On 28/03/17 17:34, Akinobu Mita wrote:
> This adds max1117/max1118/max1119 8-bit, dual-channel ADC driver.
>
> This new driver uses the zero length spi_transfers with the cs_change
> flag set and/or the non-zero delay_usecs.
>
> 1. The zero length transfer with the spi_transfer.cs_change set is
> required in order to select CH1. The chip select line must be brought
> high and low again without transfer.
>
> 2. The zero length transfer with the spi_transfer.delay_usecs > 0 is
> required for waiting the conversion to be complete. The conversion
> begins with the falling edge of the chip select. During the conversion
> process, SCLK is ignored.
>
> These two usages are unusual. But the spi controller drivers that use
> a default implementation of transfer_one_message() are likely to work.
> (I've tested this adc driver with spi-omap2-mcspi and spi-xilinx)
>
> On the other hand, some spi controller drivers that have their own
> transfer_one_message() may not work. But at least for the zero length
> transfer with delay_usecs > 0, I'm proposing a new testcase for the
> spi-loopback-test that can test whether the delay_usecs setting has
> taken effect.
Thanks for the detailed description. As you might imagine I'll
be looking for an Ack from Mark Brown on this one - or if the discussion
is proceeding elsewhere, please post a link.
Otherwise driver looks great to me.
Give me a poke in a week or two if I seem to have forgotten it.
Jonathan
>
> Acked-by: Rob Herring <robh@xxxxxxxxxx>
> Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>
> Cc: Jonathan Cameron <jic23@xxxxxxxxxx>
> Cc: Hartmut Knaack <knaack.h@xxxxxx>
> Cc: Lars-Peter Clausen <lars@xxxxxxxxxx>
> Cc: Peter Meerwald-Stadler <pmeerw@xxxxxxxxxx>
> Cc: Rob Herring <robh+dt@xxxxxxxxxx>
> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> Cc: Mark Brown <broonie@xxxxxxxxxx>
> ---
> * v2
> - move max1118_remove() after max1118_probe() for usual code ordering
> - make the probe() fail for max1118 if vref-supply isn't acquired
> - add acked-by line
>
> .../devicetree/bindings/iio/adc/max1118.txt | 21 ++
> drivers/iio/adc/Kconfig | 12 +
> drivers/iio/adc/Makefile | 1 +
> drivers/iio/adc/max1118.c | 307 +++++++++++++++++++++
> 4 files changed, 341 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/iio/adc/max1118.txt
> create mode 100644 drivers/iio/adc/max1118.c
>
> diff --git a/Documentation/devicetree/bindings/iio/adc/max1118.txt b/Documentation/devicetree/bindings/iio/adc/max1118.txt
> new file mode 100644
> index 0000000..cf33d0b
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/max1118.txt
> @@ -0,0 +1,21 @@
> +* MAX1117/MAX1118/MAX1119 8-bit, dual-channel ADCs
> +
> +Required properties:
> + - compatible: Should be one of
> + * "maxim,max1117"
> + * "maxim,max1118"
> + * "maxim,max1119"
> + - reg: spi chip select number for the device
> + - (max1118 only) vref-supply: The regulator supply for ADC reference voltage
> +
> +Recommended properties:
> + - spi-max-frequency: Definition as per
> + Documentation/devicetree/bindings/spi/spi-bus.txt
> +
> +Example:
> +adc@0 {
> + compatible = "maxim,max1118";
> + reg = <0>;
> + vref-supply = <&vdd_supply>;
> + spi-max-frequency = <1000000>;
> +};
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index dedae7a..66262d1 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -335,6 +335,18 @@ config MAX11100
> To compile this driver as a module, choose M here: the module will be
> called max11100.
>
> +config MAX1118
> + tristate "Maxim max1117/max1118/max1119 ADCs driver"
> + depends on SPI
> + select IIO_BUFFER
> + select IIO_TRIGGERED_BUFFER
> + help
> + Say yes here to build support for Maxim max1117/max1118/max1119
> + 8-bit, dual-channel ADCs.
> +
> + To compile this driver as a module, choose M here: the module will be
> + called max1118.
> +
> config MAX1363
> tristate "Maxim max1363 ADC driver"
> depends on I2C
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index d001262..5ef3470 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -33,6 +33,7 @@ obj-$(CONFIG_LPC18XX_ADC) += lpc18xx_adc.o
> obj-$(CONFIG_LTC2485) += ltc2485.o
> obj-$(CONFIG_MAX1027) += max1027.o
> obj-$(CONFIG_MAX11100) += max11100.o
> +obj-$(CONFIG_MAX1118) += max1118.o
> obj-$(CONFIG_MAX1363) += max1363.o
> obj-$(CONFIG_MCP320X) += mcp320x.o
> obj-$(CONFIG_MCP3422) += mcp3422.o
> diff --git a/drivers/iio/adc/max1118.c b/drivers/iio/adc/max1118.c
> new file mode 100644
> index 0000000..2e9648a
> --- /dev/null
> +++ b/drivers/iio/adc/max1118.c
> @@ -0,0 +1,307 @@
> +/*
> + * MAX1117/MAX1118/MAX1119 8-bit, dual-channel ADCs driver
> + *
> + * Copyright (c) 2017 Akinobu Mita <akinobu.mita@xxxxxxxxx>
> + *
> + * This file is subject to the terms and conditions of version 2 of
> + * the GNU General Public License. See the file COPYING in the main
> + * directory of this archive for more details.
