| Message ID | 20240517081050.168698-3-dima.fedrau@gmail.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | Add threshold events support | expand |
On Fri, 17 May 2024 10:10:50 +0200 Dimitri Fedrau <dima.fedrau@gmail.com> wrote: > The device has four programmable temperature alert outputs which can be > used to monitor hot or cold-junction temperatures and detect falling and > rising temperatures. It supports up to 255 degree celsius programmable > hysteresis. Each alert can be individually configured by setting following > options in the associated alert configuration register: > - monitor hot or cold junction temperature > - monitor rising or falling temperature > - set comparator or interrupt mode > - set output polarity > - enable alert > > This patch binds alert outputs to iio events: > - alert1: hot junction, rising temperature > - alert2: hot junction, falling temperature > - alert3: cold junction, rising temperature > - alert4: cold junction, falling temperature > > All outputs are set in comparator mode and polarity depends on interrupt > configuration. > > Signed-off-by: Dimitri Fedrau <dima.fedrau@gmail.com> Hi Dmitri Please make sure to address all questions in earlier reviews, either by changing the code, or directly answering the question. The hysteresis handling in here is completely different from normal and the diagrams in figure 5-10 suggest it should not be. Your thresholds should not include hysteresis at all as it has nothing to do with event triggering. The hysteresis is presented to userspace so it knows when a 'reset' of event detection logic occurs. It is expressed as an offset (in the obvious direction) from the current threshold. It is always positive as negative hysteresis would be very odd. It's just magnitude of how far back beyond the threshold the signal must go for a reset of the signal detection logic to occur, allowing new transitions etc. As long as you are using an edge interrupt that just means you won't get another interrupt until getting well away from what triggered the interrupt last time. Jonathan > --- > drivers/iio/temperature/mcp9600.c | 389 ++++++++++++++++++++++++++++++ > 1 file changed, 389 insertions(+) > > diff --git a/drivers/iio/temperature/mcp9600.c b/drivers/iio/temperature/mcp9600.c > index 22451d1d9e1f..91d811fe9371 100644 > --- a/drivers/iio/temperature/mcp9600.c > +++ b/drivers/iio/temperature/mcp9600.c > @@ -6,12 +6,21 @@ > * Author: <andrew.hepp@ahepp.dev> > */ > > +#include <linux/bitfield.h> > +#include <linux/bitops.h> > +#include <linux/bits.h> > #include <linux/err.h> > #include <linux/i2c.h> > #include <linux/init.h> > +#include <linux/interrupt.h> > +#include <linux/irq.h> > +#include <linux/math.h> > +#include <linux/minmax.h> > #include <linux/mod_devicetable.h> > #include <linux/module.h> > +#include <linux/mutex.h> > > +#include <linux/iio/events.h> > #include <linux/iio/iio.h> > > #define MCP9600_CHAN_HOT_JUNCTION 0 > @@ -20,11 +29,65 @@ > /* MCP9600 registers */ > #define MCP9600_HOT_JUNCTION 0x0 > #define MCP9600_COLD_JUNCTION 0x2 > +#define MCP9600_STATUS 0x4 > +#define MCP9600_STATUS_ALERT(x) BIT(x) > +#define MCP9600_ALERT_CFG1 0x8 > +#define MCP9600_ALERT_CFG(x) (MCP9600_ALERT_CFG1 + (x - 1)) > +#define MCP9600_ALERT_CFG_ENABLE BIT(0) > +#define MCP9600_ALERT_CFG_ACTIVE_HIGH BIT(2) > +#define MCP9600_ALERT_CFG_FALLING BIT(3) > +#define MCP9600_ALERT_CFG_COLD_JUNCTION BIT(4) > +#define MCP9600_ALERT_HYSTERESIS1 0xc > +#define MCP9600_ALERT_HYSTERESIS(x) (MCP9600_ALERT_HYSTERESIS1 + (x - 1)) > +#define MCP9600_ALERT_LIMIT1 0x10 > +#define MCP9600_ALERT_LIMIT(x) (MCP9600_ALERT_LIMIT1 + (x - 1)) > +#define MCP9600_ALERT_LIMIT_MASK GENMASK(15, 2) > #define MCP9600_DEVICE_ID 0x20 > > /* MCP9600 device id value */ > #define MCP9600_DEVICE_ID_MCP9600 0x40 > > +#define MCP9600_ALERT_COUNT 4 > + > +#define MCP9600_TEMP_SCALE_NUM 1000000 MICRO or just use that inline. > + > +#define MCP9600_MIN_TEMP_HOT_JUNCTION -200 > +#define MCP9600_MAX_TEMP_HOT_JUNCTION 1800 Give these units in the naming and you can include the * MICRO here. e.g. #define MCP9600_MIN_TEMP_HOT_JUNC_MICROCELCIUS -200 * MICRO etc > + > +static int mcp9600_read_thresh(struct iio_dev *indio_dev, > + const struct iio_chan_spec *chan, > + enum iio_event_type type, > + enum iio_event_direction dir, > + enum iio_event_info info, int *val, int *val2) > +{ > + struct mcp9600_data *data = iio_priv(indio_dev); > + struct i2c_client *client = data->client; > + s32 ret; > + int i; > + > + i = mcp9600_get_alert_index(chan->channel, dir); > + guard(mutex)(&data->lock); > + ret = i2c_smbus_read_word_swapped(client, MCP9600_ALERT_LIMIT(i + 1)); > + if (ret < 0) > + return ret; > + > + /* > + * Temperature is stored in two’s