Add maxim max34408/34409 ADC driver and dts
Subsystems (2)
cover Add maxim max34408/34409 ADC driver and dts
Add Maxim max34408/34409 ADC driver and dts for it. Until now it supports only current monitioring function without overcurrent threshold/delay, shutdown delay configuration, alert interrupt.
Ivan Mikhaylov (2):
dt-bindings: adc: provide max34408/9 device tree binding document
iio: adc: Add driver support for MAX34408/9
.../bindings/iio/adc/maxim,max34408.yaml | 63 ++++ drivers/iio/adc/Kconfig | 11 + drivers/iio/adc/Makefile | 1 + drivers/iio/adc/max34408.c | 334 ++++++++++++++++++ 4 files changed, 409 insertions(+) create mode 100644 Documentation/devicetree/bindings/iio/adc/maxim,max34408.yaml create mode 100644 drivers/iio/adc/max34408.c
Signature · 1 line
2.42.0
PATCH 1/2 dt-bindings: adc: provide max34408/9 device tree binding document
The i2c driver with Rsense option for current monitoring.
--- .../bindings/iio/adc/maxim,max34408.yaml | 63 +++++++++++++++++++ 1 file changed, 63 insertions(+) create mode 100644 Documentation/devicetree/bindings/iio/adc/maxim,max34408.yaml
Documentation/devicetree/bindings/iio/adc/maxim,max34408.yaml new file +63 -0
@@ -0,0 +1,63 @@ +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/iio/adc/maxim,max34408.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Two- and four-channel current monitors with overcurrent control. + +maintainers: + - Ivan Mikhaylov <[email protected]> + +description: | + The MAX34408/MAX34409 are two- and four-channel current monitors that are + configured and monitored with a standard I2C/SMBus serial interface. Each + unidirectional current sensor offers precision high-side operation with a + low full-scale sense voltage. The devices automatically sequence through + two or four channels and collect the current-sense samples and average them + to reduce the effect of impulse noise. The raw ADC samples are compared to + user-programmable digital thresholds to indicate overcurrent conditions. + Overcurrent conditions trigger a hardware output to provide an immediate + indication to shut down any necessary external circuitry. + + Specifications about the devices can be found at: + https://www.analog.com/media/en/technical-documentation/data-sheets/MAX34408-MAX34409.pdf + +properties: + compatible: + enum: + - maxim,max34408 + - maxim,max34409 + + reg: + maxItems: 1 + + interrupts: + maxItems: 1 + + maxim,rsense-val-micro-ohms: + description: + Adjust the Rsense value to monitor higher or lower current levels. + enum: [250, 500, 1000, 5000, 10000, 50000, 100000, 200000, 500000] + default: 1000 + +required: + - compatible + - reg + - maxim,rsense-val-micro-ohms + +additionalProperties: false + +examples: + - | + i2c { + + #address-cells = <1>; + #size-cells = <0>; + + adc@1e { + compatible = "maxim,max34409"; + reg = <0x1e>; + maxim,rsense-val-micro-ohms = <1000>; + }; + };
Signature · 1 line
2.42.0
Re: [PATCH 1/2] dt-bindings: adc: provide max34408/9 device tree binding document
Quoted 1 line · Ivan Mikhaylov
The i2c driver with Rsense option for current monitoring.
driver? This is a binding for a hardware device.
Quoted 13 lines
Signed-off-by Ivan Mikhaylov <[email protected]>--- .../bindings/iio/adc/maxim,max34408.yaml | 63 +++++++++++++++++++ 1 file changed, 63 insertions(+) create mode 100644 Documentation/devicetree/bindings/iio/adc/maxim,max34408.yamlDocumentation/devicetree/bindings/iio/adc/maxim,max34408.yaml new file +0
-0
Documentation/devicetree/bindings/iio/adc/maxim,max34408.yaml line 7
Quoted 7 lines
Documentation/devicetree/bindings/iio/adc/maxim,max34408.yaml new file +7
-0@@ -0,0 +1,63 @@ +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/iio/adc/maxim,max34408.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Two- and four-channel current monitors with overcurrent control.
Drop the period.
With those fixes:
Jonathan Cameron
maintainerRe: [PATCH 1/2] dt-bindings: adc: provide max34408/9 device tree binding document
In reply to Ivan MikhaylovQuoted 3 lines · On Mon, 18 Sep 2023 00:11:42 +0300 Ivan Mikhaylov <[email protected]> wrote:
The i2c driver with Rsense option for current monitoring.
Signed-off-by Ivan Mikhaylov <[email protected]>
Hi Ivan,
Welcome to IIO!
