[PATCH] rtc: add support of nvram for maxim dallas rtc ds1343

[PATCH] rtc: add support of nvram for maxim dallas rtc ds1343

[Raghavendra Ganiga]

This is a patch to add support of nvram for maxim dallas
rtc ds1343

Signed-off-by: Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>
---
 drivers/rtc/rtc-ds1343.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 73 insertions(+), 2 deletions(-)

diff --git a/drivers/rtc/rtc-ds1343.c b/drivers/rtc/rtc-ds1343.c
index c371918..ae9f997 100644
--- a/drivers/rtc/rtc-ds1343.c
+++ b/drivers/rtc/rtc-ds1343.c
@@ -4,6 +4,7 @@
  * Real Time Clock
  *
  * Author : Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>
+ *	    Ankur Srivastava <sankurece@gmail.com> : DS1343 Nvram Support
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -45,6 +46,9 @@
 #define DS1343_CONTROL_REG	0x0F
 #define DS1343_STATUS_REG	0x10
 #define DS1343_TRICKLE_REG	0x11
+#define DS1343_NVRAM		0x20
+
+#define DS1343_NVRAM_LEN	96
 
 /* DS1343 Control Registers bits */
 #define DS1343_EOSC		0x80
@@ -149,6 +153,64 @@ static ssize_t ds1343_store_glitchfilter(struct device *dev,
 static DEVICE_ATTR(glitch_filter, S_IRUGO | S_IWUSR, ds1343_show_glitchfilter,
 			ds1343_store_glitchfilter);
 
+static ssize_t ds1343_nvram_write(struct file *filp, struct kobject *kobj,
+			struct bin_attribute *attr,
+			char *buf, loff_t off, size_t count)
+{
+	int ret;
+	unsigned char address;
+	struct device *dev = kobj_to_dev(kobj);
+	struct ds1343_priv *priv = dev_get_drvdata(dev);
+
+	if (unlikely(!count))
+		return count;
+
+	if ((count + off) > DS1343_NVRAM_LEN)
+		count = DS1343_NVRAM_LEN - off;
+
+	address = DS1343_NVRAM + off;
+
+	ret = regmap_bulk_write(priv->map, address, buf, count);
+	if (ret < 0)
+		dev_err(&priv->spi->dev, "Error in nvram write %d", ret);
+
+	return (ret < 0) ? ret : count;
+}
+
+
+static ssize_t ds1343_nvram_read(struct file *filp, struct kobject *kobj,
+				struct bin_attribute *attr,
+				char *buf, loff_t off, size_t count)
+{
+	int ret;
+	unsigned char address;
+	struct device *dev = kobj_to_dev(kobj);
+	struct ds1343_priv *priv = dev_get_drvdata(dev);
+
+	if (unlikely(!count))
+		return count;
+
+	if ((count + off) > DS1343_NVRAM_LEN)
+		count = DS1343_NVRAM_LEN - off;
+
+	address = DS1343_NVRAM + off;
+
+	ret = regmap_bulk_read(priv->map, address, buf, count);
+	if (ret < 0)
+		dev_err(&priv->spi->dev, "Error in nvram read %d\n", ret);
+
+	return (ret < 0) ? ret : count;
+}
+
+
+static struct bin_attribute nvram_attr = {
+	.attr.name	= "nvram",
+	.attr.mode	= S_IRUGO | S_IWUSR,
+	.read		= ds1343_nvram_read,
+	.write		= ds1343_nvram_write,
+	.size		= DS1343_NVRAM_LEN,
+};
+
 static ssize_t ds1343_show_alarmstatus(struct device *dev,
 				struct device_attribute *attr, char *buf)
 {
@@ -274,12 +336,16 @@ static int ds1343_sysfs_register(struct device *dev)
 	if (err)
 		goto error1;
 
+	err = device_create_bin_file(dev, &nvram_attr);
+	if (err)
+		goto error2;
+
 	if (priv->irq <= 0)
 		return err;
 
 	err = device_create_file(dev, &dev_attr_alarm_mode);
 	if (err)
-		goto error2;
+		goto error3;
 
 	err = device_create_file(dev, &dev_attr_alarm_status);
 	if (!err)
@@ -287,6 +353,9 @@ static int ds1343_sysfs_register(struct device *dev)
 
 	device_remove_file(dev, &dev_attr_alarm_mode);
 
