Message-ID: <f8478361c8166ac27f539bb1eceac050ab0908ec.camel@analog.com>
Date:   Mon, 9 Mar 2020 15:15:53 +0000
From:   "Ardelean, Alexandru" <alexandru.Ardelean@...log.com>
To:     "jic23@...nel.org" <jic23@...nel.org>
CC:     "Hennerich, Michael" <Michael.Hennerich@...log.com>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-iio@...r.kernel.org" <linux-iio@...r.kernel.org>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "lars@...afoo.de" <lars@...afoo.de>
Subject: Re: [PATCH v8 5/8] iio: adc: adi-axi-adc: add support for AXI ADC IP
 core

On Mon, 2020-03-09 at 11:34 +0000, Ardelean, Alexandru wrote:
> [External]
> 
> On Sat, 2020-03-07 at 14:54 +0000, Jonathan Cameron wrote:
> > [External]
> > 
> > On Fri, 6 Mar 2020 13:00:57 +0200
> > Alexandru Ardelean <alexandru.ardelean@...log.com> wrote:
> > 
> > > From: Michael Hennerich <michael.hennerich@...log.com>
> > > 
> > > This change adds support for the Analog Devices Generic AXI ADC IP core.
> > > The IP core is used for interfacing with analog-to-digital (ADC)
> > > converters
> > > that require either a high-speed serial interface (JESD204B/C) or a source
> > > synchronous parallel interface (LVDS/CMOS).
> > > 
> > > Usually, some other interface type (i.e SPI) is used as a control
> > > interface
> > > for the actual ADC, while the IP core (controlled via this driver), will
> > > interface to the data-lines of the ADC and handle  the streaming of data
> > > into memory via DMA.
> > > 
> > > Because of this, the AXI ADC driver needs the other SPI-ADC driver to
> > > register with it. The SPI-ADC needs to be register via the SPI framework,
> > > while the AXI ADC registers as a platform driver. The two cannot be
> > > ordered
> > > in a hierarchy as both drivers have their own registers, and trying to
> > > organize this [in a hierarchy becomes] problematic when trying to map
> > > memory/registers.
> > > 
> > > There are some modes where the AXI ADC can operate as standalone ADC, but
> > > those will be implemented at a later point in time.
> > > 
> > > Link: https://wiki.analog.com/resources/fpga/docs/axi_adc_ip
> > > 
> > > Signed-off-by: Michael Hennerich <michael.hennerich@...log.com>
> > > Signed-off-by: Lars-Peter Clausen <lars@...afoo.de>
> > > Signed-off-by: Alexandru Ardelean <alexandru.ardelean@...log.com>
> > Mostly looks fine, but a few nitpicks from rereading it.
> > 
> > Thanks,
> > 
> > Jonathan
> > 
> > > ---
> > >  drivers/iio/adc/Kconfig             |  20 +
> > >  drivers/iio/adc/Makefile            |   1 +
> > >  drivers/iio/adc/adi-axi-adc.c       | 618 ++++++++++++++++++++++++++++
> > >  include/linux/iio/adc/adi-axi-adc.h |  63 +++
> > >  4 files changed, 702 insertions(+)
> > >  create mode 100644 drivers/iio/adc/adi-axi-adc.c
> > >  create mode 100644 include/linux/iio/adc/adi-axi-adc.h
> > > 
> > > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> > > index f4da821c4022..445070abf376 100644
> > > --- a/drivers/iio/adc/Kconfig
> > > +++ b/drivers/iio/adc/Kconfig
> > > @@ -246,6 +246,26 @@ config AD799X
> > >  	  To compile this driver as a module, choose M here: the module will be
> > >  	  called ad799x.
> > >  
> > > +config ADI_AXI_ADC
> > > +	tristate "Analog Devices Generic AXI ADC IP core driver"
> > > +	select IIO_BUFFER
> > > +	select IIO_BUFFER_HW_CONSUMER
> > > +	select IIO_BUFFER_DMAENGINE
> > > +	help
> > > +	  Say yes here to build support for Analog Devices Generic
> > > +	  AXI ADC IP core. The IP core is used for interfacing with
> > > +	  analog-to-digital (ADC) converters that require either a high-speed
> > > +	  serial interface (JESD204B/C) or a source synchronous parallel
> > > +	  interface (LVDS/CMOS).
> > > +	  Typically (for such devices) SPI will be used for configuration only,
> > > +	  while this IP core handles the streaming of data into memory via DMA.
> > > +
> > > +	  Link: https://wiki.analog.com/resources/fpga/docs/axi_adc_ip
> > > +	  If unsure, say N (but it's safe to say "Y").
> > > +
> > > +	  To compile this driver as a module, choose M here: the
> > > +	  module will be called adi-axi-adc.