> + *
> + * Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX1117-MAX1119.pdf
> + *
> + * SPI interface connections
> + *
> + * SPI MAXIM
> + * Master Direction MAX1117/8/9
> + * ------ --------- -----------
> + * nCS --> CNVST
> + * SCK --> SCLK
> + * MISO <-- DOUT
> + * ------ --------- -----------
> + */
> +
> +#include <linux/module.h>
> +#include <linux/spi/spi.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/buffer.h>
> +#include <linux/iio/triggered_buffer.h>
> +#include <linux/iio/trigger_consumer.h>
> +#include <linux/regulator/consumer.h>
> +
> +enum max1118_id {
> + max1117,
> + max1118,
> + max1119,
> +};
> +
> +struct max1118 {
> + struct spi_device *spi;
> + struct mutex lock;
> + struct regulator *reg;
> +
> + u8 data ____cacheline_aligned;
> +};
> +
> +#define MAX1118_CHANNEL(ch) \
> + { \
> + .type = IIO_VOLTAGE, \
> + .indexed = 1, \
> + .channel = (ch), \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
> + .scan_index = ch, \
> + .scan_type = { \
> + .sign = 'u', \
> + .realbits = 8, \
> + .storagebits = 8, \
> + }, \
> + }
> +
> +static const struct iio_chan_spec max1118_channels[] = {
> + MAX1118_CHANNEL(0),
> + MAX1118_CHANNEL(1),
> + IIO_CHAN_SOFT_TIMESTAMP(2),
> +};
> +
> +static int max1118_read(struct spi_device *spi, int channel)
> +{
> + struct iio_dev *indio_dev = spi_get_drvdata(spi);
> + struct max1118 *adc = iio_priv(indio_dev);
> + struct spi_transfer xfers[] = {
> + /*
> + * To select CH1 for conversion, CNVST pin must be brought high
> + * and low for a second time.
> + */
> + {
> + .len = 0,
> + .delay_usecs = 1, /* > CNVST Low Time 100 ns */
> + .cs_change = 1,
> + },
> + /*
> + * The acquisition interval begins with the falling edge of
> + * CNVST. The total acquisition and conversion process takes
> + * <7.5us.
> + */
> + {
> + .len = 0,
> + .delay_usecs = 8,
> + },
> + {
> + .rx_buf = &adc->data,
> + .len = 1,
> + },
> + };
> + int ret;
> +
> + if (channel == 0)
> + ret = spi_sync_transfer(spi, xfers + 1, 2);
> + else
> + ret = spi_sync_transfer(spi, xfers, 3);
> +
> + if (ret)
> + return ret;
> +
> + return adc->data;
> +}
> +
> +static int max1118_get_vref_mV(struct spi_device *spi)
> +{
> + struct iio_dev *indio_dev = spi_get_drvdata(spi);
> + struct max1118 *adc = iio_priv(indio_dev);
> + const struct spi_device_id *id = spi_get_device_id(spi);
> + int vref_uV;
> +
> + switch (id->driver_data) {
> + case max1117:
> + return 2048;
> + case max1119:
> + return 4096;
> + case max1118:
> + vref_uV = regulator_get_voltage(adc->reg);
> + if (vref_uV < 0)
> + return vref_uV;
> + return vref_uV / 1000;
> + }
> +
> + return -ENODEV;
> +}
> +
> +static int max1118_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int *val, int *val2, long mask)
> +{
> + struct max1118 *adc = iio_priv(indio_dev);
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_RAW:
> + mutex_lock(&adc->lock);
> + *val = max1118_read(adc->spi, chan->channel);
> + mutex_unlock(&adc->lock);
> + if (*val < 0)
> + return *val;
> +
> + return IIO_VAL_INT;
> + case IIO_CHAN_INFO_SCALE:
> + *val = max1118_get_vref_mV(adc->spi);
> + if (*val < 0)
> + return *val;
> + *val2 = 8;
> +
> + return IIO_VAL_FRACTIONAL_LOG2;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static const struct iio_info max1118_info = {
> + .read_raw = max1118_read_raw,
> + .driver_module = THIS_MODULE,
> +};
> +
> +static irqreturn_t max1118_trigger_handler(int irq, void *p)
> +{
> + struct iio_poll_func *pf = p;
> + struct iio_dev *indio_dev = pf->indio_dev;
> + struct max1118 *adc = iio_priv(indio_dev);
> + u8 data[16] = { }; /* 2x 8-bit ADC data + padding + 8 bytes timestamp */
> + int scan_index;
> + int i = 0;
> +
> + mutex_lock(&adc->lock);
> +
