| Message ID | 1490960707-22422-5-git-send-email-fabrice.gasnier@st.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 31/03/17 12:45, Fabrice Gasnier wrote: > STM32 DAC has built-in noise or triangle waveform generator. > Waveform generator requires trigger to be configured. > - "wave" extended attribute selects noise or triangle. > - "mamp" extended attribute selects either LFSR (linear feedback > shift register) mask for noise waveform, OR triangle amplitude. > > Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> Looks like AN3126 is the relevant doc. (a quick note from this relevant to earlier patches- doc says 1-3 channels - perhaps build that from the start with that possibility in mind). As you probably know, this wanders into a large chunk of 'poorly' defined ABI within IIO as it stands. Note there are a number of waveform generators still in staging. Not a lot of movement on getting them out of staging unfortunately (so far!) However, let us keep those drivers in mind as we work on ABI and I definitely want some input from someone at Analog. Lars, who is best for this? I see at least some of these were originally Michael's work. They do have partial docs under drivers/staging/iio/Documentation/sysfs-bus-iio-dds I'll highlight thoughts from there as I look through this... > --- > Documentation/ABI/testing/sysfs-bus-iio-dac-stm32 | 32 ++++++ > drivers/iio/dac/stm32-dac.c | 124 ++++++++++++++++++++++ > 2 files changed, 156 insertions(+) > create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-dac-stm32 > > diff --git a/Documentation/ABI/testing/sysfs-bus-iio-dac-stm32 b/Documentation/ABI/testing/sysfs-bus-iio-dac-stm32 > new file mode 100644 > index 0000000..c2432e1 > --- /dev/null > +++ b/Documentation/ABI/testing/sysfs-bus-iio-dac-stm32 > @@ -0,0 +1,32 @@ > +What: /sys/bus/iio/devices/iio:deviceX/wave > +What: /sys/bus/iio/devices/iio:deviceX/wave_available Needs to be channel associated. Whilst in your case you have basically a pair of single channel devices, in more general case, it's not usual to have multiple parallel waveform generators clocked together. Old ABI is: What: /sys/bus/iio/devices/.../out_altvoltageX_outY_wavetype etc > +KernelVersion: 4.12 > +Contact: fabrice.gasnier@st.com > +Description: > + List and/or select waveform generation provided by STM32 DAC: > + - "none": (default) means normal DAC operations none kind of hints at nothing coming out. Perhaps 'flat' would be closer? i.e. only changes when someone tells it to. > + - "noise": select noise waveform > + - "triangle": select triangle waveform > + Note: when waveform generator is used, writing _raw sysfs entry > + adds a DC offset to generated waveform. Reading it reports > + current output value. Interesting. This gets fiddly but one option would be to describe the whole device as a dds. Then we have flat type above, combined with an _offset. > + > +What: /sys/bus/iio/devices/iio:deviceX/mamp > +What: /sys/bus/iio/devices/iio:deviceX/mamp_available > +KernelVersion: 4.12 > +Contact: fabrice.gasnier@st.com > +Description: > + List and select mask/amplitude used for noise/triangle waveform > + generator, which are: > + - "0": unmask bit 0 of LFSR / triangle amplitude equal to 1 > + - "1": unmask bit [1:0] of LFSR / triangle amplitude equal to 3 > + - "2": unmask bit [2:0] of LFSR / triangle amplitude equal to 7 > + - "3": unmask bit [3:0] of LFSR / triangle amplitude equal to 15 > + - "4": unmask bit [4:0] of LFSR / triangle amplitude equal to 31 > + - "5": unmask bit [5:0] of LFSR / triangle amplitude equal to 63 > + - "6": unmask bit [6:0] of LFSR / triangle amplitude equal to 127 > + - "7": unmask bit [7:0] of LFSR / triangle amplitude equal to 255 > + - "8": unmask bit [8:0] of LFSR / triangle amplitude equal to 511 > + - "9": unmask bit [9:0] of LFSR / triangle amplitude equal to 1023 > + - "10": unmask bit [10:0] of LFSR / triangle amplitude equal to 2047 > + - "11": unmask bit [11:0] of LFSR / triangle amplitude equal to 4095 I don't fully understand what is going on here - so I'm guessing somewhat. Let us try describing these generically. If we define standard 'forms' of each waveform type. Say a 0 to 1 V peak to peak, then we could use _scale to control this nicely. > diff --git a/drivers/iio/dac/stm32-dac.c b/drivers/iio/dac/stm32-dac.c > index 62e43e9..d7dda78 100644 > --- a/drivers/iio/dac/stm32-dac.c > +++ b/drivers/iio/dac/stm32-dac.c > @@ -41,10 +41,14 @@ > /** > * struct stm32_dac - private data of DAC driver > * @common: reference to DAC common data > + * @wave: waveform generator > + * @mamp: waveform mask/amplitude > * @swtrig: Using software trigger > */ > struct stm32_dac { > struct stm32_dac_common *common; > + u32 wave; > + u32 mamp; > bool swtrig; > }; > > @@ -157,6 +161,24 @@ static int stm32_dac_is_enabled(struct stm32_dac *dac, int channel) > return !!en; > } > > +static int stm32_dac_wavegen(struct stm32_dac *dac, int channel) > +{ > + struct regmap *regmap = dac->common->regmap; > + u32 mask, val; > + > + if (channel == STM32_DAC_CHANNEL_1) { > + val = FIELD_PREP(STM32_DAC_CR_WAVE1, dac->wave) | > + FIELD_PREP(STM32_DAC_CR_MAMP1, dac->mamp); > + mask = STM32_DAC_CR_WAVE1 | STM32_DAC_CR_MAMP1; > + } else { > + val = FIELD_PREP(STM32_DAC_CR_WAVE2, dac->wave) | > + FIELD_PREP(STM32_DAC_CR_MAMP2, dac->mamp); > + mask = STM32_DAC_CR_WAVE2 | STM32_DAC_CR_MAMP2; > + } > + > + return regmap_update_bits(regmap, STM32_DAC_CR, mask, val); > +} > + > static int stm32_dac_enable(struct iio_dev *indio_dev, int channel) > { > struct stm32_dac *dac = iio_priv(indio_dev); > @@ -164,6 +186,17 @@ static int stm32_dac_enable(struct iio_dev *indio_dev, int channel) > STM32_DAC_CR_EN1 : STM32_DAC_CR_EN2; > int ret; > > + if (dac->wave && !indio_dev->trig) { > + dev_err(&indio_dev->dev, "Wavegen requires a trigger\n"); > + return -EINVAL; > + } > + > + ret = stm32_dac_wavegen(dac, channel); > + if (ret < 0) { > + dev_err(&indio_dev->dev, "Wavegen setup failed\n"); > + return ret; > + } > + > ret = stm32_dac_set_trig(dac, indio_dev->trig, channel); > if (ret < 0) { > dev_err(&indio_dev->dev, "Trigger setup failed\n"); > @@ -291,6 +324,96 @@ static int stm32_dac_debugfs_reg_access(struct iio_dev *indio_dev, > .driver_module = THIS_MODULE, > }; > > +/* waveform generator wave selection */ > +static const char * const stm32_dac_wave_desc[] = { > + "none", > + "noise", > + "triangle", > +}; > + > +static int stm32_dac_set_wave(struct iio_dev *indio_dev, > + const struct iio_chan_spec *chan, > + unsigned int type) > +{ > + struct stm32_dac *dac = iio_priv(indio_dev); > + > + if (stm32_dac_is_enabled(dac, chan->channel)) > + return -EBUSY; > + dac->wave = type; > + > + return 0; > +} > + > +static int stm32_dac_get_wave(struct iio_dev *indio_dev, > + const struct iio_chan_spec *chan) > +{ > + struct stm32_dac *dac = iio_priv(indio_dev); > + > + return dac->wave; > +} > + > +static const struct iio_enum stm32_dac_wave_enum = { > + .items = stm32_dac_wave_desc, > + .num_items = ARRAY_SIZE(stm32_dac_wave_desc), > + .get = stm32_dac_get_wave, > + .set = stm32_dac_set_wave, > +}; > + > +/* > + * waveform generator mask/amplitude selection: > + * - noise: LFSR mask (linear feedback shift register, umasks bit 0, [1:0]...) > + * - triangle: amplitude (equal to 1, 3, 5, 7... 4095) > + */ > +static const char * const stm32_dac_mamp_desc[] = { > + "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", > +}; > + > +static int stm32_dac_set_mamp(struct iio_dev *indio_dev, > + const struct iio_chan_spec *chan, > + unsigned int type) > +{ > + struct stm32_dac *dac = iio_priv(indio_dev); > + > + if (stm32_dac_is_enabled(dac, chan->channel)) > + return -EBUSY; > + dac->mamp = type; > + > + return 0; > +} > + > +static int stm32_dac_get_mamp(struct iio_dev *indio_dev, > + const struct iio_chan_spec *chan) > +{ > + struct stm32_dac *dac = iio_priv(indio_dev); > + > + return dac->mamp; > +} > + > +static const struct iio_enum stm32_dac_mamp_enum = { > + .items = stm32_dac_mamp_desc, > + .num_items = ARRAY_SIZE(stm32_dac_mamp_desc), > + .get = stm32_dac_get_mamp, > + .set = stm32_dac_set_mamp, > +}; > + > +static const struct iio_chan_spec_ext_info stm32_dac_ext_info[] = { > + IIO_ENUM("wave", IIO_SHARED_BY_ALL, &stm32_dac_wave_enum), > + { > + .name = "wave_available", > + .shared = IIO_SHARED_BY_ALL, > + .read = iio_enum_available_read, > + .private = (uintptr_t)&stm32_dac_wave_enum, > + }, > + IIO_ENUM("mamp", IIO_SHARED_BY_ALL, &stm32_dac_mamp_enum), > + { > + .name = "mamp_available", > + .shared = IIO_SHARED_BY_ALL, > + .read = iio_enum_available_read, > + .private = (uintptr_t)&stm32_dac_mamp_enum, > + }, > + {}, > +}; > + > #define STM32_DAC_CHANNEL(chan, name) { \ > .type = IIO_VOLTAGE, \ > .indexed = 1, \ > @@ -306,6 +429,7 @@ static int stm32_dac_debugfs_reg_access(struct iio_dev *indio_dev, > .storagebits = 16, \ > }, \ > .datasheet_name = name, \ > + .ext_info = stm32_dac_ext_info \ > } > > static const struct iio_chan_spec stm32_dac_channels[] = { >
