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SubjectRe: [PATCH v3 6/7] iio:dac:ad5686: Refactor the driver
On Wed, 11 Apr 2018 14:53:17 +0300
Stefan Popa <stefan.popa@analog.com> wrote:

> In this patch restructures the existing ad5686 driver by adding a module
> for SPI and a header file, while the baseline module deals with the
> chip-logic.
>
> This is a necessary step, as this driver should support in the future
> similar devices which differ only in the type of interface used (I2C
> instead of SPI).
>
> Signed-off-by: Stefan Popa <stefan.popa@analog.com>
Applied to the togreg branch of iio.git (carrying forward the change
I made earlier). Again please check I didn't mess it up.

Jonathan

> ---
> Changes in v2:
> - Refactored the patch
> - Use st->write directly instead of the ad5686_write() wrapper
> - Use st->read directly instead of the ad5686_read() wrapper
> Changes in v3:
> - Indented the the help text from the Konfig file with 2
> additional spaces.
> - Changed the license description to use an SPDX tag.
>
> MAINTAINERS | 7 ++
> drivers/iio/dac/Kconfig | 13 ++-
> drivers/iio/dac/Makefile | 1 +
> drivers/iio/dac/ad5686-spi.c | 92 +++++++++++++++++++++
> drivers/iio/dac/ad5686.c | 190 +++++++------------------------------------
> drivers/iio/dac/ad5686.h | 114 ++++++++++++++++++++++++++
> 6 files changed, 252 insertions(+), 165 deletions(-)
> create mode 100644 drivers/iio/dac/ad5686-spi.c
> create mode 100644 drivers/iio/dac/ad5686.h
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 473ac00..637e62d 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -791,6 +791,13 @@ M: Michael Hanselmann <linux-kernel@hansmi.ch>
> S: Supported
> F: drivers/macintosh/ams/
>
> +ANALOG DEVICES INC AD5686 DRIVER
> +M: Stefan Popa <stefan.popa@analog.com>
> +L: linux-pm@vger.kernel.org
> +W: http://ez.analog.com/community/linux-device-drivers
> +S: Supported
> +F: drivers/iio/dac/ad5686*
> +
> ANALOG DEVICES INC AD9389B DRIVER
> M: Hans Verkuil <hans.verkuil@cisco.com>
> L: linux-media@vger.kernel.org
> diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
> index 965d5c0..7a81f1e 100644
> --- a/drivers/iio/dac/Kconfig
> +++ b/drivers/iio/dac/Kconfig
> @@ -131,16 +131,21 @@ config LTC2632
> module will be called ltc2632.
>
> config AD5686
> - tristate "Analog Devices AD5686R/AD5685R/AD5684R DAC SPI driver"
> + tristate
> +
> +config AD5686_SPI
> + tristate "Analog Devices AD5686 and similar multi-channel DACs (SPI)"
> depends on SPI
> + select AD5686
> help
> - Say yes here to build support for Analog Devices AD5686R, AD5685R,
> - AD5684R, AD5791 Voltage Output Digital to
> - Analog Converter.
> + Say yes here to build support for Analog Devices AD5672R, AD5676,
> + AD5676R, AD5684, AD5684R, AD5684R, AD5685R, AD5686, AD5686R.
> + Voltage Output Digital to Analog Converter.
>
> To compile this driver as a module, choose M here: the
> module will be called ad5686.
