treewide: remove redundant IS_ERR() before error code check

[linux/fpc-iii.git] / drivers / thermal / armada_thermal.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Marvell EBU Armada SoCs thermal sensor driver
 *
 * Copyright (C) 2013 Marvell
 */
#include <linux/device.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/of_device.h>
#include <linux/thermal.h>
#include <linux/iopoll.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
#include <linux/interrupt.h>

#include "thermal_core.h"

/* Thermal Manager Control and Status Register */
#define PMU_TDC0_SW_RST_MASK            (0x1 << 1)
#define PMU_TM_DISABLE_OFFS             0
#define PMU_TM_DISABLE_MASK             (0x1 << PMU_TM_DISABLE_OFFS)
#define PMU_TDC0_REF_CAL_CNT_OFFS       11
#define PMU_TDC0_REF_CAL_CNT_MASK       (0x1ff << PMU_TDC0_REF_CAL_CNT_OFFS)
#define PMU_TDC0_OTF_CAL_MASK           (0x1 << 30)
#define PMU_TDC0_START_CAL_MASK         (0x1 << 25)

#define A375_UNIT_CONTROL_SHIFT         27
#define A375_UNIT_CONTROL_MASK          0x7
#define A375_READOUT_INVERT             BIT(15)
#define A375_HW_RESETn                  BIT(8)

/* Errata fields */
#define CONTROL0_TSEN_TC_TRIM_MASK      0x7
#define CONTROL0_TSEN_TC_TRIM_VAL       0x3

#define CONTROL0_TSEN_START             BIT(0)
#define CONTROL0_TSEN_RESET             BIT(1)
#define CONTROL0_TSEN_ENABLE            BIT(2)
#define CONTROL0_TSEN_AVG_BYPASS        BIT(6)
#define CONTROL0_TSEN_CHAN_SHIFT        13
#define CONTROL0_TSEN_CHAN_MASK         0xF
#define CONTROL0_TSEN_OSR_SHIFT         24
#define CONTROL0_TSEN_OSR_MAX           0x3
#define CONTROL0_TSEN_MODE_SHIFT        30
#define CONTROL0_TSEN_MODE_EXTERNAL     0x2
#define CONTROL0_TSEN_MODE_MASK         0x3

#define CONTROL1_TSEN_AVG_MASK          0x7
#define CONTROL1_EXT_TSEN_SW_RESET      BIT(7)
#define CONTROL1_EXT_TSEN_HW_RESETn     BIT(8)
#define CONTROL1_TSEN_INT_EN            BIT(25)
#define CONTROL1_TSEN_SELECT_OFF        21
#define CONTROL1_TSEN_SELECT_MASK       0x3

#define STATUS_POLL_PERIOD_US           1000
#define STATUS_POLL_TIMEOUT_US          100000
#define OVERHEAT_INT_POLL_DELAY_MS      1000

struct armada_thermal_data;

/* Marvell EBU Thermal Sensor Dev Structure */
struct armada_thermal_priv {
        struct device *dev;
        struct regmap *syscon;
        char zone_name[THERMAL_NAME_LENGTH];
        /* serialize temperature reads/updates */
        struct mutex update_lock;
        struct armada_thermal_data *data;
        struct thermal_zone_device *overheat_sensor;
        int interrupt_source;
        int current_channel;
        long current_threshold;
        long current_hysteresis;
};

struct armada_thermal_data {
        /* Initialize the thermal IC */
        void (*init)(struct platform_device *pdev,
                     struct armada_thermal_priv *priv);

        /* Formula coeficients: temp = (b - m * reg) / div */
        s64 coef_b;
        s64 coef_m;
        u32 coef_div;
        bool inverted;
        bool signed_sample;

        /* Register shift and mask to access the sensor temperature */
        unsigned int temp_shift;
        unsigned int temp_mask;
        unsigned int thresh_shift;
        unsigned int hyst_shift;
        unsigned int hyst_mask;
        u32 is_valid_bit;

        /* Syscon access */
        unsigned int syscon_control0_off;
        unsigned int syscon_control1_off;
        unsigned int syscon_status_off;
        unsigned int dfx_irq_cause_off;
        unsigned int dfx_irq_mask_off;
        unsigned int dfx_overheat_irq;
        unsigned int dfx_server_irq_mask_off;
        unsigned int dfx_server_irq_en;