JonathanOn 04/02/2017 02:19 PM, Jonathan Cameron wrote: > On 31/03/17 12:45, Fabrice Gasnier wrote: >> STM32 DAC has built-in noise or triangle waveform generator. >> Waveform generator requires trigger to be configured. >> - "wave" extended attribute selects noise or triangle. >> - "mamp" extended attribute selects either LFSR (linear feedback >> shift register) mask for noise waveform, OR triangle amplitude. >> >> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> > > Looks like AN3126 is the relevant doc. > (a quick note from this relevant to earlier patches- doc says > 1-3 channels - perhaps build that from the start with that > possibility in mind). Hi Jonathan, Just to clarify this, some products like STM32F334xx have 3 channels, yes. Several STM32 DAC IPs (& so registers) are instantiated: DAC1 have two outputs (dac1_out1 & dac1_out2), DAC2 have one output (e.g. dac2_out1). Driver can be instantiated several times. Is it ok ? > > As you probably know, this wanders into a large chunk of 'poorly' > defined ABI within IIO as it stands. > > Note there are a number of waveform generators still in staging. > Not a lot of movement on getting them out of staging unfortunately > (so far!) > > However, let us keep those drivers in mind as we work on ABI and > I definitely want some input from someone at Analog. > Lars, who is best for this? I see at least some of these were > originally Michael's work. > > They do have partial docs under > drivers/staging/iio/Documentation/sysfs-bus-iio-dds > I'll highlight thoughts from there as I look through this... Thanks for pointing this out. > > >> --- >> Documentation/ABI/testing/sysfs-bus-iio-dac-stm32 | 32 ++++++ >> drivers/iio/dac/stm32-dac.c | 124 ++++++++++++++++++++++ >> 2 files changed, 156 insertions(+) >> create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-dac-stm32 >> >> diff --git a/Documentation/ABI/testing/sysfs-bus-iio-dac-stm32 b/Documentation/ABI/testing/sysfs-bus-iio-dac-stm32 >> new file mode 100644 >> index 0000000..c2432e1 >> --- /dev/null >> +++ b/Documentation/ABI/testing/sysfs-bus-iio-dac-stm32 >> @@ -0,0 +1,32 @@ >> +What: /sys/bus/iio/devices/iio:deviceX/wave >> +What: /sys/bus/iio/devices/iio:deviceX/wave_available > Needs to be channel associated. Whilst in your case you have basically > a pair of single channel devices, in more general case, it's not usual > to have multiple parallel waveform generators clocked together. > > Old ABI is: > What: /sys/bus/iio/devices/.../out_altvoltageX_outY_wavetype etc > I'll rework this in V2. > >> +KernelVersion: 4.12 >> +Contact: fabrice.gasnier@st.com >> +Description: >> + List and/or select waveform generation provided by STM32 DAC: >> + - "none": (default) means normal DAC operations > none kind of hints at nothing coming out. Perhaps 'flat' would be closer? > i.e. only changes when someone tells it to. > >> + - "noise": select noise waveform >> + - "triangle": select triangle waveform >> + Note: when waveform generator is used, writing _raw sysfs entry >> + adds a DC offset to generated waveform. Reading it reports >> + current output value. > Interesting. This gets fiddly but one option would be to describe the whole > device as a dds. > > Then we have flat type above, combined with an _offset. I'll update from 'none' to 'flat' in V2, and use _offset. > >> + >> +What: /sys/bus/iio/devices/iio:deviceX/mamp >> +What: /sys/bus/iio/devices/iio:deviceX/mamp_available >> +KernelVersion: 4.12 >> +Contact: fabrice.gasnier@st.com >> +Description: >> + List and select mask/amplitude used for noise/triangle waveform >> + generator, which are: >> + - "0": unmask bit 0 of LFSR / triangle amplitude equal to 1 >> + - "1": unmask bit [1:0] of LFSR / triangle amplitude equal to 3 >> + - "2": unmask bit [2:0] of LFSR / triangle amplitude equal to 7 >> + - "3": unmask bit [3:0] of LFSR / triangle amplitude equal to 15 >> + - "4": unmask bit [4:0] of LFSR / triangle amplitude equal to 31 >> + - "5": unmask bit [5:0] of LFSR / triangle amplitude equal to 63 >> + - "6": unmask bit [6:0] of LFSR / triangle amplitude equal to 127 >> + - "7": unmask bit [7:0] of LFSR / triangle amplitude equal to 255 >> + - "8": unmask bit [8:0] of LFSR / triangle amplitude equal to 511 >> + - "9": unmask bit [9:0] of LFSR / triangle amplitude equal to 1023 >> + - "10": unmask bit [10:0] of LFSR / triangle amplitude equal to 2047 >> + - "11": unmask bit [11:0] of LFSR / triangle amplitude equal to 4095 > I don't fully understand what is going on