linux-kernel - Re: [PATCH 04/15] drivers: thermal: tsens: Add debugfs support

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Date:   Mon, 19 Aug 2019 13:28:23 +0530
From:   Amit Kucheria <amit.kucheria@...aro.org>
To:     Stephen Boyd <swboyd@...omium.org>
Cc:     Andy Gross <agross@...nel.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Mark Rutland <mark.rutland@....com>,
        Rob Herring <robh+dt@...nel.org>,
        Zhang Rui <rui.zhang@...el.com>,
        Andy Gross <andy.gross@...aro.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Eduardo Valentin <edubezval@...il.com>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Linux PM list <linux-pm@...r.kernel.org>
Subject: Re: [PATCH 04/15] drivers: thermal: tsens: Add debugfs support

On Sat, Aug 17, 2019 at 9:37 AM Stephen Boyd <swboyd@...omium.org> wrote:
>
> Quoting Amit Kucheria (2019-07-25 15:18:39)
> > Dump some basic version info and sensor details into debugfs
> >
>
> Maybe you can put some sample output in the commit text.

Will do.

> > Signed-off-by: Amit Kucheria <amit.kucheria@...aro.org>
> > ---
> >  drivers/thermal/qcom/tsens-common.c | 85 +++++++++++++++++++++++++++++
> >  drivers/thermal/qcom/tsens.c        |  2 +
> >  drivers/thermal/qcom/tsens.h        |  6 ++
> >  3 files changed, 93 insertions(+)
> >
> > diff --git a/drivers/thermal/qcom/tsens-common.c b/drivers/thermal/qcom/tsens-common.c
> > index 7437bfe196e5..7ab2e740a1da 100644
> > --- a/drivers/thermal/qcom/tsens-common.c
> > +++ b/drivers/thermal/qcom/tsens-common.c
> > @@ -3,6 +3,7 @@
> >   * Copyright (c) 2015, The Linux Foundation. All rights reserved.
> >   */
> >
> > +#include <linux/debugfs.h>
> >  #include <linux/err.h>
> >  #include <linux/io.h>
> >  #include <linux/nvmem-consumer.h>
> > @@ -139,6 +140,79 @@ int get_temp_common(struct tsens_sensor *s, int *temp)
> >         return 0;
> >  }
> >
> > +#ifdef CONFIG_DEBUG_FS
> > +static int dbg_sensors_show(struct seq_file *s, void *data)
> > +{
> > +       struct platform_device *pdev = s->private;
> > +       struct tsens_priv *priv = platform_get_drvdata(pdev);
> > +       int i;
> > +
> > +       seq_printf(s, "max: %2d\nnum: %2d\n\n",
> > +                  priv->feat->max_sensors, priv->num_sensors);
> > +
> > +       seq_puts(s, "      id   slope  offset\n------------------------\n");
> > +       for (i = 0;  i < priv->num_sensors; i++) {
> > +               seq_printf(s, "%8d%8d%8d\n", priv->sensor[i].hw_id,
>
> Does this not have spaces between the digits on purpose?

Nice catch. The 8-char width above hid the problem. Will add.

> > +                          priv->sensor[i].slope, priv->sensor[i].offset);
> > +       }
> > +
> > +       return 0;
> > +}
> > +
> > +static int dbg_version_show(struct seq_file *s, void *data)
> > +{
> > +       struct platform_device *pdev = s->private;
> > +       struct tsens_priv *priv = platform_get_drvdata(pdev);
> > +       u32 maj_ver, min_ver, step_ver;
> > +       int ret;
> > +
> > +       if (tsens_ver(priv) > VER_0_1) {
> > +               ret = regmap_field_read(priv->rf[VER_MAJOR], &maj_ver);
> > +               if (ret)
> > +                       return ret;
> > +               ret = regmap_field_read(priv->rf[VER_MINOR], &min_ver);
> > +               if (ret)
> > +                       return ret;
> > +               ret = regmap_field_read(priv->rf[VER_STEP], &step_ver);
> > +               if (ret)
> > +                       return ret;
> > +               seq_printf(s, "%d.%d.%d\n", maj_ver, min_ver, step_ver);
> > +       } else {
> > +               seq_puts(s, "0.1.0\n");
> > +       }
> > +
> > +       return 0;
> > +}
> > +
> > +DEFINE_SHOW_ATTRIBUTE(dbg_version);
> > +DEFINE_SHOW_ATTRIBUTE(dbg_sensors);
> > +
> > +static void tsens_debug_init(struct platform_device *pdev)
> > +{
> > +       struct tsens_priv *priv = platform_get_drvdata(pdev);
> > +       struct dentry *root, *file;
> > +
> > +       root = debugfs_lookup("tsens", NULL);
>
> Does this get created many times? Why doesn't tsens have a pointer to
> the root saved away somewhere globally?
>

I guess we could call the statement below to create the root dir and
save away the pointer. I was trying to avoid #ifdef CONFIG_DEBUG_FS in
init_common() and instead have all of it in a single function that
gets called once per instance of the tsens controller.

> > +       if (!root)
> > +               priv->debug_root = debugfs_create_dir("tsens", NULL);
> > +       else
> > +               priv->debug_root = root;
> > +
> > +       file = debugfs_lookup("version", priv->debug_root);
> > +       if (!file)
> > +               debugfs_create_file("version", 0444, priv->debug_root,
> > +                                   pdev, &dbg_version_fops);
> > +
> > +       /* A directory for each instance of the TSENS IP */
> > +       priv->debug = debugfs_create_dir(dev_name(&pdev->dev), priv->debug_root);
> > +       debugfs_create_file("sensors", 0444, priv->debug, pdev, &dbg_sensors_fops);
> > +
> > +       return;
> > +}