complement format in bits(15:2), > + * LSB is 0.25 degree celsius. > + */ > + *val = sign_extend32(FIELD_GET(MCP9600_ALERT_LIMIT_MASK, ret), 13); > + *val2 = 4; > + if (info == IIO_EV_INFO_VALUE) > + return IIO_VAL_FRACTIONAL; > + > + ret = i2c_smbus_read_byte_data(client, MCP9600_ALERT_HYSTERESIS(i + 1)); > + if (ret < 0) > + return ret; > + > + /* > + * Hysteresis is stored as unsigned offset from threshold. The alert > + * direction bit in the alert configuration register defines whether the > + * value is below or above the corresponding threshold. I'm still very very confused by this. I raised a question in the first review and you didn't provide more information. This is not how hysteresis is normally defined. It should not affect the threshold at all, but instead affect when a reset occurs of the threshold detection logic. It also does not correspond to the diagrams in Figure 5-10 which look exactly like normal hysteresis controls. > + */ > + if (dir == IIO_EV_DIR_RISING) > + *val -= (*val2 * ret); > + else > + *val += (*val2 * ret); > + > + return IIO_VAL_FRACTIONAL; > +} > + > +static int mcp9600_write_thresh(struct iio_dev *indio_dev, > + const struct iio_chan_spec *chan, > + enum iio_event_type type, > + enum iio_event_direction dir, > + enum iio_event_info info, int val, int val2) > +{ > + struct mcp9600_data *data = iio_priv(indio_dev); > + struct i2c_client *client = data->client; > + int s_val, s_thresh, i; > + s16 thresh; > + s32 ret; > + u8 hyst; > + > + /* Scale value to include decimal part into calculations */ > + s_val = (val < 0) ? ((val * MCP9600_TEMP_SCALE_NUM) - val2) : > + ((val * MCP9600_TEMP_SCALE_NUM) + val2); > + > + /* Hot junction temperature range is from –200 to 1800 degree celsius */ > + if (chan->channel == MCP9600_CHAN_HOT_JUNCTION && > + (s_val < (MCP9600_MIN_TEMP_HOT_JUNCTION * MCP9600_TEMP_SCALE_NUM) || > + s_val > (MCP9600_MAX_TEMP_HOT_JUNCTION * MCP9600_TEMP_SCALE_NUM))) As above, change the units of the defines to simplify this or perhaps just treat these as numbers and put them here rather than using defines at all. > + return -EINVAL; > + > + /* Cold junction temperature range is from –40 to 125 degree celsius */ > + if (chan->channel == MCP9600_CHAN_COLD_JUNCTION && > + (s_val < (MCP9600_MIN_TEMP_COLD_JUNCTION * MCP9600_TEMP_SCALE_NUM) || > + s_val > (MCP9600_MAX_TEMP_COLD_JUNCTION * MCP9600_TEMP_SCALE_NUM))) > + return -EINVAL; > + > + i = mcp9600_get_alert_index(chan->channel, dir); > + guard(mutex)(&data->lock); > + switch (info) { > + case IIO_EV_INFO_VALUE: > + /* > + * Shift length 4 bits = 2(15:2) + 2(0.25 LSB), temperature is > + * stored in two’s complement format. > + */ > + thresh = (s16)(s_val / (MCP9600_TEMP_SCALE_NUM >> 4)); > + return i2c_smbus_write_word_swapped(client, > + MCP9600_ALERT_LIMIT(i + 1), > + thresh); > + case IIO_EV_INFO_HYSTERESIS: > + /* Read out threshold, hysteresis is stored as offset */ > + ret = i2c_smbus_read_word_swapped(client, MCP9600_ALERT_LIMIT(i + 1)); > + if (ret < 0) > + return ret; > + > + /* Shift length 4 bits = 2(15:2) + 2(0.25 LSB), see above. */ > + s_thresh = sign_extend32(ret, 15) * (MCP9600_TEMP_SCALE_NUM >> 4); > + > + /* > + * Hysteresis is stored as offset, for rising temperatures, the > + * hysteresis range is below the alert limit where, as for falling > + * temperatures, the hysteresis range is above the alert limit. > + */ I don't understand this comment. Hysteresis as a parameter in sysfs in IIO is also an offset, so why is the current threshold relevant? Normally hysteresis is about allowing repeat events. I.e. you have to drop below threshold - hysteresis before rising again to trigger a rising event when passing threshold. > + hyst = min(255, abs(s_thresh - s_val) / MCP9600_TEMP_SCALE_NUM); > + > + return i2c_smbus_write_byte_data(client, > + MCP9600_ALERT_HYSTERESIS(i + 1), > + hyst); > + default: > + return -EINVAL; > + } > +} > +static irqreturn_t mcp9600_alert3_handler(int irq, void *private) > +{ > + struct iio_dev *indio_dev = private; > + struct mcp9600_data *data = iio_priv(indio_dev); > + int ret; > + > + ret = i2c_smbus_read_byte_data(data->client, MCP9600_STATUS); > + if (ret < 0) > + return IRQ_HANDLED; > + > + if (!(ret & MCP9600_STATUS_ALERT(MCP9600_ALERT3))) This duplicates far too much all these call a function that takes a) This bit, b) the related channel index. C) the direction and call that from all these separate handlers. Each individual handler become simply: return mcp9600_alert_handler(private, MCP9600_ALERT3, MCP9600_CHAN_COLD_JUNCTION, IIO_EV_DIR_RISING); etc. > + return IRQ_NONE; > + > + iio_push_event(indio_dev, > + IIO_MOD_EVENT_CODE(IIO_TEMP, MCP9600_CHAN_COLD_JUNCTION, > + IIO_NO_MOD, IIO_EV_TYPE_THRESH, > + IIO_EV_DIR_RISING), > + iio_get_time_ns(indio_dev)); > + > + return IRQ_HANDLED; > +} > + > + > +static irqreturn_t (*mcp9600_alert_handler[MCP9600_ALERT_COUNT]) (int, void *) = { > + mcp9600_alert1_handler, > + mcp9600_alert2_handler, > + mcp9600_alert3_handler, > + mcp9600_alert4_handler, > };
