From: Jean-Francois Dagenais Date: Wed, 6 Mar 2019 20:56:06 +0000 (-0500) Subject: iio: dac: mcp4725: add missing powerdown bits in store eeprom X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=06003531502d06bc89d32528f6ec96bf978790f9;p=openwrt%2Fstaging%2Fblogic.git iio: dac: mcp4725: add missing powerdown bits in store eeprom When issuing the write DAC register and write eeprom command, the two powerdown bits (PD0 and PD1) are assumed by the chip to be present in the bytes sent. Leaving them at 0 implies "powerdown disabled" which is a different state that the current one. By adding the current state of the powerdown in the i2c write, the chip will correctly power-on exactly like as it is at the moment of store_eeprom call. This is documented in MCP4725's datasheet, FIGURE 6-2: "Write Commands for DAC Input Register and EEPROM" and MCP4726's datasheet, FIGURE 6-3: "Write All Memory Command". Signed-off-by: Jean-Francois Dagenais Acked-by: Peter Meerwald-Stadler Cc: Signed-off-by: Jonathan Cameron --- diff --git a/drivers/iio/dac/mcp4725.c b/drivers/iio/dac/mcp4725.c index 6d71fd905e29..c701a45469f6 100644 --- a/drivers/iio/dac/mcp4725.c +++ b/drivers/iio/dac/mcp4725.c @@ -92,6 +92,7 @@ static ssize_t mcp4725_store_eeprom(struct device *dev, inoutbuf[0] = 0x60; /* write EEPROM */ inoutbuf[0] |= data->ref_mode << 3; + inoutbuf[0] |= data->powerdown ? ((data->powerdown_mode + 1) << 1) : 0; inoutbuf[1] = data->dac_value >> 4; inoutbuf[2] = (data->dac_value & 0xf) << 4;