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SubjectRe: [PATCH 2/2] hwmon: Add ads1000/ads1100 voltage ADCs driver
On Mon, Jun 03, 2019 at 12:11:17PM +0100, Jonathan Cameron wrote:
> On Thu, 30 May 2019 05:55:10 -0700
> Guenter Roeck <linux@roeck-us.net> wrote:
>
> > Hi,
> >
> > On Wed, May 15, 2019 at 01:58:09AM +0300, Serge Semin wrote:
> > > These are simple Texas Instruments ADC working over i2c-interface with
> > > just one differential input and with configurable 12-16 bits resolution.
> > > Sample rate is fixed to 128 for ads1000 and can vary from 8 to 128 for
> > > ads1100. Vdd value reference value must be supplied so to properly
> > > translate the sampled code to the real voltage. All of these configs are
> > > implemented in the device drivers for hwmon subsystem. The next dts
> > > properties should be specified to comply the device platform setup:
> > > - vdd-supply - voltage regulator connected to the Vdd pin of the device
> > > - ti,gain - programmable gain amplifier
> > > - ti,datarate - converter data rate
> > > - ti,voltage-divider - possible resistors-base external divider
> > > See bindings documentation file for details.
> > >
> > > Even though these devices seem more like ads1015 series, they
> > > in fact pretty much different. First of all ads1000/ads1100 got less
> > > capabilities: just one port, no configurations of digital comparator, no
> > > input multi-channel multiplexer, smaller PGA and data-rate ranges.
> > > In addition they haven't got internal voltage reference, but instead
> > > are created to use Vdd pin voltage. Finally the output code value is
> > > provided in different format. As a result it was much easier for
> > > development and for future support to create a separate driver.
> > >
> >
> > This chicp doesn't have any real hardware monitoring characteristics
> > (no limit registers). It seems to be better suited to be implemented
> > as iio driver. If it is used as hardware monitor, the iio-hwmon bridge
> > should work just fine.
> >
> > Jonathan, what do you think ?
> Sorry for slow response, was on vacation.
>
> Agreed, this looks like a standard multipurpose ADC so probably more suited
> to IIO. Whether you bother with a buffered /chardev interface or not given it
> is a fairly slow device is a separate question (can always be added later
> when someone wants it).
>
> Note the voltage-divider in the DT properties is something that should
> have a generic representation. In IIO we have drivers/iio/afe/iio-rescale.c
> for that, in this case using the voltage divider binding.
>
> gain and datarate are both characteristics that should be controlled from
> userspace rather than via a binding.
>

In summary: Serge, please re-implement the driver as iio adc driver.

Thanks,
Guenter

> Thanks,
>
> Jonathan
> >
> > Thanks,
> > Guenter
> >
> > > Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
> > > ---
> > > MAINTAINERS | 8 +
> > > drivers/hwmon/Kconfig | 10 +
> > > drivers/hwmon/Makefile | 1 +
> > > drivers/hwmon/ads1000.c | 320 ++++++++++++++++++++++++++
> > > include/linux/platform_data/ads1000.h | 20 ++
> > > 5 files changed, 359 insertions(+)
> > > create mode 100644 drivers/hwmon/ads1000.c
> > > create mode 100644 include/linux/platform_data/ads1000.h
> > >
> > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > index ce573aaa04df..5c3a8107ef1a 100644
> > > --- a/MAINTAINERS
> > > +++ b/MAINTAINERS
> > > @@ -517,6 +517,14 @@ W: http://ez.analog.com/community/linux-device-drivers
> > > S: Supported
> > > F: drivers/video/backlight/adp8860_bl.c
> > >
> > > +ADS1000 HARDWARE MONITOR DRIVER
> > > +M: Serge Semin <fancer.lancer@gmail.com>
> > > +L: linux-hwmon@vger.kernel.org
> > > +S: Maintained
> > > +F: Documentation/hwmon/ads1000.rst
> > > +F: drivers/hwmon/ads1000.c
> > > +F: include/linux/platform_data/ads1000.h
> > > +
> > > ADS1015 HARDWARE MONITOR DRIVER
> > > M: Dirk Eibach <eibach@gdsys.de>
> > > L: linux-hwmon@vger.kernel.org
> > > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> > > index 1915a18b537b..a1220cc48f2f 100644
> > > --- a/drivers/hwmon/Kconfig
> > > +++ b/drivers/hwmon/Kconfig
> > > @@ -1569,6 +1569,16 @@ config SENSORS_ADC128D818
> > > This driver can also be built as a module. If so, the module
> > > will be called adc128d818.
