linux-kernel - Re: [PATCH 3/4] thermal: ti-soc-thermal: Simplify polling with iopoll

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Date:   Sat, 6 Feb 2021 07:02:01 -0600
From:   Adam Ford <aford173@...il.com>
To:     Tony Lindgren <tony@...mide.com>
Cc:     Amit Kucheria <amitk@...nel.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Zhang Rui <rui.zhang@...el.com>,
        Eduardo Valentin <edubezval@...il.com>,
        Keerthy <j-keerthy@...com>, linux-pm@...r.kernel.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux-OMAP <linux-omap@...r.kernel.org>,
        Carl Philipp Klemm <philipp@...s.xyz>,
        "H . Nikolaus Schaller" <hns@...delico.com>,
        Merlijn Wajer <merlijn@...zup.org>,
        Pavel Machek <pavel@....cz>,
        Peter Ujfalusi <peter.ujfalusi@...il.com>,
        Sebastian Reichel <sre@...nel.org>
Subject: Re: [PATCH 3/4] thermal: ti-soc-thermal: Simplify polling with iopoll

On Fri, Feb 5, 2021 at 7:45 AM Tony Lindgren <tony@...mide.com> wrote:
>
> We can use iopoll for checking the EOCZ (end of conversion) bit. And with
> this we now also want to handle the timeout errors properly.
>
> For omap3, we need about 1.2ms for the single mode sampling to wait for
> EOCZ down, so let's use 1.5ms timeout there. Waiting for sampling to start
> is faster and we can use 1ms timeout.
>
> Cc: Adam Ford <aford173@...il.com>
> Cc: Carl Philipp Klemm <philipp@...s.xyz>
> Cc: Eduardo Valentin <edubezval@...il.com>
> Cc: H. Nikolaus Schaller <hns@...delico.com>
> Cc: Merlijn Wajer <merlijn@...zup.org>
> Cc: Pavel Machek <pavel@....cz>
> Cc: Peter Ujfalusi <peter.ujfalusi@...il.com>
> Cc: Sebastian Reichel <sre@...nel.org>
> Signed-off-by: Tony Lindgren <tony@...mide.com>

For the series,

Tested-by: Adam Ford <aford173@...il.com> #logicpd-torpedo-37xx-devkit

> ---
>  drivers/thermal/ti-soc-thermal/ti-bandgap.c | 30 ++++++++++-----------
>  1 file changed, 14 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/thermal/ti-soc-thermal/ti-bandgap.c b/drivers/thermal/ti-soc-thermal/ti-bandgap.c
> --- a/drivers/thermal/ti-soc-thermal/ti-bandgap.c
> +++ b/drivers/thermal/ti-soc-thermal/ti-bandgap.c
> @@ -15,7 +15,6 @@
>  #include <linux/kernel.h>
>  #include <linux/interrupt.h>
>  #include <linux/clk.h>
> -#include <linux/delay.h>
>  #include <linux/gpio/consumer.h>
>  #include <linux/platform_device.h>
>  #include <linux/err.h>
> @@ -27,6 +26,7 @@
>  #include <linux/of_platform.h>
>  #include <linux/of_irq.h>
>  #include <linux/io.h>
> +#include <linux/iopoll.h>
>  #include <linux/cpu_pm.h>
>  #include <linux/device.h>
>  #include <linux/pm_runtime.h>
> @@ -604,7 +604,9 @@ static int
>  ti_bandgap_force_single_read(struct ti_bandgap *bgp, int id)
>  {
>         struct temp_sensor_registers *tsr = bgp->conf->sensors[id].registers;
> -       u32 counter;
> +       void __iomem *temp_sensor_ctrl = bgp->base + tsr->temp_sensor_ctrl;
> +       int error;
> +       u32 val;
>
>         /* Select continuous or single conversion mode */
>         if (TI_BANDGAP_HAS(bgp, MODE_CONFIG)) {
> @@ -619,26 +621,22 @@ ti_bandgap_force_single_read(struct ti_bandgap *bgp, int id)
>                 RMW_BITS(bgp, id, temp_sensor_ctrl, bgap_soc_mask, 1);
>
>                 /* Wait for EOCZ going up */
> -               counter = 1000;
> -               while (--counter) {
> -                       if (ti_bandgap_readl(bgp, tsr->temp_sensor_ctrl) &
> -                           tsr->bgap_eocz_mask)
> -                               break;
> -                       udelay(1);
> -               }
> +               error = readl_poll_timeout_atomic(temp_sensor_ctrl, val,
> +                                                 val & tsr->bgap_eocz_mask,
> +                                                 1, 1000);
> +               if (error)
> +                       dev_warn(bgp->dev, "eocz timed out waiting high\n");
>
>                 /* Clear Start of Conversion if available */
>                 RMW_BITS(bgp, id, temp_sensor_ctrl, bgap_soc_mask, 0);
>         }
>
>         /* Wait for EOCZ going down, always needed even if no bgap_soc_mask */
> -       counter = 1000;
> -       while (--counter) {
> -               if (!(ti_bandgap_readl(bgp, tsr->temp_sensor_ctrl) &
> -                     tsr->bgap_eocz_mask))
> -                       break;
> -               udelay(1);
> -       }
> +       error = readl_poll_timeout_atomic(temp_sensor_ctrl, val,
> +                                         !(val & tsr->bgap_eocz_mask),
> +                                         1, 1500);
> +       if (error)
> +               dev_warn(bgp->dev, "eocz timed out waiting low\n");
>
>         return 0;
>  }
> --
> 2.30.0