On Mon, 2 Aug 2021 15:04:41 +0200
Rodolfo Giometti <giometti@xxxxxxxxxxxx> wrote:
> This adds a new driver for the TI TLA2528 ADC chip.
>
> Signed-off-by: Rodolfo Giometti <giometti@xxxxxxxxxxxx>
Hi Rodolfo,
Comments inline,
Thanks,
Jonathan
> ---
> 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
>
> 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@xxxxxxxxxxxx>
> + */
> +
> +#include <linux/module.h>
Alphabetical order preferred, but fine to group the iio ones separately.
> +#include <linux/i2c.h>
> +#include <linux/delay.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/of.h>
Include mod_devicetable.h instead of of.h
> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
I don't think you are using anything from iio/sysfs.h
> +
> +#define TLA2528_OP_READ_REG 0x10
> +#define TLA2528_OP_WRITE_REG 0x08
> +
> +#define TLA2528_GENERAL_CFG 0x01
I suggest using naming to make ti celar which of these is a
field, and which is a register address. Given _REG is already
in use for something else perhaps
TLA2528_GENERAL_CFG_ADR etc?
It makes it easier to read the resulting code.
> +#define TLA2528_GENERAL_CFG_CNVST BIT(3)
> +#define TLA2528_DATA_CFG 0x02
> +#define TLA2528_DATA_CFG_APPEND_STATUS BIT(4)
Hmm. Datasheet oddly describes this one bit as being in a 2 bit field.
Guessing that's a typo and bit 5 is reserved.
> +#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];
Make this the actual type which seems to be __be16 from the code
below.
> + int ret;
> +
> + msg[0].addr = client->addr;
> + msg[0].flags = I2C_M_RD;
> + msg[0].buf = (u8 *) &data;
No need for cast here, but irrelevant anyway as the code will be gone
if you use i2c_master_recv()
> + msg[0].len = 2;
> +
> + ret = i2c_transfer(client->adapter, msg, 1);
i2c_master_recv()
> + if (ret < 0)
> + return ret;
> +
> + return le16_to_cpu(data[1] | (data[0] << 8));
This doesn't make any sense as the manual shifting
is converting from big endian to whatever the cpu is...
return be16_to_cpup(data); is probably what is intended.
> +}
> +
> +static s32 i2c_smbus_write_reg(const struct i2c_client *client, u8 reg, u8 val)
This naming is odd given these are not generic functions...
> +{
> + 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);
i2c_master_send() and have this return an int.
> +}
> +
> +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;
> +
> + /* 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@xxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Texas Instruments TLA2528 ADC driver");
> +MODULE_LICENSE("GPL v2");