+error3:
+	device_remove_bin_file(dev, &nvram_attr);
+
 error2:
 	device_remove_file(dev, &dev_attr_trickle_charger);
 
@@ -302,6 +371,7 @@ static void ds1343_sysfs_unregister(struct device *dev)
 
 	device_remove_file(dev, &dev_attr_glitch_filter);
 	device_remove_file(dev, &dev_attr_trickle_charger);
+	device_remove_bin_file(dev, &nvram_attr);
 
 	if (priv->irq <= 0)
 		return;
@@ -684,6 +754,7 @@ static struct spi_driver ds1343_driver = {
 module_spi_driver(ds1343_driver);
 
 MODULE_DESCRIPTION("DS1343 RTC SPI Driver");
-MODULE_AUTHOR("Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>");
+MODULE_AUTHOR("Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>,"
+		"Ankur Srivastava <sankurece@gmail.com>");
 MODULE_LICENSE("GPL v2");
 MODULE_VERSION(DS1343_DRV_VERSION);
-- 
1.9.1

Re: [rtc-linux] [PATCH] rtc: add support of nvram for maxim dallas rtc ds1343

[Andrew Morton]

On Sat, 24 May 2014 21:34:33 +0530 Raghavendra Ganiga <ravi23ganiga@gmail.com> wrote:

> This is a patch to add support of nvram for maxim dallas
> rtc ds1343
> 
> ...
>
> --- a/drivers/rtc/rtc-ds1343.c
> +++ b/drivers/rtc/rtc-ds1343.c
> @@ -4,6 +4,7 @@
>   * Real Time Clock
>   *
>   * Author : Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>
> + *	    Ankur Srivastava <sankurece@gmail.com> : DS1343 Nvram Support
>   *
>   * This program is free software; you can redistribute it and/or modify
>   * it under the terms of the GNU General Public License version 2 as
> @@ -45,6 +46,9 @@
>  #define DS1343_CONTROL_REG	0x0F
>  #define DS1343_STATUS_REG	0x10
>  #define DS1343_TRICKLE_REG	0x11
> +#define DS1343_NVRAM		0x20
> +
> +#define DS1343_NVRAM_LEN	96
>  
>  /* DS1343 Control Registers bits */
>  #define DS1343_EOSC		0x80
> @@ -149,6 +153,64 @@ static ssize_t ds1343_store_glitchfilter(struct device *dev,
>  static DEVICE_ATTR(glitch_filter, S_IRUGO | S_IWUSR, ds1343_show_glitchfilter,
>  			ds1343_store_glitchfilter);
>  
> +static ssize_t ds1343_nvram_write(struct file *filp, struct kobject *kobj,
> +			struct bin_attribute *attr,
> +			char *buf, loff_t off, size_t count)
> +{
> +	int ret;
> +	unsigned char address;
> +	struct device *dev = kobj_to_dev(kobj);
> +	struct ds1343_priv *priv = dev_get_drvdata(dev);
> +
> +	if (unlikely(!count))
> +		return count;
> +
> +	if ((count + off) > DS1343_NVRAM_LEN)

I worry about what happens if (count + off) wraps through zero.

> +		count = DS1343_NVRAM_LEN - off;

We might end up with an enormous value in `count'?

> +	address = DS1343_NVRAM + off;
> +
> +	ret = regmap_bulk_write(priv->map, address, buf, count);
> +	if (ret < 0)
> +		dev_err(&priv->spi->dev, "Error in nvram write %d", ret);
> +
> +	return (ret < 0) ? ret : count;
> +}
> +
> +
> +static ssize_t ds1343_nvram_read(struct file *filp, struct kobject *kobj,
> +				struct bin_attribute *attr,
> +				char *buf, loff_t off, size_t count)
> +{
> +	int ret;
> +	unsigned char address;
> +	struct device *dev = kobj_to_dev(kobj);
> +	struct ds1343_priv *priv = dev_get_drvdata(dev);
> +
> +	if (unlikely(!count))
> +		return count;
> +
> +	if ((count + off) > DS1343_NVRAM_LEN)
> +		count = DS1343_NVRAM_LEN - off;

Here too.

> +	address = DS1343_NVRAM + off;
> +
> +	ret = regmap_bulk_read(priv->map, address, buf, count);
> +	if (ret < 0)
> +		dev_err(&priv->spi->dev, "Error in nvram read %d\n", ret);
> +
> +	return (ret < 0) ? ret : count;
> +}
> +
> +