> > > +
> > >  config ASPEED_ADC
> > >  	tristate "Aspeed ADC"
> > >  	depends on ARCH_ASPEED || COMPILE_TEST
> > > diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> > > index 8462455b4228..7c6594d049f9 100644
> > > --- a/drivers/iio/adc/Makefile
> > > +++ b/drivers/iio/adc/Makefile
> > > @@ -26,6 +26,7 @@ obj-$(CONFIG_AD7793) += ad7793.o
> > >  obj-$(CONFIG_AD7887) += ad7887.o
> > >  obj-$(CONFIG_AD7949) += ad7949.o
> > >  obj-$(CONFIG_AD799X) += ad799x.o
> > > +obj-$(CONFIG_ADI_AXI_ADC) += adi-axi-adc.o
> > >  obj-$(CONFIG_ASPEED_ADC) += aspeed_adc.o
> > >  obj-$(CONFIG_AT91_ADC) += at91_adc.o
> > >  obj-$(CONFIG_AT91_SAMA5D2_ADC) += at91-sama5d2_adc.o
> > > diff --git a/drivers/iio/adc/adi-axi-adc.c b/drivers/iio/adc/adi-axi-adc.c
> > > new file mode 100644
> > > index 000000000000..17ee20015d71
> > > --- /dev/null
> > > +++ b/drivers/iio/adc/adi-axi-adc.c
> > > @@ -0,0 +1,618 @@
> > > +// SPDX-License-Identifier: GPL-2.0-only
> > > +/*
> > > + * Analog Devices Generic AXI ADC IP core
> > > + * Link: https://wiki.analog.com/resources/fpga/docs/axi_adc_ip
> > > + *
> > > + * Copyright 2012-2020 Analog Devices Inc.
> > > + */
> > > +
> > > +#include <linux/bitfield.h>
> > > +#include <linux/clk.h>
> > > +#include <linux/io.h>
> > > +#include <linux/delay.h>
> > > +#include <linux/module.h>
> > > +#include <linux/platform_device.h>
> > > +#include <linux/slab.h>
> > > +
> > > +#include <linux/iio/iio.h>
> > > +#include <linux/iio/sysfs.h>
> > > +#include <linux/iio/buffer.h>
> > > +#include <linux/iio/buffer-dmaengine.h>
> > > +
> > > +#include <linux/fpga/adi-axi-common.h>
> > > +#include <linux/iio/adc/adi-axi-adc.h>
> > > +
> > > +/**
> > > + * Register definitions:
> > > + *   https://wiki.analog.com/resources/fpga/docs/axi_adc_ip#register_map
> > > + */
> > > +
> > > +#define LOWER5_MSK			GENMASK(4, 0)
> > > +#define LOWER5_SET(x)			FIELD_PREP(LOWER5_MSK, x)
> > > +#define LOWER5_GET(x)			FIELD_GET(LOWER5_MSK, x)
> > 
> > Whilst it may cause more repetition, I'd rather just see these used where
> > relevant inline.  That will be slightly easier to review.
> 
> ack
> i wasn't too decided on whether these need to be defined yet
> 
> > > +
> > > +#define LOWER8_MSK			GENMASK(7, 0)
> > > +#define LOWER8_SET(x)			FIELD_PREP(LOWER8_MSK, x)
> > > +#define LOWER8_GET(x)			FIELD_GET(LOWER8_MSK, x)
> > > +
> > > +#define UPPER16_MSK			GENMASK(31, 16)
> > > +#define UPPER16_SET(x)			FIELD_PREP(UPPER16_MSK, x)
> > > +#define UPPER16_GET(x)			FIELD_GET(UPPER16_MSK, x)
> > > +
> > > +#define LOWER16_MSK			GENMASK(15, 0)
> > > +#define LOWER16_SET(x)			FIELD_PREP(LOWER16_MSK, x)
> > > +#define LOWER16_GET(x)			FIELD_GET(LOWER16_MSK, x)
> > > +
> > > +/* ADC controls */
> > > +
> > > +#define REG_RSTN				0x0040
> > 
> > Usual stuff: These should be prefixed with driver relevant prefix
> > maybe ADI_AXI_
> 
> my only concern [about the prefix] is that it makes the macro-names too long;
> after re-looking at these reg definitions, what bothered me is that some of
> the
> bit-field-names collide; so i went with concatenanting reg-names + reg-
> bitnames, 
> which made them look too long [so i removed the prefix]
> 
> there's also the possibility of going back to the regmap-doc and shortening
> these reg-name/bitnames;
> but they've been like this for a while, and i admit going to the HDL team
> makes
> me sometimes lazy;
> 
> i'll re-add teh ADI_AXI prefix; and will see how these look

i talked to HDL
so, we'll have a round of renaming these [in the docs];

but now, i'm wondering if it's ok to drop the regs that are [currently] unused
and add them when functionality gets later-added;
in the meantime, the names can be re-worked/shortened/prettify-ed;
we'll also need to re-do an inventory of the current HDL IP cores and see how
the regmaps hold-up/match against the docs;

> 
> > > +#define   REG_RSTN_CE_N				BIT(2)
> > > +#define   REG_RSTN_MMCM_RSTN			BIT(1)
> > > +#define   REG_RSTN_RSTN				BIT(0)
> > > +
> > > +#define REG_CNTRL				0x0044
> > > +#define   REG_CNTRL_SYNC			BIT(3)
> > > +#define   REG_CNTRL_R1_MODE			BIT(2)
> > > +#define   REG_CNTRL_DDR_EDGESEL			BIT(1)
> > > +#define   REG_CNTRL_PIN_MODE			BIT(0)
> > > +
> > > +#define REG_CLK_FREQ				0x0054
> > > +#define REG_CLK_RATIO				0x0058
> > > +
> > > +#define REG_STATUS				0x005C
> > > +#define   REG_STATUS_PN_ERR			BIT(3)
> > > +#define   REG_STATUS_PN_OOS			BIT(2)
> > > +#define   REG_STATUS_OVER_RANGE			BIT(1)
> > > +#define   REG_STATUS_STATUS			BIT(0)
> > > +
> > > +#define REG_SYNC_STATUS				0x0068
> > > +#define   REG_SYNC_STATUS_SYNC			BIT(0)
> > > +
> > > +#define REG_DRP_CNTRL				0x0070
> > > +#define   REG_DRP_CNTRL_DRP_RWN			BIT(28)
> > > +#define   REG_DRP_CNTRL_DRP_ADDRESS_MSK		GENMASK(27, 16)
> > > +#define   REG_DRP_CNTRL_DRP_ADDRESS_SET(x)	\
> > > +		FIELD_PREP(REG_DRP_CNTRL_DRP_ADDRESS_MSK, x)
> > > +#define   REG_DRP_CNTRL_DRP_ADDRESS_GET(x)	\
> > > +		FIELD_GET(REG_DRP_CNTRL_DRP_ADDRESS_MSK, x)
> > > +
> > > +#define REG_DRP_STATUS				0x0074
> > > +#define   REG_DRP_STATUS_DRP_LOCKED		BIT(17)
> > > +#define   REG_DRP_STATUS_DRP_STATUS		BIT(16)
> > > +
> > > +#define REG_DRP_WDATA				0x0078
> > > +#define   REG_DRP_WDATA_SET			LOWER16_SET
> > > +#define   REG_DRP_WDATA_GET			LOWER16_GET
> > 
> > As mentioned above, I'd rather see the mask here.  Unless used
> > an awful lot, I'd rather just see the FIELD_PREP and FIELD_GET
> > used inline rather than defining a bunch of _SET/_GET only some
> > of which seem to be used so far.