Am Sun, May 19, 2024 at 05:42:48PM +0100 schrieb Jonathan Cameron: > On Fri, 17 May 2024 10:10:50 +0200 > Dimitri Fedrau <dima.fedrau@gmail.com> wrote: > > > The device has four programmable temperature alert outputs which can be > > used to monitor hot or cold-junction temperatures and detect falling and > > rising temperatures. It supports up to 255 degree celsius programmable > > hysteresis. Each alert can be individually configured by setting following > > options in the associated alert configuration register: > > - monitor hot or cold junction temperature > > - monitor rising or falling temperature > > - set comparator or interrupt mode > > - set output polarity > > - enable alert > > > > This patch binds alert outputs to iio events: > > - alert1: hot junction, rising temperature > > - alert2: hot junction, falling temperature > > - alert3: cold junction, rising temperature > > - alert4: cold junction, falling temperature > > > > All outputs are set in comparator mode and polarity depends on interrupt > > configuration. > > > > Signed-off-by: Dimitri Fedrau <dima.fedrau@gmail.com> > Hi Dmitri Hi Jonathan, > Please make sure to address all questions in earlier reviews, either by > changing the code, or directly answering the question. > I did, see: https://lore.kernel.org/linux-iio/20240509204559.GB3614@debian/T/#u or did I miss anything ? I'm a little bit confused. > The hysteresis handling in here is completely different from normal > and the diagrams in figure 5-10 suggest it should not be. > > Your thresholds should not include hysteresis at all as it has nothing to > do with event triggering. The hysteresis is presented to userspace so it > knows when a 'reset' of event detection logic occurs. It is expressed > as an offset (in the obvious direction) from the current threshold. > > It is always positive as negative hysteresis would be very odd. It's just > magnitude of how far back beyond the threshold the signal must go for > a reset of the signal detection logic to occur, allowing new transitions etc. > > As long as you are using an edge interrupt that just means you won't get > another interrupt until getting well away from what triggered the interrupt > last time. > You are right. Thanks a lot for your explanation. I just didn't know it, assumed the hysteresis is represented same way as the threshold. > Jonathan > > > --- > > drivers/iio/temperature/mcp9600.c | 389 ++++++++++++++++++++++++++++++ > > 1 file changed, 389 insertions(+) > > > > diff --git a/drivers/iio/temperature/mcp9600.c b/drivers/iio/temperature/mcp9600.c > > index 22451d1d9e1f..91d811fe9371 100644 > > --- a/drivers/iio/temperature/mcp9600.c > > +++ b/drivers/iio/temperature/mcp9600.c > > @@ -6,12 +6,21 @@ > > * Author: <andrew.hepp@ahepp.dev> > > */ > > > > +#include <linux/bitfield.h> > > +#include <linux/bitops.h> > > +#include <linux/bits.h> > > #include <linux/err.h> > > #include <linux/i2c.h> > > #include <linux/init.h> > > +#include <linux/interrupt.h> > > +#include <linux/irq.h> > > +#include <linux/math.h> > > +#include <linux/minmax.h> > > #include <linux/mod_devicetable.h> > > #include <linux/module.h> > > +#include <linux/mutex.h> > > > > +#include <linux/iio/events.h> > > #include <linux/iio/iio.h> > > > > #define MCP9600_CHAN_HOT_JUNCTION 0 > > @@ -20,11 +29,65 @@ > > /* MCP9600 registers */ > > #define MCP9600_HOT_JUNCTION 0x0 > > #define MCP9600_COLD_JUNCTION 0x2 > > +#define MCP9600_STATUS 0x4 > > +#define MCP9600_STATUS_ALERT(x) BIT(x) > > +#define MCP9600_ALERT_CFG1 0x8 > > +#define MCP9600_ALERT_CFG(x) (MCP9600_ALERT_CFG1 + (x - 1)) > > +#define MCP9600_ALERT_CFG_ENABLE BIT(0) > > +#define MCP9600_ALERT_CFG_ACTIVE_HIGH BIT(2) > > +#define MCP9600_ALERT_CFG_FALLING BIT(3) > > +#define MCP9600_ALERT_CFG_COLD_JUNCTION BIT(4) > > +#define MCP9600_ALERT_HYSTERESIS1 0xc > > +#define MCP9600_ALERT_HYSTERESIS(x) (MCP9600_ALERT_HYSTERESIS1 + (x - 1)) > > +#define MCP9600_ALERT_LIMIT1 0x10 > > +#define MCP9600_ALERT_LIMIT(x) (MCP9600_ALERT_LIMIT1 + (x - 1)) > > +#define MCP9600_ALERT_LIMIT_MASK GENMASK(15, 2) > > #define MCP9600_DEVICE_ID 0x20 > > > > /* MCP9600 device id value */ > > #define MCP9600_DEVICE_ID_MCP9600 0x40 > > > > +#define MCP9600_ALERT_COUNT 4 > > + > > +#define MCP9600_TEMP_SCALE_NUM 1000000 > > MICRO or just use that inline. > > > + > > +#define MCP9600_MIN_TEMP_HOT_JUNCTION -200 > > +#define MCP9600_MAX_TEMP_HOT_JUNCTION 1800 > Give these units in the