Re: [PATCH v5 4/4] drivers/hwmon/menf21bmc_hwmon: introduce MEN14F021P00 BMC HWMON driver

[Andreas Werner]

On Tue, Aug 26, 2014 at 10:15:41AM -0700, Guenter Roeck wrote:
> On Tue, Aug 26, 2014 at 07:46:53PM +0200, Andreas Werner wrote:
> > Added driver to support the 14F021P00 BMC Hardware Monitoring.
> > The BMC is a Board Management Controller including monitoring of the
> > board voltages.
> > 
> > Signed-off-by: Andreas Werner <andreas.werner@xxxxxx>
> 
> Hi Andreas,
> 
> Couple of additional comments below. Sorry I didn't notice earlier.
> 
> Guenter
> 
> > ---
> >  Documentation/hwmon/menf21bmc   |  49 +++++++++
> >  drivers/hwmon/Kconfig           |   7 ++
> >  drivers/hwmon/Makefile          |   1 +
> >  drivers/hwmon/menf21bmc_hwmon.c | 230 ++++++++++++++++++++++++++++++++++++++++
> >  4 files changed, 287 insertions(+)
> >  create mode 100644 Documentation/hwmon/menf21bmc
> >  create mode 100644 drivers/hwmon/menf21bmc_hwmon.c
> > 
> > diff --git a/Documentation/hwmon/menf21bmc b/Documentation/hwmon/menf21bmc
> > new file mode 100644
> > index 0000000..22b6840
> > --- /dev/null
> > +++ b/Documentation/hwmon/menf21bmc
> > @@ -0,0 +1,49 @@
> > +Kernel driver menf21bmc_hwmon
> > +=============================
> > +
> > +Supported chips:
> > +	* MEN 14F021P00
> > +	  Prefix: 'menf21bmc_hwmon'
> > +	  Adresses scanned: -
> > +
> > +Author: Andreas Werner <andreas.werner@xxxxxx>
> > +
> > +Description
> > +-----------
> > +
> > +The menf21bmc is a Board Management Controller (BMC) which provides an I2C
> > +interface to the host to access the features implemented in the BMC.
> > +
> > +This driver gives access to the voltage monitoring feature of the main
> > +voltages of the board.
> > +The voltage sensors are connected to the ADC inputs of the BMC which is
> > +a PIC16F917 Mikrocontroller.
> > +
> > +Usage Notes
> > +-----------
> > +
> > +This driver does not auto-detect devices. You will have to instantiate the
> > +devices explicitly. Please see Documentation/i2c/instantiating-devices for
> > +details.
> > +
> > +Sysfs entries
> > +-------------
> > +
> > +The following attributes are supported. All attributes are read only
> > +The Limits are read once by the driver.
> > +
> > +in0_input	+3.3V input voltage
> > +in1_input	+5.0V input voltage
> > +in2_input	+12.0V input voltage
> > +in3_input	+5V Standby input voltage
> > +in4_input	VBAT (on board battery)
> > +
> > +in[0-4]_min	Minimum voltage limit
> > +in[0-4]_max	Maximum voltage limit
> > +
> > +in0_label	"MON_3_3V"
> > +in1_label	"MON_5V"
> > +in2_label	"MON_12V"
> > +in3_label	"5V_STANDBY"
> > +in4_label	"VBAT"
> > +
> 
> The empty line adds a whitespace error when applying the patch.
>

OK, will delete the line.
 
> > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> > index 37908ff..db3a6eb 100644
> > --- a/drivers/hwmon/Kconfig
> > +++ b/drivers/hwmon/Kconfig
> > @@ -828,6 +828,13 @@ config SENSORS_MCP3021
> >  	  This driver can also be built as a module.  If so, the module
> >  	  will be called mcp3021.
> >  
> > +config SENSORS_MENF21BMC_HWMON
> > +	tristate "MEN 14F021P00 BMC Hardware Monitoring"
> > +	depends on MFD_MENF21BMC
> > +	help
> > +	  Say Y here to include support for the MEN 14F021P00 BMC
> > +	  hardware monitoring.
> > +
> It is customary to add a note describing how the module is called
> if the driver is built as module.
> 

OK i just write a line which describes the module name.