> > 
> 
> sure;
> will remove all these _SET/_GET shorthands
> 
> a lot of them will be used;
> and we may implement all reg-definitions at some point;
> 
> this driver is a re-write/adaptation of this one:
> https://github.com/analogdevicesinc/linux/blob/master/drivers/iio/adc/cf_axi_adc_core.c
> 
> which has grown quite a lot and trying to clean it up is... ¯\_(ツ)_/¯
> 
> 
> > > +
> > > +#define REG_DRP_RDATA				0x007C
> > > +#define   REG_DRP_RDATA_SET			LOWER16_SET
> > > +#define   REG_DRP_RDATA_GET			LOWER16_GET
> > > +
> > > +#define REG_UI_STATUS				0x0088
> > > +#define   REG_UI_STATUS_OVF			BIT(2)
> > > +#define   REG_UI_STATUS_UNF			BIT(1)
> > > +
> > > +#define REG_USR_CNTRL_1				0x00A0
> > > +#define   REG_USR_CNTRL_1_USR_CHANMAX_MSK	LOWER8_MSK
> > > +#define   REG_USR_CNTRL_1_USR_CHANMAX_SET	LOWER8_SET
> > > +#define   REG_USR_CNTRL_1_USR_CHANMAX_GET	LOWER8_GET
> > > +
> > > +#define REG_ADC_START_CODE			0x00A4
> > > +#define REG_ADC_GPIO_IN				0x00B8
> > > +#define REG_ADC_GPIO_OUT			0x00BC
> > > +
> > > +#define REG_PPS_COUNTER				0x00C0
> > > +
> > > +#define REG_PPS_STATUS				0x00C4
> > > +#define   REG_PPS_STATUS_PPS_STATUS		BIT(0)
> > > +
> > > +/* ADC Channel controls */
> > > +
> > > +#define REG_CHAN_CNTRL(c)			(0x0400 + (c) * 0x40)
> > > +#define   REG_CHAN_CNTRL_LB_OWR			BIT(11)
> > > +#define   REG_CHAN_CNTRL_PN_SEL_OWR		BIT(10)
> > > +#define   REG_CHAN_CNTRL_IQCOR_ENB		BIT(9)
> > > +#define   REG_CHAN_CNTRL_DCFILT_ENB		BIT(8)
> > > +#define   REG_CHAN_CNTRL_FORMAT_SIGNEXT		BIT(6)
> > > +#define   REG_CHAN_CNTRL_FORMAT_TYPE		BIT(5)
> > > +#define   REG_CHAN_CNTRL_FORMAT_ENABLE		BIT(4)
> > > +#define   REG_CHAN_CNTRL_ADC_PN_TYPE_OWR	BIT(1)
> > > +#define   REG_CHAN_CNTRL_ENABLE			BIT(0)
> > > +
> > > +#define REG_CHAN_CNTRL_DEFAULTS		\
> > > +	(REG_CHAN_CNTRL_FORMAT_SIGNEXT | REG_CHAN_CNTRL_FORMAT_ENABLE |	\
> > > +	 REG_CHAN_CNTRL_IQCOR_ENB | REG_CHAN_CNTRL_ENABLE)
> > > +
> > > +#define REG_CHAN_STATUS(c)			(0x0404 + (c) * 0x40)
> > > +#define   REG_CHAN_STATUS_PN_ERR		BIT(2)
> > > +#define   REG_CHAN_STATUS_PN_OOS		BIT(1)
> > > +#define   REG_CHAN_STATUS_OVER_RANGE		BIT(0)
> > > +
> > > +#define REG_CHAN_CNTRL_1(c)			(0x0410 + (c) * 0x40)
> > > +#define   REG_CHAN_CNTRL_1_DCFILT_OFFSET_MSK	UPPER16_MSK
> > > +#define   REG_CHAN_CNTRL_1_DCFILT_OFFSET_SET	UPPER16_SET
> > > +#define   REG_CHAN_CNTRL_1_DCFILT_OFFSET_GET	UPPER16_GET
> > > +#define   REG_CHAN_CNTRL_1_DCFILT_COEFF_MSK	LOWER16_MSK
> > > +#define   REG_CHAN_CNTRL_1_DCFILT_COEFF_SET	LOWER16_SET
> > > +#define   REG_CHAN_CNTRL_1_DCFILT_COEFF_GET	LOWER16_GET
> > > +
> > > +#define REG_CHAN_CNTRL_2(c)			(0x0414 + (c) * 0x40)
> > > +#define   REG_CHAN_CNTRL_2_IQCOR_COEFF_1_MSK	UPPER16_MSK
> > > +#define   REG_CHAN_CNTRL_2_IQCOR_COEFF_1_SET	UPPER16_SET
> > > +#define   REG_CHAN_CNTRL_2_IQCOR_COEFF_1_GET	UPPER16_GET
> > > +#define   REG_CHAN_CNTRL_2_IQCOR_COEFF_2_MSK	LOWER16_MSK
> > > +#define   REG_CHAN_CNTRL_2_IQCOR_COEFF_2_SET	LOWER16_SET
> > > +#define   REG_CHAN_CNTRL_2_IQCOR_COEFF_2_GET	LOWER16_GET
> > > +
> > > +/*  format is 1.1.14 (sign, integer and fractional bits) */
> > > +#define IQCOR_INT_1				0x4000UL
> > > +#define IQCOR_SIGN_BIT				BIT(15)
> > > +
> > > +#define REG_CHAN_CNTRL_3(c)			(0x0418 + (c) * 0x40)
> > > +#define   REG_CHAN_CNTRL_3_ADC_PN_SEL_MSK	UPPER16_MSK
> > > +#define   REG_CHAN_CNTRL_3_ADC_PN_SEL_SET	UPPER16_SET
> > > +#define   REG_CHAN_CNTRL_3_ADC_PN_SEL_GET	UPPER16_GET
> > > +#define   REG_CHAN_CNTRL_3_ADC_DATA_SEL_MSK	LOWER16_MSK
> > > +#define   REG_CHAN_CNTRL_3_ADC_DATA_SEL_SET	LOWER16_SET
