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Date: Sun, 13 Jun 2010 12:12:38 +0200 (CEST)
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Alessandro Zummo <a.zummo@...ertech.it>
cc: Linux/m68k <linux-m68k@...ts.linux-m68k.org>,
rtc-linux@...glegroups.com,
Linux Kernel Development <linux-kernel@...r.kernel.org>
Subject: [PATCH] rtc: rp5c01 - Add NVRAM support
The Ricoh RP5C01 RTC contains 26 x 4 bits of NVRAM.
Provide access to it via a sysfs "nvram" attribute file.
Signed-off-by: Geert Uytterhoeven <geert@...ux-m68k.org>
--
Question: Is a spinlock in priv the right kind of locking?
Should I use e.g. rtc-device.ops_lock instead?
diff --git a/drivers/rtc/rtc-rp5c01.c b/drivers/rtc/rtc-rp5c01.c
index a95f733..36eb661 100644
--- a/drivers/rtc/rtc-rp5c01.c
+++ b/drivers/rtc/rtc-rp5c01.c
@@ -63,6 +63,8 @@ enum {
struct rp5c01_priv {
u32 __iomem *regs;
struct rtc_device *rtc;
+ spinlock_t lock; /* against concurrent RTC/NVRAM access */
+ struct bin_attribute nvram_attr;
};
static inline unsigned int rp5c01_read(struct rp5c01_priv *priv,
@@ -92,6 +94,7 @@ static int rp5c01_read_time(struct device *dev, struct rtc_time *tm)
{
struct rp5c01_priv *priv = dev_get_drvdata(dev);
+ spin_lock_irq(&priv->lock);
rp5c01_lock(priv);
tm->tm_sec = rp5c01_read(priv, RP5C01_10_SECOND) * 10 +
@@ -111,6 +114,7 @@ static int rp5c01_read_time(struct device *dev, struct rtc_time *tm)
tm->tm_year += 100;
rp5c01_unlock(priv);
+ spin_unlock_irq(&priv->lock);
return rtc_valid_tm(tm);
}
@@ -119,6 +123,7 @@ static int rp5c01_set_time(struct device *dev, struct rtc_time *tm)
{
struct rp5c01_priv *priv = dev_get_drvdata(dev);
+ spin_lock_irq(&priv->lock);
rp5c01_lock(priv);
rp5c01_write(priv, tm->tm_sec / 10, RP5C01_10_SECOND);
@@ -139,6 +144,7 @@ static int rp5c01_set_time(struct device *dev, struct rtc_time *tm)
rp5c01_write(priv, tm->tm_year % 10, RP5C01_1_YEAR);
rp5c01_unlock(priv);
+ spin_unlock_irq(&priv->lock);
return 0;
}
@@ -147,6 +153,72 @@ static const struct rtc_class_ops rp5c01_rtc_ops = {
.set_time = rp5c01_set_time,
};
+
+/*
+ * The NVRAM is organized as 2 blocks of 13 nibbles of 4 bits.
+ * We provide access to them like AmigaOS does: the high nibble of each 8-bit
+ * byte is stored in BLOCK10, the low nibble in BLOCK11.
+ */
+
+static ssize_t rp5c01_nvram_read(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr,
+ char *buf, loff_t pos, size_t size)
+{
+ struct device *dev = container_of(kobj, struct device, kobj);
+ struct rp5c01_priv *priv = dev_get_drvdata(dev);
+ ssize_t count;
+
+ spin_lock_irq(&priv->lock);
+
+ for (count = 0; size > 0 && pos < RP5C01_MODE; count++, size--) {
+ u8 data;
+
+ rp5c01_write(priv,
+ RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK10,
+ RP5C01_MODE);
+ data = rp5c01_read(priv, pos) << 4;
+ rp5c01_write(priv,
+ RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK11,
+ RP5C01_MODE);
+ data |= rp5c01_read(priv, pos++);
+ rp5c01_write(priv, RP5C01_MODE_TIMER_EN | RP5C01_MODE_MODE01,
+ RP5C01_MODE);
+ *buf++ = data;
+ }
+
+ spin_unlock_irq(&priv->lock);
+ return count;
+}
+
+static ssize_t rp5c01_nvram_write(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr,
+ char *buf, loff_t pos, size_t size)
+{
+ struct device *dev = container_of(kobj, struct device, kobj);
+ struct rp5c01_priv *priv = dev_get_drvdata(dev);
+ ssize_t count;
+
+ spin_lock_irq(&priv->lock);
+
+ for (count = 0; size > 0 && pos < RP5C01_MODE; count++, size--) {
+ u8 data = *buf++;
+
+ rp5c01_write(priv,
+ RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK10,
+ RP5C01_MODE);
+ rp5c01_write(priv, data >> 4, pos);
+ rp5c01_write(priv,
+ RP5C01_MODE_TIMER_EN | RP5C01_MODE_RAM_BLOCK11,
+ RP5C01_MODE);
+ rp5c01_write(priv, data & 0xf, pos++);
+ rp5c01_write(priv, RP5C01_MODE_TIMER_EN | RP5C01_MODE_MODE01,
+ RP5C01_MODE);
+ }
+
+ spin_unlock_irq(&priv->lock);
+ return count;
+}
+
static int __init rp5c01_rtc_probe(struct platform_device *dev)
{
struct resource *res;
@@ -168,6 +240,15 @@ static int __init rp5c01_rtc_probe(struct platform_device *dev)
goto out_free_priv;
}
+ sysfs_bin_attr_init(&priv->nvram_attr);
+ priv->nvram_attr.attr.name = "nvram";
+ priv->nvram_attr.attr.mode = S_IRUGO | S_IWUSR;
+ priv->nvram_attr.read = rp5c01_nvram_read;
+ priv->nvram_attr.write = rp5c01_nvram_write;
+ priv->nvram_attr.size = RP5C01_MODE;
+
+ spin_lock_init(&priv->lock);
+
rtc = rtc_device_register("rtc-rp5c01", &dev->dev, &rp5c01_rtc_ops,
THIS_MODULE);
if (IS_ERR(rtc)) {
@@ -177,8 +258,15 @@ static int __init rp5c01_rtc_probe(struct platform_device *dev)
priv->rtc = rtc;
platform_set_drvdata(dev, priv);
+
+ error = sysfs_create_bin_file(&dev->dev.kobj, &priv->nvram_attr);
+ if (error)
+ goto out_unregister;
+
return 0;
+out_unregister:
+ rtc_device_unregister(rtc);
out_unmap:
iounmap(priv->regs);
out_free_priv:
@@ -190,6 +278,7 @@ static int __exit rp5c01_rtc_remove(struct platform_device *dev)
{
struct rp5c01_priv *priv = platform_get_drvdata(dev);
+ sysfs_remove_bin_file(&dev->dev.kobj, &priv->nvram_attr);
rtc_device_unregister(priv->rtc);
iounmap(priv->regs);
kfree(priv);
--
1.7.0.4
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
--
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