Hi Hartmut, On Mon, 2014-11-10 at 22:11 +0100, Hartmut Knaack wrote: > Ivan T. Ivanov schrieb am 03.11.2014 16:24: > > From: Stanimir Varbanov <svarbanov@xxxxxxxxxx> > > > > The voltage ADC is peripheral of Qualcomm SPMI PMIC chips. It has > > 15 bits resolution and register space inside PMIC accessible across > > SPMI bus. > > > > The vadc driver registers itself through IIO interface. > Reviewing again, I got the feeling that due to the complexity of adc reads (writing to register > to start conversion, waiting a decent time for the conversion to complete, reading the result), > it would be beneficial to use a mutex in vadc_read_raw or its depending functions. Hm, yes, but there is such a nice info_exist_lock :-) in core functions, which in practice serve the same purpose. > Also, I would want to double-check that the CPU in this type of chips is little endian. Yes, it is. > Besides that, a few minor issues inline. > > +static int vadc_probe(struct platform_device *pdev) > > +{ > > + struct device_node *node = pdev->dev.of_node; > > + struct device *dev = &pdev->dev; > > + struct iio_dev *indio_dev; > > + struct vadc_priv *vadc; > > + struct regmap *regmap; > > + int ret, irq_eoc; > > + u32 res; > Since vadc->base is u16, shouldn't res be u16 as well? Also think about naming it reg, as this is > the property name in DT. Yes, but #address-cells for the node is 1, so I would like to keep it 32 bits. > > + > > + regmap = dev_get_regmap(dev->parent, NULL); > > + if (!regmap) > > + return -ENODEV; > > + > > + ret = of_property_read_u32(node, "reg", &res); > For u16, there would be of_property_read_u16(). > > + if (ret < 0) > > + return -ENODEV; > Just return ret here? I am usually trying to follow these recommendations[1]. In practice driver core cares only for EPROBE_DEFER, ENODEV and ENXIO, while of_property_read_u32() can return ENODATA and EOVERFLOW, which did't not make sense for the core. Thank you, Ivan [1] http://www.gossamer-threads.com/lists/linux/kernel/1010603 -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html