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From:   Amit Kucheria <amit.kucheria@linaro.org>
Date:   Wed, 20 May 2020 17:12:53 +0530
Message-ID: <CAHLCerNct=4HGXiwxWaupBTm15+Z2yY1RW_BRBgiGGAk62svJw@mail.gmail.com>
Subject: Re: [PATCH v2 1/2] drivers: thermal: tsens: Add zeroc interrupt support
To:     Manaf Meethalavalappu Pallikunhi <manafm@codeaurora.org>
Cc:     Andy Gross <agross@kernel.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Zhang Rui <rui.zhang@intel.com>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Linux PM list <linux-pm@vger.kernel.org>,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>
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Sender: linux-kernel-owner@vger.kernel.org
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On Sun, May 17, 2020 at 4:17 PM Manaf Meethalavalappu Pallikunhi
<manafm@codeaurora.org> wrote:
>
> TSENS IP v2.6+ adds zeroc interrupt support. It triggers set

As I re-read through these patches, shouldn't we just call it the
"cold" interrupt?

> interrupt when aggregated minimum temperature of all TSENS falls
> below zeroc preset threshold and triggers reset interrupt when

Again, cold would just capture the intent much better given that it
doesn't even triggered at zero but at 5 degrees. And this value could
change in firmware.

> aggregated minimum temperature of all TSENS crosses above reset
> threshold. Add support for this interrupt in the driver.
>
> It adds another sensor to the of-thermal along with all individual
> TSENS. It enables to add any mitigation for zeroc interrupt.
>
> Signed-off-by: Manaf Meethalavalappu Pallikunhi <manafm@codeaurora.org>
> ---
>  drivers/thermal/qcom/tsens-v2.c |   5 ++
>  drivers/thermal/qcom/tsens.c    | 107 +++++++++++++++++++++++++++++++-
>  drivers/thermal/qcom/tsens.h    |  10 +++
>  3 files changed, 120 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/thermal/qcom/tsens-v2.c b/drivers/thermal/qcom/tsens-v2.c
> index b293ed32174b..8f30b859ab22 100644
> --- a/drivers/thermal/qcom/tsens-v2.c
> +++ b/drivers/thermal/qcom/tsens-v2.c
> @@ -23,6 +23,7 @@
>  #define TM_Sn_UPPER_LOWER_THRESHOLD_OFF 0x0020
>  #define TM_Sn_CRITICAL_THRESHOLD_OFF   0x0060
>  #define TM_Sn_STATUS_OFF               0x00a0
> +#define TM_ZEROC_INT_STATUS_OFF                0x00e0
>  #define TM_TRDY_OFF                    0x00e4
>  #define TM_WDOG_LOG_OFF                0x013c
>
> @@ -86,6 +87,9 @@ static const struct reg_field tsens_v2_regfields[MAX_REGFIELDS] = {
>         REG_FIELD_FOR_EACH_SENSOR16(CRITICAL_STATUS, TM_Sn_STATUS_OFF, 19,  19),
>         REG_FIELD_FOR_EACH_SENSOR16(MAX_STATUS,      TM_Sn_STATUS_OFF, 20,  20),
>
> +       /* ZEROC INTERRUPT STATUS */
> +       [ZEROC_STATUS] = REG_FIELD(TM_ZEROC_INT_STATUS_OFF, 0, 0),
> +
>         /* TRDY: 1=ready, 0=in progress */
>         [TRDY] = REG_FIELD(TM_TRDY_OFF, 0, 0),
>  };
> @@ -93,6 +97,7 @@ static const struct reg_field tsens_v2_regfields[MAX_REGFIELDS] = {
>  static const struct tsens_ops ops_generic_v2 = {
>         .init           = init_common,
>         .get_temp       = get_temp_tsens_valid,
> +       .get_zeroc_status  = get_tsens_zeroc_status,
>  };
>
>  struct tsens_plat_data data_tsens_v2 = {
> diff --git a/drivers/thermal/qcom/tsens.c b/drivers/thermal/qcom/tsens.c
> index 8d3e94d2a9ed..dd0172f05eb6 100644
> --- a/drivers/thermal/qcom/tsens.c
> +++ b/drivers/thermal/qcom/tsens.c
> @@ -205,7 +205,8 @@ static void tsens_set_interrupt_v1(struct tsens_priv *priv, u32 hw_id,
>                 index = LOW_INT_CLEAR_0 + hw_id;
>                 break;
>         case CRITICAL:
> -               /* No critical interrupts before v2 */
> +       case ZEROC:
> +               /* No critical and zeroc interrupts before v2 */
>                 return;
>         }
>         regmap_field_write(priv->rf[index], enable ? 0 : 1);
> @@ -236,6 +237,9 @@ static void tsens_set_interrupt_v2(struct tsens_priv *priv, u32 hw_id,
>                 index_mask  = CRIT_INT_MASK_0 + hw_id;
>                 index_clear = CRIT_INT_CLEAR_0 + hw_id;
>                 break;
> +       case ZEROC:
> +               /* Nothing to handle for zeroc interrupt */
> +               return;
>         }
>
>         if (enable) {
> @@ -367,6 +371,35 @@ static inline u32 masked_irq(u32 hw_id, u32 mask, enum tsens_ver ver)
>         return 0;
>  }
>
> +/**
> + * tsens_zeroc_irq_thread - Threaded interrupt handler for zeroc interrupt
> + * @irq: irq number
> + * @data: tsens controller private data
> + *
> + * Whenever interrupt triggers notify thermal framework using
> + * thermal_zone_device_update().
> + *
> + * Return: IRQ_HANDLED
> + */
> +
> +irqreturn_t tsens_zeroc_irq_thread(int irq, void *data)
> +{
> +       struct tsens_priv *priv = data;
> +       struct tsens_sensor *s = &priv->sensor[priv->num_sensors];
> +       int temp, ret;
> +
> +       ret = regmap_field_read(priv->rf[ZEROC_STATUS], &temp);
> +       if (ret)
> +               return ret;
> +
> +       dev_dbg(priv->dev, "[%u] %s: zeroc interrupt is %s\n",
> +               s->hw_id, __func__, temp ? "triggered" : "cleared");

