[PATCH v2 1/3] iio: dac: add support for ltc1660

[PATCH v2 1/3] iio: dac: add support for ltc1660

[Marcus Folkesson]

LTC1665/LTC1660 is a 8/10-bit Digital-to-Analog Converter
(DAC) with eight individual channels.

Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
---

Notes:
    v2:
    	- rename all instances of ltc166x to ltc1660
    	- read regulator value "in-place" instead of cache voltage
    	- fix error handling in ltc1660_write_raw

 drivers/iio/dac/Kconfig   |  10 ++
 drivers/iio/dac/Makefile  |   1 +
 drivers/iio/dac/ltc1660.c | 250 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 261 insertions(+)
 create mode 100644 drivers/iio/dac/ltc1660.c

diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
index 76db0768e454..cbee80bd111e 100644
--- a/drivers/iio/dac/Kconfig
+++ b/drivers/iio/dac/Kconfig
@@ -120,6 +120,16 @@ config AD5624R_SPI
 	  Say yes here to build support for Analog Devices AD5624R, AD5644R and
 	  AD5664R converters (DAC). This driver uses the common SPI interface.
 
+config LTC1660
+	tristate "Linear Technology LTC1660/LTC1665 DAC SPI driver"
+	depends on SPI
+	help
+	  Say yes here to build support for Linear Technology
+	  LTC1660 and LTC1665 Digital to Analog Converters.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ltc1660.
+
 config LTC2632
 	tristate "Linear Technology LTC2632-12/10/8 DAC spi driver"
 	depends on SPI
diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile
index 81e710ed7491..e446eeb09c85 100644
--- a/drivers/iio/dac/Makefile
+++ b/drivers/iio/dac/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_CIO_DAC) += cio-dac.o
 obj-$(CONFIG_DPOT_DAC) += dpot-dac.o
 obj-$(CONFIG_DS4424) += ds4424.o
 obj-$(CONFIG_LPC18XX_DAC) += lpc18xx_dac.o
+obj-$(CONFIG_LTC1660) += ltc1660.o
 obj-$(CONFIG_LTC2632) += ltc2632.o
 obj-$(CONFIG_M62332) += m62332.o
 obj-$(CONFIG_MAX517) += max517.o
diff --git a/drivers/iio/dac/ltc1660.c b/drivers/iio/dac/ltc1660.c
new file mode 100644
index 000000000000..10866838c72a
--- /dev/null
+++ b/drivers/iio/dac/ltc1660.c
@@ -0,0 +1,250 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for Linear Technology LTC1665/LTC1660, 8 channels DAC
+ *
+ * Copyright (C) 2018 Marcus Folkesson <marcus.folkesson@gmail.com>
+ */
+#include <linux/bitops.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+
+#define LTC1660_REG_WAKE	0x0
+#define LTC1660_REG_DAC_A	0x1
+#define LTC1660_REG_DAC_B	0x2
+#define LTC1660_REG_DAC_C	0x3
+#define LTC1660_REG_DAC_D	0x4
+#define LTC1660_REG_DAC_E	0x5
+#define LTC1660_REG_DAC_F	0x6
+#define LTC1660_REG_DAC_G	0x7
+#define LTC1660_REG_DAC_H	0x8
+#define LTC1660_REG_SLEEP	0xe
+
+#define LTC1660_NUM_CHANNELS	8
+
+static const struct regmap_config ltc1660_regmap_config = {
+	.reg_bits = 4,
+	.val_bits = 12,
+};
+
+enum ltc1660_supported_device_ids {
+	ID_LTC1660,
+	ID_LTC1665,
+};
+
+struct ltc1660_priv {
+	struct spi_device *spi;
+	struct regmap *regmap;
+	struct regulator *vref_reg;
+	unsigned int value[LTC1660_NUM_CHANNELS];
+	unsigned int vref_mv;
+};
+
+static int ltc1660_read_raw(struct iio_dev *indio_dev,
+		struct iio_chan_spec const *chan,
+		int *val,
+		int *val2,
+		long mask)
+{
+	struct ltc1660_priv *priv = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		*val = priv->value[chan->channel];
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		*val = regulator_get_voltage(priv->vref_reg);
+		if (*val < 0) {
+			dev_err(&priv->spi->dev, "failed to read vref regulator: %d\n",
+					*val);
+			return *val;
+		}
+
+		/* Convert to mV */
+		*val /= 1000;
+		*val2 = chan->scan_type.realbits;
+		return IIO_VAL_FRACTIONAL_LOG2;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ltc1660_write_raw(struct iio_dev *indio_dev,
+		struct iio_chan_spec const *chan,
+		int val,
+		int val2,
+		long mask)
+{
+	struct ltc1660_priv *priv = iio_priv(indio_dev);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		if (val2 != 0)
+			return -EINVAL;
+
+		if (val < 0 || val > GENMASK(chan->scan_type.realbits - 1, 0))
+			return -EINVAL;
+
+		ret = regmap_write(priv->regmap, chan->channel,
+					(val << chan->scan_type.shift));
+		if (!ret)
+			priv->value[chan->channel] = val;
