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authorH Hartley Sweeten <hsweeten@visionengravers.com>2017-02-10 11:11:57 -0700
committerAlexandre Belloni <alexandre.belloni@free-electrons.com>2017-02-12 01:08:01 +0100
commitb180cf8b0bce3e0e1eb9c5d78bfc9ef2559a0b22 (patch)
treedbaa0128da3c7e3075e5b9f5d34c1028fc720d74 /drivers/rtc
parent8057c86d43a6579421c97b00c6df1ab0bc5e51a0 (diff)
rtc: m48t86: add NVRAM support
This RTC has 114 bytes of NVRAM. Provide access to it via a binary sysfs 'nvram' attribute file. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Diffstat (limited to 'drivers/rtc')
-rw-r--r--drivers/rtc/rtc-m48t86.c41
1 files changed, 41 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-m48t86.c b/drivers/rtc/rtc-m48t86.c
index 4dcdbd2a2408..4dc4af41c03d 100644
--- a/drivers/rtc/rtc-m48t86.c
+++ b/drivers/rtc/rtc-m48t86.c
@@ -38,6 +38,8 @@
#define M48T86_C 0x0c
#define M48T86_D 0x0d
#define M48T86_D_VRT BIT(7)
+#define M48T86_NVRAM(x) (0x0e + (x))
+#define M48T86_NVRAM_LEN 114
struct m48t86_rtc_info {
void __iomem *index_reg;
@@ -170,6 +172,35 @@ static const struct rtc_class_ops m48t86_rtc_ops = {
.proc = m48t86_rtc_proc,
};
+static ssize_t m48t86_nvram_read(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *attr,
+ char *buf, loff_t off, size_t count)
+{
+ struct device *dev = kobj_to_dev(kobj);
+ unsigned int i;
+
+ for (i = 0; i < count; i++)
+ buf[i] = m48t86_readb(dev, M48T86_NVRAM(off + i));
+
+ return count;
+}
+
+static ssize_t m48t86_nvram_write(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *attr,
+ char *buf, loff_t off, size_t count)
+{
+ struct device *dev = kobj_to_dev(kobj);
+ unsigned int i;
+
+ for (i = 0; i < count; i++)
+ m48t86_writeb(dev, buf[i], M48T86_NVRAM(off + i));
+
+ return count;
+}
+
+static BIN_ATTR(nvram, 0644, m48t86_nvram_read, m48t86_nvram_write,
+ M48T86_NVRAM_LEN);
+
static int m48t86_rtc_probe(struct platform_device *pdev)
{
struct m48t86_rtc_info *info;
@@ -210,6 +241,15 @@ static int m48t86_rtc_probe(struct platform_device *pdev)
dev_info(&pdev->dev, "battery %s\n",
(reg & M48T86_D_VRT) ? "ok" : "exhausted");
+ if (device_create_bin_file(&pdev->dev, &bin_attr_nvram))
+ dev_err(&pdev->dev, "failed to create nvram sysfs entry\n");
+
+ return 0;
+}
+
+static int m48t86_rtc_remove(struct platform_device *pdev)
+{
+ device_remove_bin_file(&pdev->dev, &bin_attr_nvram);
return 0;
}
@@ -218,6 +258,7 @@ static struct platform_driver m48t86_rtc_platform_driver = {
.name = "rtc-m48t86",
},
.probe = m48t86_rtc_probe,
+ .remove = m48t86_rtc_remove,
};
module_platform_driver(m48t86_rtc_platform_driver);