> > > +#define   REG_CHAN_CNTRL_3_ADC_DATA_SEL_GET	LOWER16_GET
> > > +
> > > +#define REG_CHAN_USR_CNTRL_1(c)					(0x0420
> > > + (c) * 0x40)
> > > +#define   REG_CHAN_USR_CNTRL_1_USR_DATATYPE_BE			BIT(25)
> > > +#define   REG_CHAN_USR_CNTRL_1_USR_DATATYPE_SIGNED		BIT(24)
> > > +#define   REG_CHAN_USR_CNTRL_1_USR_DATATYPE_SHIFT_MSK		GENMASK(
> > > 23, 16)
> > > +#define   REG_CHAN_USR_CNTRL_1_USR_DATATYPE_SHIFT_SET(x)	\
> > > +		FIELD_PREP(REG_CHAN_USR_CNTRL_1_USR_DATATYPE_SHIFT_MSK, x)
> > > +#define   REG_CHAN_USR_CNTRL_1_USR_DATATYPE_SHIFT_GET		\
> > > +		FIELD_GET(REG_CHAN_USR_CNTRL_1_USR_DATATYPE_SHIFT_MSK, x)
> > > +#define   REG_CHAN_USR_CNTRL_1_USR_DATATYPE_TOTAL_BITS_MSK	GENMASK(
> > > 15, 8)
> > > +#define   REG_CHAN_USR_CNTRL_1_USR_DATATYPE_TOTAL_BITS_SET(x)	\
> > > +		FIELD_PREP(REG_CHAN_USR_CNTRL_1_USR_DATATYPE_TOTAL_BITS_MSK, x)
> > > +#define   REG_CHAN_USR_CNTRL_1_USR_DATATYPE_TOTAL_BITS_GET(x)	\
> > > +		FIELD_GET(REG_CHAN_USR_CNTRL_1_USR_DATATYPE_TOTAL_BITS_MSK, x)
> > > +#define   REG_CHAN_USR_CNTRL_1_USR_DATATYPE_BITS_MSK		LOWER8_M
> > > SK
> > > +#define   REG_CHAN_USR_CNTRL_1_USR_DATATYPE_BITS_SET		LOWER8_S
> > > ET
> > > +#define   REG_CHAN_USR_CNTRL_1_USR_DATATYPE_BITS_GET		LOWER8_G
> > > ET
> > > +
> > > +#define REG_CHAN_USR_CNTRL_2(c)				(0x0424 + (c) *
> > > 0x40)
> > > +#define   REG_CHAN_USR_CNTRL_2_USR_DECIMATION_M_MSK	UPPER16_MSK
> > > +#define   REG_CHAN_USR_CNTRL_2_USR_DECIMATION_M_SET	UPPER16_SET
> > > +#define   REG_CHAN_USR_CNTRL_2_USR_DECIMATION_M_GET	UPPER16_GET
> > > +#define   REG_CHAN_USR_CNTRL_2_USR_DECIMATION_N_MSK	LOWER16_MSK
> > > +#define   REG_CHAN_USR_CNTRL_2_USR_DECIMATION_N_SET	LOWER16_SET
> > > +#define   REG_CHAN_USR_CNTRL_2_USR_DECIMATION_N_GET	LOWER16_GET
> > > +
> > > +/* IO Delay controls */
> > > +#define __REG_DELAY_CONTROL(base, lane)		((base) + ((lane) *
> > > 0x04))
> > > +
> > > +#define REG_DELAY_CONTROL(lane)			\
> > > +			__REG_DELAY_CONTROL(0x0800, lane)
> > > +#define    REG_DELAY_CONTROL_MSK		LOWER5_MSK
> > > +#define    REG_DELAY_CONTROL_SET		LOWER5_SET
> > > +#define    REG_DELAY_CONTROL_GET		LOWER5_GET
> > > +
> > > +struct adi_axi_adc_core_info {
> > > +	unsigned int				version;
> > > +};
> > > +
> > > +struct adi_axi_adc_state {
> > > +	struct mutex				lock;
> > > +
> > > +	struct adi_axi_adc_client		*client;
> > > +	void __iomem				*regs;
> > > +};
> > > +
> > > +struct adi_axi_adc_client {
> > > +	struct list_head			entry;
> > > +	struct adi_axi_adc_conv			conv;
> > > +	struct adi_axi_adc_state		*state;
> > > +	struct device				*dev;
> > > +	const struct adi_axi_adc_core_info	*info;
> > > +};
> > > +
> > > +static LIST_HEAD(registered_clients);
> > > +static DEFINE_MUTEX(registered_clients_lock);
> > > +
> > > +static struct adi_axi_adc_client *conv_to_client(struct adi_axi_adc_conv
> > > *conv)
> > > +{
> > > +	if (!conv)
> > > +		return NULL;
> > > +	return container_of(conv, struct adi_axi_adc_client, conv);
> > > +}
> > > +
> > > +void *adi_axi_adc_conv_priv(struct adi_axi_adc_conv *conv)
> > > +{
> > > +	struct adi_axi_adc_client *cl = conv_to_client(conv);
> > > +
> > > +	if (!cl)
> > > +		return NULL;
> > > +
> > > +	return (char *)cl + ALIGN(sizeof(struct adi_axi_adc_client), IIO_ALIGN);
> > > +}
> > > +EXPORT_SYMBOL_GPL(adi_axi_adc_conv_priv);
> > > +
> > > +static void adi_axi_adc_write(struct adi_axi_adc_state *st,
> > > +			      unsigned int reg,
> > > +			      unsigned int val)
> > > +{
> > > +	iowrite32(val, st->regs + reg);
> > > +}
> > > +