        /* One sensor is in the thermal IC, the others are in the CPUs if any */
        unsigned int cpu_nr;
};

struct armada_drvdata {
        enum drvtype {
                LEGACY,
                SYSCON
        } type;
        union {
                struct armada_thermal_priv *priv;
                struct thermal_zone_device *tz;
        } data;
};

/*
 * struct armada_thermal_sensor - hold the information of one thermal sensor
 * @thermal: pointer to the local private structure
 * @tzd: pointer to the thermal zone device
 * @id: identifier of the thermal sensor
 */
struct armada_thermal_sensor {
        struct armada_thermal_priv *priv;
        int id;
};

static void armadaxp_init(struct platform_device *pdev,
                          struct armada_thermal_priv *priv)
{
        struct armada_thermal_data *data = priv->data;
        u32 reg;

        regmap_read(priv->syscon, data->syscon_control1_off, &reg);
        reg |= PMU_TDC0_OTF_CAL_MASK;

        /* Reference calibration value */
        reg &= ~PMU_TDC0_REF_CAL_CNT_MASK;
        reg |= (0xf1 << PMU_TDC0_REF_CAL_CNT_OFFS);

        /* Reset the sensor */
        reg |= PMU_TDC0_SW_RST_MASK;

        regmap_write(priv->syscon, data->syscon_control1_off, reg);

        reg &= ~PMU_TDC0_SW_RST_MASK;
        regmap_write(priv->syscon, data->syscon_control1_off, reg);

        /* Enable the sensor */
        regmap_read(priv->syscon, data->syscon_status_off, &reg);
        reg &= ~PMU_TM_DISABLE_MASK;
        regmap_write(priv->syscon, data->syscon_status_off, reg);
}

static void armada370_init(struct platform_device *pdev,
                           struct armada_thermal_priv *priv)
{
        struct armada_thermal_data *data = priv->data;
        u32 reg;

        regmap_read(priv->syscon, data->syscon_control1_off, &reg);
        reg |= PMU_TDC0_OTF_CAL_MASK;

        /* Reference calibration value */
        reg &= ~PMU_TDC0_REF_CAL_CNT_MASK;
        reg |= (0xf1 << PMU_TDC0_REF_CAL_CNT_OFFS);

        /* Reset the sensor */
        reg &= ~PMU_TDC0_START_CAL_MASK;

        regmap_write(priv->syscon, data->syscon_control1_off, reg);

        msleep(10);
}

static void armada375_init(struct platform_device *pdev,
                           struct armada_thermal_priv *priv)
{
        struct armada_thermal_data *data = priv->data;
        u32 reg;

        regmap_read(priv->syscon, data->syscon_control1_off, &reg);
        reg &= ~(A375_UNIT_CONTROL_MASK << A375_UNIT_CONTROL_SHIFT);
        reg &= ~A375_READOUT_INVERT;
        reg &= ~A375_HW_RESETn;
        regmap_write(priv->syscon, data->syscon_control1_off, reg);

        msleep(20);

        reg |= A375_HW_RESETn;
        regmap_write(priv->syscon, data->syscon_control1_off, reg);

        msleep(50);
}

static int armada_wait_sensor_validity(struct armada_thermal_priv *priv)
{
        u32 reg;

        return regmap_read_poll_timeout(priv->syscon,
                                        priv->data->syscon_status_off, reg,
                                        reg & priv->data->is_valid_bit,
                                        STATUS_POLL_PERIOD_US,
                                        STATUS_POLL_TIMEOUT_US);
}

static void armada380_init(struct platform_device *pdev,
                           struct armada_thermal_priv *priv)
{
        struct armada_thermal_data *data = priv->data;
        u32 reg;

        /* Disable the HW/SW reset */
        regmap_read(priv->syscon, data->syscon_control1_off, &reg);
        reg |= CONTROL1_EXT_TSEN_HW_RESETn;
        reg &= ~CONTROL1_EXT_TSEN_SW_RESET;
        regmap_write(priv->syscon, data->syscon_control1_off, reg);

