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Message-ID: <20100621163133.GA11311@ericsson.com>
Date: Mon, 21 Jun 2010 09:31:33 -0700
From: Guenter Roeck <guenter.roeck@...csson.com>
To: Jonathan Cameron <kernel@...23.retrosnub.co.uk>
CC: Jean Delvare <khali@...ux-fr.org>,
Hans de Goede <hdegoede@...hat.com>,
Mark Brown <broonie@...nsource.wolfsonmicro.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Samuel Ortiz <sameo@...ux.intel.com>,
"lm-sensors@...sensors.org" <lm-sensors@...sensors.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 1/3] hwmon: Driver for SMM665 Six-Channel Active DC
Output Controller/Monitor
On Mon, Jun 21, 2010 at 12:04:18PM -0400, Jonathan Cameron wrote:
> On 06/21/10 16:06, Guenter Roeck wrote:
> > On Mon, Jun 21, 2010 at 05:29:28AM -0400, Jonathan Cameron wrote:
> >> On 06/20/10 20:19, Guenter Roeck wrote:
> >>> This driver adds support for the monitoring features of the Summit
> >>> Microelectronics SMM665 Six-Channel Active DC Output Controller/Monitor.
> >>>
> >>> Signed-off-by: Guenter Roeck <guenter.roeck@...csson.com>
> >>
> >> Hi Guenter,
> >>
> >> Few more comments below. Please don't eat errors when there
> >> is no reason to do so.
> >>
> >> Also I would hold this driver for a few days to see if anyone
> >> has comments on the critical values attributes. It would be
> >> good to see them supported as well (afterall you have pretty
> >> much all the code here anyway!)
> >>
> > Sounds good to me. I'll be out travelling for the next few days anyway.
> >
> > Comments inline.
> >
> > Thanks a lot for the review!
> >
> > Guenter
> >
> >> Jonathan
> >>> ---
> >>> drivers/hwmon/Kconfig | 15 +
> >>> drivers/hwmon/Makefile | 1 +
> >>> drivers/hwmon/smm665.c | 681 ++++++++++++++++++++++++++++++++++++++++++++++++
> >>> 3 files changed, 697 insertions(+), 0 deletions(-)
> >>> create mode 100644 drivers/hwmon/smm665.c
> >>>
> >>> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> >>> index e19cf8e..c45c17e 100644
> >>> --- a/drivers/hwmon/Kconfig
> >>> +++ b/drivers/hwmon/Kconfig
> >>> @@ -739,6 +739,21 @@ config SENSORS_SIS5595
> >>> This driver can also be built as a module. If so, the module
> >>> will be called sis5595.
> >>>
> >>> +config SENSORS_SMM665
> >>> + tristate "Summit Microelectronics SMM665"
> >>> + depends on I2C && EXPERIMENTAL
> >>> + default n
> >>> + help
> >>> + If you say yes here you get support for the hardware monitoring
> >>> + features of the Summit Microelectronics SMM665/SMM665B Six-Channel
> >>> + Active DC Output Controller / Monitor.
> >>> +
> >>> + Other supported chips are SMM465, SMM665C, SMM764, and SMM766.
> >>> + Support for those chips is untested.
> >>> +
> >>> + This driver can also be built as a module. If so, the module will
> >>> + be called smm665.
> >>> +
> >>> config SENSORS_DME1737
> >>> tristate "SMSC DME1737, SCH311x and compatibles"
> >>> depends on I2C && EXPERIMENTAL
> >>> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> >>> index 2138ceb..55b0940 100644
> >>> --- a/drivers/hwmon/Makefile
> >>> +++ b/drivers/hwmon/Makefile
> >>> @@ -86,6 +86,7 @@ obj-$(CONFIG_SENSORS_PCF8591) += pcf8591.o
> >>> obj-$(CONFIG_SENSORS_S3C) += s3c-hwmon.o
> >>> obj-$(CONFIG_SENSORS_SHT15) += sht15.o
> >>> obj-$(CONFIG_SENSORS_SIS5595) += sis5595.o
> >>> +obj-$(CONFIG_SENSORS_SMM665) += smm665.o
> >>> obj-$(CONFIG_SENSORS_SMSC47B397)+= smsc47b397.o
> >>> obj-$(CONFIG_SENSORS_SMSC47M1) += smsc47m1.o
> >>> obj-$(CONFIG_SENSORS_SMSC47M192)+= smsc47m192.o
> >>> diff --git a/drivers/hwmon/smm665.c b/drivers/hwmon/smm665.c
> >>> new file mode 100644
> >>> index 0000000..b4e7c8f
> >>> --- /dev/null
> >>> +++ b/drivers/hwmon/smm665.c
> >>> @@ -0,0 +1,681 @@
> >>> +/*
> >>> + * Driver for SMM665 Power Controller / Monitor
> >>> + *
> >>> + * Copyright (C) 2010 Ericsson AB.
> >>> + *
> >>> + * 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; version 2 of the License.
> >>> + *
> >>> + * This driver should also work for SMM465, SMM764, and SMM766, but is untested
> >>> + * for those chips. Only monitoring functionality is implemented.
