diff options
Diffstat (limited to 'drivers/hwmon/bt1-pvt.c')
| -rw-r--r-- | drivers/hwmon/bt1-pvt.c | 1204 |
1 files changed, 1204 insertions, 0 deletions
diff --git a/drivers/hwmon/bt1-pvt.c b/drivers/hwmon/bt1-pvt.c new file mode 100644 index 000000000..3e1d56585 --- /dev/null +++ b/drivers/hwmon/bt1-pvt.c @@ -0,0 +1,1204 @@ +// 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/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 pvt_poly __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 pvt_poly 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 pvt_poly __maybe_unused poly_volt_to_N = { + .total_divider = 10, + .terms = { + {1, 18658, 1000, 1}, + {0, -11572, 1, 1} + } +}; + +static const struct pvt_poly poly_N_to_volt = { + .total_divider = 10, + .terms = { + {1, 100000, 18658, 1}, + {0, 115720000, 1, 18658} + } +}; + +/* + * Here is the polynomial calculation function, which performs the + * redistributed terms calculations. It's pretty straightforward. We walk + * over each degree term up to the free one, and perform the redistributed + * multiplication of the term coefficient, its divider (as for the rationale + * fraction representation), data power and the rational fraction divider + * leftover. Then all of this is collected in a total sum variable, which + * value is normalized by the total divider before being returned. + */ +static long pvt_calc_poly(const struct pvt_poly *poly, long data) +{ + const struct pvt_poly_term *term = poly->terms; + long tmp, ret = 0; + int deg; + + do { + tmp = term->coef; + for (deg = 0; deg < term->deg; ++deg) + tmp = mult_frac(tmp, data, term->divider); + ret += tmp / term->divider_leftover; + } while ((term++)->deg); + + return ret / poly->total_divider; +} + +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 = pvt_calc_poly(&poly_N_to_temp, data); + else + *val = pvt_calc_poly(&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 = pvt_calc_poly(&poly_N_to_temp, data); + else + *val = pvt_calc_poly(&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 = pvt_calc_poly(&poly_temp_to_N, val); + } else { + val = clamp(val, PVT_VOLT_MIN, PVT_VOLT_MAX); + data = pvt_calc_poly(&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 = pvt_calc_poly(&poly_N_to_temp, data); + else + *val = pvt_calc_poly(&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)) { + dev_err(pvt->dev, "Couldn't map PVT registers\n"); + 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"); |