Re: [PATCH 1/1] iio adc: add driver for Texas Instruments TLA2528 adc

[Alexandru Ardelean <ardeleanalex@gmail.com>]

On Mon, Aug 2, 2021 at 4:37 PM Alexandru Ardelean
<ardeleanalex@gmail.com> wrote:
>
> On Mon, Aug 2, 2021 at 4:06 PM Rodolfo Giometti <giometti@enneenne.com> wrote:
> >
> > This adds a new driver for the TI TLA2528 ADC chip.
> >
>
> Hey,
>
> The patch should include a V2 in the title.

Oh, apologies for the noise.
I just noticed that the Changelog and V2 tags are in patch 0/1

>
> > Signed-off-by: Rodolfo Giometti <giometti@enneenne.com>
> > ---
> >  drivers/iio/adc/Kconfig      |  10 ++
> >  drivers/iio/adc/Makefile     |   1 +
> >  drivers/iio/adc/ti-tla2528.c | 247 +++++++++++++++++++++++++++++++++++
> >  3 files changed, 258 insertions(+)
> >  create mode 100644 drivers/iio/adc/ti-tla2528.c
> >
>
> A changelog is a good idea here [in this place] :)
>
> > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> > index db0c8fb60515..f42e6d84c8f3 100644
> > --- a/drivers/iio/adc/Kconfig
> > +++ b/drivers/iio/adc/Kconfig
> > @@ -1178,6 +1178,16 @@ config TI_AM335X_ADC
> >           To compile this driver as a module, choose M here: the module will be
> >           called ti_am335x_adc.
> >
> > +config TI_TLA2528
> > +       tristate "Texas Instruments TLA2528 ADC driver"
> > +       depends on I2C
> > +       help
> > +         Say yes here to build support for Texas Instruments TLA2528
> > +         12-Bit 8-Channel ADC.
> > +
> > +         To compile this driver as a module, choose M here: the module will be
> > +         called ti-tla2528.
> > +
> >  config TI_TLC4541
> >         tristate "Texas Instruments TLC4541 ADC driver"
> >         depends on SPI
> > diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> > index f70d877c555a..0bf287672838 100644
> > --- a/drivers/iio/adc/Makefile
> > +++ b/drivers/iio/adc/Makefile
> > @@ -105,6 +105,7 @@ obj-$(CONFIG_TI_ADS8688) += ti-ads8688.o
> >  obj-$(CONFIG_TI_ADS124S08) += ti-ads124s08.o
> >  obj-$(CONFIG_TI_ADS131E08) += ti-ads131e08.o
> >  obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o
> > +obj-$(CONFIG_TI_TLA2528) += ti-tla2528.o
> >  obj-$(CONFIG_TI_TLC4541) += ti-tlc4541.o
> >  obj-$(CONFIG_TI_TSC2046) += ti-tsc2046.o
> >  obj-$(CONFIG_TWL4030_MADC) += twl4030-madc.o
> > diff --git a/drivers/iio/adc/ti-tla2528.c b/drivers/iio/adc/ti-tla2528.c
> > new file mode 100644
> > index 000000000000..5c362f846bae
> > --- /dev/null
> > +++ b/drivers/iio/adc/ti-tla2528.c
> > @@ -0,0 +1,247 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Driver for Texas Instruments TLA2528 ADC
> > + *
> > + * Copyright (C) 2020-2021 Rodolfo Giometti <giometti@enneenne.com>
> > + */
> > +
> > +#include <linux/module.h>
> > +#include <linux/i2c.h>
> > +#include <linux/delay.h>
> > +#include <linux/regulator/consumer.h>
> > +#include <linux/of.h>
> > +
> > +#include <linux/iio/iio.h>
> > +#include <linux/iio/sysfs.h>
> > +
> > +#define TLA2528_OP_READ_REG            0x10
> > +#define TLA2528_OP_WRITE_REG           0x08
> > +
> > +#define TLA2528_GENERAL_CFG            0x01
> > +#define TLA2528_GENERAL_CFG_CNVST      BIT(3)
> > +#define TLA2528_DATA_CFG               0x02
> > +#define TLA2528_DATA_CFG_APPEND_STATUS BIT(4)
> > +#define TLA2528_DATA_CFG_FIX_PAT       BIT(7)
> > +#define TLA2528_PIN_CFG                        0x05
> > +#define TLA2528_SEQUENCE_CFG           0x10
> > +#define TLA2528_CHANNEL_SEL            0x11
> > +
> > +struct tla2528_st {
> > +       struct i2c_client *client;
> > +       struct regulator *ref;
> > +
> > +       u8 last_read_channel;
> > +};
> > +
> > +static s32 i2c_smbus_read_sample(const struct i2c_client *client)
> > +{