> >>> + *
> >>> + * Datasheets:
> >>> + * http://www.summitmicro.com/prod_select/summary/SMM665/SMM665B_2089_20.pdf
> >>> + * http://www.summitmicro.com/prod_select/summary/SMM766B/SMM766B_2122.pdf
> >>> + */
> >>> +
> >>> +#include <linux/kernel.h>
> >>> +#include <linux/module.h>
> >>> +#include <linux/init.h>
> >>> +#include <linux/err.h>
> >>> +#include <linux/slab.h>
> >>> +#include <linux/i2c.h>
> >>> +#include <linux/hwmon.h>
> >>> +#include <linux/hwmon-sysfs.h>
> >>> +#include <linux/delay.h>
> >>> +
> >>> +/* Internal reference voltage (VREF, x 1000 */
> >>> +#define SMM665_VREF_ADC_X1000 1250
> >>> +
> >>> +/* module parameters */
> >>> +static int vref = SMM665_VREF_ADC_X1000;
> >>> +module_param(vref, int, 0);
> >>> +MODULE_PARM_DESC(vref, "Reference voltage in mV");
> >>> +
> >>> +enum chips { smm465, smm665, smm665c, smm764, smm766 };
> >>> +
> >>> +/*
> >>> + * ADC channel addresses
> >>> + */
> >>> +#define SMM665_MISC16_ADC_DATA_A 0x00
> >>> +#define SMM665_MISC16_ADC_DATA_B 0x01
> >>> +#define SMM665_MISC16_ADC_DATA_C 0x02
> >>> +#define SMM665_MISC16_ADC_DATA_D 0x03
> >>> +#define SMM665_MISC16_ADC_DATA_E 0x04
> >>> +#define SMM665_MISC16_ADC_DATA_F 0x05
> >>> +#define SMM665_MISC16_ADC_DATA_VDD 0x06
> >>> +#define SMM665_MISC16_ADC_DATA_12V 0x07
> >>> +#define SMM665_MISC16_ADC_DATA_INT_TEMP 0x08
> >>> +#define SMM665_MISC16_ADC_DATA_AIN1 0x09
> >>> +#define SMM665_MISC16_ADC_DATA_AIN2 0x0a
> >>> +
> >>> +/*
> >>> + * Command registers
> >>> + */
> >>> +#define SMM665_MISC8_CMD_STS 0x80
> >>> +#define SMM665_MISC8_STATUS1 0x81
> >>> +#define SMM665_MISC8_STATUSS2 0x82
> >>> +#define SMM665_MISC8_IO_POLARITY 0x83
> >>> +#define SMM665_MISC8_PUP_POLARITY 0x84
> >>> +#define SMM665_MISC8_ADOC_STATUS1 0x85
> >>> +#define SMM665_MISC8_ADOC_STATUS2 0x86
> >>> +#define SMM665_MISC8_WRITE_PROT 0x87
> >>> +#define SMM665_MISC8_STS_TRACK 0x88
> >>> +
> >>> +/*
> >>> + * Configuration registers and register groups
> >>> + */
> >>> +#define SMM665_ADOC_ENABLE 0x0d
> >>> +#define SMM665_LIMIT_BASE 0x80 /* First limit register */
> >>> +
> >>> +/*
> >>> + * Limit register bit masks
> >>> + */
> >>> +#define SMM665_TRIGGER_RST 0x8000
> >>> +#define SMM665_TRIGGER_HEALTHY 0x4000
> >>> +#define SMM665_TRIGGER_POWEROFF 0x2000
> >>> +#define SMM665_TRIGGER_SHUTDOWN 0x1000
> >>> +#define SMM665_ADC_MASK 0x03ff
> >>> +
> >>> +#define smm665_is_critical(lim) ((lim) & (SMM665_TRIGGER_RST \
> >>> + | SMM665_TRIGGER_POWEROFF \
> >>> + | SMM665_TRIGGER_SHUTDOWN))
> >>> +/*
> >>> + * Fault register bit definitions
> >>> + * Values are merged from status registers 1/2,
> >>> + * with status register 1 providing the upper 8 bits.
> >>> + */
> >>> +#define SMM665_FAULT_A 0x0001
> >>> +#define SMM665_FAULT_B 0x0002
> >>> +#define SMM665_FAULT_C 0x0004
> >>> +#define SMM665_FAULT_D 0x0008
> >>> +#define SMM665_FAULT_E 0x0010
> >>> +#define SMM665_FAULT_F 0x0020
> >>> +#define SMM665_FAULT_VDD 0x0040
> >>> +#define SMM665_FAULT_12V 0x0080
> >>> +#define SMM665_FAULT_TEMP 0x0100
> >>> +#define SMM665_FAULT_AIN1 0x0200
> >>> +#define SMM665_FAULT_AIN2 0x0400
> >>> +
> >>> +/*
> >>> + * I2C Register addresses
> >>> + *
> >>> + * The configuration register needs to be the configured base register.
> >>> + * The command/status register address is derived from it.