> > >
> > > +config SENSORS_ADS1000
> > > + tristate "Texas Instruments ADS1000"
> > > + depends on I2C
> > > + help
> > > + If you say yes here you get support for Texas Instruments
> > > + ADS1000/ADS1100 12-16-bit single channel ADC device.
> > > +
> > > + This driver can also be built as a module. If so, the module
> > > + will be called ads1000.
> > > +
> > > config SENSORS_ADS1015
> > > tristate "Texas Instruments ADS1015"
> > > depends on I2C
> > > diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> > > index 8db472ea04f0..2cd82f6c651e 100644
> > > --- a/drivers/hwmon/Makefile
> > > +++ b/drivers/hwmon/Makefile
> > > @@ -35,6 +35,7 @@ obj-$(CONFIG_SENSORS_ADM1026) += adm1026.o
> > > obj-$(CONFIG_SENSORS_ADM1029) += adm1029.o
> > > obj-$(CONFIG_SENSORS_ADM1031) += adm1031.o
> > > obj-$(CONFIG_SENSORS_ADM9240) += adm9240.o
> > > +obj-$(CONFIG_SENSORS_ADS1000) += ads1000.o
> > > obj-$(CONFIG_SENSORS_ADS1015) += ads1015.o
> > > obj-$(CONFIG_SENSORS_ADS7828) += ads7828.o
> > > obj-$(CONFIG_SENSORS_ADS7871) += ads7871.o
> > > diff --git a/drivers/hwmon/ads1000.c b/drivers/hwmon/ads1000.c
> > > new file mode 100644
> > > index 000000000000..a88b738f56bd
> > > --- /dev/null
> > > +++ b/drivers/hwmon/ads1000.c
> > > @@ -0,0 +1,320 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +/*
> > > + * Driver for ADS1000/ADS1100 12-16-bit ADC
> > > + *
> > > + * Copyright (C) 2019 T-platforms JSC (fancer.lancer@gmail.com)
> > > + *
> > > + * Based on the ads1015 driver by Dirk Eibach.
> > > + *
> > > + * Datasheet available at: http://focus.ti.com/lit/ds/symlink/ads1000.pdf
> > > + */
> > > +
> > > +#include <linux/module.h>
> > > +#include <linux/init.h>
> > > +#include <linux/slab.h>
> > > +#include <linux/delay.h>
> > > +#include <linux/i2c.h>
> > > +#include <linux/hwmon.h>
> > > +#include <linux/hwmon-sysfs.h>
> > > +#include <linux/err.h>
> > > +#include <linux/mutex.h>
> > > +#include <linux/regulator/consumer.h>
> > > +#include <linux/of_device.h>
> > > +#include <linux/of.h>
> > > +#include <linux/platform_data/ads1000.h>
> > > +
> > > +/* Data rates scale table */
> > > +static const unsigned int scale_table[4] = {
> > > + 2048, 8192, 16384, 32768
> > > +};
> > > +
> > > +/* Minimal data rates in samples per second */
> > > +static const unsigned int data_rate_table[4] = {
> > > + 100, 25, 12, 5
> > > +};
> > > +
> > > +#define ADS1000_DEFAULT_PGA 0
> > > +#define ADS1000_DEFAULT_DATA_RATE 0
> > > +#define ADS1000_DEFAULT_R1_DIVIDER 0
> > > +#define ADS1000_DEFAULT_R2_DIVIDER 0
> > > +
> > > +enum ads1000_chips {
> > > + ads1000,
> > > + ads1100,
> > > +};
> > > +
> > > +struct ads1000 {
> > > + struct device *hwmon_dev;
> > > + struct mutex update_lock;
> > > + struct i2c_client *client;
> > > + struct ads1000_platform_data data;
> > > + enum ads1000_chips id;
> > > +};
