OSCL-LXR linux-6.0.1/​drivers/​hwmon/​bt1-pvt.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
  *
  * Authors:
  *   Maxim Kaurkin <maxim.kaurkin@baikalelectronics.ru>
  *   Serge Semin <Sergey.Semin@baikalelectronics.ru>
  *
  * Baikal-T1 Process, Voltage, Temperature sensor driver
  */
 
 #include <linux/bitfield.h>
 #include <linux/bitops.h>
 #include <linux/clk.h>
 #include <linux/completion.h>
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/hwmon-sysfs.h>
 #include <linux/hwmon.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/ktime.h>
 #include <linux/limits.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/polynomial.h>
 #include <linux/seqlock.h>
 #include <linux/sysfs.h>
 #include <linux/types.h>
 
 #include "bt1-pvt.h"
 
 /*
  * For the sake of the code simplification we created the sensors info table
  * with the sensor names, activation modes, threshold registers base address
  * and the thresholds bit fields.
  */
 static const struct pvt_sensor_info pvt_info[] = {
     PVT_SENSOR_INFO(0, "CPU Core Temperature", hwmon_temp, TEMP, TTHRES),
     PVT_SENSOR_INFO(0, "CPU Core Voltage", hwmon_in, VOLT, VTHRES),
     PVT_SENSOR_INFO(1, "CPU Core Low-Vt", hwmon_in, LVT, LTHRES),
     PVT_SENSOR_INFO(2, "CPU Core High-Vt", hwmon_in, HVT, HTHRES),
     PVT_SENSOR_INFO(3, "CPU Core Standard-Vt", hwmon_in, SVT, STHRES),
 };
 
 /*
  * The original translation formulae of the temperature (in degrees of Celsius)
  * to PVT data and vice-versa are following:
  * N = 1.8322e-8*(T^4) + 2.343e-5*(T^3) + 8.7018e-3*(T^2) + 3.9269*(T^1) +
  *     1.7204e2,
  * T = -1.6743e-11*(N^4) + 8.1542e-8*(N^3) + -1.8201e-4*(N^2) +
  *     3.1020e-1*(N^1) - 4.838e1,
  * where T = [-48.380, 147.438]C and N = [0, 1023].
  * They must be accordingly altered to be suitable for the integer arithmetics.
  * The technique is called 'factor redistribution', which just makes sure the
  * multiplications and divisions are made so to have a result of the operations
  * within the integer numbers limit. In addition we need to translate the
  * formulae to accept millidegrees of Celsius. Here what they look like after
  * the alterations:
  * N = (18322e-20*(T^4) + 2343e-13*(T^3) + 87018e-9*(T^2) + 39269e-3*T +
  *     17204e2) / 1e4,
  * T = -16743e-12*(D^4) + 81542e-9*(D^3) - 182010e-6*(D^2) + 310200e-3*D -
  *     48380,
  * where T = [-48380, 147438] mC and N = [0, 1023].
  */
 static const struct polynomial __maybe_unused poly_temp_to_N = {
     .total_divider = 10000,
     .terms = {
         {4, 18322, 10000, 10000},
         {3, 2343, 10000, 10},
         {2, 87018, 10000, 10},
         {1, 39269, 1000, 1},
         {0, 1720400, 1, 1}
     }
 };
 
 static const struct polynomial poly_N_to_temp = {
     .total_divider = 1,
     .terms = {
         {4, -16743, 1000, 1},
         {3, 81542, 1000, 1},
         {2, -182010, 1000, 1},
         {1, 310200, 1000, 1},
         {0, -48380, 1, 1}
     }
 };
 
 /*
  * Similar alterations are performed for the voltage conversion equations.
  * The original formulae are:
  * N = 1.8658e3*V - 1.1572e3,
  * V = (N + 1.1572e3) / 1.8658e3,
  * where V = [0.620, 1.168] V and N = [0, 1023].
  * After the optimization they looks as follows:
  * N = (18658e-3*V - 11572) / 10,
  * V = N * 10^5 / 18658 + 11572 * 10^4 / 18658.
  */
 static const struct polynomial __maybe_unused poly_volt_to_N = {
     .total_divider = 10,
     .terms = {
         {1, 18658, 1000, 1},
         {0, -11572, 1, 1}
     }
 };
 
 static const struct polynomial poly_N_to_volt = {
     .total_divider = 10,
     .terms = {
         {1, 100000, 18658, 1},
         {0, 115720000, 1, 18658}
     }
 };
 
 static inline u32 pvt_update(void __iomem *reg, u32 mask, u32 data)
 {
     u32 old;
 
     old = readl_relaxed(reg);
     writel((old & ~mask) | (data & mask), reg);
 
     return old & mask;
 }
 
 /*
  * Baikal-T1 PVT mode can be updated only when the controller is disabled.
  * So first we disable it, then set the new mode together with the controller
  * getting back enabled. The same concerns the temperature trim and
  * measurements timeout. If it is necessary the interface mutex is supposed
  * to be locked at the time the operations are performed.
  */
 static inline void pvt_set_mode(struct pvt_hwmon *pvt, u32 mode)
 {
     u32 old;
 