> >>> + */
> >>> +#define SMM665_REGMASK 0x78
> >>> +#define SMM665_CMDREG_BASE 0x48
> >>> +#define SMM665_CONFREG_BASE 0x50
> >>> +
> >>> +/*
> >>> + * Equations given by chip manufacturer to calculate voltage/temperature values
> >>> + * vref = Reference voltage on VREF_ADC pin (module parameter)
> >>> + * adc = 10bit ADC value read back from registers
> >>> + */
> >>> +
> >>> +/* Voltage A-F and VDD */
> >>> +#define SMM665_VMON_ADC_TO_VOLTS(adc) ((adc) * vref / 256)
> >>> +
> >>> +/* Voltage 12VIN */
> >>> +#define SMM665_12VIN_ADC_TO_VOLTS(adc) ((adc) * vref * 3 / 256)
> >>> +
> >>> +/* Voltage AIN1, AIN2 */
> >>> +#define SMM665_AIN_ADC_TO_VOLTS(adc) ((adc) * vref / 512)
> >>> +
> >>> +/* Temp Sensor */
> >>> +#define SMM665_TEMP_ADC_TO_CELSIUS(adc) ((adc) <= 511) ? \
> >>> + ((int)(adc) * 1000 / 4) : \
> >>> + (((int)(adc) - 0x400) * 1000 / 4)
> >>> +
> >>> +#define SMM665_NUM_ADC 11
> >>> +
> >>> +/*
> >>> + * Chip dependent ADC conversion time, in uS
> >>> + */
> >>> +#define SMM665_ADC_WAIT_SMM665 70
> >>> +#define SMM665_ADC_WAIT_SMM766 185
> >>> +
> >>> +struct smm665_data {
> >>> + enum chips type;
> >>> + int conversion_time; /* ADC conversion time */
> >>> + struct device *hwmon_dev;
> >>> + struct mutex update_lock;
> >>> + bool valid;
> >>> + unsigned long last_updated; /* in jiffies */
> >>> + u16 adc[SMM665_NUM_ADC]; /* adc values (raw) */
> >>> + u16 faults; /* fault status */
> >>> + /* The following values are in mV */
> >>> + int critical_under_limit[SMM665_NUM_ADC];
> >>> + int alarm_under_limit[SMM665_NUM_ADC];
> >>> + int critical_over_limit[SMM665_NUM_ADC];
> >>> + int alarm_over_limit[SMM665_NUM_ADC];
> >>> + struct i2c_client *cmdreg;
> >>> +};
> >>> +
> >>> +/*
> >>> + * smm665_read16()
> >>> + *
> >>> + * Read 16 bit value from <reg>, <reg+1>. Upper 8 bits are in <reg>.
> >>> + */
> >>> +static int smm665_read16(struct i2c_client *client, int reg)
> >>> +{
> >>> + int rv, val;
> >>> +
> >>> + rv = i2c_smbus_read_byte_data(client, reg);
> >>> + if (rv < 0)
> >>> + return rv;
> >>> + val = rv << 8;
> >>> + rv = i2c_smbus_read_byte_data(client, reg + 1);
> >>> + if (rv < 0)
> >>> + return rv;
> >>> + val |= rv;
> >>> + return val;
> >>> +}
> >>> +
> >>> +/*
> >>> + * Read adc value.
> >>> + */
> >>> +static int smm665_read_adc(struct smm665_data *data, int adc)
> >>> +{
> >>> + struct i2c_client *client = data->cmdreg;
> >>> + int rv;
> >>> + int radc;
> >>> +
> >>> + /*
> >>> + * Algorithm for reading ADC, per SMM665 datasheet
> >>> + *
> >>> + * {[S][addr][W][Ack]} {[offset][Ack]} {[S][addr][R][Nack]}
> >>> + * [wait conversion time]
> >>> + * {[S][addr][R][Ack]} {[datahi][Ack]} {[datalo][Ack][P]}
> >>> + *
> >>> + * To implement the first part of this exchange,
> >>> + * do a full read transaction and expect a failure/Nack.
> >>> + * This sets up the address pointer on the SMM665
> >>> + * and starts the ADC conversion.
> >>> + * Then do a two-byte read transaction.
> >>> + */
> >>> + rv = i2c_smbus_read_byte_data(client, adc << 3);
> >>> + if (rv != -ENXIO) {
> >>> + /*
> >>> + * We expect ENXIO to reflect NACK
> >>> + * (per Documentation/i2c/fault-codes).
> >>> + * Everything else is an error.
> >>> + */
> >>> + dev_dbg(&client->dev,
> >>> + "Unexpected return code %d when setting ADC index", rv);
> >> Better to pass on the return code rather than eat it like this.
> >
> > Code would then look like
> > return (rv < 0) ? rv : -EIO;
> > so it adds a little bit of complexity. Since this is an unlikely case,
> > guess that should be ok.
> Yup, not a lot of complexity for the gain in information if this
> goes all the way to userspace.
> >
> >>> + return -1;
> >>> + }
> >>> +
> >>> + udelay(data->conversion_time);
> >>> +
> >>> + /*
> >>> + * Now read two bytes.