Rename temp to cold or something similar since you're not really
returning temperature but a boolean state on whether we're in cold
zone or not.

> +
> +       thermal_zone_device_update(s->tzd, THERMAL_EVENT_UNSPECIFIED);
> +
> +       return IRQ_HANDLED;
> +}
> +
>  /**
>   * tsens_critical_irq_thread() - Threaded handler for critical interrupts
>   * @irq: irq number
> @@ -575,6 +608,20 @@ void tsens_disable_irq(struct tsens_priv *priv)
>         regmap_field_write(priv->rf[INT_EN], 0);
>  }
>
> +int get_tsens_zeroc_status(const struct tsens_sensor *s, int *temp)
> +{
> +       struct tsens_priv *priv = s->priv;
> +       int last_temp = 0, ret;
> +
> +       ret = regmap_field_read(priv->rf[ZEROC_STATUS], &last_temp);
> +       if (ret)
> +               return ret;
> +
> +       *temp = last_temp;

same here. Don't use temp and last_temp. Use cold and prev_cold, for example.

> +
> +       return 0;
> +}
> +
>  int get_temp_tsens_valid(const struct tsens_sensor *s, int *temp)
>  {
>         struct tsens_priv *priv = s->priv;
> @@ -843,6 +890,19 @@ int __init init_common(struct tsens_priv *priv)
>                 regmap_field_write(priv->rf[CC_MON_MASK], 1);
>         }
>
> +       if (tsens_version(priv) > VER_1_X &&  ver_minor > 5) {
> +               /* ZEROC interrupt is present only on v2.6+ */
> +               priv->feat->zeroc_int = 1;
> +               priv->rf[ZEROC_STATUS] = devm_regmap_field_alloc(
> +                                               dev,
> +                                               priv->tm_map,
> +                                               priv->fields[ZEROC_STATUS]);
> +               if (IS_ERR(priv->rf[ZEROC_STATUS])) {
> +                       ret = PTR_ERR(priv->rf[ZEROC_STATUS]);
> +                       goto err_put_device;
> +               }
> +       }
> +
>         spin_lock_init(&priv->ul_lock);
>         tsens_enable_irq(priv);
>         tsens_debug_init(op);
> @@ -852,6 +912,17 @@ int __init init_common(struct tsens_priv *priv)
>         return ret;
>  }
>
> +static int tsens_zeroc_get_temp(void *data, int *temp)

Add kernel doc to this function since it doesn't return temperature,
but a cold state, 0 or 1, on success.