     mode = FIELD_PREP(PVT_CTRL_MODE_MASK, mode);
 
     old = pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, 0);
     pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_MODE_MASK | PVT_CTRL_EN,
            mode | old);
 }
 
 static inline u32 pvt_calc_trim(long temp)
 {
     temp = clamp_val(temp, 0, PVT_TRIM_TEMP);
 
     return DIV_ROUND_UP(temp, PVT_TRIM_STEP);
 }
 
 static inline void pvt_set_trim(struct pvt_hwmon *pvt, u32 trim)
 {
     u32 old;
 
     trim = FIELD_PREP(PVT_CTRL_TRIM_MASK, trim);
 
     old = pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, 0);
     pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_TRIM_MASK | PVT_CTRL_EN,
            trim | old);
 }
 
 static inline void pvt_set_tout(struct pvt_hwmon *pvt, u32 tout)
 {
     u32 old;
 
     old = pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, 0);
     writel(tout, pvt->regs + PVT_TTIMEOUT);
     pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, old);
 }
 
 /*
  * This driver can optionally provide the hwmon alarms for each sensor the PVT
  * controller supports. The alarms functionality is made compile-time
  * configurable due to the hardware interface implementation peculiarity
  * described further in this comment. So in case if alarms are unnecessary in
  * your system design it's recommended to have them disabled to prevent the PVT
  * IRQs being periodically raised to get the data cache/alarms status up to
  * date.
  *
  * Baikal-T1 PVT embedded controller is based on the Analog Bits PVT sensor,
  * but is equipped with a dedicated control wrapper. It exposes the PVT
  * sub-block registers space via the APB3 bus. In addition the wrapper provides
  * a common interrupt vector of the sensors conversion completion events and
  * threshold value alarms. Alas the wrapper interface hasn't been fully thought
  * through. There is only one sensor can be activated at a time, for which the
  * thresholds comparator is enabled right after the data conversion is
  * completed. Due to this if alarms need to be implemented for all available
  * sensors we can't just set the thresholds and enable the interrupts. We need
  * to enable the sensors one after another and let the controller to detect
  * the alarms by itself at each conversion. This also makes pointless to handle
  * the alarms interrupts, since in occasion they happen synchronously with
  * data conversion completion. The best driver design would be to have the
  * completion interrupts enabled only and keep the converted value in the
  * driver data cache. This solution is implemented if hwmon alarms are enabled
  * in this driver. In case if the alarms are disabled, the conversion is
  * performed on demand at the time a sensors input file is read.
  */
 
 #if defined(CONFIG_SENSORS_BT1_PVT_ALARMS)
 
 #define pvt_hard_isr NULL
 
 static irqreturn_t pvt_soft_isr(int irq, void *data)
 {
     const struct pvt_sensor_info *info;
     struct pvt_hwmon *pvt = data;
     struct pvt_cache *cache;
     u32 val, thres_sts, old;
 
     /*
      * DVALID bit will be cleared by reading the data. We need to save the
      * status before the next conversion happens. Threshold events will be
      * handled a bit later.
      */
     thres_sts = readl(pvt->regs + PVT_RAW_INTR_STAT);
 
     /*
      * Then lets recharge the PVT interface with the next sampling mode.
      * Lock the interface mutex to serialize trim, timeouts and alarm
      * thresholds settings.
      */
     cache = &pvt->cache[pvt->sensor];
     info = &pvt_info[pvt->sensor];
     pvt->sensor = (pvt->sensor == PVT_SENSOR_LAST) ?
               PVT_SENSOR_FIRST : (pvt->sensor + 1);
 
     /*
      * For some reason we have to mask the interrupt before changing the
      * mode, otherwise sometimes the temperature mode doesn't get
      * activated even though the actual mode in the ctrl register
      * corresponds to one. Then we read the data. By doing so we also
      * recharge the data conversion. After this the mode corresponding
      * to the next sensor in the row is set. Finally we enable the
      * interrupts back.
      */
     mutex_lock(&pvt->iface_mtx);
 
     old = pvt_update(pvt->regs + PVT_INTR_MASK, PVT_INTR_DVALID,
              PVT_INTR_DVALID);
 
     val = readl(pvt->regs + PVT_DATA);
 
     pvt_set_mode(pvt, pvt_info[pvt->sensor].mode);
 
     pvt_update(pvt->regs + PVT_INTR_MASK, PVT_INTR_DVALID, old);
 
     mutex_unlock(&pvt->iface_mtx);
 
     /*
      * We can now update the data cache with data just retrieved from the
      * sensor. Lock write-seqlock to make sure the reader has a coherent
      * data.
      */
     write_seqlock(&cache->data_seqlock);
 
     cache->data = FIELD_GET(PVT_DATA_DATA_MASK, val);
 
     write_sequnlock(&cache->data_seqlock);
 