> >>> + *
> >>> + * Neither i2c_smbus_read_byte() nor
> >>> + * i2c_smbus_read_block_data() worked here,
> >>> + * so use i2c_smbus_read_word_data() instead.
> >>> + * We could also try to use i2c_master_recv(),
> >>> + * but that is not always supported.
> >>> + */
> >>> + rv = i2c_smbus_read_word_data(client, 0);
> >>> + if (rv < 0) {
> >>> + dev_dbg(&client->dev, "Failed to read ADC value: error %d", rv);
> >>> + return -1;
> >> Again, don't eat return codes. Pass them on as far as you can
> >
> > Ok.
> >
> >>> + }
> >>> + /*
> >>> + * Validate/verify readback adc channel (in bit 11..14).
> >>> + * High byte is in lower 8 bit of rv, so only shift by 3.
> >>> + */
> >>> + radc = (rv >> 3) & 0x0f;
> >>> + if (radc != adc) {
> >>> + dev_dbg(&client->dev, "Unexpected RADC: Expected %d got %d",
> >>> + adc, radc);
> >> Not quite sure what the right error code here would be...
> >
> > I would assume -EAGAIN. The device reported an ADC value, but for the wrong ADC,
> > so requesting a retry would probably be the best reaction.
> -EAGAIN is typically used for a 'device is busy' circumstance rather than it failed
> this time and might work next.
Ok, I'll use -EIO, unless you have a better idea. After all, it should not fail
in the first place unless something odd is going on.
> >
> >>> + return -1;
> >>> + }
> >>> + /*
> >>> + * Chip replies with H/L, while SMBus expects L/H.
> >>> + * Thus, byte order is reversed, and we have to swap
> >>> + * the result.
> >>> + */
> >>> + rv = swab16(rv) & SMM665_ADC_MASK;
> >>> +
> >>> + return rv;
> >>> +}
> >>> +
> >>> +static struct smm665_data *smm665_update_device(struct device *dev)
> >>> +{
> >>> + struct i2c_client *client = to_i2c_client(dev);
> >>> + struct smm665_data *data = i2c_get_clientdata(client);
> >>> +
> >>> + mutex_lock(&data->update_lock);
> >>> +
> >>> + if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
> >>> + int i, faults;
> >>> +
> >>> + /*
> >>> + * read status registers
> >>> + */
> >>> + faults = smm665_read16(client, SMM665_MISC8_STATUS1);
> >>> + if (unlikely(faults < 0))
> >>> + data->faults = 0;
> >>> + else
> >>> + data->faults = faults;
> >>> +
> >>> + /* Read adc registers */
> >>> + for (i = 0; i < SMM665_NUM_ADC; i++) {
> >>> + int val = smm665_read_adc(data, i);
> >>> + if (unlikely(val < 0))
> >> So this is going to keep hammering a device that has already reported
> >> an error. Ideally this would drop out and pass the error code all
> >> the way up to user space.
> >
> > Yes, but do we know if this is a transient error ? Code would get quite
> > complicated if I would try to sort out the reason for a failure and act on it.
> If an error occurs then report it (via return from sysfs read). That way userspace
> can know that 'all' data might be invalid. Doesn't matter if some of it is actually
> fine.
>
Makes sense. I'll check if I can store the error in the adc variable and return
the stored error when it is read via sysfs.
> >
> > Looking through other hwmon drivers, they either do the same (such as ltc4245,
> > which I used as starting point), or ignore the error - up to the point
> > where it is reported as ADC reading to the user (eg lm80).
> Yup, there are occasionally patches to clean up error handling to ensure it goes
> to userspace where possible. It is one of those things that is nice to get right
> in new drivers but no one can be bothered to fix the older ones. If it adds a
> lot of complexity then don't bother. I doubt anyone will be that fussy.
>
> >
> > Ultimately, there is no API for reporting this kind of error to userland,
> > so I rather stick with precedent and do nothing.
> The passing them up to userspace is the api for reporting errors. Whether
> user space acts on them is up to user space. So if one reads a sysfs file
> and gets an error it should go all the way.
Ok.
> >
> > One exception here is that we have a bit of vagueness in respect to the ADC reading code
> > and the NACK mechanism. I think it makes sense to try reading an ADC value during device
> > initialization (ie in the probe function), to make sure the code works as expected.
> > This will catch problems if the bus driver does not return -ENXIO as response to NACK as
> > expected. I'll add that code to the probe function.
> I wouldn't bother unless you have reports of cases where it causes trouble. Just
> pass any errors that occur anywhere to userspace if possible. If they happen during
> probe then the probe should fail (again returning the error code).
Ok.