One question: You need to poll this value from userspace, right? For
the userspace interface being discussed on the list currently, you
would still not get automatic notifications for this interrupt unless
you plan to add trip points that will cause thermal core to trigger
userspace events.

> +{
> +       struct tsens_sensor *s = data;
> +       struct tsens_priv *priv = s->priv;
> +
> +       if (priv->ops->get_zeroc_status)
> +               return priv->ops->get_zeroc_status(s, temp);
> +
> +       return -ENOTSUPP;
> +}
> +
>  static int tsens_get_temp(void *data, int *temp)
>  {
>         struct tsens_sensor *s = data;
> @@ -923,6 +994,10 @@ static const struct thermal_zone_of_device_ops tsens_of_ops = {
>         .set_trips = tsens_set_trips,
>  };
>
> +static const struct thermal_zone_of_device_ops tsens_zeroc_of_ops = {
> +       .get_temp = tsens_zeroc_get_temp,
> +};
> +
>  static int tsens_register_irq(struct tsens_priv *priv, char *irqname,
>                               irq_handler_t thread_fn)
>  {
> @@ -980,6 +1055,21 @@ static int tsens_register(struct tsens_priv *priv)
>                 ret = tsens_register_irq(priv, "critical",
>                                          tsens_critical_irq_thread);
>
> +       if (priv->feat->zeroc_int && priv->zeroc_en) {
> +               priv->sensor[priv->num_sensors].priv = priv;
> +               tzd = devm_thermal_zone_of_sensor_register(priv->dev,
> +                                       priv->sensor[priv->num_sensors].hw_id,
> +                                       &priv->sensor[priv->num_sensors],
> +                                       &tsens_zeroc_of_ops);
> +               if (IS_ERR(tzd)) {
> +                       ret = 0;
> +                       return ret;
> +               }
> +
> +               priv->sensor[priv->num_sensors].tzd = tzd;
> +               ret = tsens_register_irq(priv, "zeroc", tsens_zeroc_irq_thread);
> +       }
> +
>         return ret;
>  }
>
> @@ -992,6 +1082,7 @@ static int tsens_probe(struct platform_device *pdev)
>         const struct tsens_plat_data *data;
>         const struct of_device_id *id;
>         u32 num_sensors;
> +       bool zeroc_en = false;
>
>         if (pdev->dev.of_node)
>                 dev = &pdev->dev;
> @@ -1016,6 +1107,12 @@ static int tsens_probe(struct platform_device *pdev)
>                 return -EINVAL;
>         }
>
> +       /* Check whether zeroc interrupt is enabled or not */
> +       if (platform_get_irq_byname(pdev, "zeroc") > 0) {
> +               zeroc_en = true;

This check can be done in tsens_register_irq() from tsens_register. It
is OK to have an extra struct tsens_sensor allocated even on platforms
that don't have it.

> +               num_sensors++;
> +       }
> +
>         priv = devm_kzalloc(dev,
>                              struct_size(priv, sensor, num_sensors),

make this num_sensors + 1 to account for the zeroc virtual sensor. See below.

>                              GFP_KERNEL);
> @@ -1023,7 +1120,7 @@ static int tsens_probe(struct platform_device *pdev)
>                 return -ENOMEM;
>
>         priv->dev = dev;
> -       priv->num_sensors = num_sensors;
> +       priv->num_sensors = zeroc_en ? num_sensors - 1 : num_sensors;
>         priv->ops = data->ops;
>         for (i = 0;  i < priv->num_sensors; i++) {
>                 if (data->hw_ids)
> @@ -1031,6 +1128,12 @@ static int tsens_probe(struct platform_device *pdev)
>                 else
>                         priv->sensor[i].hw_id = i;
>         }
> +
> +       if (zeroc_en) {
> +               priv->zeroc_en = zeroc_en;
> +               priv->sensor[num_sensors].hw_id = data->feat->max_sensors;

This is going to break as soon as we have a platform that actually
uses all 16 sensors. i.e. you won't have a spare one to use if
num_sensors >= max_sensors.

