rtc: m48t59: use generic nvmem

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@bootlin.com>

diff --git a/drivers/rtc/rtc-m48t59.c b/drivers/rtc/rtc-m48t59.c
index e248e56..d2ba7d7 100644 (file)
--- 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 +384,14 @@ 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,
+               .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);
@@ -484,27 +483,21 @@ 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);
+       nvmem_cfg.size = pdata->offset;
+       ret = rtc_nvmem_register(m48t59->rtc, &nvmem_cfg);
        if (ret)
                return ret;
 
-       m48t59_nvram_attr.size = pdata->offset;
-
-       ret = sysfs_create_bin_file(&pdev->dev.kobj, &m48t59_nvram_attr);
+       ret = rtc_register_device(m48t59->rtc);
        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;
-}
-
 /* work with hotplug and coldplug */
 MODULE_ALIAS("platform:rtc-m48t59");
 
@@ -513,7 +506,6 @@ static struct platform_driver m48t59_rtc_driver = {
                .name   = "rtc-m48t59",
        },
        .probe          = m48t59_rtc_probe,
-       .remove         = m48t59_rtc_remove,
 };
 
 module_platform_driver(m48t59_rtc_driver);