+
+		return ret;
+	default:
+		return -EINVAL;
+	}
+}
+
+#define LTC1660_CHAN(chan, bits) {			\
+	.type = IIO_VOLTAGE,				\
+	.indexed = 1,					\
+	.output = 1,					\
+	.channel = chan,				\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
+	.scan_type = {					\
+		.sign = 'u',				\
+		.realbits = (bits),			\
+		.storagebits = 16,			\
+		.shift = 12 - (bits),			\
+	},						\
+}
+
+#define  LTC1660_OCTAL_CHANNELS(bits) {			\
+		LTC1660_CHAN(LTC1660_REG_DAC_A, bits),	\
+		LTC1660_CHAN(LTC1660_REG_DAC_B, bits),	\
+		LTC1660_CHAN(LTC1660_REG_DAC_C, bits),	\
+		LTC1660_CHAN(LTC1660_REG_DAC_D, bits),	\
+		LTC1660_CHAN(LTC1660_REG_DAC_E, bits),	\
+		LTC1660_CHAN(LTC1660_REG_DAC_F, bits),	\
+		LTC1660_CHAN(LTC1660_REG_DAC_G, bits),	\
+		LTC1660_CHAN(LTC1660_REG_DAC_H, bits),	\
+}
+
+static const struct iio_chan_spec ltc1660_channels[][LTC1660_NUM_CHANNELS] = {
+	[ID_LTC1660] = LTC1660_OCTAL_CHANNELS(10),
+	[ID_LTC1665] = LTC1660_OCTAL_CHANNELS(8),
+};
+
+static const struct iio_info ltc1660_info = {
+	.read_raw = &ltc1660_read_raw,
+	.write_raw = &ltc1660_write_raw,
+};
+
+static int __maybe_unused ltc1660_suspend(struct device *dev)
+{
+	struct ltc1660_priv *priv = iio_priv(spi_get_drvdata(
+						to_spi_device(dev)));
+	return regmap_write(priv->regmap, LTC1660_REG_SLEEP, 0x00);
+}
+
+static int __maybe_unused ltc1660_resume(struct device *dev)
+{
+	struct ltc1660_priv *priv = iio_priv(spi_get_drvdata(
+						to_spi_device(dev)));
+	return regmap_write(priv->regmap, LTC1660_REG_WAKE, 0x00);
+}
+static SIMPLE_DEV_PM_OPS(ltc1660_pm_ops, ltc1660_suspend, ltc1660_resume);
+
+static int ltc1660_probe(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev;
+	struct ltc1660_priv *priv;
+	const struct spi_device_id *id = spi_get_device_id(spi);
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*priv));
+	if (indio_dev == NULL)
+		return -ENOMEM;
+
+	priv = iio_priv(indio_dev);
+	priv->regmap = devm_regmap_init_spi(spi, &ltc1660_regmap_config);
+	if (IS_ERR(priv->regmap)) {
+		dev_err(&spi->dev, "failed to register spi regmap %ld\n",
+			PTR_ERR(priv->regmap));
+		return PTR_ERR(priv->regmap);
+	}
+
+	priv->vref_reg = devm_regulator_get(&spi->dev, "vref");
+	if (IS_ERR(priv->vref_reg)) {
+		dev_err(&spi->dev, "vref regulator not specified\n");
+		return PTR_ERR(priv->vref_reg);
+	}
+
+	ret = regulator_enable(priv->vref_reg);
+	if (ret) {
+		dev_err(&spi->dev, "failed to enable vref regulator: %d\n",
+				ret);
+		return ret;
+	}
+
+	priv->spi = spi;
+	spi_set_drvdata(spi, indio_dev);
+	indio_dev->dev.parent = &spi->dev;
+	indio_dev->info = &ltc1660_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = ltc1660_channels[id->driver_data];
+	indio_dev->num_channels = LTC1660_NUM_CHANNELS;
+	indio_dev->name = id->name;
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		dev_err(&spi->dev, "failed to register iio device: %d\n",
+				ret);
+		goto error_disable_reg;
+	}
+
+	return 0;
+
+error_disable_reg:
+	regulator_disable(priv->vref_reg);
+
+	return ret;
+}
+
+static int ltc1660_remove(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev = spi_get_drvdata(spi);
+	struct ltc1660_priv *priv = iio_priv(indio_dev);
+
+	iio_device_unregister(indio_dev);
+	regulator_disable(priv->vref_reg);
+
+	return 0;
+}
+
+static const struct of_device_id ltc1660_dt_ids[] = {
+	{ .compatible = "lltc,ltc1660", .data = (void *)ID_LTC1660 },
+	{ .compatible = "lltc,ltc1665", .data = (void *)ID_LTC1665 },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, ltc1660_dt_ids);
+
+static const struct spi_device_id ltc1660_id[] = {
+	{"ltc1660", ID_LTC1660},
+	{"ltc1665", ID_LTC1665},
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(spi, ltc1660_id);
+
+static struct spi_driver ltc1660_driver = {
+	.driver = {
+		.name = "ltc1660",
+		.of_match_table = ltc1660_dt_ids,
+		.pm = &ltc1660_pm_ops,
+	},
+	.probe	= ltc1660_probe,
+	.remove = ltc1660_remove,
+	.id_table = ltc1660_id,
+};
+module_spi_driver(ltc1660_driver);
+
+MODULE_AUTHOR("Marcus Folkesson <marcus.folkesson@gmail.com>");
+MODULE_DESCRIPTION("Linear Technology LTC1660/LTC1665 DAC");
+MODULE_LICENSE("GPL v2");
-- 
2.11.0.rc2