> > > +static unsigned int adi_axi_adc_read(struct adi_axi_adc_state *st,
> > > +				     unsigned int reg)
> > > +{
> > > +	return ioread32(st->regs + reg);
> > > +}
> > > +
> > > +static int adi_axi_adc_config_dma_buffer(struct device *dev,
> > > +					 struct iio_dev *indio_dev)
> > > +{
> > > +	struct iio_buffer *buffer;
> > > +	const char *dma_name;
> > > +
> > > +	if (!device_property_present(dev, "dmas"))
> > > +		return 0;
> > > +
> > > +	if (device_property_read_string(dev, "dma-names", &dma_name))
> > > +		dma_name = "rx";
> > > +
> > > +	buffer = devm_iio_dmaengine_buffer_alloc(indio_dev->dev.parent,
> > > +						 dma_name);
> > > +	if (IS_ERR(buffer))
> > > +		return PTR_ERR(buffer);
> > > +
> > > +	indio_dev->modes |= INDIO_BUFFER_HARDWARE;
> > > +	iio_device_attach_buffer(indio_dev, buffer);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static int adi_axi_adc_read_raw(struct iio_dev *indio_dev,
> > > +				struct iio_chan_spec const *chan,
> > > +				int *val, int *val2, long mask)
> > > +{
> > > +	struct adi_axi_adc_state *st = iio_priv(indio_dev);
> > > +	struct adi_axi_adc_conv *conv = &st->client->conv;
> > > +
> > > +	if (!conv->read_raw)
> > > +		return -EOPNOTSUPP;
> > > +
> > > +	return conv->read_raw(conv, chan, val, val2, mask);
> > > +}
> > > +
> > > +static int adi_axi_adc_write_raw(struct iio_dev *indio_dev,
> > > +				 struct iio_chan_spec const *chan,
> > > +				 int val, int val2, long mask)
> > > +{
> > > +	struct adi_axi_adc_state *st = iio_priv(indio_dev);
> > > +	struct adi_axi_adc_conv *conv = &st->client->conv;
> > > +
> > > +	if (!conv->write_raw)
> > > +		return -EOPNOTSUPP;
> > > +
> > > +	return conv->write_raw(conv, chan, val, val2, mask);
> > > +}
> > > +
> > > +static int adi_axi_adc_update_scan_mode(struct iio_dev *indio_dev,
> > > +					const unsigned long *scan_mask)
> > > +{
> > > +	struct adi_axi_adc_state *st = iio_priv(indio_dev);
> > > +	struct adi_axi_adc_conv *conv = &st->client->conv;
> > > +	unsigned int i, ctrl;
> > > +
> > > +	for (i = 0; i < conv->chip_info->num_channels; i++) {
> > > +		ctrl = adi_axi_adc_read(st, REG_CHAN_CNTRL(i));
> > > +
> > > +		if (test_bit(i, scan_mask))
> > > +			ctrl |= REG_CHAN_CNTRL_ENABLE;
> > > +		else
> > > +			ctrl &= ~REG_CHAN_CNTRL_ENABLE;
> > > +
> > > +		adi_axi_adc_write(st, REG_CHAN_CNTRL(i), ctrl);
> > > +	}
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static struct adi_axi_adc_conv *adi_axi_adc_conv_register(struct device
> > > *dev,
> > > +							  int sizeof_priv)
> > > +{
> > > +	struct adi_axi_adc_client *cl;
> > > +	size_t alloc_size;
> > > +
> > > +	alloc_size = sizeof(struct adi_axi_adc_client);
> > > +	if (sizeof_priv) {
> > > +		alloc_size = ALIGN(alloc_size, IIO_ALIGN);
> > > +		alloc_size += sizeof_priv;
> > > +	}
> > > +	alloc_size += IIO_ALIGN - 1;
> > > +
> > > +	cl = kzalloc(alloc_size, GFP_KERNEL);
> > > +	if (!cl)
> > > +		return ERR_PTR(-ENOMEM);
> > > +
> > > +	mutex_lock(&registered_clients_lock);
> > > +
> > > +	get_device(dev);
> > > +	cl->dev = dev;
> > > +
> > > +	list_add_tail(&cl->entry, &registered_clients);
> > > +
> > > +	mutex_unlock(&registered_clients_lock);
> > > +
> > > +	return &cl->conv;
> > > +}
> > > +
> > > +static void adi_axi_adc_conv_unregister(struct adi_axi_adc_conv *conv)
> > > +{
> > > +	struct adi_axi_adc_client *cl = conv_to_client(conv);
> > > +
> > > +	if (!cl)
> > > +		return;
> > > +
> > > +	mutex_lock(&registered_clients_lock);
> > > +
> > > +	put_device(cl->dev);
> > > +	list_del(&cl->entry);
> > This isn't reverse of register.  Why?