here - so I'm guessing somewhat. Sorry for this, this is basically amplitude. I think best is to rename above to something like 'amplitude' and 'amplitude_available'. I'll rework this in V2. > > > Let us try describing these generically. If we define standard 'forms' of each > waveform type. Say a 0 to 1 V peak to peak, then we could use _scale to control > this nicely. > >> diff --git a/drivers/iio/dac/stm32-dac.c b/drivers/iio/dac/stm32-dac.c >> index 62e43e9..d7dda78 100644 >> --- a/drivers/iio/dac/stm32-dac.c >> +++ b/drivers/iio/dac/stm32-dac.c >> @@ -41,10 +41,14 @@ >> /** >> * struct stm32_dac - private data of DAC driver >> * @common: reference to DAC common data >> + * @wave: waveform generator >> + * @mamp: waveform mask/amplitude >> * @swtrig: Using software trigger >> */ >> struct stm32_dac { >> struct stm32_dac_common *common; >> + u32 wave; >> + u32 mamp; >> bool swtrig; >> }; >> >> @@ -157,6 +161,24 @@ static int stm32_dac_is_enabled(struct stm32_dac *dac, int channel) >> return !!en; >> } >> >> +static int stm32_dac_wavegen(struct stm32_dac *dac, int channel) >> +{ >> + struct regmap *regmap = dac->common->regmap; >> + u32 mask, val; >> + >> + if (channel == STM32_DAC_CHANNEL_1) { >> + val = FIELD_PREP(STM32_DAC_CR_WAVE1, dac->wave) | >> + FIELD_PREP(STM32_DAC_CR_MAMP1, dac->mamp); >> + mask = STM32_DAC_CR_WAVE1 | STM32_DAC_CR_MAMP1; >> + } else { >> + val = FIELD_PREP(STM32_DAC_CR_WAVE2, dac->wave) | >> + FIELD_PREP(STM32_DAC_CR_MAMP2, dac->mamp); >> + mask = STM32_DAC_CR_WAVE2 | STM32_DAC_CR_MAMP2; >> + } >> + >> + return regmap_update_bits(regmap, STM32_DAC_CR, mask, val); >> +} >> + >> static int stm32_dac_enable(struct iio_dev *indio_dev, int channel) >> { >> struct stm32_dac *dac = iio_priv(indio_dev); >> @@ -164,6 +186,17 @@ static int stm32_dac_enable(struct iio_dev *indio_dev, int channel) >> STM32_DAC_CR_EN1 : STM32_DAC_CR_EN2; >> int ret; >> >> + if (dac->wave && !indio_dev->trig) { >> + dev_err(&indio_dev->dev, "Wavegen requires a trigger\n"); >> + return -EINVAL; >> + } >> + >> + ret = stm32_dac_wavegen(dac, channel); >> + if (ret < 0) { >> + dev_err(&indio_dev->dev, "Wavegen setup failed\n"); >> + return ret; >> + } >> + >> ret = stm32_dac_set_trig(dac, indio_dev->trig, channel); >> if (ret < 0) { >> dev_err(&indio_dev->dev, "Trigger setup failed\n"); >> @@ -291,6 +324,96 @@ static int stm32_dac_debugfs_reg_access(struct iio_dev *indio_dev, >> .driver_module = THIS_MODULE, >> }; >> >> +/* waveform generator wave selection */ >> +static const char * const stm32_dac_wave_desc[] = { >> + "none", >> + "noise", >> + "triangle", >> +}; >> + >> +static int stm32_dac_set_wave(struct iio_dev *indio_dev, >> + const struct iio_chan_spec *chan, >> + unsigned int type) >> +{ >> + struct stm32_dac *dac = iio_priv(indio_dev); >> + >> + if (stm32_dac_is_enabled(dac, chan->channel)) >> + return -EBUSY; >> + dac->wave = type; >> + >> + return 0; >> +} >> + >> +static int stm32_dac_get_wave(struct iio_dev *indio_dev, >> + const struct iio_chan_spec *chan) >> +{ >> + struct stm32_dac *dac = iio_priv(indio_dev); >> + >> + return dac->wave; >> +} >> + >> +static const struct iio_enum stm32_dac_wave_enum = { >> + .items = stm32_dac_wave_desc, >> + .num_items = ARRAY_SIZE(stm32_dac_wave_desc), >> + .get = stm32_dac_get_wave, >> + .set = stm32_dac_set_wave, >> +}; >> + >> +/* >> + * waveform generator mask/amplitude selection: >> + * - noise: LFSR mask (linear feedback shift register, umasks bit 0, [1:0]...) >> + * - triangle: amplitude (equal to 1, 3, 5, 7... 4095) >> + */ >> +static const char * const stm32_dac_mamp_desc[] = { >> + "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", >> +}; >> + >> +static int stm32_dac_set_mamp(struct iio_dev *indio_dev, >> + const struct iio_chan_spec *chan, >> + unsigned int type) >> +{ >> + struct stm32_dac *dac = iio_priv(indio_dev); >> + >> + if (stm32_dac_is_enabled(dac, chan->channel)) >> + return -EBUSY; >> + dac->mamp = type; >> + >> + return 0; >> +} >> + >> +static int stm32_dac_get_mamp(struct iio_dev *indio_dev, >> + const struct iio_chan_spec *chan) >> +{ >> + struct stm32_dac *dac = iio_priv(indio_dev); >> + >> + return dac->mamp; >> +} >> + >> +static const struct iio_enum stm32_dac_mamp_enum = { >> + .items = stm32_dac_mamp_desc, >> + .num_items = ARRAY_SIZE(stm32_dac_mamp_desc), >> + .get = stm32_dac_get_mamp, >> + .set = stm32_dac_set_mamp, >> +}; >> + >> +static const struct iio_chan_spec_ext_info stm32_dac_ext_info[] = { >> + IIO_ENUM("wave", IIO_SHARED_BY_ALL, &stm32_dac_wave_enum), >> + { >> + .name = "wave_available", >> + .shared = IIO_SHARED_BY_ALL, >> + .read = iio_enum_available_read, >> + .private = (uintptr_t)&stm32_dac_wave_enum, >> + }, >> + IIO_ENUM("mamp", IIO_SHARED_BY_ALL, &stm32_dac_mamp_enum), >> + { >> + .name = "mamp_available", >> + .shared = IIO_SHARED_BY_ALL, >> + .read = iio_enum_available_read, >> + .private = (uintptr_t)&stm32_dac_mamp_enum, >> + }, >> + {}, >> +}; >> + >> #define STM32_DAC_CHANNEL(chan, name) { \ >> .type = IIO_VOLTAGE, \ >> .indexed = 1, \ >> @@ -306,6 +429,7 @@ static int stm32_dac_debugfs_reg_access(struct iio_dev *indio_dev, >> .storagebits = 16, \ >> }, \ >> .datasheet_name = name, \ >> + .ext_info = stm32_dac_ext_info \ >> } >> >> static const struct iio_chan_spec stm32_dac_channels[] = { >> >
On 05/04/17 17:46, Fabrice Gasnier wrote: > JonathanOn 04/02/2017 02:19 PM, Jonathan Cameron wrote: >> On 31/03/17 12:45, Fabrice Gasnier wrote: >>> STM32 DAC has built-in noise or triangle waveform generator. >>> Waveform generator requires trigger to be configured. >>> - "wave" extended attribute selects noise or triangle. >>> - "mamp" extended attribute selects either LFSR (linear feedback >>> shift register) mask for noise waveform, OR triangle amplitude. >>> >>> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> >> >> Looks like AN3126 is the relevant doc. >> (a quick note from this relevant to earlier patches- doc says >> 1-3 channels - perhaps build that from the start with that >> possibility in mind). > Hi Jonathan, > > Just to clarify this, some products like STM32F334xx have 3 channels, > yes. Several STM32 DAC IPs (& so registers) are instantiated: DAC1 have > two outputs (dac1_out1 & dac1_out2), DAC2 have one output (e.g. > dac2_out1). Driver can be instantiated several times. Is it ok ? Sure - I'd missed the complex structure when reading the doc. > >> >> As you probably know, this wanders into a large chunk of 'poorly' >> defined ABI within IIO as it stands. >> >> Note there are a number of waveform generators still in staging. >> Not a lot of movement on getting them out of staging unfortunately >> (so far!) >> >> However, let us keep those drivers in mind as we work on ABI and >> I definitely want some input from someone at Analog. >> Lars, who is best for this? I see at least some of these were >> originally Michael's work. >> >> They do have partial docs under >> drivers/staging/iio/Documentation/sysfs-bus-iio-dds >> I'll highlight thoughts from there as I look through this... > > Thanks for pointing this out. > >> >> >>> --- >>> Documentation/ABI/testing/sysfs-bus-iio-dac-stm32 | 32 ++++++ >>> drivers/iio/dac/stm32-dac.c | 124 ++++++++++++++++++++++ >>> 2 files changed, 156 insertions(+) >>> create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-dac-stm32 >>> >>> diff --git a/Documentation/ABI/testing/sysfs-bus-iio-dac-stm32 b/Documentation/ABI/testing/sysfs-bus-iio-dac-stm32 >>> new file mode 100644 >>> index 0000000..c2432e1 >>> --- /dev/null >>> +++ b/Documentation/ABI/testing/sysfs-bus-iio-dac-stm32 >>> @@ -0,0 +1,32 @@ >>> +What: /sys/bus/iio/devices/iio:deviceX/wave >>> +What: /sys/bus/iio/devices/iio:deviceX/wave_available >> Needs to be channel associated. Whilst in your case you have basically >> a pair of single channel devices, in more general case, it's not usual >> to have multiple parallel waveform generators clocked together. >> >> Old ABI is: >> What: /sys/bus/iio/devices/.../out_altvoltageX_outY_wavetype etc >> > I'll rework this in V2. >> >>> +KernelVersion: 4.12 >>> +Contact: fabrice.gasnier@st.com >>> +Description: >>> + List and/or select waveform generation provided by STM32 DAC: >>> + - "none": (default) means normal DAC operations >> none kind of hints at nothing coming out. Perhaps 'flat' would be closer? >> i.e. only changes when someone tells it to. >> >>> + - "noise": select noise waveform >>> + - "triangle": select triangle waveform >>> + Note: when waveform generator is used, writing _raw sysfs entry >>> + adds a DC offset to generated waveform. Reading it reports >>> + current output value. >> Interesting. This gets fiddly but one option would be to describe the whole >> device as a dds. >> >> Then we have flat type above, combined with an _offset. > > I'll update from 'none' to 'flat' in V2, and use _offset. It's a bit ugly and doesn't generalize well to driving this via DMA for example... J >> >>> + >>> +What: /sys/bus/iio/devices/iio:deviceX/mamp >>> +What: /sys/bus/iio/devices/iio:deviceX/mamp_available >>> +KernelVersion: 4.12 >>> +Contact: fabrice.gasnier@st.com >>> +Description: >>> + List and select mask/amplitude used for noise/triangle waveform >>> + generator, which are: >>> + - "0": unmask bit 0 of LFSR / triangle amplitude equal to 1 >>> + - "1": unmask bit [1:0] of LFSR / triangle amplitude equal to 3 >>> + - "2": unmask bit [2:0] of LFSR / triangle amplitude equal to 7 >>> + - "3": unmask bit [3:0] of LFSR / triangle amplitude equal to 15 >>> + - "4": unmask bit [4:0] of LFSR / triangle amplitude equal to 31 >>> + - "5": unmask bit [5:0] of LFSR / triangle amplitude equal to 63 >>> + - "6": unmask bit [6:0] of LFSR / triangle amplitude equal to 127 >>> + - "7": unmask bit [7:0] of LFSR / triangle amplitude equal to 255 >>> + - "8": unmask bit [8:0] of LFSR / triangle amplitude equal to 511 >>> + - "9": unmask bit [9:0] of LFSR / triangle amplitude equal to 1023 >>> + - "10": unmask bit [10:0] of LFSR / triangle amplitude equal to 2047 >>> + - "11": unmask bit [11:0] of LFSR / triangle amplitude equal to 4095 >> I don't fully understand what is going on here - so I'm guessing somewhat. > Sorry for this, this is basically amplitude. > > I think best is to rename above to something like 'amplitude' and > 'amplitude_available'. > > I'll rework this in V2. >> >> >> Let us try describing these generically. If we define standard 'forms' of each >> waveform type. Say a 0 to 1 V peak to peak, then we could use _scale to control >> this nicely. >> >>> diff --git a/drivers/iio/dac/stm32-dac.c b/drivers/iio/dac/stm32-dac.c >>> index 62e43e9..d7dda78 100644 >>> --- a/drivers/iio/dac/stm32-dac.c >>> +++ b/drivers/iio/dac/stm32-dac.c >>> @@ -41,10 +41,14 @@ >>> /** >>> * struct stm32_dac - private data of DAC driver >>> * @common: reference to DAC common data >>> + * @wave: waveform generator >>> + * @mamp: waveform mask/amplitude >>> * @swtrig: Using software trigger >>> */ >>> struct stm32_dac { >>> struct stm32_dac_common *common; >>> + u32 wave; >>> + u32 mamp; >>> bool swtrig; >>> }; >>> >>> @@ -157,6 +161,24 @@ static int stm32_dac_is_enabled(struct stm32_dac *dac, int channel) >>> return !!en; >>> } >>> >>> +static int stm32_dac_wavegen(struct stm32_dac *dac, int channel) >>> +{ >>> + struct regmap *regmap = dac->common->regmap; >>> + u32 mask, val; >>> + >>> + if (channel == STM32_DAC_CHANNEL_1) { >>> + val = FIELD_PREP(STM32_DAC_CR_WAVE1, dac->wave) | >>> + FIELD_PREP(STM32_DAC_CR_MAMP1, dac->mamp); >>> + mask = STM32_DAC_CR_WAVE1 | STM32_DAC_CR_MAMP1; >>> + } else { >>> + val = FIELD_PREP(STM32_DAC_CR_WAVE2, dac->wave) | >>> + FIELD_PREP(STM32_DAC_CR_MAMP2, dac->mamp); >>> + mask = STM32_DAC_CR_WAVE2 | STM32_DAC_CR_MAMP2; >>> + } >>> + >>> + return regmap_update_bits(regmap, STM32_DAC_CR, mask, val); >>> +} >>> + >>> static int stm32_dac_enable(struct iio_dev *indio_dev, int channel) >>> { >>> struct stm32_dac *dac = iio_priv(indio_dev); >>> @@ -164,6 +186,17 @@ static int stm32_dac_enable(struct iio_dev *indio_dev, int channel) >>> STM32_DAC_CR_EN1 : STM32_DAC_CR_EN2; >>> int ret; >>> >>> + if (dac->wave && !indio_dev->trig) { >>> + dev_err(&indio_dev->dev, "Wavegen requires a trigger\n"); >>> + return -EINVAL; >>> + } >>> + >>> + ret = stm32_dac_wavegen(dac, channel); >>> + if (ret < 0) { >>> + dev_err(&indio_dev->dev, "Wavegen setup failed\n"); >>> + return ret; >>> + } >>> + >>> ret = stm32_dac_set_trig(dac, indio_dev->trig, channel); >>> if (ret < 0) { >>> dev_err(&indio_dev->dev, "Trigger setup failed\n"); >>> @@ -291,6 +324,96 @@ static int stm32_dac_debugfs_reg_access(struct iio_dev *indio_dev, >>> .driver_module = THIS_MODULE, >>> }; >>> >>> +/* waveform generator wave selection */ >>> +static const char * const stm32_dac_wave_desc[] = { >>> + "none", >>> + "noise", >>> + "triangle", >>> +}; >>> + >>> +static int stm32_dac_set_wave(struct iio_dev *indio_dev, >>> + const struct iio_chan_spec *chan, >>> + unsigned int type) >>> +{ >>> + struct stm32_dac *dac = iio_priv(indio_dev); >>> + >>> + if (stm32_dac_is_enabled(dac, chan->channel)) >>> + return -EBUSY; >>> + dac->wave = type; >>> + >>> + return 0; >>> +} >>> + >>> +static int stm32_dac_get_wave(struct iio_dev *indio_dev, >>> + const struct iio_chan_spec *chan) >>> +{ >>> + struct stm32_dac *dac = iio_priv(indio_dev); >>> + >>> + return dac->wave; >>> +} >>> + >>> +static const struct iio_enum stm32_dac_wave_enum = { >>> + .items = stm32_dac_wave_desc, >>> + .num_items = ARRAY_SIZE(stm32_dac_wave_desc), >>> + .get = stm32_dac_get_wave, >>> + .set = stm32_dac_set_wave, >>> +}; >>> + >>> +/* >>> + * waveform generator mask/amplitude selection: >>> + * - noise: LFSR mask (linear feedback shift register, umasks bit 0, [1:0]...) >>> + * - triangle: amplitude (equal to 1, 3, 5, 7... 