[PATCH v2 2/3] dt-bindings: iio: dac: add bindings for ltc1660

[Marcus Folkesson]

LTC1665/LTC1660 is a 8/10-bit Digital-to-Analog Converter (DAC)
with eight individual channels.

Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
---

Notes:
    v2:
    	- rename file, ltc166x -> ltc1660

 .../devicetree/bindings/iio/dac/ltc1660.txt         | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/dac/ltc1660.txt

diff --git a/Documentation/devicetree/bindings/iio/dac/ltc1660.txt b/Documentation/devicetree/bindings/iio/dac/ltc1660.txt
new file mode 100644
index 000000000000..c5b5f22d6c64
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/dac/ltc1660.txt
@@ -0,0 +1,21 @@
+* Linear Technology Micropower octal 8-Bit and 10-Bit DACs
+
+Required properties:
+ - compatible: Must be one of the following:
+		"lltc,ltc1660"
+		"lltc,ltc1665"
+ - reg: SPI chip select number for the device
+ - vref-supply: Phandle to the voltage reference supply
+
+Recommended properties:
+ - spi-max-frequency: Definition as per
+	 Documentation/devicetree/bindings/spi/spi-bus.txt.
+	 Max frequency for this chip is 5 MHz.
+
+Example:
+dac@0 {
+	compatible = "lltc,ltc1660";
+	reg = <0>;
+	spi-max-frequency = <5000000>;
+	vref-supply = <&vref_reg>;
+};
-- 
2.11.0.rc2

Re: [PATCH v2 2/3] dt-bindings: iio: dac: add bindings for ltc1660

[Marcus Folkesson]

On Tue, Aug 21, 2018 at 09:31:25PM +0200, Marcus Folkesson wrote:
> LTC1665/LTC1660 is a 8/10-bit Digital-to-Analog Converter (DAC)
> with eight individual channels.
> 
> Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>

Rob, sorry I missed your tag.

