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/*
* Freescale STMP378X Persistent bits manipulation driver
*
* Author: Pantelis Antoniou <pantelis@embeddedalley.com>
*
* Copyright 2008-2010 Freescale Semiconductor, Inc.
* Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
*/
/*
* The code contained herein is licensed under the GNU General Public
* License. You may obtain a copy of the GNU General Public License
* Version 2 or later at the following locations:
*
* http://www.opensource.org/licenses/gpl-license.html
* http://www.gnu.org/copyleft/gpl.html
*/
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/sysdev.h>
#include <linux/bitops.h>
#include <linux/platform_device.h>
#include <linux/sysfs.h>
#include <mach/hardware.h>
#include <asm/irq.h>
#include <mach/device.h>
#include <mach/regs-rtc.h>
struct mxs_persistent_data {
struct device *dev;
struct mxs_platform_persistent_data *pdata;
int count;
struct attribute_group attr_group;
unsigned int base;
/* attribute ** follow */
/* device_attribute follow */
};
#define pd_attribute_ptr(x) \
((struct attribute **)((x) + 1))
#define pd_device_attribute_ptr(x) \
((struct device_attribute *)(pd_attribute_ptr(x) + (x)->count + 1))
static inline u32 persistent_reg_read(struct mxs_persistent_data *pdata,
int reg)
{
u32 msk;
/* wait for stable value */
msk = BF_RTC_STAT_STALE_REGS((0x1 << reg));
while (__raw_readl(pdata->base + HW_RTC_STAT) & msk)
cpu_relax();
return __raw_readl(pdata->base + 0x60 + (reg * 0x10));
}
static inline void persistent_reg_wait_settle(struct mxs_persistent_data *pdata
, int reg)
{
u32 msk;
/* wait until the change is propagated */
msk = BF_RTC_STAT_NEW_REGS((0x1 << reg));
while (__raw_readl(pdata->base + HW_RTC_STAT) & msk)
cpu_relax();
}
static inline void persistent_reg_write(struct mxs_persistent_data *pdata,
u32 val, int reg)
{
__raw_writel(val, pdata->base + 0x60 + (reg * 0x10));
persistent_reg_wait_settle(pdata, reg);
}
static inline void persistent_reg_set(struct mxs_persistent_data *pdata,
u32 val, int reg)
{
__raw_writel(val, pdata->base + 0x60 + (reg * 0x10) + 0x4);
persistent_reg_wait_settle(pdata, reg);
}
static inline void persistent_reg_clr(struct mxs_persistent_data *pdata,
u32 val, int reg)
{
__raw_writel(val, pdata->base + 0x60 + (reg * 0x10) + 0x8);
persistent_reg_wait_settle(pdata, reg);
}
static inline void persistent_reg_tog(struct mxs_persistent_data *pdata,
u32 val, int reg)
{
__raw_writel(val, pdata->base + 0x60 + (reg * 0x10) + 0xc);
persistent_reg_wait_settle(pdata, reg);
}
static ssize_t
persistent_show(struct device *dev, struct device_attribute *attr, char *buf)
{
struct platform_device *pdev = to_platform_device(dev);
struct mxs_persistent_data *pd = platform_get_drvdata(pdev);
struct device_attribute *devattr = pd_device_attribute_ptr(pd);
const struct mxs_persistent_bit_config *pb;
int idx;
u32 val;
idx = attr - devattr;
if ((unsigned int)idx >= pd->count)
return -EINVAL;
pb = &pd->pdata->bit_config_tab[idx];
/* read value and shift */
val = persistent_reg_read(pd, pb->reg);
val >>= pb->start;
val &= (1 << pb->width) - 1;
return sprintf(buf, "%u\n", val);
}
static ssize_t
persistent_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct platform_device *pdev = to_platform_device(dev);