> > Should be list_del then put_device.
> > 
> > > +	kfree(cl);
> > 
> > To reverse the register precisely the kfree(cl) should be outside
> > the lock...
> 
> yeah; i was a bit careless/relaxed when writing this bit of code;
> will update;
> 
> > > +
> > > +	mutex_unlock(&registered_clients_lock);
> > > +}
> > > +
> > > +static void devm_adi_axi_adc_conv_release(struct device *dev, void *res)
> > > +{
> > > +	adi_axi_adc_conv_unregister(*(struct adi_axi_adc_conv **)res);
> > > +}
> > > +
> > > +struct adi_axi_adc_conv *devm_adi_axi_adc_conv_register(struct device
> > > *dev,
> > > +							int sizeof_priv)
> > > +{
> > > +	struct adi_axi_adc_conv **ptr, *conv;
> > > +
> > > +	ptr = devres_alloc(devm_adi_axi_adc_conv_release, sizeof(*ptr),
> > > +			   GFP_KERNEL);
> > > +	if (!ptr)
> > > +		return ERR_PTR(-ENOMEM);
> > > +
> > > +	conv = adi_axi_adc_conv_register(dev, sizeof_priv);
> > > +	if (IS_ERR(conv)) {
> > > +		devres_free(ptr);
> > > +		return ERR_CAST(conv);
> > > +	}
> > > +
> > > +	*ptr = conv;
> > > +	devres_add(dev, ptr);
> > > +
> > > +	return conv;
> > > +}
> > > +EXPORT_SYMBOL_GPL(devm_adi_axi_adc_conv_register);
> > > +
> > > +static ssize_t in_voltage_scale_available_show(struct device *dev,
> > > +					       struct device_attribute *attr,
> > > +					       char *buf)
> > > +{
> > > +	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> > > +	struct adi_axi_adc_state *st = iio_priv(indio_dev);
> > > +	struct adi_axi_adc_conv *conv = &st->client->conv;
> > > +	size_t len = 0;
> > > +	int i;
> > > +
> > > +	if (!conv->chip_info->num_scales) {
> > > +		buf[0] = '\n';
> > > +		return 1;
> > 
> > I'd prefer to see this done using the core available handling.
> > That way drivers that don't provide this would just not register
> > it in the first place. It will be a characteristic of the channels.
> 
> ack
> will take a look closer here;
> i am a bit vague [at this point] on how to do it; but i'll figure it out
> 
> > > +	}
> > > +
> > > +	for (i = 0; i < conv->chip_info->num_scales; i++) {
> > > +		const unsigned int *s = conv->chip_info->scale_table[i];
> > > +
> > > +		len += scnprintf(buf + len, PAGE_SIZE - len,
> > > +				 "%u.%06u ", s[0], s[1]);
> > > +	}
> > > +	buf[len - 1] = '\n';
> > > +
> > > +	return len;
> > > +}
> > > +
> > > +static IIO_DEVICE_ATTR_RO(in_voltage_scale_available, 0);
> > > +
> > > +static struct attribute *adi_axi_adc_attributes[] = {
> > > +	&iio_dev_attr_in_voltage_scale_available.dev_attr.attr,
> > > +	NULL,
> > > +};
> > > +
> > > +static const struct attribute_group adi_axi_adc_attribute_group = {
> > > +	.attrs = adi_axi_adc_attributes,
> > > +};
> > > +
> > > +static const struct iio_info adi_axi_adc_info = {
> > > +	.read_raw = &adi_axi_adc_read_raw,
> > > +	.write_raw = &adi_axi_adc_write_raw,
> > > +	.attrs = &adi_axi_adc_attribute_group,
> > > +	.update_scan_mode = &adi_axi_adc_update_scan_mode,
> > > +};
> > > +
> > > +static const struct adi_axi_adc_core_info adi_axi_adc_10_0_a_info = {
> > > +	.version = ADI_AXI_PCORE_VER(10, 0, 'a'),
> > > +};
> > > +
> > > +/* Match table for of_platform binding */
> > > +static const struct of_device_id adi_axi_adc_of_match[] = {
> > > +	{ .compatible = "adi,axi-adc-10.0.a", .data = &adi_axi_adc_10_0_a_info
> > > },
> > > +	{ /* end of list */ },
> > > +};
> > > +MODULE_DEVICE_TABLE(of, adi_axi_adc_of_match);
> > > +
> > > +struct adi_axi_adc_client *adi_axi_adc_attach_client(struct device *dev)
> > > +{
> > > +	const struct of_device_id *id;
> > > +	struct adi_axi_adc_client *cl;
> > > +	struct device_node *cln;
> > > +
> > > +	if (!dev->of_node) {
> > > +		dev_err(dev, "DT node is null\n");
> > > +		return ERR_PTR(-ENODEV);
> > > +	}
> > > +
> > > +	id = of_match_node(adi_axi_adc_of_match, dev->of_node);
> > > +	if (!id)
> > > +		return ERR_PTR(-ENODEV);
> > > +
> > > +	cln = of_parse_phandle(dev->of_node, "adi,adc-dev", 0);
