On Thu, Oct 26, 2023 at 05:44:01PM +0300, Daniel Matyas wrote:
> Used fwnode to retrieve data from the devicetree in the init_client
> function.
>
> If the uint32 properties are not present, the default values are used
> for max31827 chip.
>
> Signed-off-by: Daniel Matyas <daniel.matyas@xxxxxxxxxx>
> ---
>
> v4 -> v5: Removed comment from __bf_shf() and used ffs() instead of
> ffs64().
You don't use ffs(). You still define a variant of it and use __ffs().
> Added tabs where there was a need.
> Removed i2c_client from private structure. In init_client() passed
> device structure, because I only used that.
> Changed error message when the data in adi,fault-q is invalid.
> Fwnode is initialized in init_client().
>
> v3 -> v4: Renamed property names to correspond with binding.
>
> v2 -> v3: Separated patch into 2. Fixed 'WARNING: Unexpected
> indentation.'
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
>
> v2: Added patch.
>
> Documentation/hwmon/max31827.rst | 48 +++++++++++++++++++-----
> drivers/hwmon/max31827.c | 64 +++++++++++++++++++++++++++++---
> 2 files changed, 97 insertions(+), 15 deletions(-)
>
> diff --git a/Documentation/hwmon/max31827.rst b/Documentation/hwmon/max31827.rst
> index 9a1055a007cf..a8bbfb85dd02 100644
> --- a/Documentation/hwmon/max31827.rst
> +++ b/Documentation/hwmon/max31827.rst
> @@ -52,13 +52,21 @@ MAX31827 has low and over temperature alarms with an effective value and a
> hysteresis value: -40 and -30 degrees for under temperature alarm and +100 and
> +90 degrees for over temperature alarm.
>
> -The alarm can be configured in comparator and interrupt mode. Currently only
> -comparator mode is implemented. In Comparator mode, the OT/UT status bits have a
> -value of 1 when the temperature rises above the TH value or falls below TL,
> -which is also subject to the Fault Queue selection. OT status returns to 0 when
> -the temperature drops below the TH_HYST value or when shutdown mode is entered.
> -Similarly, UT status returns to 0 when the temperature rises above TL_HYST value
> -or when shutdown mode is entered.
> +The alarm can be configured in comparator and interrupt mode from the
> +devicetree. In Comparator mode, the OT/UT status bits have a value of 1 when the
> +temperature rises above the TH value or falls below TL, which is also subject to
> +the Fault Queue selection. OT status returns to 0 when the temperature drops
> +below the TH_HYST value or when shutdown mode is entered. Similarly, UT status
> +returns to 0 when the temperature rises above TL_HYST value or when shutdown
> +mode is entered.
> +
> +In interrupt mode exceeding TH also sets OT status to 1, which remains set until
> +a read operation is performed on the configuration/status register (max or min
> +attribute); at this point, it returns to 0. Once OT status is set to 1 from
> +exceeding TH and reset, it is set to 1 again only when the temperature drops
> +below TH_HYST. The output remains asserted until it is reset by a read. It is
> +set again if the temperature rises above TH, and so on. The same logic applies
> +to the operation of the UT status bit.
>
> Putting the MAX31827 into shutdown mode also resets the OT/UT status bits. Note
> that if the mode is changed while OT/UT status bits are set, an OT/UT status
> @@ -68,6 +76,18 @@ clear the status bits before changing the operating mode.
>
> The conversions can be manual with the one-shot functionality and automatic with
> a set frequency. When powered on, the chip measures temperatures with 1 conv/s.
> +The conversion rate can be modified with update_interval attribute of the chip.
> +Conversion/second = 1/update_interval. Thus, the available options according to
> +the data sheet are:
> +
> +- 64000 (ms) = 1 conv/64 sec
> +- 32000 (ms) = 1 conv/32 sec
> +- 16000 (ms) = 1 conv/16 sec
> +- 4000 (ms) = 1 conv/4 sec
> +- 1000 (ms) = 1 conv/sec (default)
> +- 250 (ms) = 4 conv/sec
> +- 125 (ms) = 8 conv/sec
> +
> Enabling the device when it is already enabled has the side effect of setting
> the conversion frequency to 1 conv/s. The conversion time varies depending on
> the resolution. The conversion time doubles with every bit of increased
> @@ -83,8 +103,18 @@ in the writing of alarm values too. For positive numbers the user-input value
> will always be rounded down to the nearest possible value, for negative numbers
> the user-input will always be rounded up to the nearest possible value.
>
> +Bus timeout resets the I2C-compatible interface when SCL is low for more than
> +30ms (nominal).
> +
> +Alarm polarity determines if the active state of the alarm is low or high. The
> +behavior for both settings is dependent on the Fault Queue setting. The ALARM
> +pin is an open-drain output and requires a pullup resistor to operate.
> +
> +The Fault Queue bits select how many consecutive temperature faults must occur
> +before overtemperature or undertemperature faults are indicated in the
> +corresponding status bits.
