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

[Guenter Roeck]

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.

> 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.

>  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.

> +	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).

> +	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.

> +		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.

> +	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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