LTC2617 device (and the other devices from Linear Technology) have
a different behavior for power down than the Analog Device devices.
The command must be addressed with the right channel address. Also,
only a single power down mode (90k to ground) is available.
This patch adjusts the driver to handle the LTC case specifically.
I decided to implement the different power down modes as a
separate iio_ext_info structure. An alternative implementation
would be to set the iio_ext_info structure not const
and then adjust the enum in the probe() function based on a
chip_info setting. In my view this would be less ideal because
it uses more memory for the kernel.
The different addressing is handled with a flag in the chip_info
structure. Alternatively we could implement a copy of all
set_powerdown_...() functions. I think this is less nice.
I've added the new setting 90kohm_to_gnd to the ABI sysfs-bus-iio
documentation.
Signed-off-by: Marc Andre <marc.andre@xxxxxxxxxx>
---
Documentation/ABI/testing/sysfs-bus-iio | 1 +
drivers/iio/dac/ad5064.c | 120 ++++++++++++++++++++++----------
2 files changed, 83 insertions(+), 38 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
index 42d360f..3e8b778 100644
--- a/Documentation/ABI/testing/sysfs-bus-iio
+++ b/Documentation/ABI/testing/sysfs-bus-iio
@@ -496,6 +496,7 @@ Description:
1kohm_to_gnd: connected to ground via an 1kOhm resistor,
6kohm_to_gnd: connected to ground via a 6kOhm resistor,
20kohm_to_gnd: connected to ground via a 20kOhm resistor,
+ 90kohm_to_gnd: connected to ground via a 90kOhm resistor,
100kohm_to_gnd: connected to ground via an 100kOhm resistor,
500kohm_to_gnd: connected to ground via a 500kOhm resistor,
three_state: left floating.
diff --git a/drivers/iio/dac/ad5064.c b/drivers/iio/dac/ad5064.c
index a76f4cf..1b89625 100644
--- a/drivers/iio/dac/ad5064.c
+++ b/drivers/iio/dac/ad5064.c
@@ -1,8 +1,8 @@
/*
* AD5024, AD5025, AD5044, AD5045, AD5064, AD5064-1, AD5065, AD5628, AD5629R,
* AD5648, AD5666, AD5668, AD5669R, LTC2606, LTC2607, LTC2609, LTC2616,
- * LTC2617, LTC2619, LTC2626, LTC2627, LTC2629
- * Digital to analog converters driver
+ * LTC2617, LTC2619, LTC2626, LTC2627, LTC2629 Digital to analog converters
+ * driver
*
* Copyright 2011 Analog Devices Inc.
*
@@ -52,10 +52,12 @@
/**
* struct ad5064_chip_info - chip specific information
* @shared_vref: whether the vref supply is shared between channels
- * @internal_vref: internal reference voltage. 0 if the chip has no internal
- * vref.
+ * @internal_vref: internal reference voltage. 0 if the chip has no
+ internal vref.
* @channel: channel specification
* @num_channels: number of channels
+ * @powerdown_ltc: Use alternative power down addressing as required by
+ * ltc2617 and others.