        /* Set Tsen Tc Trim to correct default value (errata #132698) */
        regmap_read(priv->syscon, data->syscon_control0_off, &reg);
        reg &= ~CONTROL0_TSEN_TC_TRIM_MASK;
        reg |= CONTROL0_TSEN_TC_TRIM_VAL;
        regmap_write(priv->syscon, data->syscon_control0_off, reg);
}

static void armada_ap806_init(struct platform_device *pdev,
                              struct armada_thermal_priv *priv)
{
        struct armada_thermal_data *data = priv->data;
        u32 reg;

        regmap_read(priv->syscon, data->syscon_control0_off, &reg);
        reg &= ~CONTROL0_TSEN_RESET;
        reg |= CONTROL0_TSEN_START | CONTROL0_TSEN_ENABLE;

        /* Sample every ~2ms */
        reg |= CONTROL0_TSEN_OSR_MAX << CONTROL0_TSEN_OSR_SHIFT;

        /* Enable average (2 samples by default) */
        reg &= ~CONTROL0_TSEN_AVG_BYPASS;

        regmap_write(priv->syscon, data->syscon_control0_off, reg);
}

static void armada_cp110_init(struct platform_device *pdev,
                              struct armada_thermal_priv *priv)
{
        struct armada_thermal_data *data = priv->data;
        u32 reg;

        armada380_init(pdev, priv);

        /* Sample every ~2ms */
        regmap_read(priv->syscon, data->syscon_control0_off, &reg);
        reg |= CONTROL0_TSEN_OSR_MAX << CONTROL0_TSEN_OSR_SHIFT;
        regmap_write(priv->syscon, data->syscon_control0_off, reg);

        /* Average the output value over 2^1 = 2 samples */
        regmap_read(priv->syscon, data->syscon_control1_off, &reg);
        reg &= ~CONTROL1_TSEN_AVG_MASK;
        reg |= 1;
        regmap_write(priv->syscon, data->syscon_control1_off, reg);
}

static bool armada_is_valid(struct armada_thermal_priv *priv)
{
        u32 reg;

        if (!priv->data->is_valid_bit)
                return true;

        regmap_read(priv->syscon, priv->data->syscon_status_off, &reg);

        return reg & priv->data->is_valid_bit;
}

static void armada_enable_overheat_interrupt(struct armada_thermal_priv *priv)
{
        struct armada_thermal_data *data = priv->data;
        u32 reg;

        /* Clear DFX temperature IRQ cause */
        regmap_read(priv->syscon, data->dfx_irq_cause_off, &reg);

        /* Enable DFX Temperature IRQ */
        regmap_read(priv->syscon, data->dfx_irq_mask_off, &reg);
        reg |= data->dfx_overheat_irq;
        regmap_write(priv->syscon, data->dfx_irq_mask_off, reg);

        /* Enable DFX server IRQ */
        regmap_read(priv->syscon, data->dfx_server_irq_mask_off, &reg);
        reg |= data->dfx_server_irq_en;
        regmap_write(priv->syscon, data->dfx_server_irq_mask_off, reg);

        /* Enable overheat interrupt */
        regmap_read(priv->syscon, data->syscon_control1_off, &reg);
        reg |= CONTROL1_TSEN_INT_EN;
        regmap_write(priv->syscon, data->syscon_control1_off, reg);
}

static void __maybe_unused
armada_disable_overheat_interrupt(struct armada_thermal_priv *priv)
{
        struct armada_thermal_data *data = priv->data;
        u32 reg;

        regmap_read(priv->syscon, data->syscon_control1_off, &reg);
        reg &= ~CONTROL1_TSEN_INT_EN;
        regmap_write(priv->syscon, data->syscon_control1_off, reg);
}

/* There is currently no board with more than one sensor per channel */
static int armada_select_channel(struct armada_thermal_priv *priv, int channel)
{
        struct armada_thermal_data *data = priv->data;
        u32 ctrl0;

        if (channel < 0 || channel > priv->data->cpu_nr)
                return -EINVAL;

        if (priv->current_channel == channel)
                return 0;

