Re: [PATCH v2 1/4] iio: adc: ad7606: Add support for AD7606B ADC

[Jonathan Cameron <jonathan.cameron@huawei.com>]

On Wed, 7 Aug 2019 18:41:40 +0200
Peter Meerwald-Stadler <pmeerw@pmeerw.net> wrote:

> On Wed, 7 Aug 2019, Beniamin Bia wrote:
> 
> > From: Stefan Popa <stefan.popa@analog.com>  
> 
> please see some minor comments below
> 
> > The AD7606B is a 16-bit ADC that supports simultaneous sampling of 8
> > channels. It is pin compatible to AD7606, but adds extra modes by
> > writing to the register map.
> > 
> > The AD7606B can be configured to work in software mode by setting all
> > oversampling pins to high. This mode is selected by default.
> > The oversampling ratio is configured from the OS_MODE register (address
> > 0x08) with the addition of OS=128 and OS=256 that were not available in
> > hardware mode.
> > 
> > The device is configured to output data on a single spi channel, but this
> > configuration must be done right after restart. That is why the delay was
> > removed for devices which doesn't require it.
> > 
> > Moreover, in software mode, the range gpio has no longer its function.
> > Instead, the scale can be configured individually for each channel from
> > the RANGE_CH registers (address 0x03 to 0x06). Besides the already
> > supported ±10 V and ±5 V ranges, software mode can also accommodate the
> > ±2.5 V range.
> > 
> > Signed-off-by: Stefan Popa <stefan.popa@analog.com>
> > Co-developed-by: Beniamin Bia <beniamin.bia@analog.com>
> > Signed-off-by: Beniamin Bia <beniamin.bia@analog.com>
> > Acked-by: Jonathan Cameron <jic23@kernel.org>
> > ---
> > Changes in v2:
> > -nothing changed
> > 
> >  drivers/iio/adc/ad7606.c     |  13 ++++-
> >  drivers/iio/adc/ad7606.h     |   4 ++
> >  drivers/iio/adc/ad7606_spi.c | 107 +++++++++++++++++++++++++++++++++++
> >  3 files changed, 122 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/iio/adc/ad7606.c b/drivers/iio/adc/ad7606.c
> > index ed2d08437e5d..f5ba94c03a8d 100644
> > --- a/drivers/iio/adc/ad7606.c
> > +++ b/drivers/iio/adc/ad7606.c
> > @@ -410,12 +410,19 @@ static const struct ad7606_chip_info ad7606_chip_info_tbl[] = {
> >  		.oversampling_avail = ad7606_oversampling_avail,
> >  		.oversampling_num = ARRAY_SIZE(ad7606_oversampling_avail),
> >  	},
> > +	[ID_AD7606B] = {
> > +		.channels = ad7606_channels,
> > +		.num_channels = 9,
> > +		.oversampling_avail = ad7606_oversampling_avail,
> > +		.oversampling_num = ARRAY_SIZE(ad7606_oversampling_avail),
> > +	},
> >  	[ID_AD7616] = {
> >  		.channels = ad7616_channels,
> >  		.num_channels = 17,
> >  		.oversampling_avail = ad7616_oversampling_avail,
> >  		.oversampling_num = ARRAY_SIZE(ad7616_oversampling_avail),
> >  		.os_req_reset = true,
> > +		.init_delay_ms = 15,
> >  	},
> >  };
> >  
> > @@ -631,8 +638,10 @@ int ad7606_probe(struct device *dev, int irq, void __iomem *base_address,
> >  		dev_warn(st->dev, "failed to RESET: no RESET GPIO specified\n");
> >  
> >  	/* AD7616 requires al least 15ms to reconfigure after a reset */
> > -	if (msleep_interruptible(15))
> > -		return -ERESTARTSYS;
> > +	if (st->chip_info->init_delay_ms) {
> > +		if (msleep_interruptible(st->chip_info->init_delay_ms))
> > +			return -ERESTARTSYS;
