Re: [PATCH 1/3] iio: adc: hi-843x: Holt HI-8435/8436/8437 descrete ADC

Hello Peter,

Thank you for the review.

On 01.06.2015 15:55, Peter Meerwald wrote:

quoted

Add Holt descrete ADC driver for HI-8435/8436/8437 chips

discrete

Thx, will replace in the next try.

link to datasheet would be nice, comments below

the official link is here:
http://www.holtic.com/products/3081-hi-8435.aspx

what is the purpose of the driver?

Support hi-8435/36/37 chips in linux kernel via IIO subsystem with use 
of iio-buffer and triggered-buffer features.

the driver-specific ABI needs to be documented under
Documentation/ABI/testing/sys-bus-iio-*

Thanks, I will add this in the next try.

quoted

Signed-off-by: Vladimir Barinov <vladimir.barinov-M4DtvfQ/ZS1MRgGoP+s0PdBPR1lH4CV8@public.gmane.org>
---
  drivers/iio/adc/Kconfig   |  12 +
  drivers/iio/adc/Makefile  |   1 +
  drivers/iio/adc/hi-843x.c | 777 ++++++++++++++++++++++++++++++++++++++++++++++
  3 files changed, 790 insertions(+)
  create mode 100644 drivers/iio/adc/hi-843x.c

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index e36a73e..71b0efc 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig

@@ -164,6 +164,18 @@ config EXYNOS_ADC
  	  of SoCs for drivers such as the touchscreen and hwmon to use to share
  	  this resource.
  
+config HI_843X

we recommend against using a placeholder in a drivers name;
we suggest to name the driver after the first/primary chip it supports
(that you test with most)

Ok, I will name the driver as hi8435_adc/HI8435_ADC in the next try.

+#include <linux/interrupt.h>
+
+#define DRV_NAME "hi-843x"
HI84.. prefix

sure, as mentioned above I will also use hi8435_adc name and rename all 
functions appropriately with this prefix.

+static int hi843x_readw(struct hi843x_priv *priv, u8 reg, u16 *val)
+{
+	int ret;
+
+	reg |= HI843X_READ_OPCODE;
+	ret = spi_write_then_read(priv->spi, &reg, 1, val, 2);
+	*val = swab16p(val);
will this work on big- and little-endian CPUs?

Actually I've tested it with little-endian CPU.
I will replace it with  be16_to_cpup in the next try and the same for 
swab32p -> be32_to_cpup.

+#define HI843X_VOLTAGE_CHANNEL(num)				\
+	{							\
+		.type = IIO_VOLTAGE,				\
+		.indexed = 1,					\
+		.channel = num,					\
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
+		.scan_index = num,				\
+		.scan_type = {					\
+			.sign = 'u',				\
+			.realbits = 1,				\
huh? this is unusual for an ADC

This is discrete ADC, only 2 possible results: 0 or 1.

Regards,
Vladimir