On Sun, Jul 3, 2016 at 6:04 AM, Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
> On 02/07/16 23:05, Matt Ranostay wrote:
>> Add support for Texas Instruments ADC141S626, and ADC161S626 chips.
>>
>> Signed-off-by: Matt Ranostay <mranostay@xxxxxxxxx>
> Few little points inline and: No wild cards in driver names!
> (though I'm occasionally half asleep and let one in).
>
> Storage bits should always be a power of 2. (I let some
> of those slip in as well in the past... oops).
>
> Otherwise a few tiny corners where things could, I think,
> be a little more readable at the cost of slightly more code.
>
> Basically a nice little driver.
>
> Jonathan
>> ---
>> .../devicetree/bindings/iio/adc/ti-adc1x1s.txt | 16 ++
>> drivers/iio/adc/Kconfig | 12 ++
>> drivers/iio/adc/Makefile | 1 +
>> drivers/iio/adc/ti-adc1x1s.c | 233 +++++++++++++++++++++
>> 4 files changed, 262 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/iio/adc/ti-adc1x1s.txt
>> create mode 100644 drivers/iio/adc/ti-adc1x1s.c
>>
>> diff --git a/Documentation/devicetree/bindings/iio/adc/ti-adc1x1s.txt b/Documentation/devicetree/bindings/iio/adc/ti-adc1x1s.txt
>> new file mode 100644
>> index 000000000000..9cf7db434aee
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/iio/adc/ti-adc1x1s.txt
> Arguably could go in spi trivial devices binding file (unless you are going
> to suplement this soon anyway in which case it may be less churn to keep it
> here).
There doesn't seem to be a trivial-devices.txt for spi device bindings.
>> @@ -0,0 +1,16 @@
>> +* Texas Instruments' ADC141S626, and ADC161S626 chip
>> +
>> +Required properties:
>> + - compatible: Should be "ti,adc141s626" or "ti,ac161s626"
>> + - reg: spi chip select number for the device
>> +
>> +Recommended properties:
>> + - spi-max-frequency: Definition as per
>> + Documentation/devicetree/bindings/spi/spi-bus.txt
>> +
>> +Example:
>> +adc@0 {
>> + compatible = "ti,adc161s626";
>> + reg = <0>;
>> + spi-max-frequency = <4300000>;
>> +};
>> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
>> index 25378c5882e2..cb5e4ae3279d 100644
>> --- a/drivers/iio/adc/Kconfig
>> +++ b/drivers/iio/adc/Kconfig
>> @@ -414,6 +414,18 @@ config TI_ADC128S052
>> This driver can also be built as a module. If so, the module will be
>> called ti-adc128s052.
>>
>> +config TI_ADC1X1S
>> + tristate "Texas Instruments ADC1X1S 1-channel differential ADCs"
>> + depends on SPI
>> + select IIO_BUFFER
>> + select IIO_TRIGGERED_BUFFER
>> + help
>> + If you say yes here you get support for Texas Instruments ADC141S626,
>> + and ADC161S626 chips.
>> +
>> + This driver can also be build as a module. If so, the module will be
>> + called ti-adc1x1s.
>> +
>> config TI_ADS1015
>> tristate "Texas Instruments ADS1015 ADC"
>> depends on I2C && !SENSORS_ADS1015
>> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
>> index 38638d46f972..855ff407fd0d 100644
>> --- a/drivers/iio/adc/Makefile
>> +++ b/drivers/iio/adc/Makefile
>> @@ -40,6 +40,7 @@ obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
>> obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
>> obj-$(CONFIG_TI_ADC0832) += ti-adc0832.o
>> obj-$(CONFIG_TI_ADC128S052) += ti-adc128s052.o
>> +obj-$(CONFIG_TI_ADC1X1S) += ti-adc1x1s.o
>> obj-$(CONFIG_TI_ADS1015) += ti-ads1015.o
>> obj-$(CONFIG_TI_ADS8688) += ti-ads8688.o
>> obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o
>> diff --git a/drivers/iio/adc/ti-adc1x1s.c b/drivers/iio/adc/ti-adc1x1s.c
>> new file mode 100644
>> index 000000000000..889399968694
>> --- /dev/null
>> +++ b/drivers/iio/adc/ti-adc1x1s.c
>> @@ -0,0 +1,233 @@
>> +/*
>> + * ti-adc1x1s.c - Support for the Texas Instruments 1-channel differential ADCs
>> + *
>> + * ADC Devices Supported:
>> + * adc141s626 - 14-bit ADC
>> + * adc161s626 - 16-bit ADC
>> + *
>> + * Copyright (C) 2016 Matt Ranostay <mranostay@xxxxxxxxx>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License as published by
>> + * the Free Software Foundation; either version 2 of the License, or
>> + * (at your option) any later version.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> + * GNU General Public License for more details.