     /*
      * While PVT core is doing the next mode data conversion, we'll check
      * whether the alarms were triggered for the current sensor. Note that
      * according to the documentation only one threshold IRQ status can be
      * set at a time, that's why if-else statement is utilized.
      */
     if ((thres_sts & info->thres_sts_lo) ^ cache->thres_sts_lo) {
         WRITE_ONCE(cache->thres_sts_lo, thres_sts & info->thres_sts_lo);
         hwmon_notify_event(pvt->hwmon, info->type, info->attr_min_alarm,
                    info->channel);
     } else if ((thres_sts & info->thres_sts_hi) ^ cache->thres_sts_hi) {
         WRITE_ONCE(cache->thres_sts_hi, thres_sts & info->thres_sts_hi);
         hwmon_notify_event(pvt->hwmon, info->type, info->attr_max_alarm,
                    info->channel);
     }
 
     return IRQ_HANDLED;
 }
 
 static inline umode_t pvt_limit_is_visible(enum pvt_sensor_type type)
 {
     return 0644;
 }
 
 static inline umode_t pvt_alarm_is_visible(enum pvt_sensor_type type)
 {
     return 0444;
 }
 
 static int pvt_read_data(struct pvt_hwmon *pvt, enum pvt_sensor_type type,
              long *val)
 {
     struct pvt_cache *cache = &pvt->cache[type];
     unsigned int seq;
     u32 data;
 
     do {
         seq = read_seqbegin(&cache->data_seqlock);
         data = cache->data;
     } while (read_seqretry(&cache->data_seqlock, seq));
 
     if (type == PVT_TEMP)
         *val = polynomial_calc(&poly_N_to_temp, data);
     else
         *val = polynomial_calc(&poly_N_to_volt, data);
 
     return 0;
 }
 
 static int pvt_read_limit(struct pvt_hwmon *pvt, enum pvt_sensor_type type,
               bool is_low, long *val)
 {
     u32 data;
 
     /* No need in serialization, since it is just read from MMIO. */
     data = readl(pvt->regs + pvt_info[type].thres_base);
 
     if (is_low)
         data = FIELD_GET(PVT_THRES_LO_MASK, data);
     else
         data = FIELD_GET(PVT_THRES_HI_MASK, data);
 
     if (type == PVT_TEMP)
         *val = polynomial_calc(&poly_N_to_temp, data);
     else
         *val = polynomial_calc(&poly_N_to_volt, data);
 
     return 0;
 }
 
 static int pvt_write_limit(struct pvt_hwmon *pvt, enum pvt_sensor_type type,
                bool is_low, long val)
 {
     u32 data, limit, mask;
     int ret;
 
     if (type == PVT_TEMP) {
         val = clamp(val, PVT_TEMP_MIN, PVT_TEMP_MAX);
         data = polynomial_calc(&poly_temp_to_N, val);
     } else {
         val = clamp(val, PVT_VOLT_MIN, PVT_VOLT_MAX);
         data = polynomial_calc(&poly_volt_to_N, val);
     }
 
     /* Serialize limit update, since a part of the register is changed. */
     ret = mutex_lock_interruptible(&pvt->iface_mtx);
     if (ret)
         return ret;
 
     /* Make sure the upper and lower ranges don't intersect. */
     limit = readl(pvt->regs + pvt_info[type].thres_base);
     if (is_low) {
         limit = FIELD_GET(PVT_THRES_HI_MASK, limit);
         data = clamp_val(data, PVT_DATA_MIN, limit);
         data = FIELD_PREP(PVT_THRES_LO_MASK, data);
         mask = PVT_THRES_LO_MASK;
     } else {
         limit = FIELD_GET(PVT_THRES_LO_MASK, limit);
         data = clamp_val(data, limit, PVT_DATA_MAX);
         data = FIELD_PREP(PVT_THRES_HI_MASK, data);
         mask = PVT_THRES_HI_MASK;
     }
 
     pvt_update(pvt->regs + pvt_info[type].thres_base, mask, data);
 
     mutex_unlock(&pvt->iface_mtx);
 
     return 0;
 }
 
 static int pvt_read_alarm(struct pvt_hwmon *pvt, enum pvt_sensor_type type,
               bool is_low, long *val)
 {
     if (is_low)
         *val = !!READ_ONCE(pvt->cache[type].thres_sts_lo);
     else
         *val = !!READ_ONCE(pvt->cache[type].thres_sts_hi);
 
     return 0;
 }
 
 static const struct hwmon_channel_info *pvt_channel_info[] = {
     HWMON_CHANNEL_INFO(chip,
                HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL),
     HWMON_CHANNEL_INFO(temp,
                HWMON_T_INPUT | HWMON_T_TYPE | HWMON_T_LABEL |
                HWMON_T_MIN | HWMON_T_MIN_ALARM |
                HWMON_T_MAX | HWMON_T_MAX_ALARM |
                HWMON_T_OFFSET),
     HWMON_CHANNEL_INFO(in,
                HWMON_I_INPUT | HWMON_I_LABEL |
                HWMON_I_MIN | HWMON_I_MIN_ALARM |
                HWMON_I_MAX | HWMON_I_MAX_ALARM,
                HWMON_I_INPUT | HWMON_I_LABEL |
                HWMON_I_MIN | HWMON_I_MIN_ALARM |
                HWMON_I_MAX | HWMON_I_MAX_ALARM,
                HWMON_I_INPUT | HWMON_I_LABEL |
                HWMON_I_MIN | HWMON_I_MIN_ALARM |
                HWMON_I_MAX | HWMON_I_MAX_ALARM,
                HWMON_I_INPUT | HWMON_I_LABEL |
                HWMON_I_MIN | HWMON_I_MIN_ALARM |
                HWMON_I_MAX | HWMON_I_MAX_ALARM),
     NULL
 };
 