I think you should introduce a new member 'struct tsens_sensor
zeroc_sensor' in tsens_priv and avoid playing with num_sensors
completely.

> +       }
> +
>         priv->feat = data->feat;
>         priv->fields = data->fields;
>
> diff --git a/drivers/thermal/qcom/tsens.h b/drivers/thermal/qcom/tsens.h
> index 59d01162c66a..34d24332b320 100644
> --- a/drivers/thermal/qcom/tsens.h
> +++ b/drivers/thermal/qcom/tsens.h
> @@ -34,6 +34,7 @@ enum tsens_irq_type {
>         LOWER,
>         UPPER,
>         CRITICAL,
> +       ZEROC,
>  };
>
>  /**
> @@ -64,6 +65,7 @@ struct tsens_sensor {
>   * @suspend: Function to suspend the tsens device
>   * @resume: Function to resume the tsens device
>   * @get_trend: Function to get the thermal/temp trend
> + * @get_zeroc_status: Function to get the zeroc interrupt status
>   */
>  struct tsens_ops {
>         /* mandatory callbacks */
> @@ -76,6 +78,7 @@ struct tsens_ops {
>         int (*suspend)(struct tsens_priv *priv);
>         int (*resume)(struct tsens_priv *priv);
>         int (*get_trend)(struct tsens_sensor *s, enum thermal_trend *trend);
> +       int (*get_zeroc_status)(const struct tsens_sensor *s, int *temp);

this fn doesn't return temp, but a boolean status of whether we're in
cold zone or not. Replace 'int *temp' with 'boolean *zeroc'?

>  };
>
>  #define REG_FIELD_FOR_EACH_SENSOR11(_name, _offset, _startbit, _stopbit) \
> @@ -485,6 +488,8 @@ enum regfield_ids {
>         MAX_STATUS_14,
>         MAX_STATUS_15,
>
> +       ZEROC_STATUS,   /* ZEROC INTERRUPT status */

Indent comment at same level as others above it


> +
>         /* Keep last */
>         MAX_REGFIELDS
>  };
> @@ -497,6 +502,7 @@ enum regfield_ids {
>   * @srot_split: does the IP neatly splits the register space into SROT and TM,
>   *              with SROT only being available to secure boot firmware?
>   * @has_watchdog: does this IP support watchdog functionality?
> + * @zeroc_int: does this IP support ZEROC interrupt ?
>   * @max_sensors: maximum sensors supported by this version of the IP
>   */
>  struct tsens_features {
> @@ -505,6 +511,7 @@ struct tsens_features {
>         unsigned int adc:1;
>         unsigned int srot_split:1;
>         unsigned int has_watchdog:1;
> +       unsigned int zeroc_int:1;
>         unsigned int max_sensors;
>  };
>
> @@ -549,6 +556,7 @@ struct tsens_context {
>   * @feat: features of the IP
>   * @fields: bitfield locations
>   * @ops: pointer to list of callbacks supported by this device
> + * @zeroc_en: variable to check zeroc interrupt sensor is enabled or not
>   * @debug_root: pointer to debugfs dentry for all tsens
>   * @debug: pointer to debugfs dentry for tsens controller
>   * @sensor: list of sensors attached to this device
> @@ -568,6 +576,7 @@ struct tsens_priv {
>         struct tsens_features           *feat;
>         const struct reg_field          *fields;
>         const struct tsens_ops          *ops;
> +       bool                            zeroc_en;
>
>         struct dentry                   *debug_root;
>         struct dentry                   *debug;
> @@ -580,6 +589,7 @@ void compute_intercept_slope(struct tsens_priv *priv, u32 *pt1, u32 *pt2, u32 mo
>  int init_common(struct tsens_priv *priv);
>  int get_temp_tsens_valid(const struct tsens_sensor *s, int *temp);
>  int get_temp_common(const struct tsens_sensor *s, int *temp);
> +int get_tsens_zeroc_status(const struct tsens_sensor *s, int *temp);
>
>  /* TSENS target */
>  extern struct tsens_plat_data data_8960;
> --
> 2.26.2