4095) >>> + */ >>> +static const char * const stm32_dac_mamp_desc[] = { >>> + "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", >>> +}; >>> + >>> +static int stm32_dac_set_mamp(struct iio_dev *indio_dev, >>> + const struct iio_chan_spec *chan, >>> + unsigned int type) >>> +{ >>> + struct stm32_dac *dac = iio_priv(indio_dev); >>> + >>> + if (stm32_dac_is_enabled(dac, chan->channel)) >>> + return -EBUSY; >>> + dac->mamp = type; >>> + >>> + return 0; >>> +} >>> + >>> +static int stm32_dac_get_mamp(struct iio_dev *indio_dev, >>> + const struct iio_chan_spec *chan) >>> +{ >>> + struct stm32_dac *dac = iio_priv(indio_dev); >>> + >>> + return dac->mamp; >>> +} >>> + >>> +static const struct iio_enum stm32_dac_mamp_enum = { >>> + .items = stm32_dac_mamp_desc, >>> + .num_items = ARRAY_SIZE(stm32_dac_mamp_desc), >>> + .get = stm32_dac_get_mamp, >>> + .set = stm32_dac_set_mamp, >>> +}; >>> + >>> +static const struct iio_chan_spec_ext_info stm32_dac_ext_info[] = { >>> + IIO_ENUM("wave", IIO_SHARED_BY_ALL, &stm32_dac_wave_enum), >>> + { >>> + .name = "wave_available", >>> + .shared = IIO_SHARED_BY_ALL, >>> + .read = iio_enum_available_read, >>> + .private = (uintptr_t)&stm32_dac_wave_enum, >>> + }, >>> + IIO_ENUM("mamp", IIO_SHARED_BY_ALL, &stm32_dac_mamp_enum), >>> + { >>> + .name = "mamp_available", >>> + .shared = IIO_SHARED_BY_ALL, >>> + .read = iio_enum_available_read, >>> + .private = (uintptr_t)&stm32_dac_mamp_enum, >>> + }, >>> + {}, >>> +}; >>> + >>> #define STM32_DAC_CHANNEL(chan, name) { \ >>> .type = IIO_VOLTAGE, \ >>> .indexed = 1, \ >>> @@ -306,6 +429,7 @@ static int stm32_dac_debugfs_reg_access(struct iio_dev *indio_dev, >>> .storagebits = 16, \ >>> }, \ >>> .datasheet_name = name, \ >>> + .ext_info = stm32_dac_ext_info \ >>> } >>> >>> static const struct iio_chan_spec stm32_dac_channels[] = { >>> >> > -- > To unsubscribe from this list: send the line "unsubscribe linux-iio" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >
diff --git a/Documentation/ABI/testing/sysfs-bus-iio-dac-stm32 b/Documentation/ABI/testing/sysfs-bus-iio-dac-stm32 new file mode 100644 index 0000000..c2432e1 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-iio-dac-stm32 @@ -0,0 +1,32 @@ +What: /sys/bus/iio/devices/iio:deviceX/wave +What: /sys/bus/iio/devices/iio:deviceX/wave_available +KernelVersion: 4.12 +Contact: fabrice.gasnier@st.com +Description: + List and/or select waveform generation provided by STM32 DAC: + - "none": (default) means normal DAC operations + - "noise": select noise waveform + - "triangle": select triangle waveform + Note: when waveform generator is used, writing _raw sysfs entry + adds a DC offset to generated waveform. Reading it reports + current output value. + +What: /sys/bus/iio/devices/iio:deviceX/mamp +What: /sys/bus/iio/devices/iio:deviceX/mamp_available +KernelVersion: 4.12 +Contact: fabrice.gasnier@st.com +Description: + List and select mask/amplitude used for noise/triangle waveform + generator, which are: + - "0": unmask bit 0 of LFSR / triangle amplitude equal to 1 + - "1": unmask bit [1:0] of LFSR / triangle amplitude equal to 3 + - "2": unmask bit [2:0] of LFSR / triangle amplitude equal to 7 + - "3": unmask bit [3:0] of LFSR / triangle amplitude equal to 15 + - "4": unmask bit [4:0] of LFSR / triangle amplitude equal to 31 + - "5": unmask bit [5:0] of LFSR / triangle amplitude equal to 63 + - "6": unmask bit [6:0] of LFSR / triangle amplitude equal to 127 + - "7": unmask bit [7:0] of LFSR / triangle amplitude equal to 255 + - "8": unmask bit [8:0] of LFSR / triangle amplitude equal to 511 + - "9": unmask bit [9:0] of LFSR / triangle amplitude equal to 1023 + - "10": unmask bit [10:0] of LFSR / triangle amplitude equal to 2047 + - "11": unmask bit [11:0] of LFSR / triangle amplitude equal to 4095 diff --git a/drivers/iio/dac/stm32-dac.c b/drivers/iio/dac/stm32-dac.c index 62e43e9..d7dda78 100644 --- a/drivers/iio/dac/stm32-dac.c +++ b/drivers/iio/dac/stm32-dac.c @@ -41,10 +41,14 @@ /** * struct stm32_dac - private data of DAC driver * @common: reference to DAC common data + * @wave: waveform generator + * @mamp: waveform mask/amplitude * @swtrig: Using software trigger */ struct stm32_dac { struct stm32_dac_common *common; + u32 wave; + u32 