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <linux/init.h>
>> +#include <linux/err.h>
>> +#include <linux/spi/spi.h>
>> +#include <linux/iio/iio.h>
>> +#include <linux/iio/trigger.h>
>> +#include <linux/iio/buffer.h>
>> +#include <linux/iio/trigger_consumer.h>
>> +#include <linux/iio/triggered_buffer.h>
>> +
>> +#define TI_ADC_DRV_NAME "adc1x1s"
> I really dislike wild cards.... Just pick a part and name it after that.
>
>> +
>> +enum {
>> + TI_ADC141S626,
>> + TI_ADC161S626,
>> +};
>> +
>> +static const struct iio_chan_spec ti_adc141s626_channels[] = {
>> + {
>> + .type = IIO_VOLTAGE,
>> + .channel = 0,
>> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
>> + .scan_index = 0,
>> + .scan_type = {
>> + .sign = 's',
>> + .realbits = 14,
>> + .storagebits = 16,
>> + },
>> + },
>> + IIO_CHAN_SOFT_TIMESTAMP(1),
>> +};
>> +
>> +static const struct iio_chan_spec ti_adc161s626_channels[] = {
>> + {
>> + .type = IIO_VOLTAGE,
>> + .channel = 0,
>> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
>> + .scan_index = 0,
>> + .scan_type = {
>> + .sign = 's',
>> + .realbits = 16,
>> + .storagebits = 24,
> Storage bits should be a power of 2.
>> + .shift = 6,
>> + },
>> + },
>> + IIO_CHAN_SOFT_TIMESTAMP(1),
>> +};
>> +
>> +struct ti_adc_data {
>> + struct iio_dev *indio_dev;
>> + struct spi_device *spi;
>> + int read_size;
>> +
> enforce cacheline alignment or this is going to cause possible fun on
> dma using spi devices.
>> + u8 buffer[16]; /* 3 byte data + 5 byte pad + 8 byte timestamp */
>> +};
>> +
>> +static irqreturn_t ti_adc_trigger_handler(int irq, void *private)
>> +{
>> + struct iio_poll_func *pf = private;
>> + struct iio_dev *indio_dev = pf->indio_dev;
>> + struct ti_adc_data *data = iio_priv(indio_dev);
>> + int ret;
>> +
>> + ret = spi_read(data->spi, &data->buffer, data->read_size);
>> + if (!ret)
>> + iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
>> + iio_get_time_ns());
>> +
>> + iio_trigger_notify_done(indio_dev->trig);
>> +
>> + return IRQ_HANDLED;
>> +}
>> +
>> +static int ti_adc_read_measurement(struct ti_adc_data *data,
>> + struct iio_chan_spec const *chan, int *val)
>> +{
>> + __be32 buf;
>> + int ret;
>> +
>> + ret = spi_read(data->spi, (void *) &buf, data->read_size);
>> + if (ret)
>> + return ret;
>> +
>> + switch (data->read_size) {
>> + case 2:
>> + *val = be16_to_cpu(buf);
> Inelegant as buf is clearly marked as 32 bit by it's type. I'd move the
> read into the switch statement then read into the appropriate sized
> local variable. More code but easier to read (slightly)
>> + break;
>> + case 3:
>> + *val = be32_to_cpu(buf) >> 8;
>> + break;
>> + }
>> +
>> + *val = sign_extend32(*val >> chan->scan_type.shift,
>> + chan->scan_type.realbits - 1);
>> +
>> + return 0;
>> +}
>> +
>> +static int ti_adc_read_raw(struct iio_dev *indio_dev,
>> + struct iio_chan_spec const *chan,
>> + int *val, int *val2, long mask)
>> +{
>> + struct ti_adc_data *data = iio_priv(indio_dev);
>> + int ret;
>> +
>> + if (mask != IIO_CHAN_INFO_RAW)
>> + return -EINVAL;
>> +
>> + if (iio_device_claim_direct_mode(indio_dev))
>> + return -EBUSY;
> Should technically store and return the result of iio_device_claim_direct_mode.