Reviewed-by: Rob Herring <robh@kernel.org>

> ---
> 
> Notes:
>     v2:
>     	- rename file, ltc166x -> ltc1660
> 
>  .../devicetree/bindings/iio/dac/ltc1660.txt         | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/dac/ltc1660.txt
> 
> diff --git a/Documentation/devicetree/bindings/iio/dac/ltc1660.txt b/Documentation/devicetree/bindings/iio/dac/ltc1660.txt
> new file mode 100644
> index 000000000000..c5b5f22d6c64
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/dac/ltc1660.txt
> @@ -0,0 +1,21 @@
> +* Linear Technology Micropower octal 8-Bit and 10-Bit DACs
> +
> +Required properties:
> + - compatible: Must be one of the following:
> +		"lltc,ltc1660"
> +		"lltc,ltc1665"
> + - reg: SPI chip select number for the device
> + - vref-supply: Phandle to the voltage reference supply
> +
> +Recommended properties:
> + - spi-max-frequency: Definition as per
> +	 Documentation/devicetree/bindings/spi/spi-bus.txt.
> +	 Max frequency for this chip is 5 MHz.
> +
> +Example:
> +dac@0 {
> +	compatible = "lltc,ltc1660";
> +	reg = <0>;
> +	spi-max-frequency = <5000000>;
> +	vref-supply = <&vref_reg>;
> +};
> -- 
> 2.11.0.rc2
> 

Re: [PATCH v2 2/3] dt-bindings: iio: dac: add bindings for ltc1660

[Jonathan Cameron]

On Wed, 22 Aug 2018 21:25:18 +0200
Marcus Folkesson <marcus.folkesson@gmail.com> wrote:

> On Tue, Aug 21, 2018 at 09:31:25PM +0200, Marcus Folkesson wrote:
> > LTC1665/LTC1660 is a 8/10-bit Digital-to-Analog Converter (DAC)
> > with eight individual channels.
> > 
> > Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>  
> 
> Rob, sorry I missed your tag.
> 
> Reviewed-by: Rob Herring <robh@kernel.org>
Applied to the togreg branch of iio.git and pushed out as testing
to be largely ignored by the autobuilders.

Thanks,

Jonathan

> 
> > ---
> > 
> > Notes:
> >     v2:
> >     	- rename file, ltc166x -> ltc1660
> > 
> >  .../devicetree/bindings/iio/dac/ltc1660.txt         | 21 +++++++++++++++++++++
> >  1 file changed, 21 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/iio/dac/ltc1660.txt
> > 
> > diff --git a/Documentation/devicetree/bindings/iio/dac/ltc1660.txt b/Documentation/devicetree/bindings/iio/dac/ltc1660.txt
> > new file mode 100644
> > index 000000000000..c5b5f22d6c64
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/iio/dac/ltc1660.txt
> > @@ -0,0 +1,21 @@
> > +* Linear Technology Micropower octal 8-Bit and 10-Bit DACs
> > +
> > +Required properties:
> > + - compatible: Must be one of the following:
> > +		"lltc,ltc1660"
> > +		"lltc,ltc1665"
> > + - reg: SPI chip select number for the device
> > + - vref-supply: Phandle to the voltage reference supply
> > +
> > +Recommended properties:
> > + - spi-max-frequency: Definition as per
> > +	 Documentation/devicetree/bindings/spi/spi-bus.txt.
> > +	 Max frequency for this chip is 5 MHz.
> > +
> > +Example:
> > +dac@0 {
> > +	compatible = "lltc,ltc1660";
> > +	reg = <0>;
> > +	spi-max-frequency = <5000000>;
> > +	vref-supply = <&vref_reg>;
> > +};
> > -- 
> > 2.11.0.rc2
> >   

[PATCH v2 3/3] MAINTAINERS: add entry for ltc1660 DAC driver

[Marcus Folkesson]

Add entry for ltc1660 DAC driver and add myself as
maintainer of this driver.

Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
---

Notes:
    v2:
    	- rename enumerated files, ltc166x* -> ltc1660*

 MAINTAINERS | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 9276da915d9d..3db1edaf68bd 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8363,6 +8363,13 @@ L:	linux-scsi@vger.kernel.org
 S:	Maintained
 F:	drivers/scsi/sym53c8xx_2/
 
+LTC1660 DAC DRIVER
+M:	Marcus Folkesson <marcus.folkesson@gmail.com>
+L:	linux-iio@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/iio/dac/ltc1660.txt
+F:	drivers/iio/dac/ltc1660.c
+
 LTC4261 HARDWARE MONITOR DRIVER
 M:	Guenter Roeck <linux@roeck-us.net>
 L:	linux-hwmon@vger.kernel.org
-- 
2.11.0.rc2

Re: [PATCH v2 3/3] MAINTAINERS: add entry for ltc1660 DAC driver

[Jonathan Cameron]

On Tue, 21 Aug 2018 21:31:26 +0200
Marcus Folkesson <marcus.folkesson@gmail.com> wrote:

> Add entry for ltc1660 DAC driver and add myself as
> maintainer of this driver.
> 
> Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Applied.

