[PATCH 26/45] rtc: m48t59: use generic nvmem

From: Alexandre Belloni
Date: Mon Feb 12 2018 - 17:49:37 EST


Instead of adding a binary sysfs attribute from the driver (which suffers
from a race condition as the attribute appears after the device), use the
core to register an nvmem device.

Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
---
drivers/rtc/rtc-m48t59.c | 56 ++++++++++++++++++++----------------------------
1 file changed, 23 insertions(+), 33 deletions(-)

diff --git a/drivers/rtc/rtc-m48t59.c b/drivers/rtc/rtc-m48t59.c
index e248e56ff8a1..399fc4255d54 100644
--- a/drivers/rtc/rtc-m48t59.c
+++ b/drivers/rtc/rtc-m48t59.c
@@ -334,16 +334,16 @@ static const struct rtc_class_ops m48t02_rtc_ops = {
.set_time = m48t59_rtc_set_time,
};

-static ssize_t m48t59_nvram_read(struct file *filp, struct kobject *kobj,
- struct bin_attribute *bin_attr,
- char *buf, loff_t pos, size_t size)
+static int m48t59_nvram_read(void *priv, unsigned int offset, void *val,
+ size_t size)
{
- struct device *dev = container_of(kobj, struct device, kobj);
- struct platform_device *pdev = to_platform_device(dev);
+ struct platform_device *pdev = priv;
+ struct device *dev = &pdev->dev;
struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
ssize_t cnt = 0;
unsigned long flags;
+ u8 *buf = val;

spin_lock_irqsave(&m48t59->lock, flags);

@@ -352,19 +352,19 @@ static ssize_t m48t59_nvram_read(struct file *filp, struct kobject *kobj,

spin_unlock_irqrestore(&m48t59->lock, flags);

- return cnt;
+ return 0;
}

-static ssize_t m48t59_nvram_write(struct file *filp, struct kobject *kobj,
- struct bin_attribute *bin_attr,
- char *buf, loff_t pos, size_t size)
+static int m48t59_nvram_write(void *priv, unsigned int offset, void *val,
+ size_t size)
{
- struct device *dev = container_of(kobj, struct device, kobj);
- struct platform_device *pdev = to_platform_device(dev);
+ struct platform_device *pdev = priv;
+ struct device *dev = &pdev->dev;
struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
struct m48t59_private *m48t59 = platform_get_drvdata(pdev);
ssize_t cnt = 0;
unsigned long flags;
+ u8 *buf = val;

spin_lock_irqsave(&m48t59->lock, flags);

@@ -373,18 +373,9 @@ static ssize_t m48t59_nvram_write(struct file *filp, struct kobject *kobj,

spin_unlock_irqrestore(&m48t59->lock, flags);

- return cnt;
+ return 0;
}

-static struct bin_attribute m48t59_nvram_attr = {
- .attr = {
- .name = "nvram",
- .mode = S_IRUGO | S_IWUSR,
- },
- .read = m48t59_nvram_read,
- .write = m48t59_nvram_write,
-};
-
static int m48t59_rtc_probe(struct platform_device *pdev)
{
struct m48t59_plat_data *pdata = dev_get_platdata(&pdev->dev);
@@ -393,6 +384,15 @@ static int m48t59_rtc_probe(struct platform_device *pdev)
int ret = -ENOMEM;
char *name;
const struct rtc_class_ops *ops;
+ struct nvmem_config nvmem_cfg = {
+ .name = "m48t59-",
+ .word_size = 1,
+ .stride = 1,
+ .size = pdata->offset,
+ .reg_read = m48t59_nvram_read,
+ .reg_write = m48t59_nvram_write,
+ .priv = pdev,
+ };

/* This chip could be memory-mapped or I/O-mapped */
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -484,24 +484,15 @@ static int m48t59_rtc_probe(struct platform_device *pdev)
if (IS_ERR(m48t59->rtc))
return PTR_ERR(m48t59->rtc);

+ m48t59->rtc->nvram_old_abi = true;
m48t59->rtc->ops = ops;

ret = rtc_register_device(m48t59->rtc);
if (ret)
return ret;

- m48t59_nvram_attr.size = pdata->offset;
+ rtc_nvmem_register(m48t59->rtc, &nvmem_cfg);

- ret = sysfs_create_bin_file(&pdev->dev.kobj, &m48t59_nvram_attr);
- if (ret)
- return ret;
-
- return 0;
-}
-
-static int m48t59_rtc_remove(struct platform_device *pdev)
-{
- sysfs_remove_bin_file(&pdev->dev.kobj, &m48t59_nvram_attr);
return 0;
}

@@ -513,7 +504,6 @@ static struct platform_driver m48t59_rtc_driver = {
.name = "rtc-m48t59",
},
.probe = m48t59_rtc_probe,
- .remove = m48t59_rtc_remove,
};

module_platform_driver(m48t59_rtc_driver);
--
2.16.1