pwm: convert class code to use dev_groups

The dev_attrs field of struct class is going away soon, dev_groups
should be used instead.  This converts the PWM class code to use the
correct field.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/sysfs.c

@@ -268,6 +268,7 @@ static ssize_t pwm_export_store(struct device *parent,
 
 	return ret ? : len;
 }
+static DEVICE_ATTR(export, 0200, NULL, pwm_export_store);
 
 static ssize_t pwm_unexport_store(struct device *parent,
 				  struct device_attribute *attr,
@@ -288,27 +289,29 @@ static ssize_t pwm_unexport_store(struct device *parent,
 
 	return ret ? : len;
 }
+static DEVICE_ATTR(unexport, 0200, NULL, pwm_unexport_store);
 
-static ssize_t pwm_npwm_show(struct device *parent,
-			     struct device_attribute *attr,
-			     char *buf)
+static ssize_t npwm_show(struct device *parent, struct device_attribute *attr,
+			 char *buf)
 {
 	const struct pwm_chip *chip = dev_get_drvdata(parent);
 
 	return sprintf(buf, "%u\n", chip->npwm);
 }
+static DEVICE_ATTR_RO(npwm);
 
-static struct device_attribute pwm_chip_attrs[] = {
-	__ATTR(export, 0200, NULL, pwm_export_store),
-	__ATTR(unexport, 0200, NULL, pwm_unexport_store),
-	__ATTR(npwm, 0444, pwm_npwm_show, NULL),
-	__ATTR_NULL,
+static struct attribute *pwm_chip_attrs[] = {
+	&dev_attr_export.attr,
+	&dev_attr_unexport.attr,
+	&dev_attr_npwm.attr,
+	NULL,
 };
+ATTRIBUTE_GROUPS(pwm_chip);
 
 static struct class pwm_class = {
 	.name		= "pwm",
 	.owner		= THIS_MODULE,
-	.dev_attrs	= pwm_chip_attrs,
+	.dev_groups	= pwm_chip_groups,
 };
 
 static int pwmchip_sysfs_match(struct device *parent, const void *data)