struct mxs_persistent_data *pd = platform_get_drvdata(pdev);
struct device_attribute *devattr = pd_device_attribute_ptr(pd);
const struct mxs_persistent_bit_config *pb;
int idx, r;
unsigned long val, msk;
idx = attr - devattr;
if ((unsigned int)idx >= pd->count)
return -EINVAL;
pb = &pd->pdata->bit_config_tab[idx];
/* get value to write */
r = strict_strtoul(buf, 10, &val);
if (r != 0)
return r;
/* verify it fits */
if ((unsigned int)val > (1 << pb->width) - 1)
return -EINVAL;
/* lockless update, first clear the area */
msk = ((1 << pb->width) - 1) << pb->start;
persistent_reg_clr(pd, msk, pb->reg);
/* shift into position */
val <<= pb->start;
persistent_reg_set(pd, val, pb->reg);
return count;
}
static int __devinit mxs_persistent_probe(struct platform_device *pdev)
{
struct mxs_persistent_data *pd;
struct mxs_platform_persistent_data *pdata;
struct resource *res;
const struct mxs_persistent_bit_config *pb;
struct attribute **attr;
struct device_attribute *devattr;
int i, cnt, size;
int err;
pdata = pdev->dev.platform_data;
if (pdata == NULL)
return -ENODEV;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (res == NULL)
return -ENODEV;
cnt = pdata->bit_config_cnt;
size = sizeof(*pd) +
(cnt + 1) * sizeof(struct atrribute *) +
cnt * sizeof(struct device_attribute);
pd = kzalloc(size, GFP_KERNEL);
if (pd == NULL)
return -ENOMEM;
pd->dev = &pdev->dev;
pd->pdata = pdata;
pd->base = (unsigned int)IO_ADDRESS(res->start);
platform_set_drvdata(pdev, pd);
pd->count = cnt;
attr = pd_attribute_ptr(pd);
devattr = pd_device_attribute_ptr(pd);
/* build the attributes structures */
pd->attr_group.attrs = attr;
pb = pdata->bit_config_tab;
for (i = 0; i < cnt; i++) {
devattr[i].attr.name = pb[i].name;
devattr[i].attr.mode = S_IWUSR | S_IRUGO;
devattr[i].show = persistent_show;
devattr[i].store = persistent_store;
attr[i] = &devattr[i].attr;
}
err = sysfs_create_group(&pdev->dev.kobj, &pd->attr_group);
if (err != 0) {
platform_set_drvdata(pdev, NULL);
kfree(pd);
return err;
}
return 0;
}
static int __devexit mxs_persistent_remove(struct platform_device *pdev)
{
struct mxs_persistent_data *pd;
pd = platform_get_drvdata(pdev);
sysfs_remove_group(&pdev->dev.kobj, &pd->attr_group);
platform_set_drvdata(pdev, NULL);
kfree(pd);
return 0;
}
#ifdef CONFIG_PM
static int
mxs_persistent_suspend(struct platform_device *pdev, pm_message_t state)
{
return 0;
}
static int mxs_persistent_resume(struct platform_device *pdev)
{
return 0;
}
#else
#define mxs_persistent_suspend NULL
#define mxs_persistent_resume NULL
#endif
static struct platform_driver mxs_persistent_driver = {
.probe = mxs_persistent_probe,
.remove = __exit_p(mxs_persistent_remove),
.suspend = mxs_persistent_suspend,
.resume = mxs_persistent_resume,
.driver = {
.name = "mxs-persistent",
.owner = THIS_MODULE,
},
};
static int __init mxs_persistent_init(void)
{
return platform_driver_register(&mxs_persistent_driver);
}
static void __exit mxs_persistent_exit(void)
{
platform_driver_unregister(&mxs_persistent_driver);
}
MODULE_AUTHOR("Pantelis Antoniou <pantelis@embeddedalley.com>");
MODULE_DESCRIPTION("Persistent bits user-access driver");
MODULE_LICENSE("GPL");
module_init(mxs_persistent_init);
module_exit(mxs_persistent_exit);
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