Looks good, but there are a few things I'd add to make this describe the device a little more fully and flexibly. Ideally we want a binding to fully describe a device, even if the particular driver for Linux doesn't use all the features. Some are easy though such as enabling regulators (that are probably turned on already on your board)
Thanks,
Jonathan
Quoted 39 lines
--- .../bindings/iio/adc/maxim,max34408.yaml | 63 +++++++++++++++++++ 1 file changed, 63 insertions(+) create mode 100644 Documentation/devicetree/bindings/iio/adc/maxim,max34408.yamlDocumentation/devicetree/bindings/iio/adc/maxim,max34408.yaml new file +28
-0@@ -0,0 +1,63 @@ +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/iio/adc/maxim,max34408.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Two- and four-channel current monitors with overcurrent control. + +maintainers: + - Ivan Mikhaylov <[email protected]> + +description: | + The MAX34408/MAX34409 are two- and four-channel current monitors that are + configured and monitored with a standard I2C/SMBus serial interface. Each + unidirectional current sensor offers precision high-side operation with a + low full-scale sense voltage. The devices automatically sequence through + two or four channels and collect the current-sense samples and average them + to reduce the effect of impulse noise. The raw ADC samples are compared to + user-programmable digital thresholds to indicate overcurrent conditions. + Overcurrent conditions trigger a hardware output to provide an immediate + indication to shut down any necessary external circuitry. + + Specifications about the devices can be found at: + https://www.analog.com/media/en/technical-documentation/data-sheets/MAX34408-MAX34409.pdf + +properties: + compatible: + enum:
Documentation/devicetree/bindings/iio/adc/maxim,max34408.yaml line 38
Quoted 10 lines
Documentation/devicetree/bindings/iio/adc/maxim,max34408.yaml new file +10
-0+ - maxim,max34408 + - maxim,max34409 + + reg: + maxItems: 1 + + interrupts: + maxItems: 1 + + maxim,rsense-val-micro-ohms:
From the datasheet you link, it looks like this could be different for the inputs?
Documentation/devicetree/bindings/iio/adc/maxim,max34408.yaml line 41
Quoted 3 lines
Documentation/devicetree/bindings/iio/adc/maxim,max34408.yaml new file +3
-0+ description: + Adjust the Rsense value to monitor higher or lower current levels. + enum: [250, 500, 1000, 5000, 10000, 50000, 100000, 200000, 500000]
These come from Table 18 which is example values I think? Not sure there is anything limiting us to those particular values given the equation given just above that table should apply more generally.
Documentation/devicetree/bindings/iio/adc/maxim,max34408.yaml line 42
Quoted 1 line
Documentation/devicetree/bindings/iio/adc/maxim,max34408.yaml new file +1
-0+ default: 1000
Please add regulator definitions.
supply-vdd: true
and add it to the required properties. It might be provided by a stub regulator but we still list that as required.
Also good to add bindings for the other control pins that might be wired to be in the binding from the start - no need for the driver to use them though. Looks like we have SHTDN and ENA here that could be wired to GPIOs on the host.
Quoted 21 lines
Documentation/devicetree/bindings/iio/adc/maxim,max34408.yaml new file +21
-0+ +required: + - compatible + - reg + - maxim,rsense-val-micro-ohms + +additionalProperties: false + +examples: + - | + i2c { + + #address-cells = <1>; + #size-cells = <0>; + + adc@1e { + compatible = "maxim,max34409"; + reg = <0x1e>; + maxim,rsense-val-micro-ohms = <1000>; + }; + };
Re: [PATCH 1/2] dt-bindings: adc: provide max34408/9 device tree binding document
Quoted 83 lines · Jonathan Cameron
Quoted 3 lines · On Mon, 18 Sep 2023 00:11:42 +0300 Ivan Mikhaylov <[email protected]> wrote:
The i2c driver with Rsense option for current monitoring.
Signed-off-by Ivan Mikhaylov <[email protected]>Hi Ivan,
Welcome to IIO!
Looks good, but there are a few things I'd add to make this describe the device
a little more fully and flexibly. Ideally we want a binding to fully describe
a device, even if the particular driver for Linux doesn't use all the features.
Some are easy though such as enabling regulators (that are probably turned on
already on your board)Thanks,
Jonathan
Quoted 58 lines
---
.../bindings/iio/adc/maxim,max34408.yaml | 63
+++++++++++++++++++1 file changed, 63 insertions(+)create mode 100644
Documentation/devicetree/bindings/iio/adc/maxim,max34408.yamldiff --git
a/Documentation/devicetree/bindings/iio/adc/maxim,max34408.yamlb/Documentation/devicetree/bindings/iio/adc/maxim,max34408.yamlnew file mode 100644
index 000000000000..ae7c6ddb13d8Documentation/devicetree/bindings/iio/adc/maxim,max34408.yaml new file +7
-0@@ -0,0 +1,63 @@ +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/iio/adc/maxim,max34408.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Two- and four-channel current monitors with overcurrentcontrol.
Documentation/devicetree/bindings/iio/adc/maxim,max34408.yaml new file +6
-0+ +maintainers: + - Ivan Mikhaylov <[email protected]> + +description: | + The MAX34408/MAX34409 are two- and four-channel current monitorsthat are
+ configured and monitored with a standard I2C/SMBus serial interface. Each
+ unidirectional current sensor offers precision high-side operation with a
+ low full-scale sense voltage. The devices automatically sequence through
+ two or four channels and collect the current-sense samples and average them
+ to reduce the effect of impulse noise. The raw ADC samples are compared to
+ user-programmable digital thresholds to indicate overcurrent conditions.
+ Overcurrent conditions trigger a hardware output to provide an immediate
+ indication to shut down any necessary external circuitry. +
+ Specifications about the devices can be found at:
+
https://www.analog.com/media/en/technical-documentation/data-sheets/MAX34408-MAX34409.pdfDocumentation/devicetree/bindings/iio/adc/maxim,max34408.yaml new file +9
-0+ +properties: + compatible: + enum: + - maxim,max34408 + - maxim,max34409 + + reg: + maxItems: 1
Quoted 8 lines
Documentation/devicetree/bindings/iio/adc/maxim,max34408.yaml line 38
Quoted 5 lines
Documentation/devicetree/bindings/iio/adc/maxim,max34408.yaml new file +5
-0+ + interrupts: + maxItems: 1 + + maxim,rsense-val-micro-ohms:From the datasheet you link, it looks like this could be different for
the inputs?