        /* Stop the measurements */
        regmap_read(priv->syscon, data->syscon_control0_off, &ctrl0);
        ctrl0 &= ~CONTROL0_TSEN_START;
        regmap_write(priv->syscon, data->syscon_control0_off, ctrl0);

        /* Reset the mode, internal sensor will be automatically selected */
        ctrl0 &= ~(CONTROL0_TSEN_MODE_MASK << CONTROL0_TSEN_MODE_SHIFT);

        /* Other channels are external and should be selected accordingly */
        if (channel) {
                /* Change the mode to external */
                ctrl0 |= CONTROL0_TSEN_MODE_EXTERNAL <<
                         CONTROL0_TSEN_MODE_SHIFT;
                /* Select the sensor */
                ctrl0 &= ~(CONTROL0_TSEN_CHAN_MASK << CONTROL0_TSEN_CHAN_SHIFT);
                ctrl0 |= (channel - 1) << CONTROL0_TSEN_CHAN_SHIFT;
        }

        /* Actually set the mode/channel */
        regmap_write(priv->syscon, data->syscon_control0_off, ctrl0);
        priv->current_channel = channel;

        /* Re-start the measurements */
        ctrl0 |= CONTROL0_TSEN_START;
        regmap_write(priv->syscon, data->syscon_control0_off, ctrl0);

        /*
         * The IP has a latency of ~15ms, so after updating the selected source,
         * we must absolutely wait for the sensor validity bit to ensure we read
         * actual data.
         */
        if (armada_wait_sensor_validity(priv)) {
                dev_err(priv->dev,
                        "Temperature sensor reading not valid\n");
                return -EIO;
        }

        return 0;
}

static int armada_read_sensor(struct armada_thermal_priv *priv, int *temp)
{
        u32 reg, div;
        s64 sample, b, m;

        regmap_read(priv->syscon, priv->data->syscon_status_off, &reg);
        reg = (reg >> priv->data->temp_shift) & priv->data->temp_mask;
        if (priv->data->signed_sample)
                /* The most significant bit is the sign bit */
                sample = sign_extend32(reg, fls(priv->data->temp_mask) - 1);
        else
                sample = reg;

        /* Get formula coeficients */
        b = priv->data->coef_b;
        m = priv->data->coef_m;
        div = priv->data->coef_div;

        if (priv->data->inverted)
                *temp = div_s64((m * sample) - b, div);
        else
                *temp = div_s64(b - (m * sample), div);

        return 0;
}

static int armada_get_temp_legacy(struct thermal_zone_device *thermal,
                                  int *temp)
{
        struct armada_thermal_priv *priv = thermal->devdata;
        int ret;

        /* Valid check */
        if (!armada_is_valid(priv)) {
                dev_err(priv->dev,
                        "Temperature sensor reading not valid\n");
                return -EIO;
        }

        /* Do the actual reading */
        ret = armada_read_sensor(priv, temp);

        return ret;
}

static struct thermal_zone_device_ops legacy_ops = {
        .get_temp = armada_get_temp_legacy,
};

static int armada_get_temp(void *_sensor, int *temp)
{
        struct armada_thermal_sensor *sensor = _sensor;
        struct armada_thermal_priv *priv = sensor->priv;
        int ret;

        mutex_lock(&priv->update_lock);

        /* Select the desired channel */
        ret = armada_select_channel(priv, sensor->id);
        if (ret)
                goto unlock_mutex;

        /* Do the actual reading */
        ret = armada_read_sensor(priv, temp);
        if (ret)
                goto unlock_mutex;

        /*
         * Select back the interrupt source channel from which a potential
         * critical trip point has been set.
         */
        ret = armada_select_channel(priv, priv->interrupt_source);

unlock_mutex:
        mutex_unlock(&priv->update_lock);

        return ret;
}

static const struct thermal_zone_of_device_ops of_ops = {
        .get_temp = armada_get_temp,
};

static unsigned int armada_mc_to_reg_temp(struct armada_thermal_data *data,
                                          unsigned int temp_mc)
{
        s64 b = data->coef_b;
        s64 m = data->coef_m;
        s64 div = data->coef_div;
        unsigned int sample;

