This patch adds support for per-channel powerdown on the Microchip MCP
4902/4912/4922 family of DACs.
Signed-off-by: Chris Coffey <cmc@xxxxxxxxxxxxx>
---
drivers/iio/dac/mcp4922.c | 126 ++++++++++++++++++++++++++++++++++++++++------
1 file changed, 110 insertions(+), 16 deletions(-)
diff --git a/drivers/iio/dac/mcp4922.c b/drivers/iio/dac/mcp4922.c
index b5190d1dae..15cd17aa9d 100644
--- a/drivers/iio/dac/mcp4922.c
+++ b/drivers/iio/dac/mcp4922.c
@@ -28,6 +28,9 @@
#define MCP4922_NUM_CHANNELS 2
+#define MCP4922_OUTA_POWER_DOWN 0x20
+#define MCP4922_OUTB_POWER_DOWN 0xa0
+
enum mcp4922_supported_device_ids {
ID_MCP4902,
ID_MCP4912,
@@ -37,26 +40,13 @@ enum mcp4922_supported_device_ids {
struct mcp4922_state {
struct spi_device *spi;
unsigned int value[MCP4922_NUM_CHANNELS];
+ bool powerdown[MCP4922_NUM_CHANNELS];
+ unsigned int powerdown_mode;
unsigned int vref_mv;
struct regulator *vref_reg;
u8 mosi[2] ____cacheline_aligned;
};
-#define MCP4922_CHAN(chan, bits) { \
- .type = IIO_VOLTAGE, \
- .output = 1, \
- .indexed = 1, \
- .channel = chan, \
- .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
- .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
- .scan_type = { \
- .sign = 'u', \
- .realbits = (bits), \
- .storagebits = 16, \
- .shift = 12 - (bits), \
- }, \
-}
-
static int mcp4922_spi_write(struct mcp4922_state *state, u8 addr, u32 val)
{
state->mosi[1] = val & 0xff;
@@ -106,8 +96,10 @@ static int mcp4922_write_raw(struct iio_dev *indio_dev,
val <<= chan->scan_type.shift;
ret = mcp4922_spi_write(state, chan->channel, val);
- if (!ret)
+ if (!ret) {
state->value[chan->channel] = val;
+ state->powerdown[chan->channel] = false;
+ }
return ret;
default:
@@ -115,6 +107,108 @@ static int mcp4922_write_raw(struct iio_dev *indio_dev,
}
}
+static const char * const mcp4922_powerdown_modes[] = {
+ "500kohm_to_gnd"
+};
+
+static int mcp4922_get_powerdown_mode(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan)
+{
+ struct mcp4922_state *state = iio_priv(indio_dev);
+
+ return state->powerdown_mode;
+}
+
+static int mcp4922_set_powerdown_mode(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ unsigned int mode)
+{
+ struct mcp4922_state *state = iio_priv(indio_dev);
+
+ state->powerdown_mode = mode;
+
+ return 0;
+}
+
+static ssize_t mcp4922_read_powerdown(struct iio_dev *indio_dev,
+ uintptr_t private,
+ const struct iio_chan_spec *chan,
+ char *buf)
+{
+ struct mcp4922_state *state = iio_priv(indio_dev);
+
+ return sprintf(buf, "%d\n", state->powerdown[chan->channel]);
+}
+
+static ssize_t mcp4922_write_powerdown(struct iio_dev *indio_dev,
+ uintptr_t private,
+ const struct iio_chan_spec *chan,
+ const char *buf, size_t len)
+{
+ struct mcp4922_state *state = iio_priv(indio_dev);
+ bool powerdown;
+ int ret;
+
+ ret = strtobool(buf, &powerdown);
+ if (ret)
+ return ret;
+
+ if (powerdown) {
+ state->mosi[0] = (chan->channel == 0) ?
+ MCP4922_OUTA_POWER_DOWN :
+ MCP4922_OUTB_POWER_DOWN;
+ state->mosi[1] = 0x00;
+
+ ret = spi_write(state->spi, state->mosi, 2);
+ } else {
+ /* Restore previous voltage level */
+ ret = mcp4922_write_raw(indio_dev, chan,
+ state->value[chan->channel], 0,
+ IIO_CHAN_INFO_RAW);
+ }
+ if (!ret)
+ state->powerdown[chan->channel] = powerdown;
+
+ return ret ? ret : len;
+}
+
+static const struct iio_enum mcp4922_powerdown_mode_enum = {
+ .items = mcp4922_powerdown_modes,
+ .num_items = ARRAY_SIZE(mcp4922_powerdown_modes),
+ .get = mcp4922_get_powerdown_mode,
+ .set = mcp4922_set_powerdown_mode,
+};
+
+static const struct iio_chan_spec_ext_info mcp4922_ext_info[] = {
+ {
+ .name = "powerdown",
+ .read = mcp4922_read_powerdown,
+ .write = mcp4922_write_powerdown,
+ .shared = IIO_SEPARATE,
+ },
+ IIO_ENUM("powerdown_mode", IIO_SHARED_BY_TYPE,
+ &mcp4922_powerdown_mode_enum),
+ IIO_ENUM_AVAILABLE("powerdown_mode",
+ &mcp4922_powerdown_mode_enum),
+ { },
+};
+
+#define MCP4922_CHAN(chan, bits) { \
+ .type = IIO_VOLTAGE, \
+ .output = 1, \
+ .indexed = 1, \
+ .channel = chan, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+ .scan_type = { \
+ .sign = 'u', \
+ .realbits = (bits), \
+ .storagebits = 16, \
+ .shift = 12 - (bits), \
+ }, \
+ .ext_info = mcp4922_ext_info, \
+}
+
static const struct iio_chan_spec mcp4922_channels[3][MCP4922_NUM_CHANNELS] = {
[ID_MCP4902] = { MCP4922_CHAN(0, 8), MCP4922_CHAN(1, 8) },
[ID_MCP4912] = { MCP4922_CHAN(0, 10), MCP4922_CHAN(1, 10) },
--
2.11.0
