Re: [PATCH 2/3] iio: DAC extension for ltc2634-12/10/8

Chris Ruehl
2020-04-14T09:50:02Z

Hi Peter,

good eyes!

On 14/4/2020 3:29 pm, Peter Meerwald-Stadler wrote:
>> This patch add support for Analog Devices (Linear Technology)
>> LTC2634 Quad 12-/10-/8-Bit Rail-to-Rail DAC.
>> The SPI functionality based on them from LTC2632 therefor
>> add the definitions only and update the Kconfig.
> comments below
>
>> V2:
>> Send the documentation fix in a extra patch
>> Kconfig simplify the driver description, details to the help text
>> ltc2632.txt add to this patch-set (prepare to convert to yaml)
>>
>> Signed-off-by: Chris Ruehl <chris.ruehl@gtsys.com.hk>
>> ---
>> .../devicetree/bindings/iio/dac/ltc2632.txt | 8 ++-
>> drivers/iio/dac/Kconfig | 6 +-
>> drivers/iio/dac/ltc2632.c | 60 +++++++++++++++++++
>> 3 files changed, 70 insertions(+), 4 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/iio/dac/ltc2632.txt b/Documentation/devicetree/bindings/iio/dac/ltc2632.txt
>> index 338c3220f01a..1ab9570cf219 100644
>> --- a/Documentation/devicetree/bindings/iio/dac/ltc2632.txt
>> +++ b/Documentation/devicetree/bindings/iio/dac/ltc2632.txt
>> @@ -1,4 +1,4 @@
>> -Linear Technology LTC2632/2636 DAC
>> +Linear Technology LTC2632/2634/2636 DAC
>>
>> Required properties:
>> - compatible: Has to contain one of the following:
>> @@ -8,6 +8,12 @@ Required properties:
>> lltc,ltc2632-h12
>> lltc,ltc2632-h10
>> lltc,ltc2632-h8
>> + lltc,ltc2634-l12
>> + lltc,ltc2634-l10
>> + lltc,ltc2634-l8
>> + lltc,ltc2634-h12
>> + lltc,ltc2634-h10
>> + lltc,ltc2634-h8
>> lltc,ltc2636-l12
>> lltc,ltc2636-l10
>> lltc,ltc2636-l8
>> diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
>> index 93744011b63f..aee13ced6ddf 100644
>> --- a/drivers/iio/dac/Kconfig
>> +++ b/drivers/iio/dac/Kconfig
>> @@ -279,12 +279,12 @@ config LTC1660
>> module will be called ltc1660.
>>
>> config LTC2632
>> - tristate "Linear Technology LTC2632-12/10/8 and LTC2636-12/10/8 DAC spi driver"
>> + tristate "Linear Technology LTC2632-12/10/8 and similar DAC spi driver"
>> depends on SPI
>> help
>> Say yes here to build support for Linear Technology
>> - LTC2632-12, LTC2632-10, LTC2632-8, LTC2636-12, LTC2636-10 and
>> - LTC2636-8 converters (DAC).
>> + LTC2632, LTC2634 and LTC2636 DAC resolution 12/10/8 bit
>> + low 0-2.5V and high 0-4,096V range converters.
> this should be 0-4.096V?
> use consistent decimal separator
that call to reformat the patch indeed.

