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Subject[PATCH v3 6/7] iio:dac:ad5686: Refactor the driver
Date
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>
---
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__ */
--
2.7.4
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