> > +	}
> >  
> >  	st->write_scale = ad7606_write_scale_hw;
> >  	st->write_os = ad7606_write_os_hw;
> > diff --git a/drivers/iio/adc/ad7606.h b/drivers/iio/adc/ad7606.h
> > index eeaaa8b905db..9350ef1f63b5 100644
> > --- a/drivers/iio/adc/ad7606.h
> > +++ b/drivers/iio/adc/ad7606.h
> > @@ -46,6 +46,8 @@
> >   *			oversampling ratios.
> >   * @oversampling_num	number of elements stored in oversampling_avail array
> >   * @os_req_reset	some devices require a reset to update oversampling
> > + * @init_delay_ms	required delay in miliseconds for initialization  
> 
> mil_l_iseconds
> 
> > + *			after a restart
> >   */
> >  struct ad7606_chip_info {
> >  	const struct iio_chan_spec	*channels;
> > @@ -53,6 +55,7 @@ struct ad7606_chip_info {
> >  	const unsigned int		*oversampling_avail;
> >  	unsigned int			oversampling_num;
> >  	bool				os_req_reset;
> > +	unsigned long			init_delay_ms;
> >  };
> >  
> >  /**
> > @@ -155,6 +158,7 @@ enum ad7606_supported_device_ids {
> >  	ID_AD7606_8,
> >  	ID_AD7606_6,
> >  	ID_AD7606_4,
> > +	ID_AD7606B,
> >  	ID_AD7616,
> >  };
> >  
> > diff --git a/drivers/iio/adc/ad7606_spi.c b/drivers/iio/adc/ad7606_spi.c
> > index 98ed52b74507..070ee7e31e2c 100644
> > --- a/drivers/iio/adc/ad7606_spi.c
> > +++ b/drivers/iio/adc/ad7606_spi.c
> > @@ -31,6 +31,20 @@
> >  /* The range of the channel is stored on 2 bits*/  
> 
> space before */
> maybe: 'in' instead of 'on'
> 
> >  #define AD7616_RANGE_CH_MSK(ch)		(0b11 << (((ch) & 0b11) * 2))
> >  #define AD7616_RANGE_CH_MODE(ch, mode)	((mode) << ((((ch) & 0b11)) * 2))
> > +
> > +#define AD7606_CONFIGURATION_REGISTER	0x02
> > +#define AD7606_SINGLE_DOUT		0x0  
> 
> maybe 0x00?
> 
> > +
> > +/*
> > + * Range for AD7606B channels are stored in registers starting with address 0x3.
> > + * Each register stores range for 2 channels(4 bits per channel).
> > + */
> > +#define AD7606_RANGE_CH_MSK(ch)		(GENMASK(3, 0) << (4 * ((ch) & 0x1)))
> > +#define AD7606_RANGE_CH_MODE(ch, mode)	\
> > +	((GENMASK(3, 0) & mode) << (4 * ((ch) & 0x1)))
> > +#define AD7606_RANGE_CH_ADDR(ch)	(0x03 + ((ch) >> 1))
> > +#define AD7606_OS_MODE			0x08
> > +
> >  static const struct iio_chan_spec ad7616_sw_channels[] = {
> >  	IIO_CHAN_SOFT_TIMESTAMP(16),
> >  	AD7616_CHANNEL(0),
> > @@ -51,6 +65,22 @@ static const struct iio_chan_spec ad7616_sw_channels[] = {
> >  	AD7616_CHANNEL(15),
> >  };
> >  
> > +static const struct iio_chan_spec ad7606B_sw_channels[] = {  
> 
> I find it strange to uppercase the B (but not ad)
> 
> > +	IIO_CHAN_SOFT_TIMESTAMP(8),
> > +	AD7616_CHANNEL(0),
> > +	AD7616_CHANNEL(1),
> > +	AD7616_CHANNEL(2),
> > +	AD7616_CHANNEL(3),
> > +	AD7616_CHANNEL(4),
> > +	AD7616_CHANNEL(5),
> > +	AD7616_CHANNEL(6),
> > +	AD7616_CHANNEL(7),
> > +};
> > +
> > +static const unsigned int ad7606B_oversampling_avail[9] = {
> > +	1, 2, 4, 8, 16, 32, 64, 128, 256
> > +};
> > +
> >  static u16 ad7616_spi_rd_wr_cmd(int addr, char isWriteOp)
> >  {
> >  	/*
> > @@ -60,6 +90,16 @@ static u16 ad7616_spi_rd_wr_cmd(int addr, char isWriteOp)
> >  	return ((addr & 0x7F) << 1) | ((isWriteOp & 0x1) << 7);
> >  }
> >  
> > +static u16 ad7606B_spi_rd_wr_cmd(int addr, char isWriteOp)  
> 
> bool isWriteOp?
Also not camelCase please.

