linux/drivers/nvmem/mxs-ocotp.c
Srinivas Kandagatla 7d8867d71f nvmem: mxs-ocotp: remove nvmem regmap dependency
Regmap raw accessors are bus specific implementations, using regmap raw
apis in nvmem breaks nvmem providers based on regmap mmio.
This patch moves to nvmem support in the driver to use callback
instead of regmap, which is what the nvmem core supports now.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Acked-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-06-25 07:42:55 -07:00

219 lines
4.7 KiB
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,
.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;
}
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);
}
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");