gpiolib: cdev: support GPIO_V2_LINE_SET_VALUES_IOCTL

Add support for the GPIO_V2_LINE_SET_VALUES_IOCTL.
Signed-off-by: NKent Gibson <warthog618@gmail.com>
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>

drivers/gpio/gpiolib-cdev.c

@@ -816,6 +816,65 @@ static long linereq_get_values(struct linereq *lr, void __user *ip)
 	return 0;
 }
 
+static long linereq_set_values_unlocked(struct linereq *lr,
+					struct gpio_v2_line_values *lv)
+{
+	DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
+	struct gpio_desc **descs;
+	unsigned int i, didx, num_set;
+	int ret;
+
+	bitmap_zero(vals, GPIO_V2_LINES_MAX);
+	for (num_set = 0, i = 0; i < lr->num_lines; i++) {
+		if (lv->mask & BIT_ULL(i)) {
+			if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags))
+				return -EPERM;
+			if (lv->bits & BIT_ULL(i))
+				__set_bit(num_set, vals);
+			num_set++;
+			descs = &lr->lines[i].desc;
+		}
+	}
+	if (num_set == 0)
+		return -EINVAL;
+
+	if (num_set != 1) {
+		/* build compacted desc array and values */
+		descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL);
+		if (!descs)
+			return -ENOMEM;
+		for (didx = 0, i = 0; i < lr->num_lines; i++) {
+			if (lv->mask & BIT_ULL(i)) {
+				descs[didx] = lr->lines[i].desc;
+				didx++;
+			}
+		}
+	}
+	ret = gpiod_set_array_value_complex(false, true, num_set,
+					    descs, NULL, vals);
+
+	if (num_set != 1)
+		kfree(descs);
+	return ret;
+}
+
+static long linereq_set_values(struct linereq *lr, void __user *ip)
+{
+	struct gpio_v2_line_values lv;
+	int ret;
+
+	if (copy_from_user(&lv, ip, sizeof(lv)))
+		return -EFAULT;
+
+	mutex_lock(&lr->config_mutex);
+
+	ret = linereq_set_values_unlocked(lr, &lv);
+
+	mutex_unlock(&lr->config_mutex);
+
+	return ret;
+}
+
 static long linereq_set_config_unlocked(struct linereq *lr,
 					struct gpio_v2_line_config *lc)
 {
@@ -892,6 +951,8 @@ static long linereq_ioctl(struct file *file, unsigned int cmd,
 
 	if (cmd == GPIO_V2_LINE_GET_VALUES_IOCTL)
 		return linereq_get_values(lr, ip);
+	else if (cmd == GPIO_V2_LINE_SET_VALUES_IOCTL)
+		return linereq_set_values(lr, ip);
 	else if (cmd == GPIO_V2_LINE_SET_CONFIG_IOCTL)
 		return linereq_set_config(lr, ip);