> > > +
> > > +static inline int ads1000_enable_vdd(struct ads1000 *priv)
> > > +{
> > > + return regulator_enable(priv->data.vdd);
> > > +}
> > > +
> > > +static inline int ads1000_get_vdd(struct ads1000 *priv)
> > > +{
> > > + return regulator_get_voltage(priv->data.vdd);
> > > +}
> > > +
> > > +static int ads1000_read_adc(struct ads1000 *priv)
> > > +{
> > > + struct i2c_client *client = priv->client;
> > > + unsigned int delay_ms;
> > > + u8 data[3] = {0};
> > > + int res;
> > > +
> > > + mutex_lock(&priv->update_lock);
> > > +
> > > + delay_ms = DIV_ROUND_UP(1000, data_rate_table[priv->data.data_rate]);
> > > +
> > > + /* setup and start single conversion */
> > > + data[2] |= (1 << 7) | (1 << 4);
> > > + data[2] |= priv->data.pga;
> > > + data[2] |= priv->data.data_rate << 2;
> > > +
> > > + res = i2c_master_send(client, &data[2], 1);
> > > + if (res < 0)
> > > + goto err_unlock;
> > > +
> > > + /* wait until conversion finished */
> > > + msleep(delay_ms);
> > > + res = i2c_master_recv(client, data, 3);
> > > + if (res < 0)
> > > + goto err_unlock;
> > > +
> > > + if (data[2] & (1 << 7)) {
> > > + res = -EIO;
> > > + goto err_unlock;
> > > + }
> > > +
> > > + res = ((u16)data[0] << 8) | data[1];
> > > +
> > > +err_unlock:
> > > + mutex_unlock(&priv->update_lock);
> > > +
> > > + return res;
> > > +}
> > > +
> > > +static int ads1000_reg_to_mv(struct ads1000 *priv, s16 reg)
> > > +{
> > > + unsigned int *divider = priv->data.divider;
> > > + int voltage = ads1000_get_vdd(priv);
> > > + int gain = 1 << priv->data.pga;
> > > + int c = 0;
> > > +
> > > + voltage = reg*DIV_ROUND_CLOSEST(voltage, 1000);
> > > + gain = gain*scale_table[priv->data.data_rate];
> > > + voltage = DIV_ROUND_CLOSEST(voltage, gain);
> > > +
> > > + if (divider[0] && divider[1]) {
> > > + c = divider[0]*voltage;
> > > + c = DIV_ROUND_CLOSEST(c, (int)divider[1]);
> > > + }
> > > +
> > > + return voltage + c;
> > > +}
> > > +
> > > +static ssize_t show_in(struct device *dev, struct device_attribute *da,
> > > + char *buf)
> > > +{
> > > + struct ads1000 *priv = dev_get_drvdata(dev);
> > > + int res;
> > > +
> > > + res = ads1000_read_adc(priv);
> > > + if (res < 0)
> > > + return res;
> > > +
> > > + return sprintf(buf, "%d\n", ads1000_reg_to_mv(priv, res));
> > > +}
> > > +
> > > +static SENSOR_DEVICE_ATTR(in0_input, 0444, show_in, NULL, 0);
> > > +
> > > +static struct attribute *ads1000_attrs[] = {
> > > + &sensor_dev_attr_in0_input.dev_attr.attr,
> > > + NULL
> > > +};
> > > +ATTRIBUTE_GROUPS(ads1000);
> > > +
> > > +static struct ads1000 *ads1000_create_priv(struct i2c_client *client,
> > > + const struct i2c_device_id *id)
> > > +{
> > > + struct ads1000 *priv;
> > > +
> > > + priv = devm_kzalloc(&client->dev, sizeof(struct ads1000),
> > > + GFP_KERNEL);
> > > + if (!priv)
> > > + return ERR_PTR(-ENOMEM);