naming and you can include the * MICRO here. > e.g. > #define MCP9600_MIN_TEMP_HOT_JUNC_MICROCELCIUS -200 * MICRO > etc > Ok. > > > + > > +static int mcp9600_read_thresh(struct iio_dev *indio_dev, > > + const struct iio_chan_spec *chan, > > + enum iio_event_type type, > > + enum iio_event_direction dir, > > + enum iio_event_info info, int *val, int *val2) > > +{ > > + struct mcp9600_data *data = iio_priv(indio_dev); > > + struct i2c_client *client = data->client; > > + s32 ret; > > + int i; > > + > > + i = mcp9600_get_alert_index(chan->channel, dir); > > + guard(mutex)(&data->lock); > > + ret = i2c_smbus_read_word_swapped(client, MCP9600_ALERT_LIMIT(i + 1)); > > + if (ret < 0) > > + return ret; > > + > > + /* > > + * Temperature is stored in two’s complement format in bits(15:2), > > + * LSB is 0.25 degree celsius. > > + */ > > + *val = sign_extend32(FIELD_GET(MCP9600_ALERT_LIMIT_MASK, ret), 13); > > + *val2 = 4; > > + if (info == IIO_EV_INFO_VALUE) > > + return IIO_VAL_FRACTIONAL; > > + > > + ret = i2c_smbus_read_byte_data(client, MCP9600_ALERT_HYSTERESIS(i + 1)); > > + if (ret < 0) > > + return ret; > > + > > + /* > > + * Hysteresis is stored as unsigned offset from threshold. The alert > > + * direction bit in the alert configuration register defines whether the > > + * value is below or above the corresponding threshold. > > I'm still very very confused by this. I raised a question in the first review > and you didn't provide more information. > This is not how hysteresis is normally defined. It should not affect the > threshold at all, but instead affect when a reset occurs of the threshold detection > logic. It also does not correspond to the diagrams in Figure 5-10 which look > exactly like normal hysteresis controls. > You are right. I got it wrong here. After your explanation and having a look at https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-bus-iio it should be easy to fix this. Thanks again. > > > + */ > > + if (dir == IIO_EV_DIR_RISING) > > + *val -= (*val2 * ret); > > + else > > + *val += (*val2 * ret); > > + > > + return IIO_VAL_FRACTIONAL; > > +} > > + > > +static int mcp9600_write_thresh(struct iio_dev *indio_dev, > > + const struct iio_chan_spec *chan, > > + enum iio_event_type type, > > + enum iio_event_direction dir, > > + enum iio_event_info info, int val, int val2) > > +{ > > + struct mcp9600_data *data = iio_priv(indio_dev); > > + struct i2c_client *client = data->client; > > + int s_val, s_thresh, i; > > + s16 thresh; > > + s32 ret; > > + u8 hyst; > > + > > + /* Scale value to include decimal part into calculations */ > > + s_val = (val < 0) ? ((val * MCP9600_TEMP_SCALE_NUM) - val2) : > > + ((val * MCP9600_TEMP_SCALE_NUM) + val2); > > + > > + /* Hot junction temperature range is from –200 to 1800 degree celsius */ > > + if (chan->channel == MCP9600_CHAN_HOT_JUNCTION && > > + (s_val < (MCP9600_MIN_TEMP_HOT_JUNCTION * MCP9600_TEMP_SCALE_NUM) || > > + s_val > (MCP9600_MAX_TEMP_HOT_JUNCTION * MCP9600_TEMP_SCALE_NUM))) > > As above, change the units of the defines to simplify this or perhaps > just treat these as numbers and put them here rather than using defines at all. > Ok. > > + return -EINVAL; > > + > > + /* Cold junction temperature range is from –40 to 125 degree celsius */ > > + if (chan->channel == MCP9600_CHAN_COLD_JUNCTION && > > + (s_val < (MCP9600_MIN_TEMP_COLD_JUNCTION * MCP9600_TEMP_SCALE_NUM) || > > + s_val > (MCP9600_MAX_TEMP_COLD_JUNCTION * MCP9600_TEMP_SCALE_NUM))) > > + return -EINVAL; > > + > > + i = mcp9600_get_alert_index(chan->channel, dir); > > + guard(mutex)(&data->lock); > > + switch (info) { > > + case IIO_EV_INFO_VALUE: > > + /* > > + * Shift length 4 bits = 2(15:2) + 2(0.25 LSB), temperature is > > + * stored in two’s complement format. > > + */ > > + thresh = (s16)(s_val / (MCP9600_TEMP_SCALE_NUM >> 4)); > > + return i2c_smbus_write_word_swapped(client, > > + MCP9600_ALERT_LIMIT(i + 1), > > + thresh); > > + case IIO_EV_INFO_HYSTERESIS: > > + /* Read out threshold, hysteresis is stored as offset */ > > + ret = i2c_smbus_read_word_swapped(client, MCP9600_ALERT_LIMIT(i + 1)); > > + if (ret < 0) > > + return ret; > > + > > + /* Shift length 4 bits = 2(15:2) + 2(0.25 LSB), see above. */ > > + s_thresh = sign_extend32(ret, 15) * (MCP9600_TEMP_SCALE_NUM >> 4); > > + > > + /* > > + * Hysteresis is stored as offset, for rising temperatures, the > > + * hysteresis range is below the alert limit where, as for falling > > + * temperatures, the hysteresis range is above the alert limit. > > + */ > > I don't understand this comment. > Hysteresis as a parameter in sysfs in IIO is also an offset, so why is the current > threshold relevant? > > Normally hysteresis is about allowing repeat events. I.e. you