 #else /* !CONFIG_SENSORS_BT1_PVT_ALARMS */
 
 static irqreturn_t pvt_hard_isr(int irq, void *data)
 {
     struct pvt_hwmon *pvt = data;
     struct pvt_cache *cache;
     u32 val;
 
     /*
      * Mask the DVALID interrupt so after exiting from the handler a
      * repeated conversion wouldn't happen.
      */
     pvt_update(pvt->regs + PVT_INTR_MASK, PVT_INTR_DVALID,
            PVT_INTR_DVALID);
 
     /*
      * Nothing special for alarm-less driver. Just read the data, update
      * the cache and notify a waiter of this event.
      */
     val = readl(pvt->regs + PVT_DATA);
     if (!(val & PVT_DATA_VALID)) {
         dev_err(pvt->dev, "Got IRQ when data isn't valid\n");
         return IRQ_HANDLED;
     }
 
     cache = &pvt->cache[pvt->sensor];
 
     WRITE_ONCE(cache->data, FIELD_GET(PVT_DATA_DATA_MASK, val));
 
     complete(&cache->conversion);
 
     return IRQ_HANDLED;
 }
 
 #define pvt_soft_isr NULL
 
 static inline umode_t pvt_limit_is_visible(enum pvt_sensor_type type)
 {
     return 0;
 }
 
 static inline umode_t pvt_alarm_is_visible(enum pvt_sensor_type type)
 {
     return 0;
 }
 
 static int pvt_read_data(struct pvt_hwmon *pvt, enum pvt_sensor_type type,
              long *val)
 {
     struct pvt_cache *cache = &pvt->cache[type];
     unsigned long timeout;
     u32 data;
     int ret;
 
     /*
      * Lock PVT conversion interface until data cache is updated. The
      * data read procedure is following: set the requested PVT sensor
      * mode, enable IRQ and conversion, wait until conversion is finished,
      * then disable conversion and IRQ, and read the cached data.
      */
     ret = mutex_lock_interruptible(&pvt->iface_mtx);
     if (ret)
         return ret;
 
     pvt->sensor = type;
     pvt_set_mode(pvt, pvt_info[type].mode);
 
     /*
      * Unmask the DVALID interrupt and enable the sensors conversions.
      * Do the reverse procedure when conversion is done.
      */
     pvt_update(pvt->regs + PVT_INTR_MASK, PVT_INTR_DVALID, 0);
     pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, PVT_CTRL_EN);
 
     /*
      * Wait with timeout since in case if the sensor is suddenly powered
      * down the request won't be completed and the caller will hang up on
      * this procedure until the power is back up again. Multiply the
      * timeout by the factor of two to prevent a false timeout.
      */
     timeout = 2 * usecs_to_jiffies(ktime_to_us(pvt->timeout));
     ret = wait_for_completion_timeout(&cache->conversion, timeout);
 
     pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, 0);
     pvt_update(pvt->regs + PVT_INTR_MASK, PVT_INTR_DVALID,
            PVT_INTR_DVALID);
 
     data = READ_ONCE(cache->data);
 
     mutex_unlock(&pvt->iface_mtx);
 
     if (!ret)
         return -ETIMEDOUT;
 
     if (type == PVT_TEMP)
         *val = polynomial_calc(&poly_N_to_temp, data);
     else
         *val = polynomial_calc(&poly_N_to_volt, data);
 
     return 0;
 }
 
 static int pvt_read_limit(struct pvt_hwmon *pvt, enum pvt_sensor_type type,
               bool is_low, long *val)
 {
     return -EOPNOTSUPP;
 }
 
 static int pvt_write_limit(struct pvt_hwmon *pvt, enum pvt_sensor_type type,
                bool is_low, long val)
 {
     return -EOPNOTSUPP;
 }
 
 static int pvt_read_alarm(struct pvt_hwmon *pvt, enum pvt_sensor_type type,
               bool is_low, long *val)
 {
     return -EOPNOTSUPP;
 }
 
 static const struct hwmon_channel_info *pvt_channel_info[] = {
     HWMON_CHANNEL_INFO(chip,
                HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL),
     HWMON_CHANNEL_INFO(temp,
                HWMON_T_INPUT | HWMON_T_TYPE | HWMON_T_LABEL |
                HWMON_T_OFFSET),
     HWMON_CHANNEL_INFO(in,
                HWMON_I_INPUT | HWMON_I_LABEL,
                HWMON_I_INPUT | HWMON_I_LABEL,
                HWMON_I_INPUT | HWMON_I_LABEL,
                HWMON_I_INPUT | HWMON_I_LABEL),
     NULL
 };
 
