The persistent registers 1-5 are completely software defined. To have access
from userspace, export them via sysfs.

Signed-off-by: Steffen Trumtrar <s.trumt...@pengutronix.de>
---
 drivers/rtc/rtc-stmp3xxx.c |   69 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)

diff --git a/drivers/rtc/rtc-stmp3xxx.c b/drivers/rtc/rtc-stmp3xxx.c
index 936b0ca..16b45c8 100644
--- a/drivers/rtc/rtc-stmp3xxx.c
+++ b/drivers/rtc/rtc-stmp3xxx.c
@@ -67,6 +67,8 @@
 /* missing bitmask in headers */
 #define STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER 0x80000000
 
+#define STMP3XXX_RTC_PERSISTENT_LEN            (0xC0 - 
STMP3XXX_RTC_PERSISTENT1)
+
 enum clock_source { MXS_UNKNOWN, MXS_OSC_24M, MXS_OSC_32K, MXS_OSC_32K768 };
 
 struct stmp3xxx_rtc_data {
@@ -74,6 +76,9 @@ struct stmp3xxx_rtc_data {
        void __iomem *io;
        int irq_alarm;
        enum clock_source clk_src;
+#if IS_ENABLED(CONFIG_RTC_INTF_SYSFS)
+       struct bin_attribute *persist;
+#endif
 };
 
 #if IS_ENABLED(CONFIG_STMP3XXX_RTC_WATCHDOG)
@@ -262,6 +267,42 @@ static int stmp3xxx_rtc_set_alarm(struct device *dev, 
struct rtc_wkalrm *alm)
        return 0;
 }
 
+#if IS_ENABLED(CONFIG_RTC_INTF_SYSFS)
+static ssize_t stmp3xxx_rtc_persist_read(struct file *filep,
+                                        struct kobject *kobj,
+                                        struct bin_attribute *bin_attr,
+                                        char *buf, loff_t off, size_t size)
+{
+       struct rtc_device *rtc = container_of(kobj, struct rtc_device,
+                                             dev.kobj);
+       struct device *dev = rtc->dev.parent;
+       struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
+       ssize_t count;
+
+       for (count = 0; size; size--, off++, count++)
+               *buf++ = readl(rtc_data->io + STMP3XXX_RTC_PERSISTENT1 + off);
+
+       return count;
+}
+
+static ssize_t stmp3xxx_rtc_persist_write(struct file *filep,
+                                         struct kobject *kobj,
+                                         struct bin_attribute *bin_attr,
+                                         char *buf, loff_t off, size_t size)
+{
+       struct rtc_device *rtc = container_of(kobj, struct rtc_device,
+                                             dev.kobj);
+       struct device *dev = rtc->dev.parent;
+       struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
+       ssize_t count;
+
+       for (count = 0; size; size--, off++, count++)
+               writel(*buf++, rtc_data->io + STMP3XXX_RTC_PERSISTENT1 + off);
+
+       return count;
+}
+#endif
+
 static struct rtc_class_ops stmp3xxx_rtc_ops = {
        .alarm_irq_enable =
                          stmp3xxx_alarm_irq_enable,
@@ -278,6 +319,11 @@ static int stmp3xxx_rtc_remove(struct platform_device 
*pdev)
        if (!rtc_data)
                return 0;
 
+#if IS_ENABLED(CONFIG_RTC_INTF_SYSFS)
+       sysfs_remove_bin_file(&pdev->dev.kobj, rtc_data->persist);
+       kfree(rtc_data->persist);
+#endif
+
        writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
                        rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
        free_irq(rtc_data->irq_alarm, &pdev->dev);
@@ -384,8 +430,31 @@ static int stmp3xxx_rtc_probe(struct platform_device *pdev)
        }
 
        stmp3xxx_wdt_register(pdev);
+
+#if IS_ENABLED(CONFIG_RTC_INTF_SYSFS)
+       rtc_data->persist = kzalloc(sizeof(struct bin_attribute), GFP_KERNEL);
+       if (!rtc_data->persist) {
+               err = -ENOMEM;
+               goto out_persist;
+       }
+
+       rtc_data->persist->attr.name = "persistent";
+       rtc_data->persist->attr.mode = S_IRUGO | S_IWUSR;
+       sysfs_bin_attr_init(rtc_data->persist);
+       rtc_data->persist->read = stmp3xxx_rtc_persist_read;
+       rtc_data->persist->write = stmp3xxx_rtc_persist_write;
+       rtc_data->persist->size = STMP3XXX_RTC_PERSISTENT_LEN;
+       err = sysfs_create_bin_file(&rtc_data->rtc->dev.kobj,
+                               rtc_data->persist);
+       if (err) {
+               kfree(rtc_data->persist);
+               goto out_persist;
+       }
+#endif
+
        return 0;
 
+out_persist:
 out_irq_alarm:
        rtc_device_unregister(rtc_data->rtc);
 out_remap:
-- 
1.7.10.4

_______________________________________________
devicetree-discuss mailing list
devicetree-discuss@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/devicetree-discuss

Reply via email to