> It could in future return something else..
>> +
>> + ret = ti_adc_read_measurement(data, chan, val);
>> + if (!ret)
>> + ret = IIO_VAL_INT;
> I'd make ti_adc_read_measurement return IIO_VAL_INT if successful. Then
> the slightly odd good path handling goes away.
>> +
>> + iio_device_release_direct_mode(indio_dev);
>> +
>> + return ret;
>> +}
>> +
>> +static const struct iio_info ti_adc_info = {
>> + .driver_module = THIS_MODULE,
>> + .read_raw = ti_adc_read_raw,
>> +};
>> +
>> +static int ti_adc_probe(struct spi_device *spi)
>> +{
>> + struct iio_dev *indio_dev;
>> + struct ti_adc_data *data;
>> + int ret;
>> +
>> + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*data));
>> + if (!indio_dev)
>> + return -ENOMEM;
>> +
>> + indio_dev->info = &ti_adc_info;
>> + indio_dev->dev.parent = &spi->dev;
>> + indio_dev->dev.of_node = spi->dev.of_node;
>> + indio_dev->name = TI_ADC_DRV_NAME;
>> + indio_dev->modes = INDIO_DIRECT_MODE;
>> + spi_set_drvdata(spi, indio_dev);
>> +
>> + data = iio_priv(indio_dev);
>> + data->spi = spi;
>> +
>> + switch (spi_get_device_id(spi)->driver_data) {
>> + case TI_ADC141S626:
>> + indio_dev->channels = ti_adc141s626_channels;
>> + indio_dev->num_channels = ARRAY_SIZE(ti_adc141s626_channels);
>> + data->read_size = 2;
>> + break;
>> + case TI_ADC161S626:
>> + indio_dev->channels = ti_adc161s626_channels;
>> + indio_dev->num_channels = ARRAY_SIZE(ti_adc161s626_channels);
>> + data->read_size = 3;
>> + break;
>> + }
>> +
>> + ret = iio_triggered_buffer_setup(indio_dev, NULL,
>> + ti_adc_trigger_handler, NULL);
>> + if (ret)
>> + return ret;
>> +
>> + ret = iio_device_register(indio_dev);
>> + if (ret)
>> + goto error_unreg_buffer;
>> +
>> + return 0;
>> +
>> +error_unreg_buffer:
>> + iio_triggered_buffer_cleanup(indio_dev);
>> +
>> + return ret;
>> +}
>> +
>> +static int ti_adc_remove(struct spi_device *spi)
>> +{
>> + struct iio_dev *indio_dev = spi_get_drvdata(spi);
>> +
>> + iio_device_unregister(indio_dev);
>> + iio_triggered_buffer_cleanup(indio_dev);
>> +
>> + return 0;
>> +}
>> +
>> +static const struct of_device_id ti_adc_dt_ids[] = {
>> + { .compatible = "ti,adc141s626", },
>> + { .compatible = "ti,adc161s626", },
>> + {}
>> +};
>> +MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);
>> +
>> +static const struct spi_device_id ti_adc_id[] = {
>> + {"adc141s626", TI_ADC141S626},
>> + {"adc161s626", TI_ADC161S626},
>> + {},
>> +};
>> +MODULE_DEVICE_TABLE(spi, ti_adc_id);
>> +
>> +static struct spi_driver ti_adc_driver = {
>> + .driver = {
>> + .name = TI_ADC_DRV_NAME,
>> + .of_match_table = of_match_ptr(ti_adc_dt_ids),
>> + },
>> + .probe = ti_adc_probe,
>> + .remove = ti_adc_remove,
>> + .id_table = ti_adc_id,
>> +};
>> +module_spi_driver(ti_adc_driver);
>> +
>> +MODULE_AUTHOR("Matt Ranostay <mranostay@xxxxxxxxx>");
>> +MODULE_DESCRIPTION("Texas Instruments ADC1x1S 1-channel differential ADC");
>> +MODULE_LICENSE("GPL");
>>
>
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