[PATCH] IAD Register is yet readable trough iad sys file. Fix snprintf (%u for unsigned, count for max size).

[Julien Folly <julien.folly@gmail.com>]

Signed-off-by: Julien Folly <julien.folly@gmail.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
---
  drivers/w1/slaves/w1_ds2438.c | 66 ++++++++++++++++++++++++++++++++++---------
  1 file changed, 52 insertions(+), 14 deletions(-)

diff --git a/drivers/w1/slaves/w1_ds2438.c b/drivers/w1/slaves/w1_ds2438.c
index bf641a1..7c4e33d 100644
--- a/drivers/w1/slaves/w1_ds2438.c
+++ b/drivers/w1/slaves/w1_ds2438.c
@@ -186,8 +186,8 @@ static int w1_ds2438_change_config_bit(struct w1_slave *sl, u8 mask, u8 value)
  	return -1;
  }
  
-static uint16_t w1_ds2438_get_voltage(struct w1_slave *sl,
-				      int adc_input, uint16_t *voltage)
+static int w1_ds2438_get_voltage(struct w1_slave *sl,
+				 int adc_input, uint16_t *voltage)
  {
  	unsigned int retries = W1_DS2438_RETRIES;
  	u8 w1_buf[DS2438_PAGE_SIZE + 1 /*for CRC*/];
@@ -235,6 +235,25 @@ static uint16_t w1_ds2438_get_voltage(struct w1_slave *sl,
  	return ret;
  }
  
+static int w1_ds2438_get_current(struct w1_slave *sl, int16_t *voltage)
+{
+	u8 w1_buf[DS2438_PAGE_SIZE + 1 /*for CRC*/];
+	int ret;
+
+	mutex_lock(&sl->master->bus_mutex);
+
+	if (w1_ds2438_get_page(sl, 0, w1_buf) == 0) {
+		/* The voltage measured across current sense resistor RSENS. */
+		*voltage = (((int16_t) w1_buf[DS2438_CURRENT_MSB]) << 8) | ((int16_t) w1_buf[DS2438_CURRENT_LSB]);
+		ret = 0;
+	} else
+		ret = -1;
+
+	mutex_unlock(&sl->master->bus_mutex);
+
+	return ret;
+}
+
  static ssize_t iad_write(struct file *filp, struct kobject *kobj,
  			 struct bin_attribute *bin_attr, char *buf,
  			 loff_t off, size_t count)
@@ -257,6 +276,27 @@ static ssize_t iad_write(struct file *filp, struct kobject *kobj,
  	return ret;
  }
  
+static ssize_t iad_read(struct file *filp, struct kobject *kobj,
+			struct bin_attribute *bin_attr, char *buf,
+			loff_t off, size_t count)
+{
+	struct w1_slave *sl = kobj_to_w1_slave(kobj);
+	int ret;
+	int16_t voltage;
+
+	if (off != 0)
+		return 0;
+	if (!buf)
+		return -EINVAL;
+
+	if (w1_ds2438_get_current(sl, &voltage) == 0) {
+		ret = snprintf(buf, count, "%i\n", voltage);
+	} else
+		ret = -EIO;
+
+	return ret;
+}
+
  static ssize_t page0_read(struct file *filp, struct kobject *kobj,
  			  struct bin_attribute *bin_attr, char *buf,
  			  loff_t off, size_t count)
@@ -272,9 +312,13 @@ static ssize_t page0_read(struct file *filp, struct kobject *kobj,
  
  	mutex_lock(&sl->master->bus_mutex);
  
+	/* Read no more than page0 size */
+	if (count > DS2438_PAGE_SIZE)
+		count = DS2438_PAGE_SIZE;
+
  	if (w1_ds2438_get_page(sl, 0, w1_buf) == 0) {
-		memcpy(buf, &w1_buf, DS2438_PAGE_SIZE);
-		ret = DS2438_PAGE_SIZE;
+		memcpy(buf, &w1_buf, count);
+		ret = count;
  	} else
  		ret = -EIO;
  
@@ -289,7 +333,6 @@ static ssize_t temperature_read(struct file *filp, struct kobject *kobj,
  {
  	struct w1_slave *sl = kobj_to_w1_slave(kobj);
  	int ret;
-	ssize_t c = PAGE_SIZE;
  	int16_t temp;
  
  	if (off != 0)
@@ -298,8 +341,7 @@ static ssize_t temperature_read(struct file *filp, struct kobject *kobj,
  		return -EINVAL;
  
  	if (w1_ds2438_get_temperature(sl, &temp) == 0) {
-		c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", temp);
-		ret = PAGE_SIZE - c;
+		ret = snprintf(buf, count, "%i\n", temp);
  	} else
  		ret = -EIO;
  
@@ -312,7 +354,6 @@ static ssize_t vad_read(struct file *filp, struct kobject *kobj,
  {
  	struct w1_slave *sl = kobj_to_w1_slave(kobj);
  	int ret;
-	ssize_t c = PAGE_SIZE;
  	uint16_t voltage;
  
  	if (off != 0)
@@ -321,8 +362,7 @@ static ssize_t vad_read(struct file *filp, struct kobject *kobj,
  		return -EINVAL;
  
  	if (w1_ds2438_get_voltage(sl, DS2438_ADC_INPUT_VAD, &voltage) == 0) {
-		c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", voltage);
-		ret = PAGE_SIZE - c;
+		ret = snprintf(buf, count, "%u\n", voltage);
  	} else
  		ret = -EIO;
  
@@ -335,7 +375,6 @@ static ssize_t vdd_read(struct file *filp, struct kobject *kobj,
  {
  	struct w1_slave *sl = kobj_to_w1_slave(kobj);
  	int ret;
-	ssize_t c = PAGE_SIZE;
  	uint16_t voltage;
  
  	if (off != 0)
@@ -344,15 +383,14 @@ static ssize_t vdd_read(struct file *filp, struct kobject *kobj,
  		return -EINVAL;
  
  	if (w1_ds2438_get_voltage(sl, DS2438_ADC_INPUT_VDD, &voltage) == 0) {
-		c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", voltage);
-		ret = PAGE_SIZE - c;
+		ret = snprintf(buf, count, "%u\n", voltage);
  	} else
  		ret = -EIO;
  
  	return ret;
  }
  
-static BIN_ATTR(iad, S_IRUGO | S_IWUSR | S_IWGRP, NULL, iad_write, 1);
+static BIN_ATTR(iad, S_IRUGO | S_IWUSR | S_IWGRP, iad_read, iad_write, 0);
  static BIN_ATTR_RO(page0, DS2438_PAGE_SIZE);
  static BIN_ATTR_RO(temperature, 0/* real length varies */);
  static BIN_ATTR_RO(vad, 0/* real length varies */);
-- 
2.7.4