 #endif /* !CONFIG_SENSORS_BT1_PVT_ALARMS */
 
 static inline bool pvt_hwmon_channel_is_valid(enum hwmon_sensor_types type,
                           int ch)
 {
     switch (type) {
     case hwmon_temp:
         if (ch < 0 || ch >= PVT_TEMP_CHS)
             return false;
         break;
     case hwmon_in:
         if (ch < 0 || ch >= PVT_VOLT_CHS)
             return false;
         break;
     default:
         break;
     }
 
     /* The rest of the types are independent from the channel number. */
     return true;
 }
 
 static umode_t pvt_hwmon_is_visible(const void *data,
                     enum hwmon_sensor_types type,
                     u32 attr, int ch)
 {
     if (!pvt_hwmon_channel_is_valid(type, ch))
         return 0;
 
     switch (type) {
     case hwmon_chip:
         switch (attr) {
         case hwmon_chip_update_interval:
             return 0644;
         }
         break;
     case hwmon_temp:
         switch (attr) {
         case hwmon_temp_input:
         case hwmon_temp_type:
         case hwmon_temp_label:
             return 0444;
         case hwmon_temp_min:
         case hwmon_temp_max:
             return pvt_limit_is_visible(ch);
         case hwmon_temp_min_alarm:
         case hwmon_temp_max_alarm:
             return pvt_alarm_is_visible(ch);
         case hwmon_temp_offset:
             return 0644;
         }
         break;
     case hwmon_in:
         switch (attr) {
         case hwmon_in_input:
         case hwmon_in_label:
             return 0444;
         case hwmon_in_min:
         case hwmon_in_max:
             return pvt_limit_is_visible(PVT_VOLT + ch);
         case hwmon_in_min_alarm:
         case hwmon_in_max_alarm:
             return pvt_alarm_is_visible(PVT_VOLT + ch);
         }
         break;
     default:
         break;
     }
 
     return 0;
 }
 
 static int pvt_read_trim(struct pvt_hwmon *pvt, long *val)
 {
     u32 data;
 
     data = readl(pvt->regs + PVT_CTRL);
     *val = FIELD_GET(PVT_CTRL_TRIM_MASK, data) * PVT_TRIM_STEP;
 
     return 0;
 }
 
 static int pvt_write_trim(struct pvt_hwmon *pvt, long val)
 {
     u32 trim;
     int ret;
 
     /*
      * Serialize trim update, since a part of the register is changed and
      * the controller is supposed to be disabled during this operation.
      */
     ret = mutex_lock_interruptible(&pvt->iface_mtx);
     if (ret)
         return ret;
 
     trim = pvt_calc_trim(val);
     pvt_set_trim(pvt, trim);
 
     mutex_unlock(&pvt->iface_mtx);
 
     return 0;
 }
 
 static int pvt_read_timeout(struct pvt_hwmon *pvt, long *val)
 {
     int ret;
 
     ret = mutex_lock_interruptible(&pvt->iface_mtx);
     if (ret)
         return ret;
 
     /* Return the result in msec as hwmon sysfs interface requires. */
     *val = ktime_to_ms(pvt->timeout);
 
     mutex_unlock(&pvt->iface_mtx);
 
     return 0;
 }
 
 static int pvt_write_timeout(struct pvt_hwmon *pvt, long val)
 {
     unsigned long rate;
     ktime_t kt, cache;
     u32 data;
     int ret;
 
     rate = clk_get_rate(pvt->clks[PVT_CLOCK_REF].clk);
     if (!rate)
         return -ENODEV;
 
     /*
      * If alarms are enabled, the requested timeout must be divided
      * between all available sensors to have the requested delay
      * applicable to each individual sensor.
      */
     cache = kt = ms_to_ktime(val);
 #if defined(CONFIG_SENSORS_BT1_PVT_ALARMS)
     kt = ktime_divns(kt, PVT_SENSORS_NUM);
 #endif
 
     /*
      * Subtract a constant lag, which always persists due to the limited
      * PVT sampling rate. Make sure the timeout is not negative.
      */
     kt = ktime_sub_ns(kt, PVT_TOUT_MIN);
     if (ktime_to_ns(kt) < 0)
         kt = ktime_set(0, 0);
 
     /*
      * Finally recalculate the timeout in terms of the reference clock
      * period.
      */
     data = ktime_divns(kt * rate, NSEC_PER_SEC);
 
     /*
      * Update the measurements delay, but lock the interface first, since
      * we have to disable PVT in order to have the new delay actually
      * updated.
      */
     ret = mutex_lock_interruptible(&pvt->iface_mtx);
     if (ret)
         return ret;
 
     pvt_set_tout(pvt, data);
     pvt->timeout = cache;
 
     mutex_unlock(&pvt->iface_mtx);
 
     return 0;
 }
 
 static int pvt_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
               u32 attr, int ch, long *val)
 {
     struct pvt_hwmon *pvt = dev_get_drvdata(dev);
 
     if (!pvt_hwmon_channel_is_valid(type, ch))
         return -EINVAL;
 
