Hi Geert,
On 13/12/2016 14:21, Geert Uytterhoeven wrote:
Hi Jacopo,
On Tue, Dec 13, 2016 at 1:37 PM, Jacopo Mondi <jacopo@xxxxxxxxxx> wrote:
Add IIO driver for Maxim MAX11100 single-channel ADC.
Add DT bindings documentation.
Signed-off-by: Jacopo Mondi <jacopo@xxxxxxxxxx>
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
obj-$(CONFIG_LPC18XX_ADC) += lpc18xx_adc.o
obj-$(CONFIG_LTC2485) += ltc2485.o
obj-$(CONFIG_MAX1027) += max1027.o
+obj-$(CONFIG_MAX11100) += max11100.o
obj-$(CONFIG_MAX1363) += max1363.o
obj-$(CONFIG_MCP320X) += mcp320x.o
obj-$(CONFIG_MCP3422) += mcp3422.o
diff --git a/drivers/iio/adc/max11100.c b/drivers/iio/adc/max11100.c
new file mode 100644
index 0000000..f372ad8
--- /dev/null
+++ b/drivers/iio/adc/max11100.c
+/*
+ * LSB is the ADC single digital step
+ * 1 LSB = (vref / 2 ^ 16)
+ * AIN = (DIN * LSB)
+ */
+#define MAX11100_LSB_DIV (1 << 16)
+#define MAX11100_LSB(vref) (vref / MAX11100_LSB_DIV)
DIV_ROUND_CLOSEST()?
+struct max11100_state {
+ const struct max11100_chip_desc *desc;
+ struct spi_device *spi;
+ int vref_uv;
unsi
Was this a suggestion to turn "vref_uv" into unsigned?
As you can see in probe function it can get assigned to -EINVAL when a
dummy regulator is returned from regulator-core.
I had to make it signed for this reason
Thanks
j
It's good practice to move the smaller members to the end of the structure,
to avoid gaps due to alignment rules (struct mutex needs to be 64-bit aligned
on 64-bit platforms).
+ struct mutex lock;
+};
+static struct max11100_chip_desc {
+ unsigned int num_chan;
+ const struct iio_chan_spec *channels;
Same here (but it won't have any effect for now).
+} max11100_desc = {
+ .num_chan = ARRAY_SIZE(max11100_channels),
+ .channels = max11100_channels,
+};
+static int max11100_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ int ret;
+ struct max11100_state *state = iio_priv(indio_dev);
+ uint8_t buffer[3];
+ *val = be16_to_cpu(*(uint16_t *)&buffer[1]);
Reading the uint16_t will be an unaligned load, which is not supported on all
platforms. So you either have to use get_unaligned_le16(), or assemble the
value yourself, like you did in v1.
+ *val = *val * MAX11100_LSB(state->vref_uv) / 1000;
DIV_ROUND_CLOSEST()?
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
