From b180cf8b0bce3e0e1eb9c5d78bfc9ef2559a0b22 Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Fri, 10 Feb 2017 11:11:57 -0700 Subject: [PATCH] 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 Signed-off-by: Alexandre Belloni --- drivers/rtc/rtc-m48t86.c | 41 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) 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);