     switch (type) {
     case hwmon_chip:
         switch (attr) {
         case hwmon_chip_update_interval:
             return pvt_read_timeout(pvt, val);
         }
         break;
     case hwmon_temp:
         switch (attr) {
         case hwmon_temp_input:
             return pvt_read_data(pvt, ch, val);
         case hwmon_temp_type:
             *val = 1;
             return 0;
         case hwmon_temp_min:
             return pvt_read_limit(pvt, ch, true, val);
         case hwmon_temp_max:
             return pvt_read_limit(pvt, ch, false, val);
         case hwmon_temp_min_alarm:
             return pvt_read_alarm(pvt, ch, true, val);
         case hwmon_temp_max_alarm:
             return pvt_read_alarm(pvt, ch, false, val);
         case hwmon_temp_offset:
             return pvt_read_trim(pvt, val);
         }
         break;
     case hwmon_in:
         switch (attr) {
         case hwmon_in_input:
             return pvt_read_data(pvt, PVT_VOLT + ch, val);
         case hwmon_in_min:
             return pvt_read_limit(pvt, PVT_VOLT + ch, true, val);
         case hwmon_in_max:
             return pvt_read_limit(pvt, PVT_VOLT + ch, false, val);
         case hwmon_in_min_alarm:
             return pvt_read_alarm(pvt, PVT_VOLT + ch, true, val);
         case hwmon_in_max_alarm:
             return pvt_read_alarm(pvt, PVT_VOLT + ch, false, val);
         }
         break;
     default:
         break;
     }
 
     return -EOPNOTSUPP;
 }
 
 static int pvt_hwmon_read_string(struct device *dev,
                  enum hwmon_sensor_types type,
                  u32 attr, int ch, const char **str)
 {
     if (!pvt_hwmon_channel_is_valid(type, ch))
         return -EINVAL;
 
     switch (type) {
     case hwmon_temp:
         switch (attr) {
         case hwmon_temp_label:
             *str = pvt_info[ch].label;
             return 0;
         }
         break;
     case hwmon_in:
         switch (attr) {
         case hwmon_in_label:
             *str = pvt_info[PVT_VOLT + ch].label;
             return 0;
         }
         break;
     default:
         break;
     }
 
     return -EOPNOTSUPP;
 }
 
 static int pvt_hwmon_write(struct device *dev, enum hwmon_sensor_types type,
                u32 attr, int ch, long val)
 {
     struct pvt_hwmon *pvt = dev_get_drvdata(dev);
 
     if (!pvt_hwmon_channel_is_valid(type, ch))
         return -EINVAL;
 
     switch (type) {
     case hwmon_chip:
         switch (attr) {
         case hwmon_chip_update_interval:
             return pvt_write_timeout(pvt, val);
         }
         break;
     case hwmon_temp:
         switch (attr) {
         case hwmon_temp_min:
             return pvt_write_limit(pvt, ch, true, val);
         case hwmon_temp_max:
             return pvt_write_limit(pvt, ch, false, val);
         case hwmon_temp_offset:
             return pvt_write_trim(pvt, val);
         }
         break;
     case hwmon_in:
         switch (attr) {
         case hwmon_in_min:
             return pvt_write_limit(pvt, PVT_VOLT + ch, true, val);
         case hwmon_in_max:
             return pvt_write_limit(pvt, PVT_VOLT + ch, false, val);
         }
         break;
     default:
         break;
     }
 
     return -EOPNOTSUPP;
 }
 
 static const struct hwmon_ops pvt_hwmon_ops = {
     .is_visible = pvt_hwmon_is_visible,
     .read = pvt_hwmon_read,
     .read_string = pvt_hwmon_read_string,
     .write = pvt_hwmon_write
 };
 
 static const struct hwmon_chip_info pvt_hwmon_info = {
     .ops = &pvt_hwmon_ops,
     .info = pvt_channel_info
 };
 
 static void pvt_clear_data(void *data)
 {
     struct pvt_hwmon *pvt = data;
 #if !defined(CONFIG_SENSORS_BT1_PVT_ALARMS)
     int idx;
 
     for (idx = 0; idx < PVT_SENSORS_NUM; ++idx)
         complete_all(&pvt->cache[idx].conversion);
 #endif
 
     mutex_destroy(&pvt->iface_mtx);
 }
 
 static struct pvt_hwmon *pvt_create_data(struct platform_device *pdev)
 {
     struct device *dev = &pdev->dev;
     struct pvt_hwmon *pvt;
     int ret, idx;
 
     pvt = devm_kzalloc(dev, sizeof(*pvt), GFP_KERNEL);
     if (!pvt)
         return ERR_PTR(-ENOMEM);
 
     ret = devm_add_action(dev, pvt_clear_data, pvt);
     if (ret) {
         dev_err(dev, "Can't add PVT data clear action\n");
         return ERR_PTR(ret);
     }
 
     pvt->dev = dev;
     pvt->sensor = PVT_SENSOR_FIRST;
     mutex_init(&pvt->iface_mtx);
 
