Adds driver for the MCP48xx series of DACs.
Device uses a simplex SPI channel. To set the value of an output channel,
a 16-bit data of following format must be written:
Bit field | Description
15 [MSB] | Channel selection bit
0 -> Channel A
1 -> Channel B
13 | Output Gain Selection bit
0 -> 2x Gain (Vref = 4.096V)
1 -> 1x Gain (Vref = 2.048V)
12 | Output Shutdown Control bit
0 -> Shutdown the selected channel
1 -> Active mode operation
11-0 [LSB]| DAC Input Data bits
Value's big endian representation is taken as input for the
selected DAC channel. For devices with a resolution of less
than 12-bits, only the x most significant bits are considered
where x is the resolution of the device.
Reference: Page#22 [MCP48x2 Datasheet]
Supported devices:
+---------+--------------+-------------+
| Device | Resolution | Channels |
|---------|--------------|-------------|
| MCP4801 | 8-bit | 1 |
| MCP4802 | 8-bit | 2 |
| MCP4811 | 10-bit | 1 |
| MCP4812 | 10-bit | 2 |
| MCP4821 | 12-bit | 1 |
| MCP4822 | 12-bit | 2 |
+---------+--------------+-------------+
Devices tested:
MCP4821 [12-bit single channel]
MCP4802 [8-bit dual channel]
Tested on Raspberry Pi Zero 2W
Datasheet: https://ww1.microchip.com/downloads/en/DeviceDoc/22244B.pdf #MCP48x1
Datasheet: https://ww1.microchip.com/downloads/en/DeviceDoc/20002249B.pdf #MCP48x2
Signed-off-by: Anshul Dalal <anshulusr@gmail.com>
Link: https://lore.kernel.org/r/20231220151954.154595-2-anshulusr@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
cdf3ecb0d8