Hi Jonathan, "maxim,input1-rsense-val-micro-ohms", "maxim,input2- rsense-val-micro-ohms" and etc would be better?
Quoted 42 lines
Quoted 6 lines
+ description:
+ Adjust the Rsense value to monitor higher or lower current levels.
+ enum: [250, 500, 1000, 5000, 10000, 50000, 100000, 200000, 500000]These come from Table 18 which is example values I think? Not sure there
is anything limiting us to those particular values given the equation given
just above that table should apply more generally.Quoted 1 line
+ default: 1000
Please add regulator definitions.
supply-vdd: true
and add it to the required properties. It might be provided by a stub regulator
but we still list that as required.Also good to add bindings for the other control pins that might be wired to be
in the binding from the start - no need for the driver to use them though.
Looks like we have SHTDN and ENA here that could be wired to GPIOs on the host.Quoted 13 lines
Documentation/devicetree/bindings/iio/adc/maxim,max34408.yaml new file +13
-0+ +required: + - compatible + - reg + - maxim,rsense-val-micro-ohms + +additionalProperties: false + +examples: + - | + i2c { + + #address-cells = <1>;
Quoted 9 lines
Quoted 8 lines
+ #size-cells = <0>;
+
+ adc@1e {
+ compatible = "maxim,max34409"; + reg = <0x1e>;
+ maxim,rsense-val-micro-ohms = <1000>; + };
+ };
Rob, Jonathan, thanks for review, will do the changes which you asked.
Jonathan Cameron
maintainerRe: [PATCH 1/2] dt-bindings: adc: provide max34408/9 device tree binding document
Quoted 93 lines · On Mon, 25 Sep 2023 19:48:39 +0300 Ivan Mikhaylov <[email protected]> wrote:
Quoted 83 lines · Jonathan Cameron
Quoted 3 lines · On Mon, 18 Sep 2023 00:11:42 +0300 Ivan Mikhaylov <[email protected]> wrote:
The i2c driver with Rsense option for current monitoring.
Signed-off-by Ivan Mikhaylov <[email protected]>Hi Ivan,
Welcome to IIO!
Looks good, but there are a few things I'd add to make this describe the device
a little more fully and flexibly. Ideally we want a binding to fully describe
a device, even if the particular driver for Linux doesn't use all the features.
Some are easy though such as enabling regulators (that are probably turned on
already on your board)Thanks,
Jonathan
Quoted 58 lines
---
.../bindings/iio/adc/maxim,max34408.yaml | 63
+++++++++++++++++++1 file changed, 63 insertions(+)create mode 100644
Documentation/devicetree/bindings/iio/adc/maxim,max34408.yamldiff --git
a/Documentation/devicetree/bindings/iio/adc/maxim,max34408.yamlb/Documentation/devicetree/bindings/iio/adc/maxim,max34408.yamlnew file mode 100644
index 000000000000..ae7c6ddb13d8Documentation/devicetree/bindings/iio/adc/maxim,max34408.yaml new file +7
-0@@ -0,0 +1,63 @@ +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/iio/adc/maxim,max34408.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Two- and four-channel current monitors with overcurrentcontrol.
Documentation/devicetree/bindings/iio/adc/maxim,max34408.yaml new file +6
-0+ +maintainers: + - Ivan Mikhaylov <[email protected]> + +description: | + The MAX34408/MAX34409 are two- and four-channel current monitorsthat are
+ configured and monitored with a standard I2C/SMBus serial interface. Each
+ unidirectional current sensor offers precision high-side operation with a
+ low full-scale sense voltage. The devices automatically sequence through
+ two or four channels and collect the current-sense samples and average them
+ to reduce the effect of impulse noise. The raw ADC samples are compared to
+ user-programmable digital thresholds to indicate overcurrent conditions.
+ Overcurrent conditions trigger a hardware output to provide an immediate
+ indication to shut down any necessary external circuitry. +
+ Specifications about the devices can be found at:
+
https://www.analog.com/media/en/technical-documentation/data-sheets/MAX34408-MAX34409.pdfDocumentation/devicetree/bindings/iio/adc/maxim,max34408.yaml new file +9
-0+ +properties: + compatible: + enum: + - maxim,max34408 + - maxim,max34409 + + reg: + maxItems: 1Quoted 8 lines
Documentation/devicetree/bindings/iio/adc/maxim,max34408.yaml line 38
Quoted 5 lines
Documentation/devicetree/bindings/iio/adc/maxim,max34408.yaml new file +5
-0+ + interrupts: + maxItems: 1 + + maxim,rsense-val-micro-ohms:From the datasheet you link, it looks like this could be different for
the inputs?
Quoted 2 lines
Hi Jonathan, "maxim,input1-rsense-val-micro-ohms", "maxim,input2- rsense-val-micro-ohms" and etc would be better?
Sorry, missed this during the week (too many emails at work!)
Anyhow, I'd have suggested an array, but a better suggestion was made anyway in reply to your v2.