 #if defined(CONFIG_SENSORS_BT1_PVT_ALARMS)
     for (idx = 0; idx < PVT_SENSORS_NUM; ++idx)
         seqlock_init(&pvt->cache[idx].data_seqlock);
 #else
     for (idx = 0; idx < PVT_SENSORS_NUM; ++idx)
         init_completion(&pvt->cache[idx].conversion);
 #endif
 
     return pvt;
 }
 
 static int pvt_request_regs(struct pvt_hwmon *pvt)
 {
     struct platform_device *pdev = to_platform_device(pvt->dev);
     struct resource *res;
 
     res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
     if (!res) {
         dev_err(pvt->dev, "Couldn't find PVT memresource\n");
         return -EINVAL;
     }
 
     pvt->regs = devm_ioremap_resource(pvt->dev, res);
     if (IS_ERR(pvt->regs))
         return PTR_ERR(pvt->regs);
 
     return 0;
 }
 
 static void pvt_disable_clks(void *data)
 {
     struct pvt_hwmon *pvt = data;
 
     clk_bulk_disable_unprepare(PVT_CLOCK_NUM, pvt->clks);
 }
 
 static int pvt_request_clks(struct pvt_hwmon *pvt)
 {
     int ret;
 
     pvt->clks[PVT_CLOCK_APB].id = "pclk";
     pvt->clks[PVT_CLOCK_REF].id = "ref";
 
     ret = devm_clk_bulk_get(pvt->dev, PVT_CLOCK_NUM, pvt->clks);
     if (ret) {
         dev_err(pvt->dev, "Couldn't get PVT clocks descriptors\n");
         return ret;
     }
 
     ret = clk_bulk_prepare_enable(PVT_CLOCK_NUM, pvt->clks);
     if (ret) {
         dev_err(pvt->dev, "Couldn't enable the PVT clocks\n");
         return ret;
     }
 
     ret = devm_add_action_or_reset(pvt->dev, pvt_disable_clks, pvt);
     if (ret) {
         dev_err(pvt->dev, "Can't add PVT clocks disable action\n");
         return ret;
     }
 
     return 0;
 }
 
 static int pvt_check_pwr(struct pvt_hwmon *pvt)
 {
     unsigned long tout;
     int ret = 0;
     u32 data;
 
     /*
      * Test out the sensor conversion functionality. If it is not done on
      * time then the domain must have been unpowered and we won't be able
      * to use the device later in this driver.
      * Note If the power source is lost during the normal driver work the
      * data read procedure will either return -ETIMEDOUT (for the
      * alarm-less driver configuration) or just stop the repeated
      * conversion. In the later case alas we won't be able to detect the
      * problem.
      */
     pvt_update(pvt->regs + PVT_INTR_MASK, PVT_INTR_ALL, PVT_INTR_ALL);
     pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, PVT_CTRL_EN);
     pvt_set_tout(pvt, 0);
     readl(pvt->regs + PVT_DATA);
 
     tout = PVT_TOUT_MIN / NSEC_PER_USEC;
     usleep_range(tout, 2 * tout);
 
     data = readl(pvt->regs + PVT_DATA);
     if (!(data & PVT_DATA_VALID)) {
         ret = -ENODEV;
         dev_err(pvt->dev, "Sensor is powered down\n");
     }
 
     pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, 0);
 
     return ret;
 }
 
 static int pvt_init_iface(struct pvt_hwmon *pvt)
 {
     unsigned long rate;
     u32 trim, temp;
 
     rate = clk_get_rate(pvt->clks[PVT_CLOCK_REF].clk);
     if (!rate) {
         dev_err(pvt->dev, "Invalid reference clock rate\n");
         return -ENODEV;
     }
 
     /*
      * Make sure all interrupts and controller are disabled so not to
      * accidentally have ISR executed before the driver data is fully
      * initialized. Clear the IRQ status as well.
      */
     pvt_update(pvt->regs + PVT_INTR_MASK, PVT_INTR_ALL, PVT_INTR_ALL);
     pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, 0);
     readl(pvt->regs + PVT_CLR_INTR);
     readl(pvt->regs + PVT_DATA);
 
     /* Setup default sensor mode, timeout and temperature trim. */
     pvt_set_mode(pvt, pvt_info[pvt->sensor].mode);
     pvt_set_tout(pvt, PVT_TOUT_DEF);
 
     /*
      * Preserve the current ref-clock based delay (Ttotal) between the
      * sensors data samples in the driver data so not to recalculate it
      * each time on the data requests and timeout reads. It consists of the
      * delay introduced by the internal ref-clock timer (N / Fclk) and the
      * constant timeout caused by each conversion latency (Tmin):
      *   Ttotal = N / Fclk + Tmin
      * If alarms are enabled the sensors are polled one after another and
      * in order to get the next measurement of a particular sensor the
      * caller will have to wait for at most until all the others are
      * polled. In that case the formulae will look a bit different:
      *   Ttotal = 5 * (N / Fclk + Tmin)
      */
 #if defined(CONFIG_SENSORS_BT1_PVT_ALARMS)
     pvt->timeout = ktime_set(PVT_SENSORS_NUM * PVT_TOUT_DEF, 0);
     pvt->timeout = ktime_divns(pvt->timeout, rate);
     pvt->timeout = ktime_add_ns(pvt->timeout, PVT_SENSORS_NUM * PVT_TOUT_MIN);
 #else
     pvt->timeout = ktime_set(PVT_TOUT_DEF, 0);
     pvt->timeout = ktime_divns(pvt->timeout, rate);
     pvt->timeout = ktime_add_ns(pvt->timeout, PVT_TOUT_MIN);
 #endif
 