> >  config SENSORS_ADCXX
> >  	tristate "National Semiconductor ADCxxxSxxx"
> >  	depends on SPI_MASTER
> > diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> > index 1362382..56ab872 100644
> > --- a/drivers/hwmon/Makefile
> > +++ b/drivers/hwmon/Makefile
> > @@ -114,6 +114,7 @@ obj-$(CONFIG_SENSORS_MAX6650)	+= max6650.o
> >  obj-$(CONFIG_SENSORS_MAX6697)	+= max6697.o
> >  obj-$(CONFIG_SENSORS_MC13783_ADC)+= mc13783-adc.o
> >  obj-$(CONFIG_SENSORS_MCP3021)	+= mcp3021.o
> > +obj-$(CONFIG_SENSORS_MENF21BMC_HWMON) += menf21bmc_hwmon.o
> >  obj-$(CONFIG_SENSORS_NCT6683)	+= nct6683.o
> >  obj-$(CONFIG_SENSORS_NCT6775)	+= nct6775.o
> >  obj-$(CONFIG_SENSORS_NTC_THERMISTOR)	+= ntc_thermistor.o
> > diff --git a/drivers/hwmon/menf21bmc_hwmon.c b/drivers/hwmon/menf21bmc_hwmon.c
> > new file mode 100644
> > index 0000000..2eaec6a
> > --- /dev/null
> > +++ b/drivers/hwmon/menf21bmc_hwmon.c
> > @@ -0,0 +1,230 @@
> > +/*
> > + *  MEN 14F021P00 Board Management Controller (BMC) hwmon driver.
> > + *
> > + *  This is the core hwmon driver of the MEN 14F021P00 BMC.
> > + *  The BMC monitors the board voltages which can be access with this
> > + *  driver through sysfs.
> > + *
> > + *  Copyright (C) 2014 MEN Mikro Elektronik Nuernberg GmbH
> > + *
> > + *  This program is free software; you can redistribute  it and/or modify it
> > + *  under  the terms of  the GNU General  Public License as published by the
> > + *  Free Software Foundation;  either version 2 of the  License, or (at your
> > + *  option) any later version.
> > + */
> > +
> > +#include <linux/module.h>
> > +#include <linux/kernel.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/hwmon.h>
> > +#include <linux/hwmon-sysfs.h>
> > +#include <linux/jiffies.h>
> > +#include <linux/slab.h>
> > +#include <linux/i2c.h>
> > +
> > +#define DRV_NAME  "menf21bmc_hwmon"
> > +
> > +#define BMC_VOLT_COUNT	5
> > +#define MENF21BMC_V33	0
> > +#define MENF21BMC_V5	1
> > +#define MENF21BMC_V12	2
> > +#define MENF21BMC_V5_SB	3
> > +#define MENF21BMC_VBAT	4
> > +
> > +#define IDX_TO_VOLT_MIN_CMD(idx) (0x40 + idx)
> > +#define IDX_TO_VOLT_MAX_CMD(idx) (0x50 + idx)
> > +#define IDX_TO_VOLT_INP_CMD(idx) (0x60 + idx)
> > +
> > +struct menf21bmc_hwmon {
> > +	char valid;
> 
> Please use bool (and true / false to set it). char doesn't
> save anything and may actually increase code size depending
> on the architecture.
> 

Ok.

> > +	struct i2c_client *i2c_client;
> > +	unsigned long last_update;
> > +	u16 in_val[BMC_VOLT_COUNT];
> > +	u16 in_min[BMC_VOLT_COUNT];
> > +	u16 in_max[BMC_VOLT_COUNT];
> > +};
> > +
> > +static const char *const input_names[] = {
> > +	[MENF21BMC_V33]		= "MON_3_3V",
> > +	[MENF21BMC_V5]		= "MON_5V",
> > +	[MENF21BMC_V12]		= "MON_12V",
> > +	[MENF21BMC_V5_SB]	= "5V_STANDBY",
> > +	[MENF21BMC_VBAT]	= "VBAT"
> > +};
> > +
> > +static struct menf21bmc_hwmon *menf21bmc_hwmon_update(struct device *dev)
> > +{
> > +	int i;
> > +	uint16_t val;
> 
> That doesn't work well with the checks against < 0.
> Please compile with W=1 to find all instances of this problem
> (there is another one below).
> 

Argh, hate myself.