>
> +
> config AD5755
> tristate "Analog Devices AD5755/AD5755-1/AD5757/AD5735/AD5737 DAC driver"
> depends on SPI_MASTER
> diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile
> index 81e710e..07db92e 100644
> --- a/drivers/iio/dac/Makefile
> +++ b/drivers/iio/dac/Makefile
> @@ -20,6 +20,7 @@ obj-$(CONFIG_AD5761) += ad5761.o
> obj-$(CONFIG_AD5764) += ad5764.o
> obj-$(CONFIG_AD5791) += ad5791.o
> obj-$(CONFIG_AD5686) += ad5686.o
> +obj-$(CONFIG_AD5686_SPI) += ad5686-spi.o
> obj-$(CONFIG_AD7303) += ad7303.o
> obj-$(CONFIG_AD8801) += ad8801.o
> obj-$(CONFIG_CIO_DAC) += cio-dac.o
> diff --git a/drivers/iio/dac/ad5686-spi.c b/drivers/iio/dac/ad5686-spi.c
> new file mode 100644
> index 0000000..1cc807b
> --- /dev/null
> +++ b/drivers/iio/dac/ad5686-spi.c
> @@ -0,0 +1,92 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * AD5672R, AD5676, AD5676R, AD5684, AD5684R, AD5684R, AD5685R, AD5686, AD5686R
> + * Digital to analog converters driver
> + *
> + * Copyright 2018 Analog Devices Inc.
> + */
> +
> +#include "ad5686.h"
> +
> +#include <linux/module.h>
> +#include <linux/spi/spi.h>
> +
> +static int ad5686_spi_write(struct ad5686_state *st,
> + u8 cmd, u8 addr, u16 val)
> +{
> + struct spi_device *spi = to_spi_device(st->dev);
> +
> + st->data[0].d32 = cpu_to_be32(AD5686_CMD(cmd) |
> + AD5686_ADDR(addr) |
> + val);
> +
> + return spi_write(spi, &st->data[0].d8[1], 3);
> +}
> +
> +static int ad5686_spi_read(struct ad5686_state *st, u8 addr)
> +{
> + struct spi_transfer t[] = {
> + {
> + .tx_buf = &st->data[0].d8[1],
> + .len = 3,
> + .cs_change = 1,
> + }, {
> + .tx_buf = &st->data[1].d8[1],
> + .rx_buf = &st->data[2].d8[1],
> + .len = 3,
> + },
> + };
> + struct spi_device *spi = to_spi_device(st->dev);
> + int ret;
> +
> + st->data[0].d32 = cpu_to_be32(AD5686_CMD(AD5686_CMD_READBACK_ENABLE) |
> + AD5686_ADDR(addr));
> + st->data[1].d32 = cpu_to_be32(AD5686_CMD(AD5686_CMD_NOOP));
> +
> + ret = spi_sync_transfer(spi, t, ARRAY_SIZE(t));
> + if (ret < 0)
> + return ret;
> +
> + return be32_to_cpu(st->data[2].d32);
> +}
> +
> +static int ad5686_spi_probe(struct spi_device *spi)
> +{
> + const struct spi_device_id *id = spi_get_device_id(spi);
> +
> + return ad5686_probe(&spi->dev, id->driver_data, id->name,
> + ad5686_spi_write, ad5686_spi_read);
> +}
> +
> +static int ad5686_spi_remove(struct spi_device *spi)
> +{
> + return ad5686_remove(&spi->dev);
> +}
> +
> +static const struct spi_device_id ad5686_spi_id[] = {
> + {"ad5672r", ID_AD5672R},
> + {"ad5676", ID_AD5676},
> + {"ad5676r", ID_AD5676R},
> + {"ad5684", ID_AD5684},
> + {"ad5684r", ID_AD5684R},
> + {"ad5685r", ID_AD5685R},
> + {"ad5686", ID_AD5686},
> + {"ad5686r", ID_AD5686R},
> + {}
> +};