Thanks,

Jonathan

> ---
> 
> Notes:
>     v2:
>     	- rename enumerated files, ltc166x* -> ltc1660*
> 
>  MAINTAINERS | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 9276da915d9d..3db1edaf68bd 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -8363,6 +8363,13 @@ L:	linux-scsi@vger.kernel.org
>  S:	Maintained
>  F:	drivers/scsi/sym53c8xx_2/
>  
> +LTC1660 DAC DRIVER
> +M:	Marcus Folkesson <marcus.folkesson@gmail.com>
> +L:	linux-iio@vger.kernel.org
> +S:	Maintained
> +F:	Documentation/devicetree/bindings/iio/dac/ltc1660.txt
> +F:	drivers/iio/dac/ltc1660.c
> +
>  LTC4261 HARDWARE MONITOR DRIVER
>  M:	Guenter Roeck <linux@roeck-us.net>
>  L:	linux-hwmon@vger.kernel.org

Re: [PATCH v2 1/3] iio: dac: add support for ltc1660

[Jonathan Cameron]

On Tue, 21 Aug 2018 21:31:24 +0200
Marcus Folkesson <marcus.folkesson@gmail.com> wrote:

> LTC1665/LTC1660 is a 8/10-bit Digital-to-Analog Converter
> (DAC) with eight individual channels.
> 
> Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Great.

