> This adds TI's tlc4541 16-bit ADC driver. Which is a single channel
> ADC. Supports raw and trigger buffer access.
comments below
> Signed-off-by: Phil Reid <preid@xxxxxxxxxxxxxxxxx>
> ---
> .../devicetree/bindings/iio/adc/ti-tlc4541.txt | 16 ++
> drivers/iio/adc/Kconfig | 11 +
> drivers/iio/adc/Makefile | 1 +
> drivers/iio/adc/ti-tlc4541.c | 266 +++++++++++++++++++++
> 4 files changed, 294 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/iio/adc/ti-tlc4541.txt
> create mode 100644 drivers/iio/adc/ti-tlc4541.c
>
> diff --git a/Documentation/devicetree/bindings/iio/adc/ti-tlc4541.txt b/Documentation/devicetree/bindings/iio/adc/ti-tlc4541.txt
> new file mode 100644
> index 0000000..67caccd
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/ti-tlc4541.txt
> @@ -0,0 +1,16 @@
> +* Texas Instruments' TLC4541
> +
> +Required properties:
> + - compatible: Should be one of
> + * "ti,tlc4541"
> + - reg: spi chip select number for the device
SPI
> + - vref-supply: The regulator supply for ADC reference voltage
> + - spi-max-frequency: Max SPI frequency to use (<= 200000)
> +
> +Example:
> +adc@0 {
> + compatible = "ti,adc0832";
> + reg = <0>;
> + vref-supply = <&vdd_supply>;
> + spi-max-frequency = <200000>;
> +};
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 99c0514..4dda3f0 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -525,6 +525,17 @@ config TI_AM335X_ADC
> To compile this driver as a module, choose M here: the module will be
> called ti_am335x_adc.
>
> +config TI_TLC4541
> + tristate "Texas Instruments TLC4541 ADC driver"
> + depends on SPI
> + select IIO_BUFFER
> + select IIO_TRIGGERED_BUFFER
> + help
> + Say yes here to build support for Texas Instruments TLC4541 ADC chip.
> +
> + This driver can also be built as a module. If so, the module will be
> + called ti-tlc4541.
> +
> config TWL4030_MADC
> tristate "TWL4030 MADC (Monitoring A/D Converter)"
> depends on TWL4030_CORE
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index 7a40c04..9bf2377 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -49,6 +49,7 @@ obj-$(CONFIG_TI_ADC161S626) += ti-adc161s626.o
> obj-$(CONFIG_TI_ADS1015) += ti-ads1015.o
> obj-$(CONFIG_TI_ADS8688) += ti-ads8688.o
> obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o
> +obj-$(CONFIG_TI_TLC4541) += ti-tlc4541.o
> obj-$(CONFIG_TWL4030_MADC) += twl4030-madc.o
> obj-$(CONFIG_TWL6030_GPADC) += twl6030-gpadc.o
> obj-$(CONFIG_VF610_ADC) += vf610_adc.o
> diff --git a/drivers/iio/adc/ti-tlc4541.c b/drivers/iio/adc/ti-tlc4541.c
> new file mode 100644
> index 0000000..a767707
> --- /dev/null
> +++ b/drivers/iio/adc/ti-tlc4541.c
> @@ -0,0 +1,266 @@
> +/*
> + * TI tlc4541 ADC Driver
> + *
> + * Copyright (C) 2017 Phil Reid
> + *
> + * Datasheets can be found here:
> + * http://www.ti.com/lit/gpn/tlc4541
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * The tlc4541 requires 24 clock cycles to start a transfer.
> + * Conversion then takes 2.94us to complete before data is ready
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/interrupt.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/iio/buffer.h>
> +#include <linux/iio/trigger_consumer.h>
> +#include <linux/iio/triggered_buffer.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/slab.h>
> +#include <linux/spi/spi.h>
> +#include <linux/sysfs.h>
> +
> +struct tlc4541_state {
> + struct spi_device *spi;
> + struct regulator *reg;
> + struct spi_transfer scan_single_xfer[3];
> + struct spi_message scan_single_msg;
> +
> + /*
> + * DMA (thus cache coherency maintenance) requires the
> + * transfer buffers to live in their own cache lines.