> +MODULE_DEVICE_TABLE(spi, ad5686_spi_id);
> +
> +static struct spi_driver ad5686_spi_driver = {
> + .driver = {
> + .name = "ad5686",
> + },
> + .probe = ad5686_spi_probe,
> + .remove = ad5686_spi_remove,
> + .id_table = ad5686_spi_id,
> +};
> +
> +module_spi_driver(ad5686_spi_driver);
> +
> +MODULE_AUTHOR("Stefan Popa <stefan.popa@analog.com>");
> +MODULE_DESCRIPTION("Analog Devices AD5686 and similar multi-channel DACs");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/iio/dac/ad5686.c b/drivers/iio/dac/ad5686.c
> index 54f67d5..79abff5 100644
> --- a/drivers/iio/dac/ad5686.c
> +++ b/drivers/iio/dac/ad5686.c
> @@ -10,7 +10,6 @@
> #include <linux/device.h>
> #include <linux/module.h>
> #include <linux/kernel.h>
> -#include <linux/spi/spi.h>
> #include <linux/slab.h>
> #include <linux/sysfs.h>
> #include <linux/regulator/consumer.h>
> @@ -18,121 +17,7 @@
> #include <linux/iio/iio.h>
> #include <linux/iio/sysfs.h>
>
> -#define AD5686_ADDR(x) ((x) << 16)
> -#define AD5686_CMD(x) ((x) << 20)
> -
> -#define AD5686_ADDR_DAC(chan) (0x1 << (chan))
> -#define AD5686_ADDR_ALL_DAC 0xF
> -
> -#define AD5686_CMD_NOOP 0x0
> -#define AD5686_CMD_WRITE_INPUT_N 0x1
> -#define AD5686_CMD_UPDATE_DAC_N 0x2
> -#define AD5686_CMD_WRITE_INPUT_N_UPDATE_N 0x3
> -#define AD5686_CMD_POWERDOWN_DAC 0x4
> -#define AD5686_CMD_LDAC_MASK 0x5
> -#define AD5686_CMD_RESET 0x6
> -#define AD5686_CMD_INTERNAL_REFER_SETUP 0x7
> -#define AD5686_CMD_DAISY_CHAIN_ENABLE 0x8
> -#define AD5686_CMD_READBACK_ENABLE 0x9
> -
> -#define AD5686_LDAC_PWRDN_NONE 0x0
> -#define AD5686_LDAC_PWRDN_1K 0x1
> -#define AD5686_LDAC_PWRDN_100K 0x2
> -#define AD5686_LDAC_PWRDN_3STATE 0x3
> -
> -/**
> - * struct ad5686_chip_info - chip specific information
> - * @int_vref_mv: AD5620/40/60: the internal reference voltage
> - * @num_channels: number of channels
> - * @channel: channel specification
> -*/
> -
> -struct ad5686_chip_info {
> - u16 int_vref_mv;
> - unsigned int num_channels;
> - struct iio_chan_spec *channels;
> -};
> -
> -/**
> - * struct ad5446_state - driver instance specific data
> - * @spi: spi_device
> - * @chip_info: chip model specific constants, available modes etc
> - * @reg: supply regulator
> - * @vref_mv: actual reference voltage used
> - * @pwr_down_mask: power down mask
> - * @pwr_down_mode: current power down mode
> - * @data: spi transfer buffers
> - */
> -
> -struct ad5686_state {
> - struct spi_device *spi;
> - const struct ad5686_chip_info *chip_info;
> - struct regulator *reg;
> - unsigned short vref_mv;
> - unsigned pwr_down_mask;
> - unsigned pwr_down_mode;
> - /*
> - * DMA (thus cache coherency maintenance) requires the
> - * transfer buffers to live in their own cache lines.
