From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Hans de Goede <hdegoede@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
Jani Nikula <jani.nikula@linux.intel.com>,
Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
Rodrigo Vivi <rodrigo.vivi@intel.com>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>,
Len Brown <lenb@kernel.org>, Lee Jones <lee.jones@linaro.org>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
linux-acpi@vger.kernel.org,
intel-gfx <intel-gfx@lists.freedesktop.org>,
dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] drm/i915: DSI: select correct PWM controller to use based on the VBT
Date: Tue, 19 Nov 2019 17:47:17 +0200 [thread overview]
Message-ID: <20191119154717.GA1208@intel.com> (raw)
In-Reply-To: <20191119151818.67531-4-hdegoede@redhat.com>
On Tue, Nov 19, 2019 at 04:18:18PM +0100, Hans de Goede wrote:
> At least Bay Trail (BYT) and Cherry Trail (CHT) devices can use 1 of 2
> different PWM controllers for controlling the LCD's backlight brightness.
> Either the one integrated into the PMIC or the one integrated into the
> SoC (the 1st LPSS PWM controller).
>
> So far in the LPSS code on BYT we have skipped registering the LPSS PWM
> controller "pwm_backlight" lookup entry when a Crystal Cove PMIC is
> present, assuming that in this case the PMIC PWM controller will be used.
>
> On CHT we have been relying on only 1 of the 2 PWM controllers being
> enabled in the DSDT at the same time; and always registered the lookup.
>
> So far this has been working, but the correct way to determine which PWM
> controller needs to be used is by checking a bit in the VBT table and
> recently I've learned about 2 different BYT devices:
> Point of View MOBII TAB-P800W
> Acer Switch 10 SW5-012
>
> Which use a Crystal Cove PMIC, yet the LCD is connected to the SoC/LPSS
> PWM controller (and the VBT correctly indicates this), so here our old
> heuristics fail.
>
> This commit fixes using the wrong PWM controller on these devices by
> calling pwm_get() for the right PWM controller based on the
> VBT dsi.config.pwm_blc bit.
>
> Note this is part of a series which contains 2 other patches which renames
> the PWM lookup for the 1st SoC/LPSS PWM from "pwm_backlight" to
> "pwm_pmic_backlight" and the PWM lookup for the Crystal Cove PMIC PWM
> from "pwm_backlight" to "pwm_pmic_backlight".
>
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
> drivers/gpu/drm/i915/display/intel_panel.c | 16 +++++++++++++---
> 1 file changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_panel.c b/drivers/gpu/drm/i915/display/intel_panel.c
> index bc14e9c0285a..ddcf311d1114 100644
> --- a/drivers/gpu/drm/i915/display/intel_panel.c
> +++ b/drivers/gpu/drm/i915/display/intel_panel.c
> @@ -1840,13 +1840,22 @@ static int pwm_setup_backlight(struct intel_connector *connector,
> enum pipe pipe)
> {
> struct drm_device *dev = connector->base.dev;
> + struct drm_i915_private *dev_priv = to_i915(dev);
> struct intel_panel *panel = &connector->panel;
> + const char *desc;
> int retval;
>
> - /* Get the PWM chip for backlight control */
> - panel->backlight.pwm = pwm_get(dev->dev, "pwm_backlight");
> + /* Get the right PWM chip for DSI backlight according to VBT */
> + if (dev_priv->vbt.dsi.config->pwm_blc == PPS_BLC_PMIC) {
> + panel->backlight.pwm = pwm_get(dev->dev, "pwm_pmic_backlight");
> + desc = "PMIC";
> + } else {
> + panel->backlight.pwm = pwm_get(dev->dev, "pwm_soc_backlight");
> + desc = "SoC";
> + }
Might we want the same thing for the panel enable gpio?
> +
> if (IS_ERR(panel->backlight.pwm)) {
> - DRM_ERROR("Failed to own the pwm chip\n");
> + DRM_ERROR("Failed to get the %s PWM chip\n", desc);
> panel->backlight.pwm = NULL;
> return -ENODEV;
> }
> @@ -1873,6 +1882,7 @@ static int pwm_setup_backlight(struct intel_connector *connector,
> CRC_PMIC_PWM_PERIOD_NS);
> panel->backlight.enabled = panel->backlight.level != 0;
>
> + DRM_INFO("Using %s PWM for LCD backlight control\n", desc);
> return 0;
> }
>
> --
> 2.23.0
--
Ville Syrjälä
Intel
next prev parent reply other threads:[~2019-11-19 15:47 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-19 15:18 [PATCH 0/3] drm/i915 / LPSS / mfd: Select correct PWM controller to use based on VBT Hans de Goede
2019-11-19 15:18 ` [PATCH 1/3] ACPI / LPSS: Rename pwm_backlight pwm-lookup to pwm_soc_backlight Hans de Goede
2019-11-29 11:59 ` Rafael J. Wysocki
2019-11-19 15:18 ` [PATCH 2/3] mfd: intel_soc_pmic: Rename pwm_backlight pwm-lookup to pwm_pmic_backlight Hans de Goede
2019-12-10 8:51 ` Lee Jones
2019-12-11 17:29 ` Hans de Goede
2019-12-12 8:45 ` Lee Jones
2019-12-12 14:34 ` Hans de Goede
2019-12-12 15:52 ` Lee Jones
2019-12-12 19:02 ` Hans de Goede
2019-12-13 8:27 ` Lee Jones
2019-12-13 12:40 ` Hans de Goede
2019-12-16 9:30 ` Lee Jones
2019-12-16 10:04 ` Hans de Goede
2019-12-17 8:11 ` Lee Jones
2019-12-17 13:25 ` Jani Nikula
2019-12-17 13:51 ` Lee Jones
2019-12-18 7:14 ` Jani Nikula
2019-12-18 9:38 ` Lee Jones
2019-11-19 15:18 ` [PATCH 3/3] drm/i915: DSI: select correct PWM controller to use based on the VBT Hans de Goede
2019-11-19 15:47 ` Ville Syrjälä [this message]
2019-11-19 16:48 ` Hans de Goede
2019-11-19 15:43 ` [PATCH 0/3] drm/i915 / LPSS / mfd: Select correct PWM controller to use based on VBT Jani Nikula
2019-11-19 16:32 ` Andy Shevchenko
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