        if (data->inverted)
                sample = div_s64(((temp_mc * div) + b), m);
        else
                sample = div_s64((b - (temp_mc * div)), m);

        return sample & data->temp_mask;
}

/*
 * The documentation states:
 * high/low watermark = threshold +/- 0.4761 * 2^(hysteresis + 2)
 * which is the mathematical derivation for:
 * 0x0 <=> 1.9°C, 0x1 <=> 3.8°C, 0x2 <=> 7.6°C, 0x3 <=> 15.2°C
 */
static unsigned int hyst_levels_mc[] = {1900, 3800, 7600, 15200};

static unsigned int armada_mc_to_reg_hyst(struct armada_thermal_data *data,
                                          unsigned int hyst_mc)
{
        int i;

        /*
         * We will always take the smallest possible hysteresis to avoid risking
         * the hardware integrity by enlarging the threshold by +8°C in the
         * worst case.
         */
        for (i = ARRAY_SIZE(hyst_levels_mc) - 1; i > 0; i--)
                if (hyst_mc >= hyst_levels_mc[i])
                        break;

        return i & data->hyst_mask;
}

static void armada_set_overheat_thresholds(struct armada_thermal_priv *priv,
                                           int thresh_mc, int hyst_mc)
{
        struct armada_thermal_data *data = priv->data;
        unsigned int threshold = armada_mc_to_reg_temp(data, thresh_mc);
        unsigned int hysteresis = armada_mc_to_reg_hyst(data, hyst_mc);
        u32 ctrl1;

        regmap_read(priv->syscon, data->syscon_control1_off, &ctrl1);

        /* Set Threshold */
        if (thresh_mc >= 0) {
                ctrl1 &= ~(data->temp_mask << data->thresh_shift);
                ctrl1 |= threshold << data->thresh_shift;
                priv->current_threshold = thresh_mc;
        }

        /* Set Hysteresis */
        if (hyst_mc >= 0) {
                ctrl1 &= ~(data->hyst_mask << data->hyst_shift);
                ctrl1 |= hysteresis << data->hyst_shift;
                priv->current_hysteresis = hyst_mc;
        }

        regmap_write(priv->syscon, data->syscon_control1_off, ctrl1);
}

static irqreturn_t armada_overheat_isr(int irq, void *blob)
{
        /*
         * Disable the IRQ and continue in thread context (thermal core
         * notification and temperature monitoring).
         */
        disable_irq_nosync(irq);

        return IRQ_WAKE_THREAD;
}

static irqreturn_t armada_overheat_isr_thread(int irq, void *blob)
{
        struct armada_thermal_priv *priv = blob;
        int low_threshold = priv->current_threshold - priv->current_hysteresis;
        int temperature;
        u32 dummy;
        int ret;

        /* Notify the core in thread context */
        thermal_zone_device_update(priv->overheat_sensor,
                                   THERMAL_EVENT_UNSPECIFIED);

        /*
         * The overheat interrupt must be cleared by reading the DFX interrupt
         * cause _after_ the temperature has fallen down to the low threshold.
         * Otherwise future interrupts might not be served.
         */
        do {
                msleep(OVERHEAT_INT_POLL_DELAY_MS);
                mutex_lock(&priv->update_lock);
                ret = armada_read_sensor(priv, &temperature);
                mutex_unlock(&priv->update_lock);
                if (ret)
                        goto enable_irq;
        } while (temperature >= low_threshold);

        regmap_read(priv->syscon, priv->data->dfx_irq_cause_off, &dummy);

        /* Notify the thermal core that the temperature is acceptable again */
        thermal_zone_device_update(priv->overheat_sensor,
                                   THERMAL_EVENT_UNSPECIFIED);

enable_irq:
        enable_irq(irq);

        return IRQ_HANDLED;
}

static const struct armada_thermal_data armadaxp_data = {
        .init = armadaxp_init,
        .temp_shift = 10,
        .temp_mask = 0x1ff,
        .coef_b = 3153000000ULL,
        .coef_m = 10000000ULL,
        .coef_div = 13825,
        .syscon_status_off = 0xb0,
        .syscon_control1_off = 0x2d0,
};