> - */
> -
> - union {
> - __be32 d32;
> - u8 d8[4];
> - } data[3] ____cacheline_aligned;
> -};
> -
> -/**
> - * ad5686_supported_device_ids:
> - */
> -
> -enum ad5686_supported_device_ids {
> - ID_AD5672R,
> - ID_AD5676,
> - ID_AD5676R,
> - ID_AD5684,
> - ID_AD5684R,
> - ID_AD5685R,
> - ID_AD5686,
> - ID_AD5686R
> -};
> -static int ad5686_spi_write(struct ad5686_state *st,
> - u8 cmd, u8 addr, u16 val, u8 shift)
> -{
> - val <<= shift;
> -
> - st->data[0].d32 = cpu_to_be32(AD5686_CMD(cmd) |
> - AD5686_ADDR(addr) |
> - val);
> -
> - return spi_write(st->spi, &st->data[0].d8[1], 3);
> -}
> -
> -static int ad5686_spi_read(struct ad5686_state *st, u8 addr)
> -{
> - struct spi_transfer t[] = {
> - {
> - .tx_buf = &st->data[0].d8[1],
> - .len = 3,
> - .cs_change = 1,
> - }, {
> - .tx_buf = &st->data[1].d8[1],
> - .rx_buf = &st->data[2].d8[1],
> - .len = 3,
> - },
> - };
> - int ret;
> -
> - st->data[0].d32 = cpu_to_be32(AD5686_CMD(AD5686_CMD_READBACK_ENABLE) |
> - AD5686_ADDR(addr));
> - st->data[1].d32 = cpu_to_be32(AD5686_CMD(AD5686_CMD_NOOP));
> -
> - ret = spi_sync_transfer(st->spi, t, ARRAY_SIZE(t));
> - if (ret < 0)
> - return ret;
> -
> - return be32_to_cpu(st->data[2].d32);
> -}
> +#include "ad5686.h"
>
> static const char * const ad5686_powerdown_modes[] = {
> "1kohm_to_gnd",
> @@ -195,8 +80,9 @@ static ssize_t ad5686_write_dac_powerdown(struct iio_dev *indio_dev,
> else
> st->pwr_down_mask &= ~(0x3 << (chan->channel * 2));
>
> - ret = ad5686_spi_write(st, AD5686_CMD_POWERDOWN_DAC, 0,
> - st->pwr_down_mask & st->pwr_down_mode, 0);
> + ret = st->write(st, AD5686_CMD_POWERDOWN_DAC, 0,
> + st->pwr_down_mask & st->pwr_down_mode);
> +
>
> return ret ? ret : len;
> }
> @@ -213,7 +99,7 @@ static int ad5686_read_raw(struct iio_dev *indio_dev,
> switch (m) {
> case IIO_CHAN_INFO_RAW:
> mutex_lock(&indio_dev->mlock);
> - ret = ad5686_spi_read(st, chan->address);
> + ret = st->read(st, chan->address);
> mutex_unlock(&indio_dev->mlock);
> if (ret < 0)
> return ret;
> @@ -242,11 +128,10 @@ static int ad5686_write_raw(struct iio_dev *indio_dev,
> return -EINVAL;
>
> mutex_lock(&indio_dev->mlock);
> - ret = ad5686_spi_write(st,
> - AD5686_CMD_WRITE_INPUT_N_UPDATE_N,
> - chan->address,
> - val,
> - chan->scan_type.shift);
> + ret = st->write(st,
> + AD5686_CMD_WRITE_INPUT_N_UPDATE_N,
> + chan->address,
> + val << chan->scan_type.shift);
> mutex_unlock(&indio_dev->mlock);
> break;
> default:
> @@ -356,20 +241,27 @@ static const struct ad5686_chip_info ad5686_chip_info_tbl[] = {
> },
> };
>
> -static int ad5686_probe(struct spi_device *spi)
> +int ad5686_probe(struct device *dev,
> + enum ad5686_supported_device_ids chip_type,
> + const char *name, ad5686_write_func write,
> + ad5686_read_func read)
> {
> struct ad5686_state *st;
> struct iio_dev *indio_dev;
> int ret, voltage_uv = 0;
>
> - indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
> + indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
> if (indio_dev == NULL)