PATCH 2/2 iio: adc: Add driver support for MAX34408/9
In reply to Ivan MikhaylovThe MAX34408/MAX34409 are two- and four-channel current monitors that are configured and monitored with a standard I2C/SMBus serial interface. Each unidirectional current sensor offers precision high-side operation with a low full-scale sense voltage. The devices automatically sequence through two or four channels and collect the current-sense samples and average them to reduce the effect of impulse noise. The raw ADC samples are compared to user-programmable digital thresholds to indicate overcurrent conditions. Overcurrent conditions trigger a hardware output to provide an immediate indication to shut down any necessary external circuitry.
Add as ADC driver which only supports current monitoring for now.
--- drivers/iio/adc/Kconfig | 11 ++ drivers/iio/adc/Makefile | 1 + drivers/iio/adc/max34408.c | 334 +++++++++++++++++++++++++++++++++++++ 3 files changed, 346 insertions(+) create mode 100644 drivers/iio/adc/max34408.c
drivers/iio/adc/Kconfig +11 -0
@@ -756,6 +756,17 @@ config MAX9611 To compile this driver as a module, choose M here: the module will be called max9611. +config MAX34408 + tristate "Maxim max34408/max344089 ADC driver" + depends on I2C + help + Say yes here to build support for Maxim max34408/max34409 current sense + monitor with 8-bits ADC interface with overcurrent delay/threshold and + shutdown delay. + + To compile this driver as a module, choose M here: the module will be + called max34408. + config MCP320X tristate "Microchip Technology MCP3x01/02/04/08 and MCP3550/1/3" depends on SPI
drivers/iio/adc/Makefile +1 -0
@@ -69,6 +69,7 @@ obj-$(CONFIG_MAX1241) += max1241.o obj-$(CONFIG_MAX1363) += max1363.o obj-$(CONFIG_MAX77541_ADC) += max77541-adc.o obj-$(CONFIG_MAX9611) += max9611.o +obj-$(CONFIG_MAX34408) += max34408.o obj-$(CONFIG_MCP320X) += mcp320x.o obj-$(CONFIG_MCP3422) += mcp3422.o obj-$(CONFIG_MCP3911) += mcp3911.o
drivers/iio/adc/max34408.c new file +334 -0
334 lines not on this page · raw message
Signature · 1 line
2.42.0
Re: [PATCH 2/2] iio: adc: Add driver support for MAX34408/9
Hi,
Looks very good. Few small comments.
drivers/iio/adc/max34408.c line 184
Quoted 4 lines · Ivan Mikhaylov
[...]
drivers/iio/adc/max34408.c new file +3
-0+static int max34408_read_adc_avg (struct max34408_data *max34408,int channel,int *val) +{ +unsigned long ctrl;
Should be unsigned int so its compatible with the regmap API and you do not have to cast. Otherwise you'll run into trouble where long is 64 bit.
drivers/iio/adc/max34408.c line 197
Quoted 13 lines
drivers/iio/adc/max34408.c new file +13
-0+int rc; +u8 tmp; + +mutex_lock (&max34408->lock); + rc =regmap_read (max34408->regmap,MAX34408_CONTROL , (u32 *)&ctrl); +if (rc) + goto err_unlock; + +/* set averaging (0b100) default values*/ + tmp = ctrl; +set_bit (CONTROL_AVG2 , &ctrl); +clear_bit (CONTROL_AVG1 , &ctrl); +clear_bit (CONTROL_AVG0 , &ctrl);
While using set and clear_bit is not wrong these are the atomic versions. There is __{set,clear}_bit as the non atomic version. But in my opinion is fine to just use |= and &= here.
Quoted 29 lines
drivers/iio/adc/max34408.c new file +29
-0+ rc =regmap_write (max34408->regmap,MAX34408_CONTROL , ctrl); +if (rc) { +dev_err (max34408->dev, +"Error (%d) writing control register\n" , rc); + goto err_unlock; + } + + rc =max34408_read_adc (max34408, channel, val); +if (rc) + goto err_unlock; + +/* back to old values */ + rc =regmap_write (max34408->regmap,MAX34408_CONTROL , tmp); +if (rc) +dev_err (max34408->dev, +"Error (%d) writing control register\n" , rc); + +err_unlock: +mutex_unlock (&max34408->lock); + +return rc; +} + +static int max34408_read_raw (struct iio_dev *indio_dev, +struct iio_chan_spec const *chan, +int *val,int *val2,long mask) +{ +struct max34408_data *max34408 =iio_priv (indio_dev); +int rc;
drivers/iio/adc/max34408.c line 236
Quoted 10 lines
drivers/iio/adc/max34408.c new file +10
-0+ +switch (mask) { +case IIO_CHAN_INFO_PROCESSED : +case IIO_CHAN_INFO_AVERAGE_RAW : + rc =max34408_read_adc_avg (max34408, chan->channel, + val); +if (rc) +return rc; + +if (mask ==IIO_CHAN_INFO_PROCESSED ) {
Usually we only have either raw + offset and scale or processed. In this case I'd go with raw + scale and offset since it is a linear transformation. processed is usually only used when the transformation is non linear.