static const struct armada_thermal_data armada370_data = {
        .init = armada370_init,
        .is_valid_bit = BIT(9),
        .temp_shift = 10,
        .temp_mask = 0x1ff,
        .coef_b = 3153000000ULL,
        .coef_m = 10000000ULL,
        .coef_div = 13825,
        .syscon_status_off = 0x0,
        .syscon_control1_off = 0x4,
};

static const struct armada_thermal_data armada375_data = {
        .init = armada375_init,
        .is_valid_bit = BIT(10),
        .temp_shift = 0,
        .temp_mask = 0x1ff,
        .coef_b = 3171900000ULL,
        .coef_m = 10000000ULL,
        .coef_div = 13616,
        .syscon_status_off = 0x78,
        .syscon_control0_off = 0x7c,
        .syscon_control1_off = 0x80,
};

static const struct armada_thermal_data armada380_data = {
        .init = armada380_init,
        .is_valid_bit = BIT(10),
        .temp_shift = 0,
        .temp_mask = 0x3ff,
        .coef_b = 1172499100ULL,
        .coef_m = 2000096ULL,
        .coef_div = 4201,
        .inverted = true,
        .syscon_control0_off = 0x70,
        .syscon_control1_off = 0x74,
        .syscon_status_off = 0x78,
};

static const struct armada_thermal_data armada_ap806_data = {
        .init = armada_ap806_init,
        .is_valid_bit = BIT(16),
        .temp_shift = 0,
        .temp_mask = 0x3ff,
        .thresh_shift = 3,
        .hyst_shift = 19,
        .hyst_mask = 0x3,
        .coef_b = -150000LL,
        .coef_m = 423ULL,
        .coef_div = 1,
        .inverted = true,
        .signed_sample = true,
        .syscon_control0_off = 0x84,
        .syscon_control1_off = 0x88,
        .syscon_status_off = 0x8C,
        .dfx_irq_cause_off = 0x108,
        .dfx_irq_mask_off = 0x10C,
        .dfx_overheat_irq = BIT(22),
        .dfx_server_irq_mask_off = 0x104,
        .dfx_server_irq_en = BIT(1),
        .cpu_nr = 4,
};

static const struct armada_thermal_data armada_cp110_data = {
        .init = armada_cp110_init,
        .is_valid_bit = BIT(10),
        .temp_shift = 0,
        .temp_mask = 0x3ff,
        .thresh_shift = 16,
        .hyst_shift = 26,
        .hyst_mask = 0x3,
        .coef_b = 1172499100ULL,
        .coef_m = 2000096ULL,
        .coef_div = 4201,
        .inverted = true,
        .syscon_control0_off = 0x70,
        .syscon_control1_off = 0x74,
        .syscon_status_off = 0x78,
        .dfx_irq_cause_off = 0x108,
        .dfx_irq_mask_off = 0x10C,
        .dfx_overheat_irq = BIT(20),
        .dfx_server_irq_mask_off = 0x104,
        .dfx_server_irq_en = BIT(1),
};

static const struct of_device_id armada_thermal_id_table[] = {
        {
                .compatible = "marvell,armadaxp-thermal",
                .data       = &armadaxp_data,
        },
        {
                .compatible = "marvell,armada370-thermal",
                .data       = &armada370_data,
        },
        {
                .compatible = "marvell,armada375-thermal",
                .data       = &armada375_data,
        },
        {
                .compatible = "marvell,armada380-thermal",
                .data       = &armada380_data,
        },
        {
                .compatible = "marvell,armada-ap806-thermal",
                .data       = &armada_ap806_data,
        },
        {
                .compatible = "marvell,armada-cp110-thermal",
                .data       = &armada_cp110_data,
        },
        {
                /* sentinel */
        },
};
MODULE_DEVICE_TABLE(of, armada_thermal_id_table);

static const struct regmap_config armada_thermal_regmap_config = {
        .reg_bits = 32,
        .reg_stride = 4,
        .val_bits = 32,
        .fast_io = true,
};

static int armada_thermal_probe_legacy(struct platform_device *pdev,
                                       struct armada_thermal_priv *priv)
{
        struct armada_thermal_data *data = priv->data;
        struct resource *res;
        void __iomem *base;