> return -ENOMEM;
>
> st = iio_priv(indio_dev);
> - spi_set_drvdata(spi, indio_dev);
> + dev_set_drvdata(dev, indio_dev);
> +
> + st->dev = dev;
> + st->write = write;
> + st->read = read;
>
> - st->reg = devm_regulator_get_optional(&spi->dev, "vcc");
> + st->reg = devm_regulator_get_optional(dev, "vcc");
> if (!IS_ERR(st->reg)) {
> ret = regulator_enable(st->reg);
> if (ret)
> @@ -382,28 +274,25 @@ static int ad5686_probe(struct spi_device *spi)
> voltage_uv = ret;
> }
>
> - st->chip_info =
> - &ad5686_chip_info_tbl[spi_get_device_id(spi)->driver_data];
> + st->chip_info = &ad5686_chip_info_tbl[chip_type];
>
> if (voltage_uv)
> st->vref_mv = voltage_uv / 1000;
> else
> st->vref_mv = st->chip_info->int_vref_mv;
>
> - st->spi = spi;
> -
> /* Set all the power down mode for all channels to 1K pulldown */
> st->pwr_down_mode = 0x55;
>
> - indio_dev->dev.parent = &spi->dev;
> - indio_dev->name = spi_get_device_id(spi)->name;
> + indio_dev->dev.parent = dev;
> + indio_dev->name = name;
> indio_dev->info = &ad5686_info;
> indio_dev->modes = INDIO_DIRECT_MODE;
> indio_dev->channels = st->chip_info->channels;
> indio_dev->num_channels = st->chip_info->num_channels;
>
> - ret = ad5686_spi_write(st, AD5686_CMD_INTERNAL_REFER_SETUP, 0,
> - !!voltage_uv, 0);
> + ret = st->write(st, AD5686_CMD_INTERNAL_REFER_SETUP,
> + 0, !!voltage_uv);
> if (ret)
> goto error_disable_reg;
>
> @@ -418,10 +307,11 @@ static int ad5686_probe(struct spi_device *spi)
> regulator_disable(st->reg);
> return ret;
> }
> +EXPORT_SYMBOL_GPL(ad5686_probe);
>
> -static int ad5686_remove(struct spi_device *spi)
> +int ad5686_remove(struct device *dev)
> {
> - struct iio_dev *indio_dev = spi_get_drvdata(spi);
> + struct iio_dev *indio_dev = dev_get_drvdata(dev);
> struct ad5686_state *st = iio_priv(indio_dev);
>
> iio_device_unregister(indio_dev);
> @@ -430,29 +320,7 @@ static int ad5686_remove(struct spi_device *spi)
>
> return 0;
> }
> -
> -static const struct spi_device_id ad5686_id[] = {
> - {"ad5672r", ID_AD5672R},
> - {"ad5676", ID_AD5676},
> - {"ad5676r", ID_AD5676R},
> - {"ad5684", ID_AD5684},
> - {"ad5684r", ID_AD5684R},
> - {"ad5685r", ID_AD5685R},
> - {"ad5686", ID_AD5686},
> - {"ad5686r", ID_AD5686R},
> - {}
> -};
> -MODULE_DEVICE_TABLE(spi, ad5686_id);
> -
> -static struct spi_driver ad5686_driver = {
> - .driver = {
> - .name = "ad5686",
> - },
> - .probe = ad5686_probe,
> - .remove = ad5686_remove,
> - .id_table = ad5686_id,
> -};
> -module_spi_driver(ad5686_driver);
> +EXPORT_SYMBOL_GPL(ad5686_remove);
>
> MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
> MODULE_DESCRIPTION("Analog Devices AD5686/85/84 DAC");
> diff --git a/drivers/iio/dac/ad5686.h b/drivers/iio/dac/ad5686.h
> new file mode 100644
> index 0000000..c8e1565
> --- /dev/null
> +++ b/drivers/iio/dac/ad5686.h
> @@ -0,0 +1,114 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +/*
> + * This file is part of AD5686 DAC driver
> + *
> + * Copyright 2018 Analog Devices Inc.