mamp; bool swtrig; }; @@ -157,6 +161,24 @@ static int stm32_dac_is_enabled(struct stm32_dac *dac, int channel) return !!en; } +static int stm32_dac_wavegen(struct stm32_dac *dac, int channel) +{ + struct regmap *regmap = dac->common->regmap; + u32 mask, val; + + if (channel == STM32_DAC_CHANNEL_1) { + val = FIELD_PREP(STM32_DAC_CR_WAVE1, dac->wave) | + FIELD_PREP(STM32_DAC_CR_MAMP1, dac->mamp); + mask = STM32_DAC_CR_WAVE1 | STM32_DAC_CR_MAMP1; + } else { + val = FIELD_PREP(STM32_DAC_CR_WAVE2, dac->wave) | + FIELD_PREP(STM32_DAC_CR_MAMP2, dac->mamp); + mask = STM32_DAC_CR_WAVE2 | STM32_DAC_CR_MAMP2; + } + + return regmap_update_bits(regmap, STM32_DAC_CR, mask, val); +} + static int stm32_dac_enable(struct iio_dev *indio_dev, int channel) { struct stm32_dac *dac = iio_priv(indio_dev); @@ -164,6 +186,17 @@ static int stm32_dac_enable(struct iio_dev *indio_dev, int channel) STM32_DAC_CR_EN1 : STM32_DAC_CR_EN2; int ret; + if (dac->wave && !indio_dev->trig) { + dev_err(&indio_dev->dev, "Wavegen requires a trigger\n"); + return -EINVAL; + } + + ret = stm32_dac_wavegen(dac, channel); + if (ret < 0) { + dev_err(&indio_dev->dev, "Wavegen setup failed\n"); + return ret; + } + ret = stm32_dac_set_trig(dac, indio_dev->trig, channel); if (ret < 0) { dev_err(&indio_dev->dev, "Trigger setup failed\n"); @@ -291,6 +324,96 @@ static int stm32_dac_debugfs_reg_access(struct iio_dev *indio_dev, .driver_module = THIS_MODULE, }; +/* waveform generator wave selection */ +static const char * const stm32_dac_wave_desc[] = { + "none", + "noise", + "triangle", +}; + +static int stm32_dac_set_wave(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + unsigned int type) +{ + struct stm32_dac *dac = iio_priv(indio_dev); + + if (stm32_dac_is_enabled(dac, chan->channel)) + return -EBUSY; + dac->wave = type; + + return 0; +} + +static int stm32_dac_get_wave(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan) +{ + struct stm32_dac *dac = iio_priv(indio_dev); + + return dac->wave; +} + +static const struct iio_enum stm32_dac_wave_enum = { + .items = stm32_dac_wave_desc, + .num_items = ARRAY_SIZE(stm32_dac_wave_desc), + .get = stm32_dac_get_wave, + .set = stm32_dac_set_wave, +}; + +/* + * waveform generator mask/amplitude selection: + * - noise: LFSR mask (linear feedback shift register, umasks bit 0, [1:0]...) + * - triangle: amplitude (equal to 1, 3, 5, 7... 4095) + */ +static const char * const stm32_dac_mamp_desc[] = { + "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", +}; + +static int stm32_dac_set_mamp(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + unsigned int type) +{ + struct stm32_dac *dac = iio_priv(indio_dev); + + if (stm32_dac_is_enabled(dac, chan->channel)) + return -EBUSY; + dac->mamp = type; + + return 0; +} + +static int stm32_dac_get_mamp(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan) +{ + struct stm32_dac *dac = iio_priv(indio_dev); + + return dac->mamp; +} + +static const struct iio_enum stm32_dac_mamp_enum = { + .items = stm32_dac_mamp_desc, + .num_items = ARRAY_SIZE(stm32_dac_mamp_desc), + .get = stm32_dac_get_mamp, + .set = stm32_dac_set_mamp, +}; + +static const struct iio_chan_spec_ext_info stm32_dac_ext_info[] = { + IIO_ENUM("wave", IIO_SHARED_BY_ALL, &stm32_dac_wave_enum), + { + .name = "wave_available", + .shared = IIO_SHARED_BY_ALL, + .read = iio_enum_available_read, + .private = (uintptr_t)&stm32_dac_wave_enum, + }, + IIO_ENUM("mamp", IIO_SHARED_BY_ALL, &stm32_dac_mamp_enum), + { + .name = "mamp_available", + .shared = IIO_SHARED_BY_ALL, + .read = iio_enum_available_read, + .private = (uintptr_t)&stm32_dac_mamp_enum, + }, + {}, +}; + #define STM32_DAC_CHANNEL(chan, name) { \ .type = IIO_VOLTAGE, \ .indexed = 1, \ @@ -306,6 +429,7 @@ static int stm32_dac_debugfs_reg_access(struct iio_dev *indio_dev, .storagebits = 16, \ }, \ .datasheet_name = name, \ + .ext_info = stm32_dac_ext_info \ } static const struct iio_chan_spec stm32_dac_channels[] = {
STM32 DAC has built-in noise or triangle waveform generator. Waveform generator requires trigger to be configured. - "wave" extended attribute selects noise or triangle. - "mamp" extended attribute selects either LFSR (linear feedback shift register) mask for noise waveform, OR triangle amplitude. Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> --- Documentation/ABI/testing/sysfs-bus-iio-dac-stm32 | 32 ++++++ drivers/iio/dac/stm32-dac.c | 124 ++++++++++++++++++++++ 2 files changed, 156 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-dac-stm32