> > > +	if (!cln) {
> > > +		dev_err(dev, "No 'adi,adc-dev' node defined\n");
> > > +		return ERR_PTR(-ENODEV);
> > > +	}
> > > +
> > > +	mutex_lock(&registered_clients_lock);
> > > +
> > > +	list_for_each_entry(cl, &registered_clients, entry) {
> > > +		if (!cl->dev)
> > > +			continue;
> > > +		if (cl->dev->of_node == cln) {
> > > +			if (!try_module_get(dev->driver->owner)) {
> > > +				mutex_unlock(&registered_clients_lock);
> > > +				return ERR_PTR(-ENODEV);
> > > +			}
> > > +			get_device(dev);
> > > +			cl->info = id->data;
> > > +			mutex_unlock(&registered_clients_lock);
> > > +			return cl;
> > > +		}
> > > +	}
> > > +
> > > +	mutex_unlock(&registered_clients_lock);
> > > +
> > > +	return ERR_PTR(-EPROBE_DEFER);
> > > +}
> > > +
> > > +static int adi_axi_adc_setup_channels(struct device *dev,
> > > +				      struct adi_axi_adc_state *st)
> > > +{
> > > +	struct adi_axi_adc_conv *conv = conv = &st->client->conv;
> > > +	unsigned int val;
> > > +	int i, ret;
> > > +
> > > +	if (conv->preenable_setup) {
> > > +		ret = conv->preenable_setup(conv);
> > > +		if (ret)
> > > +			return ret;
> > > +	}
> > > +
> > > +	for (i = 0; i < conv->chip_info->num_channels; i++) {
> > > +		if (i & 1)
> > > +			val = REG_CHAN_CNTRL_2_IQCOR_COEFF_2_SET(IQCOR_INT_1);
> > > +		else
> > > +			val = REG_CHAN_CNTRL_2_IQCOR_COEFF_1_SET(IQCOR_INT_1);
> > > +		adi_axi_adc_write(st, REG_CHAN_CNTRL_2(i), val);
> > > +
> > > +		adi_axi_adc_write(st, REG_CHAN_CNTRL(i),
> > > +			REG_CHAN_CNTRL_DEFAULTS);
> > > +	}
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static void axi_adc_reset(struct adi_axi_adc_state *st)
> > > +{
> > > +	adi_axi_adc_write(st, REG_RSTN, 0);
> > > +	mdelay(10);
> > > +	adi_axi_adc_write(st, REG_RSTN, REG_RSTN_MMCM_RSTN);
> > > +	mdelay(10);
> > > +	adi_axi_adc_write(st, REG_RSTN,
> > > +			  REG_RSTN_RSTN | REG_RSTN_MMCM_RSTN);
> > > +}
> > > +
> > > +static void adi_axi_adc_cleanup(void *data)
> > > +{
> > > +	struct adi_axi_adc_client *cl = data;
> > > +
> > > +	put_device(cl->dev);
> > > +	module_put(cl->dev->driver->owner);
> > > +}
> > > +
> > > +static int adi_axi_adc_probe(struct platform_device *pdev)
> > > +{
> > > +	struct adi_axi_adc_conv *conv;
> > > +	struct iio_dev *indio_dev;
> > > +	struct adi_axi_adc_client *cl;
> > > +	struct adi_axi_adc_state *st;
> > > +	unsigned int ver;
> > > +	int ret;
> > > +
> > > +	cl = adi_axi_adc_attach_client(&pdev->dev);
> > > +	if (IS_ERR(cl))
> > > +		return PTR_ERR(cl);
> > > +
> > > +	ret = devm_add_action_or_reset(&pdev->dev, adi_axi_adc_cleanup, cl);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*st));
> > > +	if (indio_dev == NULL)
> > > +		return -ENOMEM;
> > > +
> > > +	st = iio_priv(indio_dev);
> > > +	st->client = cl;
> > > +	cl->state = st;
> > > +	mutex_init(&st->lock);
> > > +
> > > +	st->regs = devm_platform_ioremap_resource(pdev, 0);
> > > +	if (IS_ERR(st->regs))
> > > +		return PTR_ERR(st->regs);
> > > +
> > > +	conv = &st->client->conv;
> > > +
> > > +	axi_adc_reset(st);
> > > +
> > > +	ver = adi_axi_adc_read(st, ADI_AXI_REG_VERSION);
> > > +
> > > +	if (cl->info->version > ver) {
> > > +		dev_err(&pdev->dev,
> > > +			"IP core version is too old. Expected %d.%.2d.%c,
> > > Reported %d.%.2d.%c\n",
> > > +			ADI_AXI_PCORE_VER_MAJOR(cl->info->version),
> > > +			ADI_AXI_PCORE_VER_MINOR(cl->info->version),
> > > +			ADI_AXI_PCORE_VER_PATCH(cl->info->version),
> > > +			ADI_AXI_PCORE_VER_MAJOR(ver),
> > > +			ADI_AXI_PCORE_VER_MINOR(ver),
> > > +			ADI_AXI_PCORE_VER_PATCH(ver));
> > > +		return -ENODEV;
> > > +	}
> > > +
> > > +	indio_dev->info = &adi_axi_adc_info;
> > > +	indio_dev->dev.parent = &pdev->dev;
> > > +	indio_dev->name = dev_name(&pdev->dev);
> > 
> > What does this result in?  Given this is supposed to be a part number
> > I kind of expected this to be hardcoded to "adi-axi-adc" or similar.
