rtc: pcf85063: do not register a RTC device if chip is not present

Add a sanity check to see if chip is present. If we can not communicate
with the chip there is no point in registering a RTC device.

Signed-off-by: Mirza Krak <mirza.krak@hostmobility.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

diff --git a/drivers/rtc/rtc-pcf85063.c b/drivers/rtc/rtc-pcf85063.c
index efb0a08ac1175182a07ef9d63a49184a20698bd4..a06dff994c8316c0062b39d3704055a1305584a8 100644 (file)
--- a/drivers/rtc/rtc-pcf85063.c
+++ b/drivers/rtc/rtc-pcf85063.c
@@ -191,12 +191,19 @@ static int pcf85063_probe(struct i2c_client *client,
                                const struct i2c_device_id *id)
 {
        struct rtc_device *rtc;
+       int err;
 
        dev_dbg(&client->dev, "%s\n", __func__);
 
        if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
                return -ENODEV;
 
+       err = i2c_smbus_read_byte_data(client, PCF85063_REG_CTRL1);
+       if (err < 0) {
+               dev_err(&client->dev, "RTC chip is not present\n");
+               return err;
+       }
+
        rtc = devm_rtc_device_register(&client->dev,
                                       pcf85063_driver.driver.name,
                                       &pcf85063_rtc_ops, THIS_MODULE);