is_write_op

> 
> > +{
> > +	/*
> > +	 * The address of register consists of one bit which
> > +	 * specifies a read command placed bit 6, followed by  
> 
> placed _in_ bit 6
> 
> > +	 * 6 bits of address.
> > +	 */
> > +	return (addr & 0x3F) | (((~isWriteOp) & 0x1) << 6);
> > +}
> > +
> >  static int ad7606_spi_read_block(struct device *dev,
> >  				 int count, void *buf)
> >  {
> > @@ -169,6 +209,23 @@ static int ad7616_write_os_sw(struct iio_dev *indio_dev, int val)
> >  				     AD7616_OS_MASK, val << 2);
> >  }
> >  
> > +static int ad7606_write_scale_sw(struct iio_dev *indio_dev, int ch, int val)
> > +{
> > +	struct ad7606_state *st = iio_priv(indio_dev);
> > +
> > +	return ad7606_spi_write_mask(st,
> > +				     AD7606_RANGE_CH_ADDR(ch),
> > +				     AD7606_RANGE_CH_MSK(ch),
> > +				     AD7606_RANGE_CH_MODE(ch, val));
> > +}
> > +
> > +static int ad7606_write_os_sw(struct iio_dev *indio_dev, int val)
> > +{
> > +	struct ad7606_state *st = iio_priv(indio_dev);
> > +
> > +	return ad7606_spi_reg_write(st, AD7606_OS_MODE, val);
> > +}
> > +
> >  static int ad7616_sw_mode_config(struct iio_dev *indio_dev)
> >  {
> >  	struct ad7606_state *st = iio_priv(indio_dev);
> > @@ -189,6 +246,42 @@ static int ad7616_sw_mode_config(struct iio_dev *indio_dev)
> >  			      AD7616_BURST_MODE | AD7616_SEQEN_MODE);
> >  }
> >  
> > +static int ad7606B_sw_mode_config(struct iio_dev *indio_dev)
> > +{
> > +	struct ad7606_state *st = iio_priv(indio_dev);
> > +	unsigned long os[3] = {1};
> > +
> > +	/*
> > +	 * Software mode is enabled when all three oversampling
> > +	 * pins are set to high. If oversampling gpios are defined
> > +	 * in the device tree, then they need to be set to high,
> > +	 * otherwise, they must be hardwired to VDD
> > +	 */
> > +	if (st->gpio_os) {
> > +		gpiod_set_array_value(ARRAY_SIZE(os),
> > +				      st->gpio_os->desc, st->gpio_os->info, os);
> > +	}
> > +	/* OS of 128 and 256 are available only in software mode */
> > +	st->oversampling_avail = ad7606B_oversampling_avail;
> > +	st->num_os_ratios = ARRAY_SIZE(ad7606B_oversampling_avail);
> > +
> > +	st->write_scale = ad7606_write_scale_sw;
> > +	st->write_os = &ad7606_write_os_sw;
> > +
> > +	/* Configure device spi to output on a single channel */
> > +	st->bops->reg_write(st,
> > +			    AD7606_CONFIGURATION_REGISTER,
> > +			    AD7606_SINGLE_DOUT);
> > +
> > +	/*
> > +	 * Scale can be configured individually for each channel
> > +	 * in software mode.
> > +	 */
> > +	indio_dev->channels = ad7606B_sw_channels;
> > +
> > +	return 0;
> > +}
> > +
> >  static const struct ad7606_bus_ops ad7606_spi_bops = {
> >  	.read_block = ad7606_spi_read_block,
> >  };
> > @@ -202,6 +295,15 @@ static const struct ad7606_bus_ops ad7616_spi_bops = {
> >  	.sw_mode_config = ad7616_sw_mode_config,
> >  };
> >  
> > +static const struct ad7606_bus_ops ad7606B_spi_bops = {
> > +	.read_block = ad7606_spi_read_block,
> > +	.reg_read = ad7606_spi_reg_read,
> > +	.reg_write = ad7606_spi_reg_write,
> > +	.write_mask = ad7606_spi_write_mask,
> > +	.rd_wr_cmd = ad7606B_spi_rd_wr_cmd,
> > +	.sw_mode_config = ad7606B_sw_mode_config,
> > +};
> > +
> >  static int ad7606_spi_probe(struct spi_device *spi)
> >  {
> >  	const struct spi_device_id *id = spi_get_device_id(spi);
> > @@ -211,6 +313,9 @@ static int ad7606_spi_probe(struct spi_device *spi)
> >  	case ID_AD7616:
> >  		bops = &ad7616_spi_bops;
> >  		break;
> > +	case ID_AD7606B:
> > +		bops = &ad7606B_spi_bops;
> > +		break;
> >  	default:
> >  		bops = &ad7606_spi_bops;
> >  		break;
> > @@ -226,6 +331,7 @@ static const struct spi_device_id ad7606_id_table[] = {
> >  	{ "ad7606-4", ID_AD7606_4 },
> >  	{ "ad7606-6", ID_AD7606_6 },
> >  	{ "ad7606-8", ID_AD7606_8 },
> > +	{ "ad7606b",  ID_AD7606B },
> >  	{ "ad7616",   ID_AD7616 },
> >  	{}
> >  };
> > @@ -236,6 +342,7 @@ static const struct of_device_id ad7606_of_match[] = {
> >  	{ .compatible = "adi,ad7606-4" },
> >  	{ .compatible = "adi,ad7606-6" },
> >  	{ .compatible = "adi,ad7606-8" },
> > +	{ .compatible = "adi,ad7606b" },
> >  	{ .compatible = "adi,ad7616" },
> >  	{ },
> >  };
> >   
>