Quoted 26 lines
drivers/iio/adc/max34408.c new file +26
-0+/* +* calcluate current for 8bit ADC with Rsense +* value. +* 10 mV * 1000 / Rsense uOhm = max current +* (max current * adc val * 1000) / (2^8 - 1) mA +*/ + *val =DIV_ROUND_CLOSEST ((10000 / max34408->rsense) * + *val *1000 ,256 ); + } + +return IIO_VAL_INT ; +case IIO_CHAN_INFO_RAW : + rc =max34408_read_adc (max34408, chan->channel, val); +if (rc) +return rc; +return IIO_VAL_INT ; +default : +return -EINVAL ; + } +} + +static const struct iio_info max34408_info = { + .read_raw = max34408_read_raw, +}; + +static int max34408_probe (struct i2c_client *client)
drivers/iio/adc/max34408.c line 272
Quoted 10 lines
drivers/iio/adc/max34408.c new file +10
-0+{ +struct device_node *np = client->dev.of_node; +struct max34408_data *max34408; +struct iio_dev *indio_dev; +struct regmap *regmap; +int rc; + + regmap =devm_regmap_init_i2c (client, &max34408_regmap_config); +if (IS_ERR (regmap)) { +dev_err (&client->dev,"regmap_init failed\n" );
There is a the dev_err_probe function, which has the advantage of having a unified formatting for the error message style.
Quoted 14 lines
drivers/iio/adc/max34408.c new file +14
-0+return PTR_ERR (regmap); + } + + indio_dev =devm_iio_device_alloc (&client->dev,sizeof (*max34408)); +if (!indio_dev) +return -ENOMEM ; + + max34408 =iio_priv (indio_dev); +i2c_set_clientdata (client, indio_dev); + max34408->regmap = regmap; + max34408->dev = &client->dev; +mutex_init (&max34408->lock); + rc = device_property_read_u32(&client->dev, + "maxim,rsense-val-micro-ohms",
drivers/iio/adc/max34408.c line 296
Quoted 10 lines
drivers/iio/adc/max34408.c new file +10
-0+ &max34408->rsense); +if (rc) +return -EINVAL ; + +/* disable ALERT and averaging */ + rc =regmap_write (max34408->regmap,MAX34408_CONTROL ,0x0 ); +if (rc) +return rc; + +if (of_device_is_compatible (np,"maxim,max34408" )) {
Instead of using of_device_is_compatible it is usually preferred to assign some sort of chip_data struct to the data field of the of the compatible array. This makes it both easier to add new chips and also other ways to instantiate the device besides devicetree.
drivers/iio/adc/max34408.c line 307
Quoted 11 lines
drivers/iio/adc/max34408.c new file +11
-0+ indio_dev->channels = max34408_channels; + indio_dev->num_channels =ARRAY_SIZE (max34408_channels); + indio_dev->name ="max34408" ; + }else if (of_device_is_compatible (np,"maxim,max34409" )) { + indio_dev->channels = max34409_channels; + indio_dev->num_channels =ARRAY_SIZE (max34409_channels); + indio_dev->name ="max34409" ; + } + indio_dev->info = &max34408_info; + indio_dev->modes =INDIO_DIRECT_MODE ; + indio_dev->dev.of_node = np;
The assignment of of_node should not be needed, the IIO core will take care of this.
Quoted 4 lines
drivers/iio/adc/max34408.c new file +4
-0+ +return devm_iio_device_register (&client->dev, indio_dev); +} +
Jonathan Cameron
maintainerRe: [PATCH 2/2] iio: adc: Add driver support for MAX34408/9
In reply to Ivan MikhaylovQuoted 11 lines · On Mon, 18 Sep 2023 00:11:43 +0300 Ivan Mikhaylov <[email protected]> wrote:
The MAX34408/MAX34409 are two- and four-channel current monitors that are configured and monitored with a standard I2C/SMBus serial interface. Each unidirectional current sensor offers precision high-side operation with a low full-scale sense voltage. The devices automatically sequence through two or four channels and collect the current-sense samples and average them to reduce the effect of impulse noise. The raw ADC samples are compared to user-programmable digital thresholds to indicate overcurrent conditions. Overcurrent conditions trigger a hardware output to provide an immediate indication to shut down any necessary external circuitry.
Add as ADC driver which only supports current monitoring for now.
Hi Ivan.
A few additional comments from me to add to what Lars said. Generally looking nice.
Jonathan
Quoted 3 lines
Link is part of the tags block, so no blank line here (tools can then handle it as a tag rather than freeform text.
Quoted 36 lines
Signed-off-by Ivan Mikhaylov <[email protected]>--- drivers/iio/adc/Kconfig | 11 ++ drivers/iio/adc/Makefile | 1 + drivers/iio/adc/max34408.c | 334 +++++++++++++++++++++++++++++++++++++ 3 files changed, 346 insertions(+) create mode 100644 drivers/iio/adc/max34408.cdrivers/iio/adc/Kconfig +11
-0@@ -756,6 +756,17 @@ config MAX9611 To compile this driver as a module, choose M here: the module will be called max9611. +config MAX34408 + tristate "Maxim max34408/max344089 ADC driver" + depends on I2C + help + Say yes here to build support for Maxim max34408/max34409 current sense + monitor with 8-bits ADC interface with overcurrent delay/threshold and + shutdown delay. + + To compile this driver as a module, choose M here: the module will be + called max34408. + config MCP320X tristate "Microchip Technology MCP3x01/02/04/08 and MCP3550/1/3" depends on SPIdrivers/iio/adc/Makefile +0
-0
drivers/iio/adc/Makefile obj-$(CONFIG_MAX1241) += max1241.o · line 72
Quoted 4 lines
drivers/iio/adc/Makefile +1
-0@@ -69,6 +69,7 @@ obj-$(CONFIG_MAX1241) += max1241.o obj-$(CONFIG_MAX1363) += max1363.o obj-$(CONFIG_MAX77541_ADC) += max77541-adc.o obj-$(CONFIG_MAX9611) += max9611.o +obj-$(CONFIG_MAX34408) += max34408.o
Hmm. For consistency should be after max1363 I think. We've gone with alphanumeric order so far rather than taking digits into account so we should keep to that.