*/
struct ad5064_chip_info {
@@ -63,6 +65,7 @@ struct ad5064_chip_info {
unsigned long internal_vref;
const struct iio_chan_spec *channels;
unsigned int num_channels;
+ bool powerdown_ltc;
};
struct ad5064_state;
@@ -147,15 +150,21 @@ static int ad5064_write(struct ad5064_state *st, unsigned int cmd,
static int ad5064_sync_powerdown_mode(struct ad5064_state *st,
const struct iio_chan_spec *chan)
{
- unsigned int val;
+ unsigned int val, address;
int ret;
- val = (0x1 << chan->address);
+ if (st->chip_info->powerdown_ltc) {
+ val = 0;
+ address = chan->address;
+ } else {
+ address = 0;
+ val = (0x1 << chan->address);
- if (st->pwr_down[chan->channel])
- val |= st->pwr_down_mode[chan->channel] << 8;
+ if (st->pwr_down[chan->channel])
+ val |= st->pwr_down_mode[chan->channel] << 8;
+ }
- ret = ad5064_write(st, AD5064_CMD_POWERDOWN_DAC, 0, val, 0);
+ ret = ad5064_write(st, AD5064_CMD_POWERDOWN_DAC, address, val, 0);
return ret;
}
@@ -166,6 +175,10 @@ static const char * const ad5064_powerdown_modes[] = {
"three_state",
};
+static const char * const ltc2617_powerdown_modes[] = {
+ "90kohm_to_gnd",
+};
+
static int ad5064_get_powerdown_mode(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan)
{
@@ -196,6 +209,13 @@ static const struct iio_enum ad5064_powerdown_mode_enum = {
.set = ad5064_set_powerdown_mode,
};
+static const struct iio_enum ltc2617_powerdown_mode_enum = {
+ .items = ltc2617_powerdown_modes,
+ .num_items = ARRAY_SIZE(ltc2617_powerdown_modes),
+ .get = ad5064_get_powerdown_mode,
+ .set = ad5064_set_powerdown_mode,
+};
+
static ssize_t ad5064_read_dac_powerdown(struct iio_dev *indio_dev,
uintptr_t private, const struct iio_chan_spec *chan, char *buf)
{
@@ -306,7 +326,19 @@ static const struct iio_chan_spec_ext_info ad5064_ext_info[] = {
{ },
};
-#define AD5064_CHANNEL(chan, addr, bits, _shift) { \
+static const struct iio_chan_spec_ext_info ltc2617_ext_info[] = {
+ {
+ .name = "powerdown",
+ .read = ad5064_read_dac_powerdown,
+ .write = ad5064_write_dac_powerdown,
+ .shared = IIO_SEPARATE,
+ },
+ IIO_ENUM("powerdown_mode", IIO_SEPARATE, <c2617_powerdown_mode_enum),
+ IIO_ENUM_AVAILABLE("powerdown_mode", <c2617_powerdown_mode_enum),
+ { },
+};
+
+#define AD5064_CHANNEL(chan, addr, bits, _shift, _ext_info) { \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.output = 1, \
@@ -320,38 +352,41 @@ static const struct iio_chan_spec_ext_info ad5064_ext_info[] = {
.storagebits = 16, \
.shift = (_shift), \
}, \
- .ext_info = ad5064_ext_info, \
+ .ext_info = (_ext_info), \
}
-#define DECLARE_AD5064_CHANNELS(name, bits, shift) \
+#define DECLARE_AD5064_CHANNELS(name, bits, shift, ext_info) \
const struct iio_chan_spec name[] = { \
- AD5064_CHANNEL(0, 0, bits, shift), \
- AD5064_CHANNEL(1, 1, bits, shift), \
- AD5064_CHANNEL(2, 2, bits, shift), \
- AD5064_CHANNEL(3, 3, bits, shift), \
- AD5064_CHANNEL(4, 4, bits, shift), \
- AD5064_CHANNEL(5, 5, bits, shift), \
- AD5064_CHANNEL(6, 6, bits, shift), \
- AD5064_CHANNEL(7, 7, bits, shift), \
+ AD5064_CHANNEL(0, 0, bits, shift, ext_info), \
+ AD5064_CHANNEL(1, 1, bits, shift, ext_info), \
+ AD5064_CHANNEL(2, 2, bits, shift, ext_info), \
+ AD5064_CHANNEL(3, 3, bits, shift, ext_info), \
+ AD5064_CHANNEL(4, 4, bits, shift, ext_info), \
+ AD5064_CHANNEL(5, 5, bits, shift, ext_info), \
+ AD5064_CHANNEL(6, 6, bits, shift, ext_info), \
