On 02/04/17 11:23, Jonathan Cameron wrote:
> 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.
I did a bit of digging and found that Mark has applied the tests
for a zero length transfer - so presumably he is happy with them!
Applied to the togreg branch of iio.git and pushed out as testing
for the autobuilders to play with it.
Will be interesting to see if we get reports of controllers that
don't handle this correctly.
Thanks,
Jonathan
>
> 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");
>>
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-iio" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