have to drop below > threshold - hysteresis before rising again to trigger a rising event when passing > threshold. > As above, I just didn't know better. > > > + hyst = min(255, abs(s_thresh - s_val) / MCP9600_TEMP_SCALE_NUM); > > + > > + return i2c_smbus_write_byte_data(client, > > + MCP9600_ALERT_HYSTERESIS(i + 1), > > + hyst); > > + default: > > + return -EINVAL; > > + } > > +} > > > > +static irqreturn_t mcp9600_alert3_handler(int irq, void *private) > > +{ > > + struct iio_dev *indio_dev = private; > > + struct mcp9600_data *data = iio_priv(indio_dev); > > + int ret; > > + > > + ret = i2c_smbus_read_byte_data(data->client, MCP9600_STATUS); > > + if (ret < 0) > > + return IRQ_HANDLED; > > + > > + if (!(ret & MCP9600_STATUS_ALERT(MCP9600_ALERT3))) > > This duplicates far too much all these call a function that takes > a) This bit, > b) the related channel index. > C) the direction > > and call that from all these separate handlers. > Each individual handler become simply: > > return mcp9600_alert_handler(private, MCP9600_ALERT3, > MCP9600_CHAN_COLD_JUNCTION, > IIO_EV_DIR_RISING); > > etc. > Yes, will use a helper function to avoid code duplication. > > + return IRQ_NONE; > > + > > + iio_push_event(indio_dev, > > + IIO_MOD_EVENT_CODE(IIO_TEMP, MCP9600_CHAN_COLD_JUNCTION, > > + IIO_NO_MOD, IIO_EV_TYPE_THRESH, > > + IIO_EV_DIR_RISING), > > + iio_get_time_ns(indio_dev)); > > + > > + return IRQ_HANDLED; > > +} > > + > > > + > > +static irqreturn_t (*mcp9600_alert_handler[MCP9600_ALERT_COUNT]) (int, void *) = { > > + mcp9600_alert1_handler, > > + mcp9600_alert2_handler, > > + mcp9600_alert3_handler, > > + mcp9600_alert4_handler, > > }; > Dimitri
On Sun, 19 May 2024 23:00:36 +0200 Dimitri Fedrau <dima.fedrau@gmail.com> wrote: > Am Sun, May 19, 2024 at 05:42:48PM +0100 schrieb Jonathan Cameron: > > On Fri, 17 May 2024 10:10:50 +0200 > > Dimitri Fedrau <dima.fedrau@gmail.com> wrote: > > > > > The device has four programmable temperature alert outputs which can be > > > used to monitor hot or cold-junction temperatures and detect falling and > > > rising temperatures. It supports up to 255 degree celsius programmable > > > hysteresis. Each alert can be individually configured by setting following > > > options in the associated alert configuration register: > > > - monitor hot or cold junction temperature > > > - monitor rising or falling temperature > > > - set comparator or interrupt mode > > > - set output polarity > > > - enable alert > > > > > > This patch binds alert outputs to iio events: > > > - alert1: hot junction, rising temperature > > > - alert2: hot junction, falling temperature > > > - alert3: cold junction, rising temperature > > > - alert4: cold junction, falling temperature > > > > > > All outputs are set in comparator mode and polarity depends on interrupt > > > configuration. > > > > > > Signed-off-by: Dimitri Fedrau <dima.fedrau@gmail.com> > > Hi Dmitri > > Hi Jonathan, > > > Please make sure to address all questions in earlier reviews, either by > > changing the code, or directly answering the question. > > > I did, see: https://lore.kernel.org/linux-iio/20240509204559.GB3614@debian/T/#u > or did I miss anything ? I'm a little bit confused. I think some emails went astray :( Sorry I didn't check the archive. Anyhow, thanks for providing the links. Jonathan
Am Mon, May 20, 2024 at 01:18:50PM +0100 schrieb Jonathan Cameron: > On Sun, 19 May 2024 23:00:36 +0200 > Dimitri Fedrau <dima.fedrau@gmail.com> wrote: > > > Am Sun, May 19, 2024 at 05:42:48PM +0100 schrieb Jonathan Cameron: > > > On Fri, 17 May 2024 10:10:50 +0200 > > > Dimitri Fedrau <dima.fedrau@gmail.com> wrote: > > > > > > > The device has four programmable temperature alert outputs which can be > > > > used to monitor hot or cold-junction temperatures and detect falling and > > > > rising temperatures. It supports up to 255 degree celsius programmable > > > > hysteresis. Each alert can be individually configured by setting following > > > > options in the associated alert configuration register: > > > > - monitor hot or cold junction temperature > > > > - monitor rising or falling temperature > > > > - set comparator or interrupt mode > > > > - set output polarity > > > > - enable alert > > > > > > > > This patch binds alert outputs to iio events: > > > > - alert1: hot junction, rising temperature > > > > - alert2: hot junction, falling temperature > > > > - alert3: cold junction, rising temperature > > > > - alert4: cold junction, falling temperature > > > > > > > > All outputs are set in comparator mode and polarity depends on interrupt > > > > configuration. > > > > > > > > Signed-off-by: Dimitri Fedrau <dima.fedrau@gmail.com> > > > Hi Dmitri > > > > Hi Jonathan, > > > > > Please make sure to address all questions in earlier reviews, either by > > > changing the code, or directly answering the question. > > > > > I did, see: https://lore.kernel.org/linux-iio/20240509204559.GB3614@debian/T/#u > > or did I miss anything ? I'm a little bit confused. > > I think some emails went astray :( Sorry I didn't check the archive. > > Anyhow, thanks for providing the links. > Just thought you were to busy to reply and that's because I had send a new version of the series. > Jonathan >