     trim = PVT_TRIM_DEF;
     if (!of_property_read_u32(pvt->dev->of_node,
          "baikal,pvt-temp-offset-millicelsius", &temp))
         trim = pvt_calc_trim(temp);
 
     pvt_set_trim(pvt, trim);
 
     return 0;
 }
 
 static int pvt_request_irq(struct pvt_hwmon *pvt)
 {
     struct platform_device *pdev = to_platform_device(pvt->dev);
     int ret;
 
     pvt->irq = platform_get_irq(pdev, 0);
     if (pvt->irq < 0)
         return pvt->irq;
 
     ret = devm_request_threaded_irq(pvt->dev, pvt->irq,
                     pvt_hard_isr, pvt_soft_isr,
 #if defined(CONFIG_SENSORS_BT1_PVT_ALARMS)
                     IRQF_SHARED | IRQF_TRIGGER_HIGH |
                     IRQF_ONESHOT,
 #else
                     IRQF_SHARED | IRQF_TRIGGER_HIGH,
 #endif
                     "pvt", pvt);
     if (ret) {
         dev_err(pvt->dev, "Couldn't request PVT IRQ\n");
         return ret;
     }
 
     return 0;
 }
 
 static int pvt_create_hwmon(struct pvt_hwmon *pvt)
 {
     pvt->hwmon = devm_hwmon_device_register_with_info(pvt->dev, "pvt", pvt,
         &pvt_hwmon_info, NULL);
     if (IS_ERR(pvt->hwmon)) {
         dev_err(pvt->dev, "Couldn't create hwmon device\n");
         return PTR_ERR(pvt->hwmon);
     }
 
     return 0;
 }
 
 #if defined(CONFIG_SENSORS_BT1_PVT_ALARMS)
 
 static void pvt_disable_iface(void *data)
 {
     struct pvt_hwmon *pvt = data;
 
     mutex_lock(&pvt->iface_mtx);
     pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, 0);
     pvt_update(pvt->regs + PVT_INTR_MASK, PVT_INTR_DVALID,
            PVT_INTR_DVALID);
     mutex_unlock(&pvt->iface_mtx);
 }
 
 static int pvt_enable_iface(struct pvt_hwmon *pvt)
 {
     int ret;
 
     ret = devm_add_action(pvt->dev, pvt_disable_iface, pvt);
     if (ret) {
         dev_err(pvt->dev, "Can't add PVT disable interface action\n");
         return ret;
     }
 
     /*
      * Enable sensors data conversion and IRQ. We need to lock the
      * interface mutex since hwmon has just been created and the
      * corresponding sysfs files are accessible from user-space,
      * which theoretically may cause races.
      */
     mutex_lock(&pvt->iface_mtx);
     pvt_update(pvt->regs + PVT_INTR_MASK, PVT_INTR_DVALID, 0);
     pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, PVT_CTRL_EN);
     mutex_unlock(&pvt->iface_mtx);
 
     return 0;
 }
 
 #else /* !CONFIG_SENSORS_BT1_PVT_ALARMS */
 
 static int pvt_enable_iface(struct pvt_hwmon *pvt)
 {
     return 0;
 }
 
 #endif /* !CONFIG_SENSORS_BT1_PVT_ALARMS */
 
 static int pvt_probe(struct platform_device *pdev)
 {
     struct pvt_hwmon *pvt;
     int ret;
 
     pvt = pvt_create_data(pdev);
     if (IS_ERR(pvt))
         return PTR_ERR(pvt);
 
     ret = pvt_request_regs(pvt);
     if (ret)
         return ret;
 
     ret = pvt_request_clks(pvt);
     if (ret)
         return ret;
 
     ret = pvt_check_pwr(pvt);
     if (ret)
         return ret;
 
     ret = pvt_init_iface(pvt);
     if (ret)
         return ret;
 
     ret = pvt_request_irq(pvt);
     if (ret)
         return ret;
 
     ret = pvt_create_hwmon(pvt);
     if (ret)
         return ret;
 
     ret = pvt_enable_iface(pvt);
     if (ret)
         return ret;
 
     return 0;
 }
 
 static const struct of_device_id pvt_of_match[] = {
     { .compatible = "baikal,bt1-pvt" },
     { }
 };
 MODULE_DEVICE_TABLE(of, pvt_of_match);
 
 static struct platform_driver pvt_driver = {
     .probe = pvt_probe,
     .driver = {
         .name = "bt1-pvt",
         .of_match_table = pvt_of_match
     }
 };
 module_platform_driver(pvt_driver);
 
 MODULE_AUTHOR("Maxim Kaurkin <maxim.kaurkin@baikalelectronics.ru>");
 MODULE_DESCRIPTION("Baikal-T1 PVT driver");
 MODULE_LICENSE("GPL v2");

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