> > +       struct i2c_msg msg[1];
> > +       u8 data[2];
> > +       int ret;
> > +
> > +       msg[0].addr = client->addr;
> > +       msg[0].flags = I2C_M_RD;
> > +       msg[0].buf = (u8 *) &data;
> > +       msg[0].len = 2;
> > +
> > +       ret = i2c_transfer(client->adapter, msg, 1);
> > +       if (ret < 0)
> > +               return ret;
> > +
> > +       return le16_to_cpu(data[1] | (data[0] << 8));
> > +}
> > +
> > +static s32 i2c_smbus_write_reg(const struct i2c_client *client, u8 reg, u8 val)
> > +{
> > +       struct i2c_msg msg[1];
> > +       u8 cmd[3] = {TLA2528_OP_WRITE_REG, reg, val};
> > +
> > +       msg[0].addr = client->addr;
> > +       msg[0].flags = 0;
> > +       msg[0].buf = cmd;
> > +       msg[0].len = 3;
> > +
> > +       return i2c_transfer(client->adapter, msg, 1);
> > +}
> > +
> > +static int tla2528_read(struct tla2528_st *st, u8 channel, int *val)
> > +{
> > +       struct i2c_client *client = st->client;
> > +       int ret;
> > +
> > +       if (channel != st->last_read_channel) {
> > +               ret = i2c_smbus_write_reg(st->client,
> > +                                       TLA2528_CHANNEL_SEL, channel);
> > +               if (ret < 0)
> > +                       return ret;
> > +
> > +               st->last_read_channel = channel;
> > +       }
> > +
> > +       /* Read ADC data (2 bytes) */
> > +       ret = i2c_smbus_read_sample(client);
> > +       if (ret < 0)  {
> > +               dev_err(&client->dev, "i2c_master_recv failed\n");
> > +               return ret;
> > +       }
> > +       *val = ret >> 4;
> > +
> > +       return 0;
> > +}
> > +
> > +static int tla2528_read_raw(struct iio_dev *indio_dev,
> > +                           struct iio_chan_spec const *chan,
> > +                           int *val, int *val2, long mask)
> > +{
> > +       struct tla2528_st *st = iio_priv(indio_dev);
> > +       int ret;
> > +
> > +       switch (mask) {
> > +       case IIO_CHAN_INFO_RAW:
> > +               mutex_lock(&indio_dev->mlock);
> > +               ret = tla2528_read(st, chan->channel, val);
> > +               mutex_unlock(&indio_dev->mlock);
> > +               if (ret < 0)
> > +                       return ret;
> > +
> > +               return IIO_VAL_INT;
> > +
> > +       case IIO_CHAN_INFO_SCALE:
> > +               ret = regulator_get_voltage(st->ref);
> > +               if (ret < 0)
> > +                       return ret;
> > +
> > +               *val = ret / 1000;
> > +               *val2 = 12;
> > +
> > +               return IIO_VAL_FRACTIONAL_LOG2;
> > +
> > +       default:
> > +               return -EINVAL;
> > +       }
> > +}
> > +
> > +#define TLA2528_CHAN(_chan, _name) { \
> > +       .type = IIO_VOLTAGE,                                    \
> > +       .channel = (_chan),                                     \
> > +       .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
> > +       .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
> > +       .datasheet_name = _name,                                \
> > +       .indexed = 1,                                           \
> > +}
> > +
> > +static const struct iio_chan_spec tla2528_channel[] = {
> > +       TLA2528_CHAN(0, "AIN0"),
> > +       TLA2528_CHAN(1, "AIN1"),
> > +       TLA2528_CHAN(2, "AIN2"),
> > +       TLA2528_CHAN(3, "AIN3"),
> > +       TLA2528_CHAN(4, "AIN4"),
> > +       TLA2528_CHAN(5, "AIN5"),
> > +       TLA2528_CHAN(6, "AIN6"),
> > +       TLA2528_CHAN(7, "AIN7"),
> > +};
> > +
> > +static const struct iio_info tla2528_info = {
> > +       .read_raw = tla2528_read_raw,
> > +};
> > +
> > +static int tla2528_probe(struct i2c_client *client,
> > +                        const struct i2c_device_id *id)