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

Thanks,

Jonathan

> ---
> 
> Notes:
>     v2:
>     	- rename all instances of ltc166x to ltc1660
>     	- read regulator value "in-place" instead of cache voltage
>     	- fix error handling in ltc1660_write_raw
> 
>  drivers/iio/dac/Kconfig   |  10 ++
>  drivers/iio/dac/Makefile  |   1 +
>  drivers/iio/dac/ltc1660.c | 250 ++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 261 insertions(+)
>  create mode 100644 drivers/iio/dac/ltc1660.c
> 
> diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
> index 76db0768e454..cbee80bd111e 100644
> --- a/drivers/iio/dac/Kconfig
> +++ b/drivers/iio/dac/Kconfig
> @@ -120,6 +120,16 @@ config AD5624R_SPI
>  	  Say yes here to build support for Analog Devices AD5624R, AD5644R and
>  	  AD5664R converters (DAC). This driver uses the common SPI interface.
>  
> +config LTC1660
> +	tristate "Linear Technology LTC1660/LTC1665 DAC SPI driver"
> +	depends on SPI
> +	help
> +	  Say yes here to build support for Linear Technology
> +	  LTC1660 and LTC1665 Digital to Analog Converters.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called ltc1660.
> +
>  config LTC2632
>  	tristate "Linear Technology LTC2632-12/10/8 DAC spi driver"
>  	depends on SPI
> diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile
> index 81e710ed7491..e446eeb09c85 100644
> --- a/drivers/iio/dac/Makefile
> +++ b/drivers/iio/dac/Makefile
> @@ -26,6 +26,7 @@ obj-$(CONFIG_CIO_DAC) += cio-dac.o
>  obj-$(CONFIG_DPOT_DAC) += dpot-dac.o
>  obj-$(CONFIG_DS4424) += ds4424.o
>  obj-$(CONFIG_LPC18XX_DAC) += lpc18xx_dac.o
> +obj-$(CONFIG_LTC1660) += ltc1660.o
>  obj-$(CONFIG_LTC2632) += ltc2632.o
>  obj-$(CONFIG_M62332) += m62332.o
>  obj-$(CONFIG_MAX517) += max517.o
> diff --git a/drivers/iio/dac/ltc1660.c b/drivers/iio/dac/ltc1660.c
> new file mode 100644
> index 000000000000..10866838c72a
> --- /dev/null
> +++ b/drivers/iio/dac/ltc1660.c
> @@ -0,0 +1,250 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Driver for Linear Technology LTC1665/LTC1660, 8 channels DAC
> + *
> + * Copyright (C) 2018 Marcus Folkesson <marcus.folkesson@gmail.com>
> + */
> +#include <linux/bitops.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/regmap.h>
> +#include <linux/spi/spi.h>
> +
> +#define LTC1660_REG_WAKE	0x0
> +#define LTC1660_REG_DAC_A	0x1
> +#define LTC1660_REG_DAC_B	0x2
> +#define LTC1660_REG_DAC_C	0x3
> +#define LTC1660_REG_DAC_D	0x4
> +#define LTC1660_REG_DAC_E	0x5
> +#define LTC1660_REG_DAC_F	0x6
> +#define LTC1660_REG_DAC_G	0x7
> +#define LTC1660_REG_DAC_H	0x8
> +#define LTC1660_REG_SLEEP	0xe
> +
> +#define LTC1660_NUM_CHANNELS	8
> +
> +static const struct regmap_config ltc1660_regmap_config = {
> +	.reg_bits = 4,
> +	.val_bits = 12,
> +};
> +
> +enum ltc1660_supported_device_ids {
> +	ID_LTC1660,
> +	ID_LTC1665,
> +};
> +
> +struct ltc1660_priv {
> +	struct spi_device *spi;
> +	struct regmap *regmap;
> +	struct regulator *vref_reg;
> +	unsigned int value[LTC1660_NUM_CHANNELS];
> +	unsigned int vref_mv;
> +};
> +
> +static int ltc1660_read_raw(struct iio_dev *indio_dev,
> +		struct iio_chan_spec const *chan,
> +		int *val,
> +		int *val2,
> +		long mask)
> +{
> +	struct ltc1660_priv *priv = iio_priv(indio_dev);
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		*val = priv->value[chan->channel];
> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_SCALE:
> +		*val = regulator_get_voltage(priv->vref_reg);
> +		if (*val < 0) {
> +			dev_err(&priv->spi->dev, "failed to read vref regulator: %d\n",
> +					*val);
> +			return *val;
> +		}
> +
> +		/* Convert to mV */
> +		*val /= 1000;
> +		*val2 = chan->scan_type.realbits;
> +		return IIO_VAL_FRACTIONAL_LOG2;
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +static int ltc1660_write_raw(struct iio_dev *indio_dev,
> +		struct iio_chan_spec const *chan,
> +		int val,
> +		int val2,
> +		long mask)
> +{
> +	struct ltc1660_priv *priv = iio_priv(indio_dev);
> +	int ret;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		if (val2 != 0)
> +			return -EINVAL;
> +
> +		if (val < 0 || val > GENMASK(chan->scan_type.realbits - 1, 0))
> +			return -EINVAL;
> +
> +		ret = regmap_write(priv->regmap, chan->channel,
> +					(val << chan->scan_type.shift));
> +		if (!ret)
> +			priv->value[chan->channel] = val;
> +
> +		return ret;
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +#define LTC1660_CHAN(chan, bits) {			\