>
>>
>> To compile this driver as a module, choose M here: the
>> module will be called ltc2632.
>> diff --git a/drivers/iio/dac/ltc2632.c b/drivers/iio/dac/ltc2632.c
>> index 2a84ea654645..e939d7f81014 100644
>> --- a/drivers/iio/dac/ltc2632.c
>> +++ b/drivers/iio/dac/ltc2632.c
>> @@ -54,6 +54,12 @@ enum ltc2632_supported_device_ids {
>> ID_LTC2632H12,
>> ID_LTC2632H10,
>> ID_LTC2632H8,
>> + ID_LTC2634L12,
>> + ID_LTC2634L10,
>> + ID_LTC2634L8,
>> + ID_LTC2634H12,
>> + ID_LTC2634H10,
>> + ID_LTC2634H8,
>> ID_LTC2636L12,
>> ID_LTC2636L10,
>> ID_LTC2636L8,
>> @@ -236,6 +242,36 @@ static const struct ltc2632_chip_info ltc2632_chip_info_tbl[] = {
>> .num_channels = 2,
>> .vref_mv = 4096,
>> },
>> + [ID_LTC2634L12] = {
>> + .channels = ltc2632x12_channels,
>> + .num_channels = 4,
>> + .vref_mv = 2500,
>> + },
>> + [ID_LTC2634L10] = {
>> + .channels = ltc2632x10_channels,
>> + .num_channels = 4,
>> + .vref_mv = 2500,
>> + },
>> + [ID_LTC2634L8] = {
>> + .channels = ltc2632x8_channels,
>> + .num_channels = 4,
>> + .vref_mv = 2500,
>> + },
>> + [ID_LTC2634H12] = {
>> + .channels = ltc2632x12_channels,
>> + .num_channels = 4,
>> + .vref_mv = 4096,
>> + },
>> + [ID_LTC2634H10] = {
>> + .channels = ltc2632x10_channels,
>> + .num_channels = 4,
>> + .vref_mv = 4096,
>> + },
>> + [ID_LTC2634H8] = {
>> + .channels = ltc2632x8_channels,
>> + .num_channels = 4,
>> + .vref_mv = 4096,
>> + },
>> [ID_LTC2636L12] = {
>> .channels = ltc2632x12_channels,
>> .num_channels = 8,
>> @@ -357,6 +393,12 @@ static const struct spi_device_id ltc2632_id[] = {
>> { "ltc2632-h12", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2632H12] },
>> { "ltc2632-h10", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2632H10] },
>> { "ltc2632-h8", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2632H8] },
>> + { "ltc2634-l12", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2634L12] },
> is kernel_ulong_t the correct type here?
>
> i.e. guaranteed to hold a pointer value, such as uintptr_t in C?
> it seems so, but why not use uintptr_t?
I tried not to change a running system, only 'extend' the functionality of the
driver.  I leave this to Jonathan, to decide if we touch that cast or not.

>> + { "ltc2634-l10", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2634L10] },
>> + { "ltc2634-l8", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2634L8] },
>> + { "ltc2634-h12", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2634H12] },
>> + { "ltc2634-h10", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2634H10] },
>> + { "ltc2634-h8", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2634H8] },
>> { "ltc2636-l12", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2636L12] },
>> { "ltc2636-l10", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2636L10] },
>> { "ltc2636-l8", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2636L8] },
>> @@ -386,6 +428,24 @@ static const struct of_device_id ltc2632_of_match[] = {
>> }, {
>> .compatible = "lltc,ltc2632-h8",
>> .data = &ltc2632_chip_info_tbl[ID_LTC2632H8]
>> + }, {
>> + .compatible = "lltc,ltc2634-l12",
>> + .data = &ltc2632_chip_info_tbl[ID_LTC2634L12]
>> + }, {
>> + .compatible = "lltc,ltc2634-l10",
>> + .data = &ltc2632_chip_info_tbl[ID_LTC2634L10]
>> + }, {
>> + .compatible = "lltc,ltc2634-l8",
>> + .data = &ltc2632_chip_info_tbl[ID_LTC2634L8]
>> + }, {
>> + .compatible = "lltc,ltc2634-h12",
>> + .data = &ltc2632_chip_info_tbl[ID_LTC2634H12]
>> + }, {
>> + .compatible = "lltc,ltc2634-h10",
>> + .data = &ltc2632_chip_info_tbl[ID_LTC2634H10]
>> + }, {
>> + .compatible = "lltc,ltc2634-h8",
>> + .data = &ltc2632_chip_info_tbl[ID_LTC2634H8]
>> }, {
>> .compatible = "lltc,ltc2636-l12",
>> .data = &ltc2632_chip_info_tbl[ID_LTC2636L12]
>>

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