From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-172.mta0.migadu.com (out-172.mta0.migadu.com [91.218.175.172]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0124F39AC9 for ; Fri, 26 Apr 2024 22:57:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714172279; cv=none; b=XChefkU0twjfK5MSj+26dLhNdKuFGo33doO5J3D+VlrW7bhHGgGDv08/HVQ5SfGPyFMWm2W9m8aaLLKr9A+DOzVtbnVrclNBNW5LNlI+Id7mouh/wx1Dgqj7dGazTGBHGGVEtRZJ6HNsLe+eqW3D4ya/37QlMZQUMxrwy3t+7oU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714172279; c=relaxed/simple; bh=jcYLChDAgnIUe4+iN8D3/9NndAF22/1Z60vNxCuSZTU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=erWf2uX4+dQw9O0ZBNyJWZAN4klLAzQMfZbLdebeyuAkSWKGU3056Oo0OXe2M1rhS+SzLhNnny5ui/aKsgOpHSpex3eYSlbWOATvmdFAA1IxiJgPlNZcE7zRDAN8u8gEhd/64pqiVtFMz8X17+iqTnNOY9ATu+8ttIqAd1SWmQA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=kl.wtf; spf=pass smtp.mailfrom=kl.wtf; dkim=pass (2048-bit key) header.d=kl.wtf header.i=@kl.wtf header.b=PyMDwgGJ; arc=none smtp.client-ip=91.218.175.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=kl.wtf Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=kl.wtf Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kl.wtf header.i=@kl.wtf header.b="PyMDwgGJ" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kl.wtf; s=key1; t=1714172276; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=4KU3jl0WoeassL0fsNyvxyf1+jr7Lzh8USMHCS2SFuk=; b=PyMDwgGJogmpa6f+Up4ClCDkkfbFDqgE0FxFFdokAgFB6B05qFPdsdg1iAe+0lyH8biu2k VuW9RVfhDJc1AMP2A7zp/0R5DLW5yDpYh5s2ootpgOVliKPMlHKVjcLzOIXSlhWGOpn2PS czThUf0Rb/1TRQHS2nhkcQmgcvUAzb7Pcq5XrQ2YjAfZdxhYE8pfR6JkTHOOcWggLboTwS 8VApmOQEq0TVmWlJS1mmV1HolJ54ZzrmhB/FTSvrzCD6MR6Awo3W7bCFZZSNb5UA74pMgZ eDQ/YMbwkzbmggPyzAo+jL3XiNFdCxH9dBBb78sFnUWvVseSmL+yA2tRulYl5A== From: Kenny Levinsen To: Jiri Kosina , Dmitry Torokhov , Benjamin Tissoires , Douglas Anderson , Hans de Goede , Maxime Ripard , Kai-Heng Feng , Johan Hovold , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, Radoslaw Biernacki , Lukasz Majczak Cc: Kenny Levinsen Subject: [PATCH v3 2/3] HID: i2c-hid: Retry HID descriptor read to wake up STM devices Date: Sat, 27 Apr 2024 00:47:08 +0200 Message-ID: <20240426225739.2166-3-kl@kl.wtf> In-Reply-To: <20240426225739.2166-1-kl@kl.wtf> References: <20240426225739.2166-1-kl@kl.wtf> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT Some STM microcontrollers need 400µs after rising clock edge in order to come out of their deep sleep state. This in turn means that the first command sent to them will fail on a bus error. Retry once on bus error to see if the device came alive, otherwise treat the error as if no device was present like before. Link: https://lore.kernel.org/all/20240405102436.3479210-1-lma@chromium.org/#t Co-developed-by: Radoslaw Biernacki Co-developed-by: Lukasz Majczak Tested-by: Lukasz Majczak Reviewed-by: Lukasz Majczak Signed-off-by: Kenny Levinsen --- drivers/hid/i2c-hid/i2c-hid-core.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c index 6ffa43d245b4..6ac1b11fb675 100644 --- a/drivers/hid/i2c-hid/i2c-hid-core.c +++ b/drivers/hid/i2c-hid/i2c-hid-core.c @@ -991,8 +991,17 @@ static int __i2c_hid_core_probe(struct i2c_hid *ihid) struct hid_device *hid = ihid->hid; int ret; + /* + * Some STM-based devices need 400µs after a rising clock edge to wake + * from deep sleep, which in turn means that our first command will + * fail on a bus error. Retry the command in this case. + */ ret = i2c_hid_fetch_hid_descriptor(ihid); - if (ret < 0) { + if (ret == -ENXIO) { + usleep_range(400, 500); + ret = i2c_hid_fetch_hid_descriptor(ihid); + } + if (ret) { i2c_hid_dbg(ihid, "failed to fetch HID descriptor: %d\n", ret); return ret; } -- 2.44.0