mirror of
https://github.com/torvalds/linux.git
synced 2024-11-23 12:42:02 +00:00
bbde5709ee
Use devm_add_action_or_reset() for cleanup to call clk_unprepare(), which can simplify the error handling in .probe, and .remove callback can be dropped. Signed-off-by: Anson Huang <Anson.Huang@nxp.com> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Link: https://lore.kernel.org/r/20200323150007.7487-5-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
198 lines
4.0 KiB
C
198 lines
4.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/*
|
|
* 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
|
|
*/
|
|
#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 void mxs_ocotp_action(void *data)
|
|
{
|
|
clk_unprepare(data);
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
ret = devm_add_action_or_reset(&pdev->dev, mxs_ocotp_action, otp->clk);
|
|
if (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))
|
|
return PTR_ERR(otp->nvmem);
|
|
|
|
platform_set_drvdata(pdev, otp);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct platform_driver mxs_ocotp_driver = {
|
|
.probe = mxs_ocotp_probe,
|
|
.driver = {
|
|
.name = "mxs-ocotp",
|
|
.of_match_table = mxs_ocotp_match,
|
|
},
|
|
};
|
|
|
|
module_platform_driver(mxs_ocotp_driver);
|
|
MODULE_AUTHOR("Stefan Wahren <wahrenst@gmx.net");
|
|
MODULE_DESCRIPTION("driver for OCOTP in i.MX23/i.MX28");
|
|
MODULE_LICENSE("GPL v2");
|