        /* First memory region points towards the status register */
        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        base = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(base))
                return PTR_ERR(base);

        /*
         * Fix up from the old individual DT register specification to
         * cover all the registers.  We do this by adjusting the ioremap()
         * result, which should be fine as ioremap() deals with pages.
         * However, validate that we do not cross a page boundary while
         * making this adjustment.
         */
        if (((unsigned long)base & ~PAGE_MASK) < data->syscon_status_off)
                return -EINVAL;
        base -= data->syscon_status_off;

        priv->syscon = devm_regmap_init_mmio(&pdev->dev, base,
                                             &armada_thermal_regmap_config);
        return PTR_ERR_OR_ZERO(priv->syscon);
}

static int armada_thermal_probe_syscon(struct platform_device *pdev,
                                       struct armada_thermal_priv *priv)
{
        priv->syscon = syscon_node_to_regmap(pdev->dev.parent->of_node);
        return PTR_ERR_OR_ZERO(priv->syscon);
}

static void armada_set_sane_name(struct platform_device *pdev,
                                 struct armada_thermal_priv *priv)
{
        const char *name = dev_name(&pdev->dev);
        char *insane_char;

        if (strlen(name) > THERMAL_NAME_LENGTH) {
                /*
                 * When inside a system controller, the device name has the
                 * form: f06f8000.system-controller:ap-thermal so stripping
                 * after the ':' should give us a shorter but meaningful name.
                 */
                name = strrchr(name, ':');
                if (!name)
                        name = "armada_thermal";
                else
                        name++;
        }

        /* Save the name locally */
        strncpy(priv->zone_name, name, THERMAL_NAME_LENGTH - 1);
        priv->zone_name[THERMAL_NAME_LENGTH - 1] = '\0';

        /* Then check there are no '-' or hwmon core will complain */
        do {
                insane_char = strpbrk(priv->zone_name, "-");
                if (insane_char)
                        *insane_char = '_';
        } while (insane_char);
}

/*
 * The IP can manage to trigger interrupts on overheat situation from all the
 * sensors. However, the interrupt source changes along with the last selected
 * source (ie. the last read sensor), which is an inconsistent behavior. Avoid
 * possible glitches by always selecting back only one channel (arbitrarily: the
 * first in the DT which has a critical trip point). We also disable sensor
 * switch during overheat situations.
 */
static int armada_configure_overheat_int(struct armada_thermal_priv *priv,
                                         struct thermal_zone_device *tz,
                                         int sensor_id)
{
        /* Retrieve the critical trip point to enable the overheat interrupt */
        const struct thermal_trip *trips = of_thermal_get_trip_points(tz);
        int ret;
        int i;

        if (!trips)
                return -EINVAL;

        for (i = 0; i < of_thermal_get_ntrips(tz); i++)
                if (trips[i].type == THERMAL_TRIP_CRITICAL)
                        break;

        if (i == of_thermal_get_ntrips(tz))
                return -EINVAL;

        ret = armada_select_channel(priv, sensor_id);
        if (ret)
                return ret;

        armada_set_overheat_thresholds(priv,
                                       trips[i].temperature,
                                       trips[i].hysteresis);
        priv->overheat_sensor = tz;
        priv->interrupt_source = sensor_id;

        armada_enable_overheat_interrupt(priv);

        return 0;
}

static int armada_thermal_probe(struct platform_device *pdev)
{
        struct thermal_zone_device *tz;
        struct armada_thermal_sensor *sensor;
        struct armada_drvdata *drvdata;
        const struct of_device_id *match;
        struct armada_thermal_priv *priv;
        int sensor_id, irq;
        int ret;

        match = of_match_device(armada_thermal_id_table, &pdev->dev);
        if (!match)
                return -ENODEV;

        priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
        if (!drvdata)
                return -ENOMEM;

        priv->dev = &pdev->dev;
        priv->data = (struct armada_thermal_data *)match->data;

        mutex_init(&priv->update_lock);