> +
> Notes
> -----
>
> -Currently fault queue, alarm polarity and resolution cannot be modified.
> -PEC is not implemented either.
> +PEC and resolution are not implemented.
> diff --git a/drivers/hwmon/max31827.c b/drivers/hwmon/max31827.c
> index 614bbf5d25fa..7976d668ffd4 100644
> --- a/drivers/hwmon/max31827.c
> +++ b/drivers/hwmon/max31827.c
> @@ -12,6 +12,13 @@
> #include <linux/i2c.h>
> #include <linux/mutex.h>
> #include <linux/regmap.h>
> +#include <linux/of_device.h>
> +
> +#define max31827__bf_shf(x) \
> + ({ \
> + typeof(x) x_ = (x); \
> + ((x_) != 0) ? __ffs(x_) : 0x0; \
> + })
>
> #define MAX31827_T_REG 0x0
> #define MAX31827_CONFIGURATION_REG 0x2
> @@ -22,6 +29,11 @@
>
> #define MAX31827_CONFIGURATION_1SHOT_MASK BIT(0)
> #define MAX31827_CONFIGURATION_CNV_RATE_MASK GENMASK(3, 1)
> +#define MAX31827_CONFIGURATION_TIMEOUT_MASK BIT(5)
> +#define MAX31827_CONFIGURATION_RESOLUTION_MASK GENMASK(7, 6)
> +#define MAX31827_CONFIGURATION_ALRM_POL_MASK BIT(8)
> +#define MAX31827_CONFIGURATION_COMP_INT_MASK BIT(9)
> +#define MAX31827_CONFIGURATION_FLT_Q_MASK GENMASK(11, 10)
> #define MAX31827_CONFIGURATION_U_TEMP_STAT_MASK BIT(14)
> #define MAX31827_CONFIGURATION_O_TEMP_STAT_MASK BIT(15)
>
> @@ -361,14 +373,54 @@ static int max31827_write(struct device *dev, enum hwmon_sensor_types type,
> return -EOPNOTSUPP;
> }
>
> -static int max31827_init_client(struct max31827_state *st)
> +static int max31827_init_client(struct max31827_state *st,
> + struct device *dev)
> {
> + struct fwnode_handle *fwnode;
> + unsigned int res = 0;
> + u32 data, lsb_idx;
> + bool prop;
> + int ret;
> +
> + fwnode = dev_fwnode(dev);
> +
> st->enable = true;
> + res |= MAX31827_DEVICE_ENABLE(1);
> +
> + res |= MAX31827_CONFIGURATION_RESOLUTION_MASK;
> +
> + prop = fwnode_property_read_bool(fwnode, "adi,comp-int");
> + res |= FIELD_PREP(MAX31827_CONFIGURATION_COMP_INT_MASK, prop);
> +
> + prop = fwnode_property_read_bool(fwnode, "adi,timeout-enable");
> + res |= FIELD_PREP(MAX31827_CONFIGURATION_TIMEOUT_MASK, !prop);
> +
> + if (fwnode_property_present(fwnode, "adi,alarm-pol")) {
> + ret = fwnode_property_read_u32(fwnode, "adi,alarm-pol", &data);
> + if (ret)
> + return ret;
> +
> + res |= FIELD_PREP(MAX31827_CONFIGURATION_ALRM_POL_MASK, !!data);
> + }
> +
> + if (fwnode_property_present(fwnode, "adi,fault-q")) {
> + ret = fwnode_property_read_u32(fwnode, "adi,fault-q", &data);
> + if (ret)
> + return ret;
> +
> + /*
> + * Convert the desired fault queue into register bits.
> + */
> + lsb_idx = max31827__bf_shf(data);
> + if (lsb_idx > 3 || data != BIT(lsb_idx)) {
Follow-up on above, why not something like
lsb_idx = __ffs(data);
if (hweight32(data) != 1 || lsb_idx > 3) {
...
Or use ffs() and work with [1..4] instead of [0..3].
I don't see the point of defining another variant of ffs()/_ffs().
Guenter
> + dev_err(dev, "Invalid data in adi,fault-q\n");
> + return -EINVAL;
> + }
> +
> + res |= FIELD_PREP(MAX31827_CONFIGURATION_FLT_Q_MASK, lsb_idx);
> + }
>
> - return regmap_update_bits(st->regmap, MAX31827_CONFIGURATION_REG,
> - MAX31827_CONFIGURATION_1SHOT_MASK |
> - MAX31827_CONFIGURATION_CNV_RATE_MASK,
> - MAX31827_DEVICE_ENABLE(1));
> + return regmap_write(st->regmap, MAX31827_CONFIGURATION_REG, res);
> }
>
> static const struct hwmon_channel_info *max31827_info[] = {
> @@ -412,7 +464,7 @@ static int max31827_probe(struct i2c_client *client)
> return dev_err_probe(dev, PTR_ERR(st->regmap),
> "Failed to allocate regmap.\n");
>
> - err = max31827_init_client(st);
> + err = max31827_init_client(st, dev);
> if (err)
> return err;
>
