e9a11 SW	127
7d8867d7 SK	128	static const struct mxs_data imx23_data = {
7d8867d7 SK	129	.size = 0x220,
c01e9a11 SW	130	};
c01e9a11 SW	131
7d8867d7 SK	132	static const struct mxs_data imx28_data = {
7d8867d7 SK	133	.size = 0x2a0,
c01e9a11 SW	134	};
	135
	136	static const struct of_device_id mxs_ocotp_match[] = {
7d8867d7 SK	137	{ .compatible = "fsl,imx23-ocotp", .data = &imx23_data },
7d8867d7 SK	138	{ .compatible = "fsl,imx28-ocotp", .data = &imx28_data },
c01e9a11 SW	139	{ /* sentinel */},
	140	};
	141	MODULE_DEVICE_TABLE(of, mxs_ocotp_match);
	142
	143	static int mxs_ocotp_probe(struct platform_device *pdev)
	144	{
	145	struct device *dev = &pdev->dev;
7d8867d7	146	const struct mxs_data *data;
c01e9a11	147	struct mxs_ocotp *otp;
c01e9a11	148	const struct of_device_id *match;
c01e9a11 SW	149	int ret;
	150
	151	match = of_match_device(dev->driver->of_match_table, dev);
	152	if (!match \|\| !match->data)
	153	return -EINVAL;
	154
	155	otp = devm_kzalloc(dev, sizeof(*otp), GFP_KERNEL);
	156	if (!otp)
	157	return -ENOMEM;
	158
794a1e22	159	otp->base = devm_platform_ioremap_resource(pdev, 0);
c01e9a11 SW	160	if (IS_ERR(otp->base))
	161	return PTR_ERR(otp->base);
	162
	163	otp->clk = devm_clk_get(&pdev->dev, NULL);
	164	if (IS_ERR(otp->clk))
	165	return PTR_ERR(otp->clk);
	166
	167	ret = clk_prepare(otp->clk);
	168	if (ret < 0) {
	169	dev_err(dev, "failed to prepare clk: %d\n", ret);
	170	return ret;
	171	}
	172
7d8867d7	173	data = match->data;
c01e9a11	174
7d8867d7 SK	175	ocotp_config.size = data->size;
7d8867d7 SK	176	ocotp_config.priv = otp;
c01e9a11	177	ocotp_config.dev = dev;
7d9f9f24	178	otp->nvmem = devm_nvmem_register(dev, &ocotp_config);
c01e9a11 SW	179	if (IS_ERR(otp->nvmem)) {
	180	ret = PTR_ERR(otp->nvmem);
	181	goto err_clk;
	182	}
	183
	184	platform_set_drvdata(pdev, otp);
	185
	186	return 0;
	187
	188	err_clk:
	189	clk_unprepare(otp->clk);
	190
	191	return ret;
	192	}
	193
	194	static int mxs_ocotp_remove(struct platform_device *pdev)
	195	{
	196	struct mxs_ocotp *otp = platform_get_drvdata(pdev);
	197
	198	clk_unprepare(otp->clk);
	199
7d9f9f24	200	return 0;
c01e9a11 SW	201	}
	202
	203	static struct platform_driver mxs_ocotp_driver = {
	204	.probe = mxs_ocotp_probe,
	205	.remove = mxs_ocotp_remove,
	206	.driver = {
	207	.name = "mxs-ocotp",
	208	.of_match_table = mxs_ocotp_match,
	209	},
	210	};
	211
	212	module_platform_driver(mxs_ocotp_driver);
	213	MODULE_AUTHOR("Stefan Wahren <stefan.wahren@i2se.com>");
	214	MODULE_DESCRIPTION("driver for OCOTP in i.MX23/i.MX28");
	215	MODULE_LICENSE("GPL v2");