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

Jonathan Cameron
2020-04-14T18:03:46Z

On Tue, 14 Apr 2020 17:49:50 +0800
Chris Ruehl <chris.ruehl@gtsys.com.hk> wrote:

> 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.
For avoidance of doubt:
1) Like Andy said
2) Any change would need to be a separate patch from this one anyway.

Jonathan

>
>
> >> + { "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]
> >>
>