> + */
> + __be16 rx_buf[2] ____cacheline_aligned;
> +};
> +
> +struct tlc4541_chip_info {
> + const struct iio_chan_spec *channels;
> + unsigned int num_channels;
> +};
> +
> +enum tlc4541_id {
> + TLC4541,
> +};
> +
> +#define TLC4541_V_CHAN(index, bits) { \
> + .type = IIO_VOLTAGE, \
> + .indexed = 1, \
no need if there is just one channel
> + .channel = index, \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
> + .address = index, \
.address not needed
> + .scan_index = index, \
> + .scan_type = { \
> + .sign = 'u', \
> + .realbits = (bits), \
> + .storagebits = 16, \
> + .endianness = IIO_BE, \
> + }, \
> + }
> +
> +#define DECLARE_TLC4541_CHANNELS(name, bits) \
this flexibility is only needed when further chips are added; maybe start
simple and only implement what is needed at first
> +const struct iio_chan_spec name ## _channels[] = { \
> + TLC4541_V_CHAN(0, bits), \
> + IIO_CHAN_SOFT_TIMESTAMP(1), \
> +}
> +
> +static DECLARE_TLC4541_CHANNELS(tlc4541, 16);
> +
> +static const struct tlc4541_chip_info tlc4541_chip_info[] = {
> + [TLC4541] = {
> + .channels = tlc4541_channels,
> + .num_channels = ARRAY_SIZE(tlc4541_channels),
> + },
> +};
> +
> +static irqreturn_t tlc4541_trigger_handler(int irq, void *p)
> +{
> + struct iio_poll_func *pf = p;
> + struct iio_dev *indio_dev = pf->indio_dev;
> + struct tlc4541_state *st = iio_priv(indio_dev);
> + u16 buf[8]; /* 2 bytes data + 6 bytes padding + 8 bytes timestamp */
> + int ret;
> +
> + ret = spi_sync(st->spi, &st->scan_single_msg);
> + if (ret < 0)
> + goto done;
> +
> + buf[0] = be16_to_cpu(st->rx_buf[0]);
endianness is set to IIO_BE in scan_type, so this conversion is not needed
and maybe also buf and the copy can be avoided if rx_buf is large enough
> + iio_push_to_buffers_with_timestamp(indio_dev, buf,
> + iio_get_time_ns(indio_dev));
> +
> +done:
> + iio_trigger_notify_done(indio_dev->trig);
> + return IRQ_HANDLED;
> +}
> +
> +static int tlc4541_get_range(struct tlc4541_state *st)
> +{
> + int vref;
> +
> + vref = regulator_get_voltage(st->reg);
> + if (vref < 0)
> + return vref;
> +
> + vref /= 1000;
> +
> + return vref;
> +}
> +
> +static int tlc4541_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int *val,
> + int *val2,
> + long m)
> +{
> + int ret = 0;
> + struct tlc4541_state *st = iio_priv(indio_dev);
> +
> + switch (m) {
> + case IIO_CHAN_INFO_RAW:
> + ret = iio_device_claim_direct_mode(indio_dev);
> + if (ret)
> + return ret;
> + ret = spi_sync(st->spi, &st->scan_single_msg);
> + iio_device_release_direct_mode(indio_dev);
> + if (ret < 0)
> + return ret;
> + *val = be16_to_cpu(st->rx_buf[0]);
on page 12 of the datasheet, the conversion results is in two registers?
and rx_buf has two elements?
haven't investigated in detail -- maybe a comment would be good to detail
operation?