diff --git a/drivers/iio/temperature/mcp9600.c b/drivers/iio/temperature/mcp9600.c index 22451d1d9e1f..91d811fe9371 100644 --- a/drivers/iio/temperature/mcp9600.c +++ b/drivers/iio/temperature/mcp9600.c @@ -6,12 +6,21 @@ * Author: <andrew.hepp@ahepp.dev> */ +#include <linux/bitfield.h> +#include <linux/bitops.h> +#include <linux/bits.h> #include <linux/err.h> #include <linux/i2c.h> #include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/math.h> +#include <linux/minmax.h> #include <linux/mod_devicetable.h> #include <linux/module.h> +#include <linux/mutex.h> +#include <linux/iio/events.h> #include <linux/iio/iio.h> #define MCP9600_CHAN_HOT_JUNCTION 0 @@ -20,11 +29,65 @@ /* MCP9600 registers */ #define MCP9600_HOT_JUNCTION 0x0 #define MCP9600_COLD_JUNCTION 0x2 +#define MCP9600_STATUS 0x4 +#define MCP9600_STATUS_ALERT(x) BIT(x) +#define MCP9600_ALERT_CFG1 0x8 +#define MCP9600_ALERT_CFG(x) (MCP9600_ALERT_CFG1 + (x - 1)) +#define MCP9600_ALERT_CFG_ENABLE BIT(0) +#define MCP9600_ALERT_CFG_ACTIVE_HIGH BIT(2) +#define MCP9600_ALERT_CFG_FALLING BIT(3) +#define MCP9600_ALERT_CFG_COLD_JUNCTION BIT(4) +#define MCP9600_ALERT_HYSTERESIS1 0xc +#define MCP9600_ALERT_HYSTERESIS(x) (MCP9600_ALERT_HYSTERESIS1 + (x - 1)) +#define MCP9600_ALERT_LIMIT1 0x10 +#define MCP9600_ALERT_LIMIT(x) (MCP9600_ALERT_LIMIT1 + (x - 1)) +#define MCP9600_ALERT_LIMIT_MASK GENMASK(15, 2) #define MCP9600_DEVICE_ID 0x20 /* MCP9600 device id value */ #define MCP9600_DEVICE_ID_MCP9600 0x40 +#define MCP9600_ALERT_COUNT 4 + +#define MCP9600_TEMP_SCALE_NUM 1000000 + +#define MCP9600_MIN_TEMP_HOT_JUNCTION -200 +#define MCP9600_MAX_TEMP_HOT_JUNCTION 1800 + +#define MCP9600_MIN_TEMP_COLD_JUNCTION -40 +#define MCP9600_MAX_TEMP_COLD_JUNCTION 125 + +enum mcp9600_alert { + MCP9600_ALERT1, + MCP9600_ALERT2, + MCP9600_ALERT3, + MCP9600_ALERT4 +}; + +static const char * const mcp9600_alert_name[MCP9600_ALERT_COUNT] = { + [MCP9600_ALERT1] = "alert1", + [MCP9600_ALERT2] = "alert2", + [MCP9600_ALERT3] = "alert3", + [MCP9600_ALERT4] = "alert4", +}; + +static const struct iio_event_spec mcp9600_events[] = { + { + .type = IIO_EV_TYPE_THRESH, + .dir = IIO_EV_DIR_RISING, + .mask_separate = BIT(IIO_EV_INFO_ENABLE) | + BIT(IIO_EV_INFO_VALUE) | + BIT(IIO_EV_INFO_HYSTERESIS), + }, + { + .type = IIO_EV_TYPE_THRESH, + .dir = IIO_EV_DIR_FALLING, + .mask_separate = BIT(IIO_EV_INFO_ENABLE) | + BIT(IIO_EV_INFO_VALUE) | + BIT(IIO_EV_INFO_HYSTERESIS), + }, +}; + static const struct iio_chan_spec mcp9600_channels[] = { { .type = IIO_TEMP, @@ -33,6 +96,8 @@ static const struct iio_chan_spec mcp9600_channels[] = { .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), .indexed = 1, + .event_spec = mcp9600_events, + .num_event_specs = ARRAY_SIZE(mcp9600_events), }, { .type = IIO_TEMP, @@ -41,11 +106,18 @@ static const struct iio_chan_spec mcp9600_channels[] = { .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), .indexed = 1, + .event_spec = mcp9600_events, + .num_event_specs = ARRAY_SIZE(mcp9600_events), }, }; struct mcp9600_data { struct i2c_client *client; + /* + * Serializes access to threshold and hysteresis values, since the + * latter are stored as offsets from thresholds on the device. + */ + struct mutex lock; }; static int mcp9600_read(struct mcp9600_data *data, @@ -84,10 +156,321 @@ static int mcp9600_read_raw(struct iio_dev *indio_dev, } } +static int mcp9600_get_alert_index(int channel, enum iio_event_direction dir) +{ + if (channel == MCP9600_CHAN_HOT_JUNCTION) { + if (dir == IIO_EV_DIR_RISING) + return MCP9600_ALERT1; + else + return MCP9600_ALERT2; + } else { + if (dir == IIO_EV_DIR_RISING) + return MCP9600_ALERT3; + else + return MCP9600_ALERT4; + } +} + +static int mcp9600_read_event_config(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + enum iio_event_type type, + enum iio_event_direction dir) +{ + struct mcp9600_data *data = iio_priv(indio_dev); + struct i2c_client *client = data->client; + int i, ret; + + i = mcp9600_get_alert_index(chan->channel, dir); + ret = i2c_smbus_read_byte_data(client, MCP9600_ALERT_CFG(i + 1)); + if (ret < 0) + return ret; + + return FIELD_GET(MCP9600_ALERT_CFG_ENABLE, ret); +} + +static int mcp9600_write_event_config(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + