This patch add the support of Tachometer which can use to monitor the
frequency of the input. The tach supports up to 16 channels and it's part
function of multi-function device "pwm-tach controller".
Signed-off-by: Billy Tsai <billy_tsai@xxxxxxxxxxxxxx>
+
+ if (ret) {
+ /* return 0 if we didn't get an answer because of timeout*/
+ if (ret == -ETIMEDOUT)
+ return 0;
+ else
+ return ret;
+static int aspeed_tach_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *np, *child;
+ struct aspeed_tach_data *priv;
+ struct device *hwmon;
+ struct platform_device *parent_dev;
+ int ret;
+
+ np = dev->parent->of_node;
+ if (!of_device_is_compatible(np, "aspeed,ast2600-pwm-tach"))
+ return dev_err_probe(dev, -ENODEV,
+ "Unsupported tach device binding\n");
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+ priv->dev = &pdev->dev;
+ priv->tach_channel =
+ devm_kzalloc(dev,
+ TACH_ASPEED_NR_TACHS * sizeof(*priv->tach_channel),
+ GFP_KERNEL);
+
+ priv->regmap = syscon_node_to_regmap(np);
+ if (IS_ERR(priv->regmap)) {
+ dev_err(priv->dev, "Couldn't get regmap\n");
+ return -ENODEV;
+ }