> >
> >>> + data->adc[i] = 0;
> >>> + else
> >>> + data->adc[i] = val;
> >>> + }
> >>> +
> >>> + data->last_updated = jiffies;
> >>> + data->valid = 1;
> >>> + }
> >>> +
> >>> + mutex_unlock(&data->update_lock);
> >>> +
> >>> + return data;
> >>> +}
> >>> +
> >>> +/* Return converted value from given adc */
> >>> +static int smm665_convert(u16 adcval, int index)
> >>> +{
> >>> + int val = 0;
> >>> +
> >>> + switch (index) {
> >>> + case SMM665_MISC16_ADC_DATA_12V:
> >>> + val = SMM665_12VIN_ADC_TO_VOLTS(adcval & SMM665_ADC_MASK);
> >>> + break;
> >>> +
> >>> + case SMM665_MISC16_ADC_DATA_VDD:
> >>> + case SMM665_MISC16_ADC_DATA_A:
> >>> + case SMM665_MISC16_ADC_DATA_B:
> >>> + case SMM665_MISC16_ADC_DATA_C:
> >>> + case SMM665_MISC16_ADC_DATA_D:
> >>> + case SMM665_MISC16_ADC_DATA_E:
> >>> + case SMM665_MISC16_ADC_DATA_F:
> >>> + val = SMM665_VMON_ADC_TO_VOLTS(adcval & SMM665_ADC_MASK);
> >>> + break;
> >>> +
> >>> + case SMM665_MISC16_ADC_DATA_AIN1:
> >>> + case SMM665_MISC16_ADC_DATA_AIN2:
> >>> + val = SMM665_AIN_ADC_TO_VOLTS(adcval & SMM665_ADC_MASK);
> >>> + break;
> >>> +
> >>> + case SMM665_MISC16_ADC_DATA_INT_TEMP:
> >>> + val = SMM665_TEMP_ADC_TO_CELSIUS(adcval & SMM665_ADC_MASK);
> >>> + break;
> >>> +
> >>> + default:
> >>> + /* If we get here, the developer messed up */
> >>> + WARN_ON_ONCE(1);
> >>> + break;
> >>> + }
> >>> +
> >>> + return val;
> >>> +}
> >>> +
> >>> +/* Return converted value from given adc */
> >>> +static int smm665_get_input(struct device *dev, int adc)
> >>> +{
> >>> + struct smm665_data *data = smm665_update_device(dev);
> >>> +
> >>> + return smm665_convert(data->adc[adc], adc);
> >>> +}
> >>> +
> >>> +static int smm665_get_min(struct device *dev, int index)
> >>> +{
> >>> + struct i2c_client *client = to_i2c_client(dev);
> >>> + struct smm665_data *data = i2c_get_clientdata(client);
> >>> +
> >>> + return data->alarm_under_limit[index];
> >>> +}
> >>> +
> >>> +static int smm665_get_max(struct device *dev, int index)
> >>> +{
> >>> + struct i2c_client *client = to_i2c_client(dev);
> >>> + struct smm665_data *data = i2c_get_clientdata(client);
> >>> +
> >>> + return data->alarm_over_limit[index];
> >>> +}
> >>> +
> >>> +static int smm665_get_crit(struct device *dev, int index)
> >>> +{
> >>> + struct i2c_client *client = to_i2c_client(dev);
> >>> + struct smm665_data *data = i2c_get_clientdata(client);
> >>> +
> >>> + return data->critical_over_limit[index];
> >>> +}
> >>> +
> >>> +static int smm665_get_fault(struct device *dev, int index)
> >>> +{
> >>> + struct smm665_data *data = smm665_update_device(dev);
> >>> +
> >>> + if (data->faults & (1 << index))
> >>> + return 1;
> >>> +
> >>> + return 0;
> >>> +}
> >>> +
> >>> +#define SMM665_SHOW(what) \
> >>> + static ssize_t smm665_show_##what(struct device *dev, \
> >>> + struct device_attribute *da, char *buf) \
> >>> +{ \
> >>> + struct sensor_device_attribute *attr = to_sensor_dev_attr(da); \
> >>> + const int val = smm665_get_##what(dev, attr->index); \
> >>> + return snprintf(buf, PAGE_SIZE, "%d\n", val); \
> >>> +}
> >>> +
> >>> +SMM665_SHOW(input);
> >>> +SMM665_SHOW(min);
> >>> +SMM665_SHOW(max);
> >>> +SMM665_SHOW(crit);
> >>> +SMM665_SHOW(fault);
> >>> +
> >>> +/* These macros are used below in constructing device attribute objects
> >>> + * for use with sysfs_create_group() to make a sysfs device file
> >>> + * for each register.