enum iio_event_type type, + enum iio_event_direction dir, + int state) +{ + struct mcp9600_data *data = iio_priv(indio_dev); + struct i2c_client *client = data->client; + int i, ret; + + i = mcp9600_get_alert_index(chan->channel, dir); + ret = i2c_smbus_read_byte_data(client, MCP9600_ALERT_CFG(i + 1)); + if (ret < 0) + return ret; + + if (state) + ret |= MCP9600_ALERT_CFG_ENABLE; + else + ret &= ~MCP9600_ALERT_CFG_ENABLE; + + return i2c_smbus_write_byte_data(client, MCP9600_ALERT_CFG(i + 1), ret); +} + +static int mcp9600_read_thresh(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + enum iio_event_type type, + enum iio_event_direction dir, + enum iio_event_info info, int *val, int *val2) +{ + struct mcp9600_data *data = iio_priv(indio_dev); + struct i2c_client *client = data->client; + s32 ret; + int i; + + i = mcp9600_get_alert_index(chan->channel, dir); + guard(mutex)(&data->lock); + ret = i2c_smbus_read_word_swapped(client, MCP9600_ALERT_LIMIT(i + 1)); + if (ret < 0) + return ret; + + /* + * Temperature is stored in two’s complement format in bits(15:2), + * LSB is 0.25 degree celsius. + */ + *val = sign_extend32(FIELD_GET(MCP9600_ALERT_LIMIT_MASK, ret), 13); + *val2 = 4; + if (info == IIO_EV_INFO_VALUE) + return IIO_VAL_FRACTIONAL; + + ret = i2c_smbus_read_byte_data(client, MCP9600_ALERT_HYSTERESIS(i + 1)); + if (ret < 0) + return ret; + + /* + * Hysteresis is stored as unsigned offset from threshold. The alert + * direction bit in the alert configuration register defines whether the + * value is below or above the corresponding threshold. + */ + if (dir == IIO_EV_DIR_RISING) + *val -= (*val2 * ret); + else + *val += (*val2 * ret); + + return IIO_VAL_FRACTIONAL; +} + +static int mcp9600_write_thresh(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, + enum iio_event_type type, + enum iio_event_direction dir, + enum iio_event_info info, int val, int val2) +{ + struct mcp9600_data *data = iio_priv(indio_dev); + struct i2c_client *client = data->client; + int s_val, s_thresh, i; + s16 thresh; + s32 ret; + u8 hyst; + + /* Scale value to include decimal part into calculations */ + s_val = (val < 0) ? ((val * MCP9600_TEMP_SCALE_NUM) - val2) : + ((val * MCP9600_TEMP_SCALE_NUM) + val2); + + /* Hot junction temperature range is from –200 to 1800 degree celsius */ + if (chan->channel == MCP9600_CHAN_HOT_JUNCTION && + (s_val < (MCP9600_MIN_TEMP_HOT_JUNCTION * MCP9600_TEMP_SCALE_NUM) || + s_val > (MCP9600_MAX_TEMP_HOT_JUNCTION * MCP9600_TEMP_SCALE_NUM))) + return -EINVAL; + + /* Cold junction temperature range is from –40 to 125 degree celsius */ + if (chan->channel == MCP9600_CHAN_COLD_JUNCTION && + (s_val < (MCP9600_MIN_TEMP_COLD_JUNCTION * MCP9600_TEMP_SCALE_NUM) || + s_val > (MCP9600_MAX_TEMP_COLD_JUNCTION * MCP9600_TEMP_SCALE_NUM))) + return -EINVAL; + + i = mcp9600_get_alert_index(chan->channel, dir); + guard(mutex)(&data->lock); + switch (info) { + case IIO_EV_INFO_VALUE: + /* + * Shift length 4 bits = 2(15:2) + 2(0.25 LSB), temperature is + * stored in two’s complement format. + */ + thresh = (s16)(s_val / (MCP9600_TEMP_SCALE_NUM >> 4)); + return i2c_smbus_write_word_swapped(client, + MCP9600_ALERT_LIMIT(i + 1), + thresh); + case IIO_EV_INFO_HYSTERESIS: + /* Read out threshold, hysteresis is stored as offset */ + ret = i2c_smbus_read_word_swapped(client, MCP9600_ALERT_LIMIT(i + 1)); + if (ret < 0) + return ret; + + /* Shift length 4 bits = 2(15:2) + 2(0.25 LSB), see above. */ + s_thresh = sign_extend32(ret, 15) * (MCP9600_TEMP_SCALE_NUM >> 4); + + /* + * Hysteresis is stored as offset, for rising temperatures, the + * hysteresis range is below the alert limit where, as for falling + * temperatures, the hysteresis range is above the alert limit. + */ + hyst = min(255, abs(s_thresh - s_val) / MCP9600_TEMP_SCALE_NUM); + + return i2c_smbus_write_byte_data(client, + MCP9600_ALERT_HYSTERESIS(i + 1), + hyst); + default: + return -EINVAL; + } +} + static const struct iio_info mcp9600_info = { .read_raw = mcp9600_read_raw, + .read_event_config = mcp9600_read_event_config, + .write_event_config = mcp9600_write_event_config, + .read_event_value = mcp9600_read_thresh, + .write_event_value = mcp9600_write_thresh, +}; + +static irqreturn_t mcp9600_alert1_handler(int irq, void *private) +{ + struct iio_dev *indio_dev = private; + struct mcp9600_data *data = iio_priv(indio_dev); + int ret; + + ret = i2c_smbus_read_byte_data(data->client, MCP9600_STATUS); + if (ret < 0) + return IRQ_HANDLED; + + if (!