> + for_each_set_bit(scan_index, indio_dev->active_scan_mask,
> + indio_dev->masklength) {
> + const struct iio_chan_spec *scan_chan =
> + &indio_dev->channels[scan_index];
> + int ret = max1118_read(adc->spi, scan_chan->channel);
> +
> + if (ret < 0) {
> + dev_warn(&adc->spi->dev,
> + "failed to get conversion data\n");
> + goto out;
> + }
> +
> + data[i] = ret;
> + i++;
> + }
> + iio_push_to_buffers_with_timestamp(indio_dev, data,
> + iio_get_time_ns(indio_dev));
> +out:
> + mutex_unlock(&adc->lock);
> +
> + iio_trigger_notify_done(indio_dev->trig);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int max1118_probe(struct spi_device *spi)
> +{
> + struct iio_dev *indio_dev;
> + struct max1118 *adc;
> + const struct spi_device_id *id = spi_get_device_id(spi);
> + int ret;
> +
> + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
> + if (!indio_dev)
> + return -ENOMEM;
> +
> + adc = iio_priv(indio_dev);
> + adc->spi = spi;
> + mutex_init(&adc->lock);
> +
> + if (id->driver_data == max1118) {
> + adc->reg = devm_regulator_get(&spi->dev, "vref");
> + if (IS_ERR(adc->reg)) {
> + dev_err(&spi->dev, "failed to get vref regulator\n");
> + return PTR_ERR(adc->reg);
> + }
> + ret = regulator_enable(adc->reg);
> + if (ret)
> + return ret;
> + }
> +
> + spi_set_drvdata(spi, indio_dev);
> +
> + indio_dev->name = spi_get_device_id(spi)->name;
> + indio_dev->dev.parent = &spi->dev;
> + indio_dev->info = &max1118_info;
> + indio_dev->modes = INDIO_DIRECT_MODE;
> + indio_dev->channels = max1118_channels;
> + indio_dev->num_channels = ARRAY_SIZE(max1118_channels);
> +
> + /*
> + * To reinitiate a conversion on CH0, it is necessary to allow for a
> + * conversion to be complete and all of the data to be read out. Once
> + * a conversion has been completed, the MAX1117/MAX1118/MAX1119 will go
> + * into AutoShutdown mode until the next conversion is initiated.
> + */
> + max1118_read(spi, 0);
> +
> + ret = iio_triggered_buffer_setup(indio_dev, NULL,
> + max1118_trigger_handler, NULL);
> + if (ret)
> + goto err_reg_disable;
> +
> + ret = iio_device_register(indio_dev);
> + if (ret)
> + goto err_buffer_cleanup;
> +
> + return 0;
> +
> +err_buffer_cleanup:
> + iio_triggered_buffer_cleanup(indio_dev);
> +err_reg_disable:
> + if (id->driver_data == max1118)
> + regulator_disable(adc->reg);
> +
> + return ret;
> +}
> +
> +static int max1118_remove(struct spi_device *spi)
> +{
> + struct iio_dev *indio_dev = spi_get_drvdata(spi);
> + struct max1118 *adc = iio_priv(indio_dev);
> + const struct spi_device_id *id = spi_get_device_id(spi);
> +
> + iio_device_unregister(indio_dev);
> + iio_triggered_buffer_cleanup(indio_dev);
> + if (id->driver_data == max1118)
> + return regulator_disable(adc->reg);
> +
> + return 0;
> +}
> +
> +static const struct spi_device_id max1118_id[] = {
> + { "max1117", max1117 },
> + { "max1118", max1118 },
> + { "max1119", max1119 },
> + {}
> +};
> +MODULE_DEVICE_TABLE(spi, max1118_id);
> +
> +#ifdef CONFIG_OF
> +
> +static const struct of_device_id max1118_dt_ids[] = {
> + { .compatible = "maxim,max1117" },
> + { .compatible = "maxim,max1118" },
> + { .compatible = "maxim,max1119" },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, max1118_dt_ids);
> +
> +#endif
> +
> +static struct spi_driver max1118_spi_driver = {
> + .driver = {
> + .name = "max1118",
> + .of_match_table = of_match_ptr(max1118_dt_ids),
> + },
> + .probe = max1118_probe,
> + .remove = max1118_remove,
> + .id_table = max1118_id,
> +};
> +module_spi_driver(max1118_spi_driver);
> +
> +MODULE_AUTHOR("Akinobu Mita <akinobu.mita@xxxxxxxxx>");
> +MODULE_DESCRIPTION("MAXIM MAX1117/MAX1118/MAX1119 ADCs driver");
> +MODULE_LICENSE("GPL v2");
>
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