Date:   Sun, 25 Aug 2019 16:14:38 +0100
From:   Jonathan Cameron <jic23@...nel.org>
To:     Beniamin Bia <beniamin.bia@...log.com>
Cc:     <lars@...afoo.de>, <Michael.Hennerich@...log.com>,
        <knaack.h@....de>, <pmeerw@...erw.net>,
        <gregkh@...uxfoundation.org>, <linux-iio@...r.kernel.org>,
        <devel@...verdev.osuosl.org>, <linux-kernel@...r.kernel.org>,
        <mark.rutland@....com>, <robh+dt@...nel.org>,
        <devicetree@...r.kernel.org>, <paulmck@...ux.ibm.com>,
        <mchehab+samsung@...nel.org>, <linus.walleij@...aro.org>,
        <nicolas.ferre@...rochip.com>, <biabeniamin@...look.com>,
        Stefan Popa <stefan.popa@...log.com>
Subject: Re: [PATCH v3 1/4] iio: adc: ad7606: Add support for AD7606B ADC

On Wed, 21 Aug 2019 17:16:53 +0300
Beniamin Bia <beniamin.bia@...log.com> wrote:

> From: Stefan Popa <stefan.popa@...log.com>
> 
> 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@...log.com>
> Co-developed-by: Beniamin Bia <beniamin.bia@...log.com>
> Signed-off-by: Beniamin Bia <beniamin.bia@...log.com>

Applied to the togreg branch of iio.git and pushed out as testing for
the autobuilders to play with it.

Thanks,

Jonathan


> ---
> Changes in v3:
> -comments reworked
> -isWriteOp renamed to is_write_op
> 
>  drivers/iio/adc/ad7606.c     |  13 ++++-
>  drivers/iio/adc/ad7606.h     |   4 ++
>  drivers/iio/adc/ad7606_spi.c | 109 ++++++++++++++++++++++++++++++++++-
>  3 files changed, 123 insertions(+), 3 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
> + *			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..29945ad07dca 100644
> --- a/drivers/iio/adc/ad7606_spi.c
> +++ b/drivers/iio/adc/ad7606_spi.c
> @@ -28,9 +28,23 @@
>   * an offset of 2 for register address.
>   */
>  #define AD7616_RANGE_CH_ADDR(ch)	((ch) >> 2)
> -/* The range of the channel is stored on 2 bits*/
> +/* The range of the channel is stored in 2 bits */
>  #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		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[] = {
> +	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 is_write_op)
> +{
> +	/*
> +	 * The address of register consists of one bit which
> +	 * specifies a read command placed in bit 6, followed by
> +	 * 6 bits of address.
> +	 */
> +	return (addr & 0x3F) | (((~is_write_op) & 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" },
>  	{ },
>  };

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