Re: [PATCH v9 4/8] iio: dac: adi-axi-dac: extend features

["Nuno Sá" <noname.nuno@gmail.com>]

On Tue, 2024-10-29 at 21:17 +0000, Jonathan Cameron wrote:
> On Tue, 29 Oct 2024 09:13:42 +0100
> Nuno Sá <noname.nuno@gmail.com> wrote:
> 
> > On Mon, 2024-10-28 at 22:45 +0100, Angelo Dureghello wrote:
> > > From: Angelo Dureghello <adureghello@baylibre.com>
> > > 
> > > Extend AXI-DAC backend with new features required to interface
> > > to the ad3552r DAC. Mainly, a new compatible string is added to
> > > support the ad3552r-axi DAC IP, very similar to the generic DAC
> > > IP but with some customizations to work with the ad3552r.
> > > 
> > > Then, a series of generic functions has been added to match with
> > > ad3552r needs. Function names has been kept generic as much as
> > > possible, to allow re-utilization from other frontend drivers.
> > > 
> > > Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
> > > ---  
> > 
> > Hi Angelo,
> > 
> > Small stuff that Jonathan might be able to change while applying... With that:
> > 
> > Reviewed-by: Nuno Sa <nuno.sa@analog.com>
> > 
> > >  drivers/iio/dac/adi-axi-dac.c | 256 +++++++++++++++++++++++++++++++++++++++--
> > > -
> > >  1 file changed, 242 insertions(+), 14 deletions(-)
> > > 
> > > diff --git a/drivers/iio/dac/adi-axi-dac.c b/drivers/iio/dac/adi-axi-dac.c
> > > index 04193a98616e..155d04ca2315 100644
> > > --- a/drivers/iio/dac/adi-axi-dac.c
> > > +++ b/drivers/iio/dac/adi-axi-dac.c
> > > @@ -46,9 +46,28 @@
> > >  #define AXI_DAC_CNTRL_1_REG			0x0044
> > >  #define   AXI_DAC_CNTRL_1_SYNC			BIT(0)
> > >  #define AXI_DAC_CNTRL_2_REG			0x0048
> > > +#define   AXI_DAC_CNTRL_2_SDR_DDR_N		BIT(16)
> > > +#define   AXI_DAC_CNTRL_2_SYMB_8B		BIT(14)
> > >  #define   ADI_DAC_CNTRL_2_R1_MODE		BIT(5)
> > > +#define   AXI_DAC_CNTRL_2_UNSIGNED_DATA		BIT(4)
> > > +#define AXI_DAC_STATUS_1_REG			0x0054
> > > +#define AXI_DAC_STATUS_2_REG			0x0058
> > >  #define AXI_DAC_DRP_STATUS_REG			0x0074
> > >  #define   AXI_DAC_DRP_STATUS_DRP_LOCKED		BIT(17)
> > > +#define AXI_DAC_CUSTOM_RD_REG			0x0080
> > > +#define AXI_DAC_CUSTOM_WR_REG			0x0084
> > > +#define   AXI_DAC_CUSTOM_WR_DATA_8		GENMASK(23, 16)
> > > +#define   AXI_DAC_CUSTOM_WR_DATA_16		GENMASK(23, 8)
> > > +#define AXI_DAC_UI_STATUS_REG			0x0088
> > > +#define   AXI_DAC_UI_STATUS_IF_BUSY		BIT(4)
> > > +#define AXI_DAC_CUSTOM_CTRL_REG			0x008C
> > > +#define   AXI_DAC_CUSTOM_CTRL_ADDRESS		GENMASK(31, 24)
> > > +#define   AXI_DAC_CUSTOM_CTRL_SYNCED_TRANSFER	BIT(2)
> > > +#define   AXI_DAC_CUSTOM_CTRL_STREAM		BIT(1)
> > > +#define   AXI_DAC_CUSTOM_CTRL_TRANSFER_DATA	BIT(0)
> > > +
> > > +#define
> > > AXI_DAC_CUSTOM_CTRL_STREAM_ENABLE	(AXI_DAC_CUSTOM_CTRL_TRANSFER_DATA | \
> > > +						 AXI_DAC_CUSTOM_CTRL_STREAM)
> > >  
> > >  /* DAC Channel controls */
> > >  #define AXI_DAC_CHAN_CNTRL_1_REG(c)		(0x0400 + (c) * 0x40)
> > > @@ -63,12 +82,21 @@
> > >  #define AXI_DAC_CHAN_CNTRL_7_REG(c)		(0x0418 + (c) * 0x40)
> > >  #define   AXI_DAC_CHAN_CNTRL_7_DATA_SEL		GENMASK(3, 0)
> > >  
> > > +#define AXI_DAC_RD_ADDR(x)			(BIT(7) | (x))
> > > +
> > >  /* 360 degrees in rad */
> > >  #define AXI_DAC_2_PI_MEGA			6283190
> > >  
> > >  enum {
> > >  	AXI_DAC_DATA_INTERNAL_TONE,
> > >  	AXI_DAC_DATA_DMA = 2,
> > > +	AXI_DAC_DATA_INTERNAL_RAMP_16BIT = 11,
> > > +};
> > > +
> > > +struct axi_dac_info {
> > > +	unsigned int version;
> > > +	const struct iio_backend_info *backend_info;
> > > +	bool has_dac_clk;
> > >  };
> > >  
> > >  struct axi_dac_state {
> > > @@ -79,9 +107,11 @@ struct axi_dac_state {
> > >  	 * data/variables.
> > >  	 */
> > >  	struct mutex lock;
> > > +	const struct axi_dac_info *info;
> > >  	u64 dac_clk;
> > >  	u32 reg_config;