> 
> ack;
> "adi-axi-adc" it is
> 
> 
> > > +	indio_dev->modes = INDIO_DIRECT_MODE;
> > > +	indio_dev->num_channels = conv->chip_info->num_channels;
> > > +	indio_dev->channels = conv->chip_info->channels;
> > > +
> > > +	ret = adi_axi_adc_config_dma_buffer(&pdev->dev, indio_dev);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	ret = adi_axi_adc_setup_channels(&pdev->dev, st);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	ret = devm_iio_device_register(&pdev->dev, indio_dev);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	dev_info(&pdev->dev, "AXI ADC IP core (%d.%.2d.%c) probed\n",
> > > +		ADI_AXI_PCORE_VER_MAJOR(ver),
> > > +		ADI_AXI_PCORE_VER_MINOR(ver),
> > > +		ADI_AXI_PCORE_VER_PATCH(ver));
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static struct platform_driver adi_axi_adc_driver = {
> > > +	.driver = {
> > > +		.name = KBUILD_MODNAME,
> > > +		.of_match_table = adi_axi_adc_of_match,
> > > +	},
> > > +	.probe = adi_axi_adc_probe,
> > > +};
> > > +module_platform_driver(adi_axi_adc_driver);
> > > +
> > > +MODULE_AUTHOR("Michael Hennerich <michael.hennerich@...log.com>");
> > > +MODULE_DESCRIPTION("Analog Devices Generic AXI ADC IP core driver");
> > > +MODULE_LICENSE("GPL v2");
> > > diff --git a/include/linux/iio/adc/adi-axi-adc.h
> > > b/include/linux/iio/adc/adi-axi-adc.h
> > > new file mode 100644
> > > index 000000000000..57974944b30b
> > > --- /dev/null
> > > +++ b/include/linux/iio/adc/adi-axi-adc.h
> > > @@ -0,0 +1,63 @@
> > > +/* SPDX-License-Identifier: GPL-2.0 */
> > > +/*
> > > + * Analog Devices Generic AXI ADC IP core driver/library
> > > + * Link: https://wiki.analog.com/resources/fpga/docs/axi_adc_ip
> > > + *
> > > + * Copyright 2012-2020 Analog Devices Inc.
> > > + */
> > > +#ifndef __ADI_AXI_ADC_H__
> > > +#define __ADI_AXI_ADC_H__
> > > +
> > > +struct device;
> > > +struct iio_chan_spec;
> > > +
> > > +/**
> > > + * struct adi_axi_adc_chip_info - Chip specific information
> > > + * @name		Chip name
> > > + * @id			Chip ID (usually product ID)
> > > + * @channels		Channel specifications of type @struct
> > > axi_adc_chan_spec
> > > + * @num_channels	Number of @channels
> > > + * @scale_table		Supported scales by the chip; tuples of 2 ints
> > > + * @num_scales		Number of scales in the table
> > > + * @max_rate		Maximum sampling rate supported by the device
> > > + */
> > > +struct adi_axi_adc_chip_info {
> > > +	const char			*name;
> > > +	unsigned int			id;
> > > +
> > > +	const struct iio_chan_spec	*channels;
> > > +	unsigned int			num_channels;
> > > +
> > > +	const unsigned int		(*scale_table)[2];
> > > +	int				num_scales;
> > > +
> > > +	unsigned long			max_rate;
> > > +};
> > > +
> > > +/**
> > > + * struct adi_axi_adc_conv - data of the ADC attached to the AXI ADC
> > > + * @chip_info		chip info details for the client ADC
> > > + * @preenable_setup	op to run in the client before enabling the AXI
> > > ADC
> > 
> > Run the kernel doc script over this and it would have moaned...
> > 
> > No reg_access.
> 
> ack;
> i'll need to start adapting that script to some CI
> it's on my todo-list
> 
> > > + * @read_raw		IIO read_raw hook for the client ADC
> > > + * @write_raw		IIO write_raw hook for the client ADC
> > > + */
> > > +struct adi_axi_adc_conv {
> > > +	const struct adi_axi_adc_chip_info		*chip_info;
> > > +
> > > +	int (*preenable_setup)(struct adi_axi_adc_conv *conv);
> > > +	int (*reg_access)(struct adi_axi_adc_conv *conv, unsigned int reg,
> > > +			  unsigned int writeval, unsigned int *readval);
> > > +	int (*read_raw)(struct adi_axi_adc_conv *conv,
> > > +			struct iio_chan_spec const *chan,
> > > +			int *val, int *val2, long mask);
> > > +	int (*write_raw)(struct adi_axi_adc_conv *conv,
> > > +			 struct iio_chan_spec const *chan,
> > > +			 int val, int val2, long mask);
> > > +};
> > > +
> > > +struct adi_axi_adc_conv *devm_adi_axi_adc_conv_register(struct device
> > > *dev,
> > > +							int sizeof_priv);
> > > +
> > > +void *adi_axi_adc_conv_priv(struct adi_axi_adc_conv *conv);
> > > +
> > > +#endif

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