> >>> + */
> >>> +
> >>> +#define SMM665_ATTR(name, type, cmd_idx) \
> >>> + static SENSOR_DEVICE_ATTR(name##_##type, S_IRUGO, \
> >>> + smm665_show_##type, NULL, cmd_idx)
> >>> +
> >>> +/* Construct a sensor_device_attribute structure for each register */
> >>> +
> >>> +/* Input voltages */
> >>> +SMM665_ATTR(in1, input, SMM665_MISC16_ADC_DATA_12V);
> >>> +SMM665_ATTR(in2, input, SMM665_MISC16_ADC_DATA_VDD);
> >>> +SMM665_ATTR(in3, input, SMM665_MISC16_ADC_DATA_A);
> >>> +SMM665_ATTR(in4, input, SMM665_MISC16_ADC_DATA_B);
> >>> +SMM665_ATTR(in5, input, SMM665_MISC16_ADC_DATA_C);
> >>> +SMM665_ATTR(in6, input, SMM665_MISC16_ADC_DATA_D);
> >>> +SMM665_ATTR(in7, input, SMM665_MISC16_ADC_DATA_E);
> >>> +SMM665_ATTR(in8, input, SMM665_MISC16_ADC_DATA_F);
> >>> +SMM665_ATTR(in9, input, SMM665_MISC16_ADC_DATA_AIN1);
> >>> +SMM665_ATTR(in10, input, SMM665_MISC16_ADC_DATA_AIN2);
> >>> +
> >>> +/* Input voltages min */
> >>> +SMM665_ATTR(in1, min, SMM665_MISC16_ADC_DATA_12V);
> >>> +SMM665_ATTR(in2, min, SMM665_MISC16_ADC_DATA_VDD);
> >>> +SMM665_ATTR(in3, min, SMM665_MISC16_ADC_DATA_A);
> >>> +SMM665_ATTR(in4, min, SMM665_MISC16_ADC_DATA_B);
> >>> +SMM665_ATTR(in5, min, SMM665_MISC16_ADC_DATA_C);
> >>> +SMM665_ATTR(in6, min, SMM665_MISC16_ADC_DATA_D);
> >>> +SMM665_ATTR(in7, min, SMM665_MISC16_ADC_DATA_E);
> >>> +SMM665_ATTR(in8, min, SMM665_MISC16_ADC_DATA_F);
> >>> +SMM665_ATTR(in9, min, SMM665_MISC16_ADC_DATA_AIN1);
> >>> +SMM665_ATTR(in10, min, SMM665_MISC16_ADC_DATA_AIN2);
> >>> +
> >>> +/* Input voltages max */
> >>> +SMM665_ATTR(in1, max, SMM665_MISC16_ADC_DATA_12V);
> >>> +SMM665_ATTR(in2, max, SMM665_MISC16_ADC_DATA_VDD);
> >>> +SMM665_ATTR(in3, max, SMM665_MISC16_ADC_DATA_A);
> >>> +SMM665_ATTR(in4, max, SMM665_MISC16_ADC_DATA_B);
> >>> +SMM665_ATTR(in5, max, SMM665_MISC16_ADC_DATA_C);
> >>> +SMM665_ATTR(in6, max, SMM665_MISC16_ADC_DATA_D);
> >>> +SMM665_ATTR(in7, max, SMM665_MISC16_ADC_DATA_E);
> >>> +SMM665_ATTR(in8, max, SMM665_MISC16_ADC_DATA_F);
> >>> +SMM665_ATTR(in9, max, SMM665_MISC16_ADC_DATA_AIN1);
> >>> +SMM665_ATTR(in10, max, SMM665_MISC16_ADC_DATA_AIN2);
> >>> +
> >>> +/* Faults */
> >>> +SMM665_ATTR(in1, fault, SMM665_FAULT_12V);
> >>> +SMM665_ATTR(in2, fault, SMM665_FAULT_VDD);
> >>> +SMM665_ATTR(in3, fault, SMM665_FAULT_A);
> >>> +SMM665_ATTR(in4, fault, SMM665_FAULT_B);
> >>> +SMM665_ATTR(in5, fault, SMM665_FAULT_C);
> >>> +SMM665_ATTR(in6, fault, SMM665_FAULT_D);
> >>> +SMM665_ATTR(in7, fault, SMM665_FAULT_E);
> >>> +SMM665_ATTR(in8, fault, SMM665_FAULT_F);
> >>> +SMM665_ATTR(in9, fault, SMM665_FAULT_AIN1);
> >>> +SMM665_ATTR(in10, fault, SMM665_FAULT_AIN2);
> >>> +
> >>> +/* Temperature */
> >>> +SMM665_ATTR(temp1, input, SMM665_MISC16_ADC_DATA_INT_TEMP);
> >>> +SMM665_ATTR(temp1, min, SMM665_MISC16_ADC_DATA_INT_TEMP);
> >>> +SMM665_ATTR(temp1, max, SMM665_MISC16_ADC_DATA_INT_TEMP);
> >>
> >> Why have critical here and nowhere else?
> >
> > Because the API defines it for temperatures, but not for voltages.
> > Also, it is "critical high", which makes sense to a point for temperatures,
> > but would be insufficient/incomplete for other measurements.
> > It would be nice to have "min_crit" and "max_crit" for temperatures
> > as well, though.
> Yup. Define them and post a patch adding them to the Documentation
> (that's more likely to get peoples attention ;)
Interesting idea. Might be worth a try ... maybe I should do the same for voltages.