> +	.type = IIO_VOLTAGE,				\
> +	.indexed = 1,					\
> +	.output = 1,					\
> +	.channel = chan,				\
> +	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
> +	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
> +	.scan_type = {					\
> +		.sign = 'u',				\
> +		.realbits = (bits),			\
> +		.storagebits = 16,			\
> +		.shift = 12 - (bits),			\
> +	},						\
> +}
> +
> +#define  LTC1660_OCTAL_CHANNELS(bits) {			\
> +		LTC1660_CHAN(LTC1660_REG_DAC_A, bits),	\
> +		LTC1660_CHAN(LTC1660_REG_DAC_B, bits),	\
> +		LTC1660_CHAN(LTC1660_REG_DAC_C, bits),	\
> +		LTC1660_CHAN(LTC1660_REG_DAC_D, bits),	\
> +		LTC1660_CHAN(LTC1660_REG_DAC_E, bits),	\
> +		LTC1660_CHAN(LTC1660_REG_DAC_F, bits),	\
> +		LTC1660_CHAN(LTC1660_REG_DAC_G, bits),	\
> +		LTC1660_CHAN(LTC1660_REG_DAC_H, bits),	\
> +}
> +
> +static const struct iio_chan_spec ltc1660_channels[][LTC1660_NUM_CHANNELS] = {
> +	[ID_LTC1660] = LTC1660_OCTAL_CHANNELS(10),
> +	[ID_LTC1665] = LTC1660_OCTAL_CHANNELS(8),
> +};
> +
> +static const struct iio_info ltc1660_info = {
> +	.read_raw = &ltc1660_read_raw,
> +	.write_raw = &ltc1660_write_raw,
> +};
> +
> +static int __maybe_unused ltc1660_suspend(struct device *dev)
> +{
> +	struct ltc1660_priv *priv = iio_priv(spi_get_drvdata(
> +						to_spi_device(dev)));
> +	return regmap_write(priv->regmap, LTC1660_REG_SLEEP, 0x00);
> +}
> +
> +static int __maybe_unused ltc1660_resume(struct device *dev)
> +{
> +	struct ltc1660_priv *priv = iio_priv(spi_get_drvdata(
> +						to_spi_device(dev)));
> +	return regmap_write(priv->regmap, LTC1660_REG_WAKE, 0x00);
> +}
> +static SIMPLE_DEV_PM_OPS(ltc1660_pm_ops, ltc1660_suspend, ltc1660_resume);
> +
> +static int ltc1660_probe(struct spi_device *spi)
> +{
> +	struct iio_dev *indio_dev;
> +	struct ltc1660_priv *priv;
> +	const struct spi_device_id *id = spi_get_device_id(spi);
> +	int ret;
> +
> +	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*priv));
> +	if (indio_dev == NULL)
> +		return -ENOMEM;
> +
> +	priv = iio_priv(indio_dev);
> +	priv->regmap = devm_regmap_init_spi(spi, &ltc1660_regmap_config);
> +	if (IS_ERR(priv->regmap)) {
> +		dev_err(&spi->dev, "failed to register spi regmap %ld\n",
> +			PTR_ERR(priv->regmap));
> +		return PTR_ERR(priv->regmap);
> +	}
> +
> +	priv->vref_reg = devm_regulator_get(&spi->dev, "vref");
> +	if (IS_ERR(priv->vref_reg)) {
> +		dev_err(&spi->dev, "vref regulator not specified\n");
> +		return PTR_ERR(priv->vref_reg);
> +	}
> +
> +	ret = regulator_enable(priv->vref_reg);
> +	if (ret) {
> +		dev_err(&spi->dev, "failed to enable vref regulator: %d\n",
> +				ret);
> +		return ret;
> +	}
> +
> +	priv->spi = spi;
> +	spi_set_drvdata(spi, indio_dev);
> +	indio_dev->dev.parent = &spi->dev;
> +	indio_dev->info = &ltc1660_info;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->channels = ltc1660_channels[id->driver_data];
> +	indio_dev->num_channels = LTC1660_NUM_CHANNELS;
> +	indio_dev->name = id->name;
> +
> +	ret = iio_device_register(indio_dev);
> +	if (ret) {
> +		dev_err(&spi->dev, "failed to register iio device: %d\n",
> +				ret);
> +		goto error_disable_reg;
> +	}
> +
> +	return 0;
> +
> +error_disable_reg:
> +	regulator_disable(priv->vref_reg);
> +
> +	return ret;
> +}
> +
> +static int ltc1660_remove(struct spi_device *spi)
> +{
> +	struct iio_dev *indio_dev = spi_get_drvdata(spi);
> +	struct ltc1660_priv *priv = iio_priv(indio_dev);
> +
> +	iio_device_unregister(indio_dev);
> +	regulator_disable(priv->vref_reg);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id ltc1660_dt_ids[] = {
> +	{ .compatible = "lltc,ltc1660", .data = (void *)ID_LTC1660 },
> +	{ .compatible = "lltc,ltc1665", .data = (void *)ID_LTC1665 },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, ltc1660_dt_ids);
> +
> +static const struct spi_device_id ltc1660_id[] = {
> +	{"ltc1660", ID_LTC1660},
> +	{"ltc1665", ID_LTC1665},
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(spi, ltc1660_id);
> +
> +static struct spi_driver ltc1660_driver = {
> +	.driver = {
> +		.name = "ltc1660",
> +		.of_match_table = ltc1660_dt_ids,
> +		.pm = &ltc1660_pm_ops,
> +	},
> +	.probe	= ltc1660_probe,
> +	.remove = ltc1660_remove,
> +	.id_table = ltc1660_id,
> +};
> +module_spi_driver(ltc1660_driver);
> +
> +MODULE_AUTHOR("Marcus Folkesson <marcus.folkesson@gmail.com>");
> +MODULE_DESCRIPTION("Linear Technology LTC1660/LTC1665 DAC");
> +MODULE_LICENSE("GPL v2");