> > +{
> > +       struct iio_dev *indio_dev;
> > +       struct tla2528_st *st;
> > +       int ret;
> > +
> > +       if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
> > +                                    I2C_FUNC_SMBUS_WRITE_BYTE))
> > +               return -EOPNOTSUPP;
> > +
> > +       indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*st));
> > +       if (!indio_dev)
> > +               return -ENOMEM;
> > +
> > +       st = iio_priv(indio_dev);
> > +       i2c_set_clientdata(client, indio_dev);
> > +       st->client = client;
> > +
> > +       indio_dev->name = id->name;
> > +       indio_dev->info = &tla2528_info;
> > +       indio_dev->modes = INDIO_DIRECT_MODE;
> > +       indio_dev->channels = tla2528_channel;
> > +       indio_dev->num_channels = ARRAY_SIZE(tla2528_channel);
> > +
> > +       st->ref = devm_regulator_get(&client->dev, "vref");
> > +       if (IS_ERR(st->ref))
> > +               return PTR_ERR(st->ref);
> > +
> > +       ret = regulator_enable(st->ref);
> > +       if (ret < 0)
> > +               return ret;
> > +
>
> I was thinking about whether to mention this earlier.
> But, an idea, is to do:
>
>         ret = devm_add_action_or_reset(&spi->dev, tla2528_reg_disable,
> st->vref);
>         if (ret)
>                 return ret;
>
> Then the i2c_set_clientdata() call can be removed, and the
> tla2528_remove() hook as well.
> A simple example can be seen in drivers/iio/adc/ti-ads8344.c
>
> I'm not insisting on it. Since the driver is simple enough.
>
> > +       /* Set all inputs as analog */
> > +       ret = i2c_smbus_write_reg(st->client, TLA2528_PIN_CFG, 0x00);
> > +       if (ret < 0)
> > +               goto err_regulator_disable;
> > +
> > +       ret = i2c_smbus_write_reg(st->client, TLA2528_DATA_CFG,
> > +                                 TLA2528_DATA_CFG_APPEND_STATUS);
> > +       if (ret < 0)
> > +               goto err_regulator_disable;
> > +
> > +       /* Set manual mode */
> > +       ret = i2c_smbus_write_reg(st->client, TLA2528_SEQUENCE_CFG, 0x00);
> > +       if (ret < 0)
> > +               goto err_regulator_disable;
> > +
> > +       /* Init private data */
> > +       st->last_read_channel = ~0;
> > +
> > +       ret = iio_device_register(indio_dev);
> > +       if (ret < 0)
> > +               goto err_regulator_disable;
> > +
> > +       return 0;
> > +
> > +err_regulator_disable:
> > +       regulator_disable(st->ref);
> > +
> > +       return ret;
> > +}
> > +
> > +static int tla2528_remove(struct i2c_client *client)
> > +{
> > +       struct iio_dev *indio_dev = i2c_get_clientdata(client);
> > +       struct tla2528_st *st = iio_priv(indio_dev);
> > +
> > +       iio_device_unregister(indio_dev);
> > +       regulator_disable(st->ref);
> > +
> > +       return 0;
> > +}
> > +
> > +static const struct i2c_device_id tla2528_id[] = {
> > +       { "tla2528", 0 },
> > +       { }
> > +};
> > +MODULE_DEVICE_TABLE(i2c, tla2528_id);
> > +
> > +static const struct of_device_id tla2528_of_match[] = {
> > +       { .compatible = "ti,tla2528", },
> > +       { }
> > +};
> > +MODULE_DEVICE_TABLE(of, tla2528_of_match);
> > +
> > +static struct i2c_driver tla2528_driver = {
> > +       .driver = {
> > +               .name = "tla2528",
> > +               .of_match_table = tla2528_of_match,
> > +       },
> > +       .probe = tla2528_probe,
> > +       .remove = tla2528_remove,
> > +       .id_table = tla2528_id,
> > +};
> > +module_i2c_driver(tla2528_driver);
> > +
> > +MODULE_AUTHOR("Rodolfo Giometti <giometti@enneenne.com>");
> > +MODULE_DESCRIPTION("Texas Instruments TLA2528 ADC driver");
> > +MODULE_LICENSE("GPL v2");
> > --
> > 2.25.1
> >