        /*
         * Legacy DT bindings only described "control1" register (also referred
         * as "control MSB" on old documentation). Then, bindings moved to cover
         * "control0/control LSB" and "control1/control MSB" registers within
         * the same resource, which was then of size 8 instead of 4.
         *
         * The logic of defining sporadic registers is broken. For instance, it
         * blocked the addition of the overheat interrupt feature that needed
         * another resource somewhere else in the same memory area. One solution
         * is to define an overall system controller and put the thermal node
         * into it, which requires the use of regmaps across all the driver.
         */
        if (IS_ERR(syscon_node_to_regmap(pdev->dev.parent->of_node))) {
                /* Ensure device name is correct for the thermal core */
                armada_set_sane_name(pdev, priv);

                ret = armada_thermal_probe_legacy(pdev, priv);
                if (ret)
                        return ret;

                priv->data->init(pdev, priv);

                /* Wait the sensors to be valid */
                armada_wait_sensor_validity(priv);

                tz = thermal_zone_device_register(priv->zone_name, 0, 0, priv,
                                                  &legacy_ops, NULL, 0, 0);
                if (IS_ERR(tz)) {
                        dev_err(&pdev->dev,
                                "Failed to register thermal zone device\n");
                        return PTR_ERR(tz);
                }

                drvdata->type = LEGACY;
                drvdata->data.tz = tz;
                platform_set_drvdata(pdev, drvdata);

                return 0;
        }

        ret = armada_thermal_probe_syscon(pdev, priv);
        if (ret)
                return ret;

        priv->current_channel = -1;
        priv->data->init(pdev, priv);
        drvdata->type = SYSCON;
        drvdata->data.priv = priv;
        platform_set_drvdata(pdev, drvdata);

        irq = platform_get_irq(pdev, 0);
        if (irq == -EPROBE_DEFER)
                return irq;

        /* The overheat interrupt feature is not mandatory */
        if (irq > 0) {
                ret = devm_request_threaded_irq(&pdev->dev, irq,
                                                armada_overheat_isr,
                                                armada_overheat_isr_thread,
                                                0, NULL, priv);
                if (ret) {
                        dev_err(&pdev->dev, "Cannot request threaded IRQ %d\n",
                                irq);
                        return ret;
                }
        }

        /*
         * There is one channel for the IC and one per CPU (if any), each
         * channel has one sensor.
         */
        for (sensor_id = 0; sensor_id <= priv->data->cpu_nr; sensor_id++) {
                sensor = devm_kzalloc(&pdev->dev,
                                      sizeof(struct armada_thermal_sensor),
                                      GFP_KERNEL);
                if (!sensor)
                        return -ENOMEM;

                /* Register the sensor */
                sensor->priv = priv;
                sensor->id = sensor_id;
                tz = devm_thermal_zone_of_sensor_register(&pdev->dev,
                                                          sensor->id, sensor,
                                                          &of_ops);
                if (IS_ERR(tz)) {
                        dev_info(&pdev->dev, "Thermal sensor %d unavailable\n",
                                 sensor_id);
                        devm_kfree(&pdev->dev, sensor);
                        continue;
                }

                /*
                 * The first channel that has a critical trip point registered
                 * in the DT will serve as interrupt source. Others possible
                 * critical trip points will simply be ignored by the driver.
                 */
                if (irq > 0 && !priv->overheat_sensor)
                        armada_configure_overheat_int(priv, tz, sensor->id);
        }

        /* Just complain if no overheat interrupt was set up */
        if (!priv->overheat_sensor)
                dev_warn(&pdev->dev, "Overheat interrupt not available\n");

        return 0;
}

static int armada_thermal_exit(struct platform_device *pdev)
{
        struct armada_drvdata *drvdata = platform_get_drvdata(pdev);

        if (drvdata->type == LEGACY)
                thermal_zone_device_unregister(drvdata->data.tz);

        return 0;
}

static struct platform_driver armada_thermal_driver = {
        .probe = armada_thermal_probe,
        .remove = armada_thermal_exit,
        .driver = {
                .name = "armada_thermal",
                .of_match_table = armada_thermal_id_table,
        },
};

module_platform_driver(armada_thermal_driver);

MODULE_AUTHOR("Ezequiel Garcia <ezequiel.garcia@free-electrons.com>");
MODULE_DESCRIPTION("Marvell EBU Armada SoCs thermal driver");
MODULE_LICENSE("GPL v2");