> >
> >>> +SMM665_ATTR(temp1, crit, SMM665_MISC16_ADC_DATA_INT_TEMP);
> >>> +SMM665_ATTR(temp1, fault, SMM665_FAULT_TEMP);
> >>> +
> >>> +/*
> >>> + * Finally, construct an array of pointers to members of the above objects,
> >>> + * as required for sysfs_create_group()
> >>> + */
> >>> +static struct attribute *smm665_attributes[] = {
> >>> + &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_fault.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_fault.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_fault.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_fault.dev_attr.attr,
> >>> +
> >>> + &sensor_dev_attr_in5_input.dev_attr.attr,
> >>> + &sensor_dev_attr_in5_min.dev_attr.attr,
> >>> + &sensor_dev_attr_in5_max.dev_attr.attr,
> >>> + &sensor_dev_attr_in5_fault.dev_attr.attr,
> >>> +
> >>> + &sensor_dev_attr_in6_input.dev_attr.attr,
> >>> + &sensor_dev_attr_in6_min.dev_attr.attr,
> >>> + &sensor_dev_attr_in6_max.dev_attr.attr,
> >>> + &sensor_dev_attr_in6_fault.dev_attr.attr,
> >>> +
> >>> + &sensor_dev_attr_in7_input.dev_attr.attr,
> >>> + &sensor_dev_attr_in7_min.dev_attr.attr,
> >>> + &sensor_dev_attr_in7_max.dev_attr.attr,
> >>> + &sensor_dev_attr_in7_fault.dev_attr.attr,
> >>> +
> >>> + &sensor_dev_attr_in8_input.dev_attr.attr,
> >>> + &sensor_dev_attr_in8_min.dev_attr.attr,
> >>> + &sensor_dev_attr_in8_max.dev_attr.attr,
> >>> + &sensor_dev_attr_in8_fault.dev_attr.attr,
> >>> +
> >>> + &sensor_dev_attr_in9_input.dev_attr.attr,
> >>> + &sensor_dev_attr_in9_min.dev_attr.attr,
> >>> + &sensor_dev_attr_in9_max.dev_attr.attr,
> >>> + &sensor_dev_attr_in9_fault.dev_attr.attr,
> >>> +
> >>> + &sensor_dev_attr_in10_input.dev_attr.attr,
> >>> + &sensor_dev_attr_in10_min.dev_attr.attr,
> >>> + &sensor_dev_attr_in10_max.dev_attr.attr,
> >>> + &sensor_dev_attr_in10_fault.dev_attr.attr,
> >>> +
> >>> + &sensor_dev_attr_temp1_input.dev_attr.attr,
> >>> + &sensor_dev_attr_temp1_min.dev_attr.attr,
> >>> + &sensor_dev_attr_temp1_max.dev_attr.attr,
> >>> + &sensor_dev_attr_temp1_crit.dev_attr.attr,
> >>> + &sensor_dev_attr_temp1_fault.dev_attr.attr,
> >>> +
> >>> + NULL,
> >>> +};
> >>> +
> >>> +static const struct attribute_group smm665_group = {
> >>> + .attrs = smm665_attributes,
> >>> +};
> >>> +
> >>> +static int smm665_probe(struct i2c_client *client,
> >>> + const struct i2c_device_id *id)
> >>> +{
> >>> + struct i2c_adapter *adapter = client->adapter;
> >>> + struct smm665_data *data;
> >>> + int i, ret;
> >>> +
> >>> + if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
> >>> + | I2C_FUNC_SMBUS_WORD_DATA))
> >>> + return -ENODEV;
> >>> +
> >>> + if (i2c_smbus_read_byte_data(client, SMM665_ADOC_ENABLE) < 0)
> >>> + return -ENODEV;
> >>> +
> >>> + ret = -ENOMEM;
> >>> + data = kzalloc(sizeof(*data), GFP_KERNEL);
> >>> + if (!data)
> >>> + goto out_kzalloc;
> >>> +
> >>> + i2c_set_clientdata(client, data);
> >>> + mutex_init(&data->update_lock);
> >>> +
> >>> + data->type = id->driver_data;
> >>> + data->cmdreg = i2c_new_dummy(adapter, (client->addr & ~SMM665_REGMASK)
> >>> + | SMM665_CMDREG_BASE);
> >>> + if (!data->cmdreg)
> >>> + goto out_new_dummy;
> >>> +
> >>> + switch (data->type) {
> >>> + case smm465:
> >>> + case smm665:
> >>> + data->conversion_time = SMM665_ADC_WAIT_SMM665;
> >>> + break;
> >>> + case smm665c:
> >>> + case smm764:
> >>> + case smm766:
> >>> + data->conversion_time = SMM665_ADC_WAIT_SMM766;
> >>> + break;
> >>> + }
> >>> +
> >>> + ret = -ENODEV;
> >>> + if (i2c_smbus_read_byte_data(data->cmdreg, SMM665_MISC8_CMD_STS) < 0)
> >>> + goto out_sysfs_create_group;
> >>> +
> >>> + /*
> >>> + * Read limits.
> >>> + *
> >>> + * Limit registers start with register SMM665_LIMIT_BASE.
> >>> + * Each channel uses 8 registers, providing four limit values
> >>> + * per channel. Each limit value requires two registers, with the
> >>> + * high byte in the first register and the low byte in the second
> >>> + * register. The first two limits are under limit values, followed
> >>> + * by two over limit values.
> >>> + *
> >>> + * Limit register order matches the ADC register order, so we use
> >>> + * ADC register defines throughout the code to index limit registers.