> > +	struct menf21bmc_hwmon *drv_data = dev_get_drvdata(dev);
> > +	struct menf21bmc_hwmon *data_ret = drv_data;
> > +
> > +	if (time_after(jiffies, drv_data->last_update + HZ) || !drv_data->valid) {
> 
> Line over 80 characters.
> 

Yes, checkpatch gave me a warning, but a thought it is better so let
it as it is instead of split the "if" line.
But it is no problem to change that.

> > +		for (i = 0; i < BMC_VOLT_COUNT; i++) {
> > +			val = i2c_smbus_read_word_data(drv_data->i2c_client,
> > +						       IDX_TO_VOLT_INP_CMD(i));
> > +			if (val < 0) {
> > +				data_ret = ERR_PTR(val);
> > +				goto abort;
> > +			}
> > +			drv_data->in_val[i] = val;
> > +		}
> > +		drv_data->last_update = jiffies;
> > +		drv_data->valid = 1;
> > +	}
> > +abort:
> > +	return data_ret;
> > +}
> > +
> > +static int menf21bmc_hwmon_get_volt_limits(struct menf21bmc_hwmon *drv_data)
> > +{
> > +	int i;
> > +	uint16_t val;
> > +
> > +	for (i = 0; i < BMC_VOLT_COUNT; i++) {
> > +		val = i2c_smbus_read_word_data(drv_data->i2c_client,
> > +					       IDX_TO_VOLT_MIN_CMD(i));
> > +		if (val < 0)
> > +			return val;
> > +
> > +		drv_data->in_min[i] = val;
> > +
> > +		val = i2c_smbus_read_word_data(drv_data->i2c_client,
> > +					       IDX_TO_VOLT_MAX_CMD(i));
> > +		if (val < 0)
> > +			return val;
> > +
> > +		drv_data->in_max[i] = val;
> > +	}
> > +	return 0;
> > +}
> > +
> > +static ssize_t
> > +show_label(struct device *dev, struct device_attribute *devattr, char *buf)
> > +{
> > +	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
> > +
> > +	return sprintf(buf, "%s\n", input_names[attr->index]);
> > +}
> > +
> > +static ssize_t
> > +show_in(struct device *dev, struct device_attribute *devattr, char *buf)
> > +{
> > +	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
> > +	struct menf21bmc_hwmon *drv_data = menf21bmc_hwmon_update(dev);
> > +
> > +	if (IS_ERR(drv_data))
> > +		return PTR_ERR(drv_data);
> > +
> > +	return sprintf(buf, "%d\n", drv_data->in_val[attr->index]);
> > +}
> > +
> > +static ssize_t
> > +show_min(struct device *dev, struct device_attribute *devattr, char *buf)
> > +{
> > +	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
> > +	struct menf21bmc_hwmon *drv_data = dev_get_drvdata(dev);
> > +
> > +	return sprintf(buf, "%d\n", drv_data->in_min[attr->index]);
> > +}
> > +
> > +static ssize_t
> > +show_max(struct device *dev, struct device_attribute *devattr, char *buf)
> > +{
> > +	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
> > +	struct menf21bmc_hwmon *drv_data = dev_get_drvdata(dev);
> > +
> > +	return sprintf(buf, "%d\n", drv_data->in_max[attr->index]);
> > +}
> > +
> > +#define create_voltage_sysfs(idx)			\
> > +static SENSOR_DEVICE_ATTR(in##idx##_input, S_IRUGO,	\
> > +			show_in, NULL, idx);		\
> > +static SENSOR_DEVICE_ATTR(in##idx##_min, S_IRUGO,	\
> > +			show_min, NULL, idx);		\
> > +static SENSOR_DEVICE_ATTR(in##idx##_max, S_IRUGO,	\
> > +			show_max, NULL, idx);		\