That also means moving it up in the Kconfig file.
I've not checked we've been consistent beyond the names I can see here though.
Quoted 19 lines
drivers/iio/adc/Makefile +0
-0obj-$(CONFIG_MCP320X) += mcp320x.o obj-$(CONFIG_MCP3422) += mcp3422.o obj-$(CONFIG_MCP3911) += mcp3911.odrivers/iio/adc/max34408.c new file +10
-0@@ -0,0 +1,334 @@ +// SPDX-License-Identifier: GPL-2.0 +/* +* IIO driver for Maxim MAX34409/34408 ADC, 4-Channels/2-Channels, 8bits, I2C +* +* Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/MAX34408-MAX34409.pdf +* +* TODO: ALERT interrupt, Overcurrent delay, Shutdown delay +*/ + +#include <linux/bitfield.h>
drivers/iio/adc/max34408.c line 20
Quoted 10 lines
drivers/iio/adc/max34408.c new file +10
-0+#include <linux/init.h> +#include <linux/i2c.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/regmap.h> + +#include <linux/iio/iio.h> +#include <linux/iio/types.h> + +#define MAX34408_STATUS 0x0
Useful to give clear naming separation between regisers
and fields. I'd stick _REG on the end.
drivers/iio/adc/max34408.c line 27
Quoted 7 lines
drivers/iio/adc/max34408.c new file +7
-0+#define MAX34408_CONTROL 0x1 +#define MAX34408_OCDELAY 0x2 +#define MAX34408_SDDELAY 0x3 + +#define MAX34408_ADC1 0x4 +#define MAX34408_ADC2 0x5 +/* ADC3 & ADC4 always returns 0x0 on 34408 */
Perhaps name them MAX34409_ADC3 to make that clearer at the point of use.
Quoted 7 lines
drivers/iio/adc/max34408.c new file +7
-0+#define MAX34408_ADC3 0x6 +#define MAX34408_ADC4 0x7 + +#define MAX34408_OCT1 0x8 +#define MAX34408_OCT2 0x9 +#define MAX34408_OCT3 0xA +#define MAX34408_OCT4 0xB
drivers/iio/adc/max34408.c
Quoted 10 lines
drivers/iio/adc/max34408.c new file +10
-0+ +#define MAX34408_DID 0xC +#define MAX34408_DCYY 0xD +#define MAX34408_DCWW 0xE + +#define MAX34408_CHANNELS 2 +#define MAX34409_CHANNELS 4 + +/* Bit masks for status register */ +#define STATUS_OC1 BIT(0
To avoid potential naming clashes with generic headers all defines should be prefixed with MA34008_STATUS_OC1
(note this is why I suggest a REG postfix for the register addreses.
drivers/iio/adc/max34408.c line 46
Quoted 2 lines
drivers/iio/adc/max34408.c new file +2
-0+#define STATUS_OC2 BIT(1) +/* OC3 & OC4 only for max34409 */
Define a mask for each.
#define MAX34008_STATUS_OC_MSK GENMASK(1, 0)
#define MAX34009_STATUS_OC_MSK GENMASK(3, 0)
and the comment isn't needed.
Quoted 9 lines
drivers/iio/adc/max34408.c new file +9
-0+#define STATUS_OC3 BIT(2) +#define STATUS_OC4 BIT(3) +#define STATUS_SHTDN BIT(4) +#define STATUS_ENA BIT(5) + +/* Bit masks for control register */ +#define CONTROL_AVG0 BIT(0) +#define CONTROL_AVG1 BIT(1) +#define CONTROL_AVG2 BIT(2)
drivers/iio/adc/max34408.c line 65
Quoted 10 lines
drivers/iio/adc/max34408.c new file +10
-0+#define CONTROL_ALERT BIT(3) + +/* Bit masks for over current delay */ +#define OCDELAY_OCD0 BIT(0) +#define OCDELAY_OCD1 BIT(1) +#define OCDELAY_OCD2 BIT(2) +#define OCDELAY_OCD3 BIT(3) +#define OCDELAY_OCD4 BIT(4) +#define OCDELAY_OCD5 BIT(5) +#define OCDELAY_OCD6 BIT(6)
Looks like a 7 bit field - clear in table 9 where
values are given as 00h to 7fh
#define OCDELAY_OCD_MASK GENMASK(6, 0
Same for other similar multi bit fields.