> + return IIO_VAL_INT;
> + case IIO_CHAN_INFO_SCALE:
> + ret = tlc4541_get_range(st);
> + if (ret < 0)
> + return ret;
> + *val = ret;
> + *val2 = chan->scan_type.realbits;
> + return IIO_VAL_FRACTIONAL_LOG2;
> + }
> + return -EINVAL;
> +}
> +
> +static const struct iio_info tlc4541_info = {
> + .read_raw = &tlc4541_read_raw,
> + .driver_module = THIS_MODULE,
> +};
> +
> +static int tlc4541_probe(struct spi_device *spi)
> +{
> + struct tlc4541_state *st;
> + struct iio_dev *indio_dev;
> + const struct tlc4541_chip_info *info;
> + int ret;
> + int8_t device_init = 0;
> +
> + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
> + if (indio_dev == NULL)
> + return -ENOMEM;
> +
> + st = iio_priv(indio_dev);
> +
> + spi_set_drvdata(spi, indio_dev);
> +
> + st->spi = spi;
> +
> + info = &tlc4541_chip_info[spi_get_device_id(spi)->driver_data];
> +
> + indio_dev->name = spi_get_device_id(spi)->name;
> + indio_dev->dev.parent = &spi->dev;
> + indio_dev->modes = INDIO_DIRECT_MODE;
> + indio_dev->channels = info->channels;
> + indio_dev->num_channels = info->num_channels;
> + indio_dev->info = &tlc4541_info;
> +
> + /* perform reset */
> + spi_write(spi, &device_init, 1);
> +
> + /* Setup default message */
> + st->scan_single_xfer[0].rx_buf = &st->rx_buf[0];
> + st->scan_single_xfer[0].len = 3;
> + st->scan_single_xfer[1].delay_usecs = 3;
> + st->scan_single_xfer[2].rx_buf = &st->rx_buf[0];
> + st->scan_single_xfer[2].len = 2;
> +
> + spi_message_init(&st->scan_single_msg);
> + spi_message_add_tail(&st->scan_single_xfer[0], &st->scan_single_msg);
> + spi_message_add_tail(&st->scan_single_xfer[1], &st->scan_single_msg);
> + spi_message_add_tail(&st->scan_single_xfer[2], &st->scan_single_msg);
> +
> + st->reg = devm_regulator_get(&spi->dev, "vref");
> + if (IS_ERR(st->reg))
> + return PTR_ERR(st->reg);
> +
> + ret = regulator_enable(st->reg);
> + if (ret)
> + return ret;
> +
> + ret = iio_triggered_buffer_setup(indio_dev, NULL,
> + &tlc4541_trigger_handler, NULL);
> + if (ret)
> + goto error_disable_reg;
> +
> + ret = iio_device_register(indio_dev);
> + if (ret)
> + goto error_cleanup_buffer;
> +
> + return 0;
> +
> +error_cleanup_buffer:
> + iio_triggered_buffer_cleanup(indio_dev);
> +error_disable_reg:
> + regulator_disable(st->reg);
> +
> + return ret;
> +}
> +
> +static int tlc4541_remove(struct spi_device *spi)
> +{
> + struct iio_dev *indio_dev = spi_get_drvdata(spi);
> + struct tlc4541_state *st = iio_priv(indio_dev);
> +
> + iio_device_unregister(indio_dev);
> + iio_triggered_buffer_cleanup(indio_dev);
> + regulator_disable(st->reg);
> +
> + return 0;
> +}
> +
> +#ifdef CONFIG_OF
> +
> +static const struct of_device_id tlc4541_dt_ids[] = {
> + { .compatible = "ti,tlc4541", },
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, tlc4541_dt_ids);
> +
> +#endif
> +
> +static const struct spi_device_id tlc4541_id[] = {
> + {"tlc4541", TLC4541},
> + {}
> +};
> +MODULE_DEVICE_TABLE(spi, tlc4541_id);
> +
> +static struct spi_driver tlc4541_driver = {
> + .driver = {
> + .name = "tlc4541",
> + .of_match_table = of_match_ptr(tlc4541_dt_ids),
> + },
> + .probe = tlc4541_probe,
> + .remove = tlc4541_remove,
> + .id_table = tlc4541_id,
> +};
> +module_spi_driver(tlc4541_driver);
> +
> +MODULE_AUTHOR("Phil Reid <preid@xxxxxxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Texas Instruments TLC4541 ADC");
> +MODULE_LICENSE("GPL v2");
>
--
Peter Meerwald-Stadler
+43-664-2444418 (mobile)
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