> > > +
> > > + if (client->dev.of_node)
> > > + priv->id = (enum ads1000_chips)
> > > + of_device_get_match_data(&client->dev);
> > > + else
> > > + priv->id = id->driver_data;
> > > +
> > > + i2c_set_clientdata(client, priv);
> > > + priv->client = client;
> > > + mutex_init(&priv->update_lock);
> > > +
> > > + return priv;
> > > +}
> > > +
> > > +#ifdef CONFIG_OF
> > > +static int ads1000_get_config_of(struct ads1000 *priv)
> > > +{
> > > + struct i2c_client *client = priv->client;
> > > + struct device_node *node = client->dev.of_node;
> > > + u32 divider[2];
> > > + u32 val;
> > > +
> > > + if (!node)
> > > + return -EINVAL;
> > > +
> > > + if (!of_property_read_u32(node, "ti,gain", &val))
> > > + priv->data.pga = val;
> > > +
> > > + if (!of_property_read_u32(node, "ti,datarate", &val))
> > > + priv->data.data_rate = val;
> > > +
> > > + if (!of_property_read_u32_array(node, "ti,voltage-divider",
> > > + divider, 2)) {
> > > + priv->data.divider[0] = divider[0];
> > > + priv->data.divider[1] = divider[1];
> > > + }
> > > +
> > > + priv->data.vdd = devm_regulator_get(&client->dev, "vdd");
> > > + if (IS_ERR(priv->data.vdd))
> > > + return PTR_ERR(priv->data.vdd);
> > > +
> > > + return 0;
> > > +}
> > > +#endif
> > > +
> > > +static int ads1000_get_config(struct ads1000 *priv)
> > > +{
> > > + struct i2c_client *client = priv->client;
> > > + struct ads1000_platform_data *pdata = dev_get_platdata(&client->dev);
> > > +
> > > + priv->data.pga = ADS1000_DEFAULT_PGA;
> > > + priv->data.data_rate = ADS1000_DEFAULT_DATA_RATE;
> > > + priv->data.divider[0] = ADS1000_DEFAULT_R1_DIVIDER;
> > > + priv->data.divider[1] = ADS1000_DEFAULT_R2_DIVIDER;
> > > +
> > > + /* prefer platform data */
> > > + if (pdata) {
> > > + memcpy(&priv->data, pdata, sizeof(priv->data));
> > > + } else {
> > > +#ifdef CONFIG_OF
> > > + int ret;
> > > +
> > > + ret = ads1000_get_config_of(priv);
> > > + if (ret)
> > > + return ret;
> > > +#endif
> > > + }
> > > +
> > > + if (!priv->data.vdd) {
> > > + dev_err(&client->dev, "No VDD regulator\n");
> > > + return -EINVAL;
> > > + }
> > > +
> > > + if (priv->data.pga > 4) {
> > > + dev_err(&client->dev, "Invalid gain, using default\n");
> > > + priv->data.pga = ADS1000_DEFAULT_PGA;
> > > + }
> > > +
> > > + if (priv->data.data_rate > 4) {
> > > + dev_err(&client->dev, "Invalid datarate, using default\n");
> > > + priv->data.data_rate = ADS1000_DEFAULT_DATA_RATE;
> > > + }
> > > +
> > > + if (priv->id == ads1000 && priv->data.data_rate != 0) {
> > > + dev_warn(&client->dev, "ADC data rate can be 128SPS only\n");
> > > + priv->data.data_rate = 0;
> > > + }
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +static int ads1000_set_config(struct ads1000 *priv)
> > > +{
> > > + u8 data = 0;
> > > + int ret;
> > > +
> > > + /* disable continuous conversion */