Quoted 7 lines
drivers/iio/adc/max34408.c new file +7
-0+#define OCDELAY_RESET BIT(7) + +/* Bit masks for shutdown delay */ +#define SDDELAY_SHD0 BIT(0) +#define SDDELAY_SHD1 BIT(1) +#define SDDELAY_SHD2 BIT(2) +#define SDDELAY_SHD3 BIT(3)
drivers/iio/adc/max34408.c line 82
Quoted 10 lines
drivers/iio/adc/max34408.c new file +10
-0+#define SDDELAY_SHD4 BIT(4) +#define SDDELAY_SHD5 BIT(5) +#define SDDELAY_SHD6 BIT(6) +#define SDDELAY_RESET BIT(7) + +/** +* struct max34408_data - max34408/max34409 specific data. +* @regmap: device register map. +* @dev: max34408 device. +* @lock: lock for protecting access to device hardware registers.
The locks in the underlying bus driver will do that for us. Perhaps this is to allow read modify write cycles? If so, give that extra detail here.
Quoted 32 lines
drivers/iio/adc/max34408.c new file +32
-0+* @rsense: Rsense value in uOhm. +*/ +struct max34408_data { +struct regmap *regmap; +struct device *dev; +struct mutex lock; +u32 rsense; +}; + +static const struct regmap_config max34408_regmap_config = { + .reg_bits =8 , + .val_bits =8 , + .max_register =MAX34408_DCWW , +}; + +static const struct iio_chan_spec max34408_channels[] = { + { + .type =IIO_CURRENT , + .info_mask_separate =BIT (IIO_CHAN_INFO_RAW ) | +BIT (IIO_CHAN_INFO_PROCESSED ) | +BIT (IIO_CHAN_INFO_AVERAGE_RAW ), + .channel =0 , + .indexed =1 , + }, + { + .type =IIO_CURRENT , + .info_mask_separate =BIT (IIO_CHAN_INFO_RAW ) | +BIT (IIO_CHAN_INFO_PROCESSED ) | +BIT (IIO_CHAN_INFO_AVERAGE_RAW ), + .channel =1 , + .indexed =1 , + },
drivers/iio/adc/max34408.c line 124
Quoted 10 lines
drivers/iio/adc/max34408.c new file +10
-0+}; + +static const struct iio_chan_spec max34409_channels[] = { + { + .type =IIO_CURRENT , + .info_mask_separate =BIT (IIO_CHAN_INFO_RAW ) | +BIT (IIO_CHAN_INFO_PROCESSED ) | +BIT (IIO_CHAN_INFO_AVERAGE_RAW ), + .channel =0 , + .indexed =1 ,
I think a macro would help here as there is only one parameter.
#define MAX34008_CHANNEL(_index) \
{ \
.type = IIO_CURRENT, \
....
.channel = (_index), \
.indexed = 1,
}Quoted 41 lines
drivers/iio/adc/max34408.c new file +41
-0+ }, + { + .type = IIO_CURRENT, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | + BIT(IIO_CHAN_INFO_PROCESSED) | + BIT(IIO_CHAN_INFO_AVERAGE_RAW), + .channel = 1, + .indexed = 1, + }, + { + .type = IIO_CURRENT, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | + BIT(IIO_CHAN_INFO_PROCESSED) | + BIT(IIO_CHAN_INFO_AVERAGE_RAW), + .channel = 2, + .indexed = 1, + }, + { + .type = IIO_CURRENT, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | + BIT(IIO_CHAN_INFO_PROCESSED) | + BIT(IIO_CHAN_INFO_AVERAGE_RAW), + .channel = 3, + .indexed = 1, + }, +}; + +static int max34408_read_adc(struct max34408_data *max34408, int channel, + int *val) +{ + int rc; + u32 adc_reg; + + switch (channel) { + case 0: + adc_reg = MAX34408_ADC1; + break; + case 1: + adc_reg = MAX34408_ADC2; + break; + case 2:
drivers/iio/adc/max34408.c line 175
Quoted 10 lines
drivers/iio/adc/max34408.c new file +10
-0+ adc_reg =MAX34408_ADC3 ; +break ; +case 3 : + adc_reg =MAX34408_ADC4 ; +break ; +default : +return -EINVAL ; + } + + rc =regmap_read (max34408->regmap, adc_reg, val);
return regmap_read();
Is same and saves us a couple of lines.
drivers/iio/adc/max34408.c line 188
Quoted 13 lines
drivers/iio/adc/max34408.c new file +13
-0+if (rc) +return rc; + +return 0 ; +} + +static int max34408_read_adc_avg (struct max34408_data *max34408,int channel,int *val) +{ +unsigned long ctrl; +int rc; +u8 tmp; + +mutex_lock (&max34408->lock);
Consider the new guard() functionality for this lock.
guard(mutex)(&max34408->lock);
That should ensure the mutex is release whatever path you take out of the function thus allowing you to drop the goto and explicit unlock.
It's new this cycle, so don't think we have any users in IIO yet, but I'll be encouraging it's use for cases like this where it provides nice simplifications to the code flow by allowing directly returning instead of dancing through manual cleanup.