> + */
> +
> +#ifndef __DRIVERS_IIO_DAC_AD5686_H__
> +#define __DRIVERS_IIO_DAC_AD5686_H__
> +
> +#include <linux/types.h>
> +#include <linux/cache.h>
> +#include <linux/mutex.h>
> +#include <linux/kernel.h>
> +
> +#define AD5686_ADDR(x) ((x) << 16)
> +#define AD5686_CMD(x) ((x) << 20)
> +
> +#define AD5686_ADDR_DAC(chan) (0x1 << (chan))
> +#define AD5686_ADDR_ALL_DAC 0xF
> +
> +#define AD5686_CMD_NOOP 0x0
> +#define AD5686_CMD_WRITE_INPUT_N 0x1
> +#define AD5686_CMD_UPDATE_DAC_N 0x2
> +#define AD5686_CMD_WRITE_INPUT_N_UPDATE_N 0x3
> +#define AD5686_CMD_POWERDOWN_DAC 0x4
> +#define AD5686_CMD_LDAC_MASK 0x5
> +#define AD5686_CMD_RESET 0x6
> +#define AD5686_CMD_INTERNAL_REFER_SETUP 0x7
> +#define AD5686_CMD_DAISY_CHAIN_ENABLE 0x8
> +#define AD5686_CMD_READBACK_ENABLE 0x9
> +
> +#define AD5686_LDAC_PWRDN_NONE 0x0
> +#define AD5686_LDAC_PWRDN_1K 0x1
> +#define AD5686_LDAC_PWRDN_100K 0x2
> +#define AD5686_LDAC_PWRDN_3STATE 0x3
> +
> +/**
> + * ad5686_supported_device_ids:
> + */
> +enum ad5686_supported_device_ids {
> + ID_AD5672R,
> + ID_AD5676,
> + ID_AD5676R,
> + ID_AD5684,
> + ID_AD5684R,
> + ID_AD5685R,
> + ID_AD5686,
> + ID_AD5686R,
> +};
> +
> +struct ad5686_state;
> +
> +typedef int (*ad5686_write_func)(struct ad5686_state *st,
> + u8 cmd, u8 addr, u16 val);
> +
> +typedef int (*ad5686_read_func)(struct ad5686_state *st, u8 addr);
> +
> +/**
> + * struct ad5686_chip_info - chip specific information
> + * @int_vref_mv: AD5620/40/60: the internal reference voltage
> + * @num_channels: number of channels
> + * @channel: channel specification
> + */
> +
> +struct ad5686_chip_info {
> + u16 int_vref_mv;
> + unsigned int num_channels;
> + struct iio_chan_spec *channels;
> +};
> +
> +/**
> + * struct ad5446_state - driver instance specific data
> + * @spi: spi_device
> + * @chip_info: chip model specific constants, available modes etc
> + * @reg: supply regulator
> + * @vref_mv: actual reference voltage used
> + * @pwr_down_mask: power down mask
> + * @pwr_down_mode: current power down mode
> + * @data: spi transfer buffers
> + */
> +
> +struct ad5686_state {
> + struct device *dev;
> + const struct ad5686_chip_info *chip_info;
> + struct regulator *reg;
> + unsigned short vref_mv;
> + unsigned int pwr_down_mask;
> + unsigned int pwr_down_mode;
> + ad5686_write_func write;
> + ad5686_read_func read;
> +
> + /*
> + * DMA (thus cache coherency maintenance) requires the
> + * transfer buffers to live in their own cache lines.
> + */
> +
> + union {
> + __be32 d32;
> + __be16 d16;
> + u8 d8[4];
> + } data[3] ____cacheline_aligned;
> +};
> +
> +
> +int ad5686_probe(struct device *dev,
> + enum ad5686_supported_device_ids chip_type,
> + const char *name, ad5686_write_func write,
> + ad5686_read_func read);
> +
> +int ad5686_remove(struct device *dev);
> +
> +
> +#endif /* __DRIVERS_IIO_DAC_AD5686_H__ */

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