> > > + data |= (1 << 4);
> > > + data |= priv->data.pga;
> > > + data |= priv->data.data_rate << 2;
> > > +
> > > + ret = i2c_master_send(priv->client, &data, 1);
> > > +
> > > + return ret < 0 ? ret : 0;
> > > +}
> > > +
> > > +static int ads1000_probe(struct i2c_client *client,
> > > + const struct i2c_device_id *id)
> > > +{
> > > + struct ads1000 *priv;
> > > + int ret;
> > > +
> > > + priv = ads1000_create_priv(client, id);
> > > + if (IS_ERR(priv))
> > > + return PTR_ERR(priv);
> > > +
> > > + ret = ads1000_get_config(priv);
> > > + if (ret)
> > > + return ret;
> > > +
> > > + ret = ads1000_enable_vdd(priv);
> > > + if (ret)
> > > + return ret;
> > > +
> > > + ret = ads1000_set_config(priv);
> > > + if (ret)
> > > + return ret;
> > > +
> > > + priv->hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev,
> > > + client->name, priv, ads1000_groups);
> > > + if (IS_ERR(priv->hwmon_dev))
> > > + return PTR_ERR(priv->hwmon_dev);
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +static const struct i2c_device_id ads1000_id[] = {
> > > + { "ads1000", ads1000},
> > > + { "ads1100", ads1100},
> > > + { }
> > > +};
> > > +MODULE_DEVICE_TABLE(i2c, ads1000_id);
> > > +
> > > +static const struct of_device_id ads1000_of_match[] = {
> > > + {
> > > + .compatible = "ti,ads1000",
> > > + .data = (void *)ads1000
> > > + },
> > > + {
> > > + .compatible = "ti,ads1100",
> > > + .data = (void *)ads1100
> > > + },
> > > + { },
> > > +};
> > > +MODULE_DEVICE_TABLE(of, ads1000_of_match);
> > > +
> > > +static struct i2c_driver ads1000_driver = {
> > > + .driver = {
> > > + .name = "ads1000",
> > > + .of_match_table = of_match_ptr(ads1000_of_match),
> > > + },
> > > + .probe = ads1000_probe,
> > > + .id_table = ads1000_id,
> > > +};
> > > +module_i2c_driver(ads1000_driver);
> > > +
> > > +MODULE_AUTHOR("Serge Semin <fancer.lancer@gmail.com>");
> > > +MODULE_DESCRIPTION("ADS1000 driver");
> > > +MODULE_LICENSE("GPL v2");
> > > diff --git a/include/linux/platform_data/ads1000.h b/include/linux/platform_data/ads1000.h
> > > new file mode 100644
> > > index 000000000000..979670483537
> > > --- /dev/null
> > > +++ b/include/linux/platform_data/ads1000.h
> > > @@ -0,0 +1,20 @@
> > > +/* SPDX-License-Identifier: GPL-2.0 */
> > > +/*
> > > + * Platform Data for ADS1000/ADS1100 12-16-bit ADC
> > > + *
> > > + * Copyright (C) 2019 T-platforms JSC (fancer.lancer@gmail.com)
> > > + */
> > > +
> > > +#ifndef LINUX_ADS1000_H
> > > +#define LINUX_ADS1000_H
> > > +
> > > +#include <linux/regulator/consumer.h>
> > > +
> > > +struct ads1000_platform_data {
> > > + unsigned int pga;
> > > + unsigned int data_rate;
> > > + struct regulator *vdd;
> > > + unsigned int divider[2];
> > > +};
> > > +
> > > +#endif /* LINUX_ADS1000_H */
>
>

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