Quoted 46 lines
drivers/iio/adc/max34408.c new file +46
-0+ rc =regmap_read (max34408->regmap,MAX34408_CONTROL , (u32 *)&ctrl); +if (rc) + goto err_unlock; + +/* set averaging (0b100) default values*/ + tmp = ctrl; +set_bit (CONTROL_AVG2 , &ctrl); +clear_bit (CONTROL_AVG1 , &ctrl); +clear_bit (CONTROL_AVG0 , &ctrl); + rc =regmap_write (max34408->regmap,MAX34408_CONTROL , ctrl); +if (rc) { +dev_err (max34408->dev, +"Error (%d) writing control register\n" , rc); + goto err_unlock; + } + + rc =max34408_read_adc (max34408, channel, val); +if (rc) + goto err_unlock; + +/* back to old values */ + rc =regmap_write (max34408->regmap,MAX34408_CONTROL , tmp); +if (rc) +dev_err (max34408->dev, +"Error (%d) writing control register\n" , rc); + +err_unlock: +mutex_unlock (&max34408->lock); + +return rc; +} + +static int max34408_read_raw (struct iio_dev *indio_dev, +struct iio_chan_spec const *chan, +int *val,int *val2,long mask) +{ +struct max34408_data *max34408 =iio_priv (indio_dev); +int rc; + +switch (mask) { +case IIO_CHAN_INFO_PROCESSED : +case IIO_CHAN_INFO_AVERAGE_RAW : + rc =max34408_read_adc_avg (max34408, chan->channel, + val); +if (rc) +return rc;
drivers/iio/adc/max34408.c line 244
Quoted 10 lines
drivers/iio/adc/max34408.c new file +10
-0+ +if (mask ==IIO_CHAN_INFO_PROCESSED ) { +/* +* calcluate current for 8bit ADC with Rsense +* value. +* 10 mV * 1000 / Rsense uOhm = max current +* (max current * adc val * 1000) / (2^8 - 1) mA +*/ + *val =DIV_ROUND_CLOSEST ((10000 / max34408->rsense) * + *val *1000 ,256 );
What Lars said about not supporting processed when we can expose the channel nicely as raw and present the scale an offset as needed to let userspace do this maths (it has floating point so will probably do it better than we can easily do in kernel).
Quoted 27 lines
drivers/iio/adc/max34408.c new file +27
-0+ } + +return IIO_VAL_INT ; +case IIO_CHAN_INFO_RAW : + rc =max34408_read_adc (max34408, chan->channel, val); +if (rc) +return rc; +return IIO_VAL_INT ; +default : +return -EINVAL ; + } +} + +static const struct iio_info max34408_info = { + .read_raw = max34408_read_raw, +}; + +static int max34408_probe (struct i2c_client *client) +{ +struct device_node *np = client->dev.of_node; +struct max34408_data *max34408; +struct iio_dev *indio_dev; +struct regmap *regmap; +int rc; + + regmap =devm_regmap_init_i2c (client, &max34408_regmap_config); +if (IS_ERR (regmap)) {
drivers/iio/adc/max34408.c line 281
Quoted 10 lines
drivers/iio/adc/max34408.c new file +10
-0+dev_err (&client->dev,"regmap_init failed\n" ); +return PTR_ERR (regmap); + } + + indio_dev =devm_iio_device_alloc (&client->dev,sizeof (*max34408)); +if (!indio_dev) +return -ENOMEM ; + + max34408 =iio_priv (indio_dev); +i2c_set_clientdata (client, indio_dev);
I don't see this being used. If it is not don't set it.
drivers/iio/adc/max34408.c line 287
Quoted 6 lines
drivers/iio/adc/max34408.c new file +6
-0+ max34408->regmap = regmap; + max34408->dev = &client->dev; +mutex_init (&max34408->lock); + rc =device_property_read_u32 (&client->dev, +"maxim,rsense-val-micro-ohms" , + &max34408->rsense);
As I mentioned in the review of the binding, I can't see why these will necessarily be the same for all channels.
Quoted 6 lines
drivers/iio/adc/max34408.c new file +6
-0+if (rc) +return -EINVAL ; + +/* disable ALERT and averaging */ + rc =regmap_write (max34408->regmap,MAX34408_CONTROL ,0x0 ); +if (rc)
drivers/iio/adc/max34408.c line 303
Quoted 10 lines
drivers/iio/adc/max34408.c new file +10
-0+return rc; + +if (of_device_is_compatible (np,"maxim,max34408" )) { + indio_dev->channels = max34408_channels; + indio_dev->num_channels =ARRAY_SIZE (max34408_channels); + indio_dev->name ="max34408" ; + }else if (of_device_is_compatible (np,"maxim,max34409" )) { + indio_dev->channels = max34409_channels; + indio_dev->num_channels =ARRAY_SIZE (max34409_channels); + indio_dev->name ="max34409" ;
Lars mentioned this already. Much prefer chip specific data to be data, not code. So this wants to go in a chip type specific structure that is static const. In general that scales much better as we get more variants supported by a driver over time + as Lars mentioned works with other firmware types. Not sure it applies elsewhere (I'm reviewing driver in reverse) but in general use the generic firmware accessors in linux/property.h not the of specific ones. We are slowly moving almost all IIO drivers over to that generic firmware approach, but it's take a while so you'll still find plenty of examples that are using of specific calls.
drivers/iio/adc/max34408.c line 307
Quoted 4 lines
drivers/iio/adc/max34408.c new file +4
-0+ } + indio_dev->info = &max34408_info; + indio_dev->modes =INDIO_DIRECT_MODE ; + indio_dev->dev.of_node = np;
That should be set by the IIO core (though it does it in a more general fashion than this).
https://elixir.bootlin.com/linux/latest/source/drivers/iio/industrialio-core.c#L1905
Quoted 3 lines
drivers/iio/adc/max34408.c new file +3
-0+ +return devm_iio_device_register (&client->dev, indio_dev); +}