> > +static SENSOR_DEVICE_ATTR(in##idx##_label, S_IRUGO,	\
> > +			show_label, NULL, idx);
> > +
> > +create_voltage_sysfs(0);
> > +create_voltage_sysfs(1);
> > +create_voltage_sysfs(2);
> > +create_voltage_sysfs(3);
> > +create_voltage_sysfs(4);
> > +
> > +static struct attribute *menf21bmc_hwmon_attrs[] = {
> > +	&sensor_dev_attr_in0_input.dev_attr.attr,
> > +	&sensor_dev_attr_in0_min.dev_attr.attr,
> > +	&sensor_dev_attr_in0_max.dev_attr.attr,
> > +	&sensor_dev_attr_in0_label.dev_attr.attr,
> > +
> > +	&sensor_dev_attr_in1_input.dev_attr.attr,
> > +	&sensor_dev_attr_in1_min.dev_attr.attr,
> > +	&sensor_dev_attr_in1_max.dev_attr.attr,
> > +	&sensor_dev_attr_in1_label.dev_attr.attr,
> > +
> > +	&sensor_dev_attr_in2_input.dev_attr.attr,
> > +	&sensor_dev_attr_in2_min.dev_attr.attr,
> > +	&sensor_dev_attr_in2_max.dev_attr.attr,
> > +	&sensor_dev_attr_in2_label.dev_attr.attr,
> > +
> > +	&sensor_dev_attr_in3_input.dev_attr.attr,
> > +	&sensor_dev_attr_in3_min.dev_attr.attr,
> > +	&sensor_dev_attr_in3_max.dev_attr.attr,
> > +	&sensor_dev_attr_in3_label.dev_attr.attr,
> > +
> > +	&sensor_dev_attr_in4_input.dev_attr.attr,
> > +	&sensor_dev_attr_in4_min.dev_attr.attr,
> > +	&sensor_dev_attr_in4_max.dev_attr.attr,
> > +	&sensor_dev_attr_in4_label.dev_attr.attr,
> > +	NULL
> > +};
> > +
> > +ATTRIBUTE_GROUPS(menf21bmc_hwmon);
> > +
> > +static int menf21bmc_hwmon_probe(struct platform_device *pdev)
> > +{
> > +	int ret;
> > +	struct menf21bmc_hwmon *drv_data;
> > +	struct i2c_client *i2c_client = to_i2c_client(pdev->dev.parent);
> > +	struct device *hwmon_dev;
> > +
> > +	drv_data = devm_kzalloc(&pdev->dev, sizeof(struct menf21bmc_hwmon),
> > +				GFP_KERNEL);
> > +	if (!drv_data)
> > +		return -ENOMEM;
> > +
> > +	drv_data->i2c_client = i2c_client;
> > +
> > +	ret = menf21bmc_hwmon_get_volt_limits(drv_data);
> > +	if (ret) {
> > +		dev_err(&pdev->dev, "failed to read sensor limits");
> > +		return ret;
> > +	}
> > +
> > +	hwmon_dev = devm_hwmon_device_register_with_groups(&pdev->dev,
> > +							   "menf21bmc", drv_data,
> > +							   menf21bmc_hwmon_groups);
> 
> Line over 80 characters. Just use less indentation for the continuation lines.
> 

Same as above, checkpatch gave me a warning. I just wanted to align it to the "("
but no problem to change that.

> > +	if (IS_ERR(hwmon_dev))
> > +		return PTR_ERR(hwmon_dev);
> > +
> > +	dev_info(&pdev->dev, "MEN 14F021P00 BMC hwmon device enabled");
> > +
> > +	return 0;
> > +}
> > +
> > +static struct platform_driver menf21bmc_hwmon = {
> > +	.probe		= menf21bmc_hwmon_probe,
> > +	.driver		= {
> > +		.name		= DRV_NAME,
> > +		.owner		= THIS_MODULE,
> > +	},
> > +};
> > +
> > +module_platform_driver(menf21bmc_hwmon);
> > +
> > +MODULE_AUTHOR("Andreas Werner <andreas.werner@xxxxxx>");
> > +MODULE_DESCRIPTION("MEN 14F021P00 BMC hwmon");
> > +MODULE_LICENSE("GPL v2");
> > +MODULE_ALIAS("platform:menf21bmc_hwmon");
> > -- 
> > 2.0.4
> > 
> > 
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