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From: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
To: gregkh@linuxfoundation.org
Cc: linuxarm@huawei.com, mauro.chehab@huawei.com,
	Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
	"Pavel Machek" <pavel@ucw.cz>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org,
	linux-leds@vger.kernel.org, linux-staging@lists.linux.dev
Subject: [PATCH 12/17] staging: nuc-wmi: better detect NUC6/NUC7 devices
Date: Sun, 16 May 2021 12:53:40 +0200	[thread overview]
Message-ID: <bca097a3ce2ab35fcd38eb3abdc8090c2c531048.1621161037.git.mchehab+huawei@kernel.org> (raw)
In-Reply-To: <cover.1621161037.git.mchehab+huawei@kernel.org>

There's no documented way to detect if the WMI API is valid,
as, when it is not valid, it just returns 4 zeros.

However, as having a value of 0x00 for the blinking state
is not valid, we can check for it at detection time, in
order to disable LEDs control on devices that won't
support it.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
---
 drivers/staging/nuc-led/nuc-wmi.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/staging/nuc-led/nuc-wmi.c b/drivers/staging/nuc-led/nuc-wmi.c
index 5bc4dcec3ea8..1a6e2b17c888 100644
--- a/drivers/staging/nuc-led/nuc-wmi.c
+++ b/drivers/staging/nuc-led/nuc-wmi.c
@@ -312,6 +312,13 @@ static int nuc_wmi_query_leds_nuc6(struct device *dev)
 		return ret;
 	}
 
+	/*
+	 * Detect if NUC6/NUC7 supports the WMI API by checking the
+	 * returned blink state, as valid values range from 0x01 to 0x07.
+	 */
+	if (output[1] == 0x00)
+		return -ENODEV;
+
 	led = &priv->led[priv->num_leds];
 	led->id = POWER_LED;
 	led->color_type = LED_BLUE_AMBER;
@@ -325,6 +332,14 @@ static int nuc_wmi_query_leds_nuc6(struct device *dev)
 		dev_warn(dev, "Get S0 Ring: error %d\n", ret);
 		return ret;
 	}
+
+	/*
+	 * Detect if NUC6/NUC7 supports the WMI API by checking the
+	 * returned blink state, as valid values range from 0x01 to 0x07.
+	 */
+	if (output[1] == 0x00)
+		return -ENODEV;
+
 	led = &priv->led[priv->num_leds];
 	led->id = RING_LED;
 	led->color_type = LED_BLUE_AMBER;
-- 
2.31.1


  parent reply	other threads:[~2021-05-16 10:54 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-16 10:53 [PATCH 00/17] Add an experimental driver for Intel NUC leds Mauro Carvalho Chehab
2021-05-16 10:53 ` [PATCH 01/17] staging: add support for NUC WMI LEDs Mauro Carvalho Chehab
2021-05-16 16:12   ` Randy Dunlap
2021-05-17  8:20   ` Greg KH
2021-05-16 10:53 ` [PATCH 02/17] staging: nuc-wmi: detect WMI API detection Mauro Carvalho Chehab
2021-05-17  9:35   ` Dan Carpenter
2021-05-16 10:53 ` [PATCH 03/17] staging: nuc-wmi: add support for changing S0 brightness Mauro Carvalho Chehab
2021-05-16 10:53 ` [PATCH 04/17] staging: nuc-wmi: add all types of brightness Mauro Carvalho Chehab
2021-05-16 10:53 ` [PATCH 05/17] staging: nuc-wmi: allow changing the LED colors Mauro Carvalho Chehab
2021-05-16 10:53 ` [PATCH 06/17] staging: nuc-wmi: add support for WMI API version 1.0 Mauro Carvalho Chehab
2021-05-16 10:53 ` [PATCH 07/17] staging: nuc-wmi: add basic support for NUC6 WMI Mauro Carvalho Chehab
2021-05-17  9:44   ` Dan Carpenter
2021-05-16 10:53 ` [PATCH 08/17] staging: muc-wmi: add brightness and color for NUC6 API Mauro Carvalho Chehab
2021-05-16 10:53 ` [PATCH 09/17] staging: nuc-wmi: Add support to blink behavior for NUC8/10 Mauro Carvalho Chehab
2021-05-16 10:53 ` [PATCH 10/17] staging: nuc-wmi: get rid of an unused variable Mauro Carvalho Chehab
2021-05-16 10:53 ` [PATCH 11/17] staging: nuc-wmi: implement blink control for NUC6 Mauro Carvalho Chehab
2021-05-16 10:53 ` Mauro Carvalho Chehab [this message]
2021-05-16 10:53 ` [PATCH 13/17] staging: nuc-led: add support for HDD activity default Mauro Carvalho Chehab
2021-05-16 10:53 ` [PATCH 14/17] staging: nuc-wmi: fix software blink behavior logic Mauro Carvalho Chehab
2021-05-16 10:53 ` [PATCH 15/17] staging: nuc-wmi: add support for changing the ethernet type indicator Mauro Carvalho Chehab
2021-05-16 10:53 ` [PATCH 16/17] staging: nuc-wmi: add support for changing the power limit scheme Mauro Carvalho Chehab
2021-05-16 10:53 ` [PATCH 17/17] staging: nuc-led: update the TODOs Mauro Carvalho Chehab
2021-05-16 18:21   ` Pavel Machek
2021-05-17  6:30     ` Mauro Carvalho Chehab
2021-05-17  8:05       ` Pavel Machek
2021-05-17  8:57         ` Mauro Carvalho Chehab
2021-05-17  9:12           ` Mauro Carvalho Chehab
2021-05-17 12:19         ` Mauro Carvalho Chehab
2021-05-17  8:18 ` [PATCH 00/17] Add an experimental driver for Intel NUC leds Greg KH
2021-05-17  9:02   ` Mauro Carvalho Chehab
2021-05-17  9:08     ` Greg KH

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