+ AD5064_CHANNEL(7, 7, bits, shift, ext_info), \
}
-#define DECLARE_AD5065_CHANNELS(name, bits, shift) \
+#define DECLARE_AD5065_CHANNELS(name, bits, shift, ext_info) \
const struct iio_chan_spec name[] = { \
- AD5064_CHANNEL(0, 0, bits, shift), \
- AD5064_CHANNEL(1, 3, bits, shift), \
+ AD5064_CHANNEL(0, 0, bits, shift, ext_info), \
+ AD5064_CHANNEL(1, 3, bits, shift, ext_info), \
}
-static DECLARE_AD5064_CHANNELS(ad5024_channels, 12, 8);
-static DECLARE_AD5064_CHANNELS(ad5044_channels, 14, 6);
-static DECLARE_AD5064_CHANNELS(ad5064_channels, 16, 4);
+static DECLARE_AD5064_CHANNELS(ad5024_channels, 12, 8, ad5064_ext_info);
+static DECLARE_AD5064_CHANNELS(ad5044_channels, 14, 6, ad5064_ext_info);
+static DECLARE_AD5064_CHANNELS(ad5064_channels, 16, 4, ad5064_ext_info);
+
+static DECLARE_AD5065_CHANNELS(ad5025_channels, 12, 8, ad5064_ext_info);
+static DECLARE_AD5065_CHANNELS(ad5045_channels, 14, 6, ad5064_ext_info);
+static DECLARE_AD5065_CHANNELS(ad5065_channels, 16, 4, ad5064_ext_info);
-static DECLARE_AD5065_CHANNELS(ad5025_channels, 12, 8);
-static DECLARE_AD5065_CHANNELS(ad5045_channels, 14, 6);
-static DECLARE_AD5065_CHANNELS(ad5065_channels, 16, 4);
+static DECLARE_AD5064_CHANNELS(ad5629_channels, 12, 4, ad5064_ext_info);
+static DECLARE_AD5064_CHANNELS(ad5669_channels, 16, 0, ad5064_ext_info);
-static DECLARE_AD5064_CHANNELS(ad5629_channels, 12, 4);
-static DECLARE_AD5064_CHANNELS(ltc2617_channels, 14, 2);
-static DECLARE_AD5064_CHANNELS(ad5669_channels, 16, 0);
+static DECLARE_AD5064_CHANNELS(ltc2607_channels, 16, 0, ltc2617_ext_info);
+static DECLARE_AD5064_CHANNELS(ltc2617_channels, 14, 2, ltc2617_ext_info);
+static DECLARE_AD5064_CHANNELS(ltc2627_channels, 12, 4, ltc2617_ext_info);
static const struct ad5064_chip_info ad5064_chip_info_tbl[] = {
[ID_AD5024] = {
@@ -464,56 +499,65 @@ static const struct ad5064_chip_info ad5064_chip_info_tbl[] = {
[ID_LTC2606] = {
.shared_vref = true,
.internal_vref = 0,
- .channels = ad5669_channels,
+ .channels = ltc2607_channels,
.num_channels = 1,
+ .powerdown_ltc = true,
},
[ID_LTC2607] = {
.shared_vref = true,
.internal_vref = 0,
- .channels = ad5669_channels,
+ .channels = ltc2607_channels,
.num_channels = 2,
+ .powerdown_ltc = true,
},
[ID_LTC2609] = {
.shared_vref = false,
.internal_vref = 0,
- .channels = ad5669_channels,
+ .channels = ltc2607_channels,
.num_channels = 4,
+ .powerdown_ltc = true,
},
[ID_LTC2616] = {
.shared_vref = true,
.internal_vref = 0,
.channels = ltc2617_channels,
.num_channels = 1,
+ .powerdown_ltc = true,
},
[ID_LTC2617] = {
.shared_vref = true,
.internal_vref = 0,
.channels = ltc2617_channels,
.num_channels = 2,
+ .powerdown_ltc = true,
},
[ID_LTC2619] = {
.shared_vref = false,
.internal_vref = 0,
.channels = ltc2617_channels,
.num_channels = 4,
+ .powerdown_ltc = true,
},
[ID_LTC2626] = {
.shared_vref = true,
.internal_vref = 0,
- .channels = ad5629_channels,
+ .channels = ltc2627_channels,
.num_channels = 1,
+ .powerdown_ltc = true,
},
[ID_LTC2627] = {
.shared_vref = true,
.internal_vref = 0,
- .channels = ad5629_channels,
+ .channels = ltc2627_channels,
.num_channels = 2,
+ .powerdown_ltc = true,
},
[ID_LTC2629] = {
.shared_vref = false,
.internal_vref = 0,
- .channels = ad5629_channels,
+ .channels = ltc2627_channels,
.num_channels = 4,
+ .powerdown_ltc = true,
},
};
--
1.9.1
--
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