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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/hwmon/bt1-pvt.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/hwmon/bt1-pvt.c')
-rw-r--r--drivers/hwmon/bt1-pvt.c1178
1 files changed, 1178 insertions, 0 deletions
diff --git a/drivers/hwmon/bt1-pvt.c b/drivers/hwmon/bt1-pvt.c
new file mode 100644
index 000000000..21ab17277
--- /dev/null
+++ b/drivers/hwmon/bt1-pvt.c
@@ -0,0 +1,1178 @@
+// 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");