(ret & MCP9600_STATUS_ALERT(MCP9600_ALERT1))) + return IRQ_NONE; + + iio_push_event(indio_dev, + IIO_MOD_EVENT_CODE(IIO_TEMP, MCP9600_CHAN_HOT_JUNCTION, + IIO_NO_MOD, IIO_EV_TYPE_THRESH, + IIO_EV_DIR_RISING), + iio_get_time_ns(indio_dev)); + + return IRQ_HANDLED; +} + +static irqreturn_t mcp9600_alert2_handler(int irq, void *private) +{ + struct iio_dev *indio_dev = private; + struct mcp9600_data *data = iio_priv(indio_dev); + int ret; + + ret = i2c_smbus_read_byte_data(data->client, MCP9600_STATUS); + if (ret < 0) + return IRQ_HANDLED; + + if (!(ret & MCP9600_STATUS_ALERT(MCP9600_ALERT2))) + return IRQ_NONE; + + iio_push_event(indio_dev, + IIO_MOD_EVENT_CODE(IIO_TEMP, MCP9600_CHAN_HOT_JUNCTION, + IIO_NO_MOD, IIO_EV_TYPE_THRESH, + IIO_EV_DIR_FALLING), + iio_get_time_ns(indio_dev)); + + return IRQ_HANDLED; +} + +static irqreturn_t mcp9600_alert3_handler(int irq, void *private) +{ + struct iio_dev *indio_dev = private; + struct mcp9600_data *data = iio_priv(indio_dev); + int ret; + + ret = i2c_smbus_read_byte_data(data->client, MCP9600_STATUS); + if (ret < 0) + return IRQ_HANDLED; + + if (!(ret & MCP9600_STATUS_ALERT(MCP9600_ALERT3))) + return IRQ_NONE; + + iio_push_event(indio_dev, + IIO_MOD_EVENT_CODE(IIO_TEMP, MCP9600_CHAN_COLD_JUNCTION, + IIO_NO_MOD, IIO_EV_TYPE_THRESH, + IIO_EV_DIR_RISING), + iio_get_time_ns(indio_dev)); + + return IRQ_HANDLED; +} + +static irqreturn_t mcp9600_alert4_handler(int irq, void *private) +{ + struct iio_dev *indio_dev = private; + struct mcp9600_data *data = iio_priv(indio_dev); + int ret; + + ret = i2c_smbus_read_byte_data(data->client, MCP9600_STATUS); + if (ret < 0) + return IRQ_HANDLED; + + if (!(ret & MCP9600_STATUS_ALERT(MCP9600_ALERT4))) + return IRQ_NONE; + + iio_push_event(indio_dev, + IIO_MOD_EVENT_CODE(IIO_TEMP, MCP9600_CHAN_COLD_JUNCTION, + IIO_NO_MOD, IIO_EV_TYPE_THRESH, + IIO_EV_DIR_FALLING), + iio_get_time_ns(indio_dev)); + + return IRQ_HANDLED; +} + +static irqreturn_t (*mcp9600_alert_handler[MCP9600_ALERT_COUNT]) (int, void *) = { + mcp9600_alert1_handler, + mcp9600_alert2_handler, + mcp9600_alert3_handler, + mcp9600_alert4_handler, }; +static int mcp9600_probe_alerts(struct iio_dev *indio_dev) +{ + struct mcp9600_data *data = iio_priv(indio_dev); + struct i2c_client *client = data->client; + struct device *dev = &client->dev; + struct fwnode_handle *fwnode = dev_fwnode(dev); + unsigned int irq_type; + int ret, irq, i; + u8 val; + + /* + * alert1: hot junction, rising temperature + * alert2: hot junction, falling temperature + * alert3: cold junction, rising temperature + * alert4: cold junction, falling temperature + */ + for (i = 0; i < MCP9600_ALERT_COUNT; i++) { + irq = fwnode_irq_get_byname(fwnode, mcp9600_alert_name[i]); + if (irq <= 0) + continue; + + val = 0; + irq_type = irq_get_trigger_type(irq); + if (irq_type == IRQ_TYPE_EDGE_RISING) + val |= MCP9600_ALERT_CFG_ACTIVE_HIGH; + + if (i == MCP9600_ALERT2 || i == MCP9600_ALERT4) + val |= MCP9600_ALERT_CFG_FALLING; + + if (i == MCP9600_ALERT3 || i == MCP9600_ALERT4) + val |= MCP9600_ALERT_CFG_COLD_JUNCTION; + + ret = i2c_smbus_write_byte_data(client, + MCP9600_ALERT_CFG(i + 1), + val); + if (ret < 0) + return ret; + + ret = devm_request_threaded_irq(dev, irq, NULL, + mcp9600_alert_handler[i], + IRQF_ONESHOT, "mcp9600", + indio_dev); + if (ret) + return ret; + } + + return 0; +} + static int mcp9600_probe(struct i2c_client *client) { struct iio_dev *indio_dev; @@ -107,6 +490,11 @@ static int mcp9600_probe(struct i2c_client *client) data = iio_priv(indio_dev); data->client = client; + mutex_init(&data->lock); + + ret = mcp9600_probe_alerts(indio_dev); + if (ret) + return ret; indio_dev->info = &mcp9600_info; indio_dev->name = "mcp9600"; @@ -139,6 +527,7 @@ static struct i2c_driver mcp9600_driver = { }; module_i2c_driver(mcp9600_driver); +MODULE_AUTHOR("Dimitri Fedrau <dima.fedrau@gmail.com>"); MODULE_AUTHOR("Andrew Hepp <andrew.hepp@ahepp.dev>"); MODULE_DESCRIPTION("Microchip MCP9600 thermocouple EMF converter driver"); MODULE_LICENSE("GPL");
The device has four programmable temperature alert outputs which can be used to monitor hot or cold-junction temperatures and detect falling and rising temperatures. It supports up to 255 degree celsius programmable hysteresis. Each alert can be individually configured by setting following options in the associated alert configuration register: - monitor hot or cold junction temperature - monitor rising or falling temperature - set comparator or interrupt mode - set output polarity - enable alert This patch binds alert outputs to iio events: - alert1: hot junction, rising temperature - alert2: hot junction, falling temperature - alert3: cold junction, rising temperature - alert4: cold junction, falling temperature All outputs are set in comparator mode and polarity depends on interrupt configuration. Signed-off-by: Dimitri Fedrau <dima.fedrau@gmail.com> --- drivers/iio/temperature/mcp9600.c | 389 ++++++++++++++++++++++++++++++ 1 file changed, 389 insertions(+)