[PATCH v2] drm/i915/bxt: use NULL for GPIO connection ID

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: "David Airlie" <airlied@linux.ie>,
	"Daniel Vetter" <daniel.vetter@intel.com>,
	intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
	"Ville Syrjälä" <ville.syrjala@linux.intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Subject: [PATCH v2] drm/i915/bxt: use NULL for GPIO connection ID
Date: Thu, 17 Aug 2017 13:55:41 +0300	[thread overview]
Message-ID: <20170817105541.63914-1-andriy.shevchenko@linux.intel.com> (raw)

The commit 213e08ad60ba
	("drm/i915/bxt: add bxt dsi gpio element support")
enables GPIO support for Broxton based platforms.

While using that API we might get into troubles in the future, because
we can't rely on label name in the driver since vendor firmware might
provide any GPIO pin there, e.g. "reset", and even mark it in _DSD (in
which case the request will fail).

To avoid inconsistency and potential issues we have two options:
a) generate GPIO ACPI mapping table and supply it via
   acpi_dev_add_driver_gpios(), or
b) just pass NULL as connection ID.

The b) approach is much simpler and would work since the driver relies
on GPIO indices only. Moreover, the _CRS fallback mechanism, when
requesting GPIO, has been made stricter, and supplying non-NULL
connection ID when neither _DSD, nor GPIO ACPI mapping is present, is
making request fail.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101921
Fixes: f10e4bf6632b ("gpio: acpi: Even more tighten up ACPI GPIO lookups")
Cc: Mika Kahola <mika.kahola@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
v2:
 - adjust commit message for proper time tenses
 - add Fixes: and Bugzilla: tags
 drivers/gpu/drm/i915/intel_dsi_vbt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_dsi_vbt.c b/drivers/gpu/drm/i915/intel_dsi_vbt.c
index 7158c7ce9c09..91c07b0c8db9 100644
--- a/drivers/gpu/drm/i915/intel_dsi_vbt.c
+++ b/drivers/gpu/drm/i915/intel_dsi_vbt.c
@@ -306,7 +306,7 @@ static void bxt_exec_gpio(struct drm_i915_private *dev_priv,
 
 	if (!gpio_desc) {
 		gpio_desc = devm_gpiod_get_index(dev_priv->drm.dev,
-						 "panel", gpio_index,
+						 NULL, gpio_index,
 						 value ? GPIOD_OUT_LOW :
 						 GPIOD_OUT_HIGH);
 
-- 
2.14.1

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