> >>> + *
> >>> + * We save the first retrieved value both as "critical" and "alarm"
> >>> + * value. The second value overwrites either the critical or the
> >>> + * alarm value, depending on its configuration. This ensures that both
> >>> + * critical and alarm values are initialized, even if both registers are
> >>> + * configured as critical or non-critical.
> >>> + *
> >>> + * Note: Critical values for voltage channels are saved, even though
> >>> + * this information is currently not used by the driver. This is mostly
> >>> + * for consistency, though it might eventually be useful if future APIs
> >>> + * support reporting "critical" voltage values.
> >>> + */
> >>> + for (i = 0; i < SMM665_NUM_ADC; i++) {
> >>> + int val;
> >>> +
> >>> + val = smm665_read16(client, SMM665_LIMIT_BASE + i * 8);
> >>> + if (unlikely(val < 0))
> >>> + goto out_sysfs_create_group;
> >>> + data->critical_under_limit[i] = data->alarm_under_limit[i]
> >>> + = smm665_convert(val, i);
> >>> + val = smm665_read16(client, SMM665_LIMIT_BASE + i * 8 + 2);
> >>> + if (unlikely(val < 0))
> >>> + goto out_sysfs_create_group;
> >>> + if (smm665_is_critical(val))
> >>> + data->critical_under_limit[i] = smm665_convert(val, i);
> >>> + else
> >>> + data->alarm_under_limit[i] = smm665_convert(val, i);
> >>> + val = smm665_read16(client, SMM665_LIMIT_BASE + i * 8 + 4);
> >>> + if (unlikely(val < 0))
> >>> + goto out_sysfs_create_group;
> >>> + data->critical_over_limit[i] = data->alarm_over_limit[i]
> >>> + = smm665_convert(val, i);
> >>> + val = smm665_read16(client, SMM665_LIMIT_BASE + i * 8 + 6);
> >>> + if (unlikely(val < 0))
> >>> + goto out_sysfs_create_group;
> >>> + if (smm665_is_critical(val))
> >>> + data->critical_over_limit[i] = smm665_convert(val, i);
> >>> + else
> >>> + data->alarm_over_limit[i] = smm665_convert(val, i);
> >>> + }
> >>> +
> >>> + /* Register sysfs hooks */
> >>> + ret = sysfs_create_group(&client->dev.kobj, &smm665_group);
> >>> + if (ret)
> >>> + goto out_sysfs_create_group;
> >>> +
> >>> + data->hwmon_dev = hwmon_device_register(&client->dev);
> >>> + if (IS_ERR(data->hwmon_dev)) {
> >>> + ret = PTR_ERR(data->hwmon_dev);
> >>> + goto out_hwmon_device_register;
> >>> + }
> >>> +
> >>> + return 0;
> >>> +
> >>> +out_hwmon_device_register:
> >>> + sysfs_remove_group(&client->dev.kobj, &smm665_group);
> >>> +out_sysfs_create_group:
> >>> + i2c_unregister_device(data->cmdreg);
> >>> +out_new_dummy:
> >>> + kfree(data);
> >>> +out_kzalloc:
> >>> + return ret;
> >>> +}
> >>> +
> >>> +static int smm665_remove(struct i2c_client *client)
> >>> +{
> >>> + struct smm665_data *data = i2c_get_clientdata(client);
> >>> +
> >>> + i2c_unregister_device(data->cmdreg);
> >>> + hwmon_device_unregister(data->hwmon_dev);
> >>> + sysfs_remove_group(&client->dev.kobj, &smm665_group);
> >>> +
> >>> + kfree(data);
> >>> +
> >>> + return 0;
> >>> +}
> >>> +
> >>> +static const struct i2c_device_id smm665_id[] = {
> >>> + {"smm465", smm465},
> >>> + {"smm665", smm665},
> >>> + {"smm665c", smm665c},
> >>> + {"smm764", smm764},
> >>> + {"smm766", smm766},
> >>> + {}
> >>> +};
> >>> +
> >>> +MODULE_DEVICE_TABLE(i2c, smm665_id);
> >>> +
> >>> +/* This is the driver that will be inserted */
> >>> +static struct i2c_driver smm665_driver = {
> >>> + .driver = {
> >>> + .name = "smm665",
> >>> + },
> >>> + .probe = smm665_probe,
> >>> + .remove = smm665_remove,
> >>> + .id_table = smm665_id,
> >>> +};
> >>> +
> >>> +static int __init smm665_init(void)
> >>> +{
> >>> + return i2c_add_driver(&smm665_driver);
> >>> +}
> >>> +
> >>> +static void __exit smm665_exit(void)
> >>> +{
> >>> + i2c_del_driver(&smm665_driver);
> >>> +}
> >>> +
> >>> +MODULE_AUTHOR("Guenter Roeck");
> >>> +MODULE_DESCRIPTION("SMM665 driver");
> >>> +MODULE_LICENSE("GPL");
> >>> +
> >>> +module_init(smm665_init);
> >>> +module_exit(smm665_exit);
> >>
>
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