> > >  	bool int_tone;
> > > +	int dac_clk_rate;
> > >  };
> > >  
> > >  static int axi_dac_enable(struct iio_backend *back)
> > > @@ -471,6 +501,11 @@ static int axi_dac_data_source_set(struct iio_backend
> > > *back, unsigned int chan,
> > >  					  AXI_DAC_CHAN_CNTRL_7_REG(chan),
> > >  					  AXI_DAC_CHAN_CNTRL_7_DATA_SEL,
> > >  					  AXI_DAC_DATA_DMA);
> > > +	case IIO_BACKEND_INTERNAL_RAMP_16BIT:
> > > +		return regmap_update_bits(st->regmap,
> > > +					  AXI_DAC_CHAN_CNTRL_7_REG(chan),
> > > +					  AXI_DAC_CHAN_CNTRL_7_DATA_SEL,
> > > +					  AXI_DAC_DATA_INTERNAL_RAMP_16BIT);
> > >  	default:
> > >  		return -EINVAL;
> > >  	}
> > > @@ -528,6 +563,154 @@ static int axi_dac_reg_access(struct iio_backend *back,
> > > unsigned int reg,
> > >  	return regmap_write(st->regmap, reg, writeval);
> > >  }
> > >  
> > > +static int axi_dac_ddr_enable(struct iio_backend *back)
> > > +{
> > > +	struct axi_dac_state *st = iio_backend_get_priv(back);
> > > +
> > > +	return regmap_clear_bits(st->regmap, AXI_DAC_CNTRL_2_REG,
> > > +				 AXI_DAC_CNTRL_2_SDR_DDR_N);
> > > +}
> > > +
> > > +static int axi_dac_ddr_disable(struct iio_backend *back)
> > > +{
> > > +	struct axi_dac_state *st = iio_backend_get_priv(back);
> > > +
> > > +	return regmap_set_bits(st->regmap, AXI_DAC_CNTRL_2_REG,
> > > +			       AXI_DAC_CNTRL_2_SDR_DDR_N);
> > > +}
> > > +
> > > +static int axi_dac_data_stream_enable(struct iio_backend *back)
> > > +{
> > > +	struct axi_dac_state *st = iio_backend_get_priv(back);
> > > +
> > > +	return regmap_set_bits(st->regmap, AXI_DAC_CUSTOM_CTRL_REG,
> > > +			       AXI_DAC_CUSTOM_CTRL_STREAM_ENABLE);
> > > +}
> > > +
> > > +static int axi_dac_data_stream_disable(struct iio_backend *back)
> > > +{
> > > +	struct axi_dac_state *st = iio_backend_get_priv(back);
> > > +
> > > +	return regmap_clear_bits(st->regmap, AXI_DAC_CUSTOM_CTRL_REG,
> > > +				 AXI_DAC_CUSTOM_CTRL_STREAM_ENABLE);
> > > +}
> > > +
> > > +static int axi_dac_data_transfer_addr(struct iio_backend *back, u32 address)
> > > +{
> > > +	struct axi_dac_state *st = iio_backend_get_priv(back);
> > > +
> > > +	if (address > FIELD_MAX(AXI_DAC_CUSTOM_CTRL_ADDRESS))
> > > +		return -EINVAL;
> > > +
> > > +	/*
> > > +	 * Sample register address, when the DAC is configured, or stream
> > > +	 * start address when the FSM is in stream state.
> > > +	 */
> > > +	return regmap_update_bits(st->regmap, AXI_DAC_CUSTOM_CTRL_REG,
> > > +				  AXI_DAC_CUSTOM_CTRL_ADDRESS,
> > > +				  FIELD_PREP(AXI_DAC_CUSTOM_CTRL_ADDRESS,
> > > +				  address));
> > > +}
> > > +
> > > +static int axi_dac_data_format_set(struct iio_backend *back, unsigned int ch,
> > > +				   const struct iio_backend_data_fmt *data)
> > > +{
> > > +	struct axi_dac_state *st = iio_backend_get_priv(back);
> > > +
> > > +	switch (data->type) {
> > > +	case IIO_BACKEND_DATA_UNSIGNED:
> > > +		return regmap_clear_bits(st->regmap, AXI_DAC_CNTRL_2_REG,
> > > +					 AXI_DAC_CNTRL_2_UNSIGNED_DATA);
> > > +	default:
> > > +		return -EINVAL;
> > > +	}
> > > +}
> > > +
> > > +static int axi_dac_bus_reg_write_locked(struct iio_backend *back, u32 reg,
> > > +					u32 val, size_t data_size)  
> > 
> > nit: this is actually unlocked and needs to be locked from the outside. So,
> > unlocked could be a better suffix. But more importantly is the extra call to
> > iio_backend_get_priv(). We can just pass *st directly from the outer function.
> 
> This naming always gets confusing. Are we naming the state, or what happens?
> 
> A lockdep marking just inside the function can be used to make it obvious
> or the old __ prefix to say 'special, check the rules'.
> 


Yeah, personally I would prefer the __ prefix...

- Nuno Sá