From patchwork Mon Apr 27 15:50:32 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans de Goede X-Patchwork-Id: 11512865 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6B3611667 for ; Mon, 27 Apr 2020 15:50:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 49BB92064C for ; Mon, 27 Apr 2020 15:50:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Zkfit/U0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728200AbgD0Pux (ORCPT ); Mon, 27 Apr 2020 11:50:53 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:45585 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728179AbgD0Puw (ORCPT ); Mon, 27 Apr 2020 11:50:52 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1588002651; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=rcDDVpZf3CSrzjYIDbLlguCG/9YpynAwlXI+zNH+P3c=; b=Zkfit/U0RWQHw3v2gOYijc/LDLC4Jn7zQdwWS1gLF6KWfOoIzrKX0XwUqZgeo/36/kB0uN hvX6bxcE5jEcr9z9DcbZxlAv+flZBbLOrcmbbWppMqpDM4UIAA+DAxuDxRTBpxEWd9rRpU moGa8EIRJd2mF7aXdQ9JHrkve2z3BKE= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-451-IkacN5IbPzeak5WFhJe6qA-1; Mon, 27 Apr 2020 11:50:49 -0400 X-MC-Unique: IkacN5IbPzeak5WFhJe6qA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7F28C46B; Mon, 27 Apr 2020 15:50:47 +0000 (UTC) Received: from x1.localdomain.com (ovpn-114-38.ams2.redhat.com [10.36.114.38]) by smtp.corp.redhat.com (Postfix) with ESMTP id F21E66063C; Mon, 27 Apr 2020 15:50:44 +0000 (UTC) From: Hans de Goede To: "Rafael J . Wysocki" , Len Brown , Darren Hart , Andy Shevchenko , Jonathan Cameron Cc: Hans de Goede , linux-acpi@vger.kernel.org, platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org, Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler , linux-iio@vger.kernel.org, Andy Shevchenko Subject: [PATCH v2 3/8] iio: light: cm32181: Handle ACPI instantiating a cm32181 client on the SMBus ARA Date: Mon, 27 Apr 2020 17:50:32 +0200 Message-Id: <20200427155037.218390-3-hdegoede@redhat.com> In-Reply-To: <20200427155037.218390-1-hdegoede@redhat.com> References: <20200427155037.218390-1-hdegoede@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org Some ACPI systems list 2 I2C resources for the CM3218 sensor. On these systems the first I2cSerialBus ACPI-resource points to the SMBus Alert Response Address (ARA, 0x0c) and the second I2cSerialBus ACPI-resource points to the actual CM3218 sensor address. From the ACPI/x86 side devices with more then 1 I2cSerialBus ACPI-resource are handled by the drivers/platform/x86/i2c-multi-instantiate.c code. This code will instantiate "cm32181" i2c_client-s for both resources. Add a check to cm32181_probe() for the client's address being the ARA address, and in that case fail the probe with -ENODEV. On these ACPI systems the sensor may have a SMBus Alert asserted at boot, if this is the case the sensor will not respond to any i2c_transfers on its actual address until we read from the ARA register to clear the Alert. Therefor we must (try to) read a byte from the client with the ARA register, before returning -ENODEV, so that we clear the Alert and when we get called again for the client instantiated for the second I2cSerialBus ACPI-resource the sensor will respond to our i2c-transfers. Reviewed-by: Andy Shevchenko Signed-off-by: Hans de Goede --- Changes in v2 - s/i2c_client-s/I2C clients/ in added comment --- drivers/iio/light/cm32181.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/drivers/iio/light/cm32181.c b/drivers/iio/light/cm32181.c index fd371b36c7b3..4c26a4a8a070 100644 --- a/drivers/iio/light/cm32181.c +++ b/drivers/iio/light/cm32181.c @@ -51,6 +51,8 @@ #define CM32181_CALIBSCALE_RESOLUTION 1000 #define MLUX_PER_LUX 1000 +#define SMBUS_ALERT_RESPONSE_ADDRESS 0x0c + static const u8 cm32181_reg[CM32181_CONF_REG_NUM] = { CM32181_REG_ADDR_CMD, }; @@ -333,6 +335,20 @@ static int cm32181_probe(struct i2c_client *client, struct iio_dev *indio_dev; int ret; + /* + * Some ACPI systems list 2 I2C resources for the CM3218 sensor, the + * SMBus Alert Response Address (ARA, 0x0c) and the actual I2C address. + * drivers/platform/x86/i2c-multi-instantiate.c instantiates "cm32181" + * I2C clients for both resources, ignore the ARA client. + * On these systems the sensor may have a SMBus Alert asserted at boot, + * in that case the ARA must be read to clear the Alert otherwise the + * sensor will not respond on its actual I2C address. + */ + if (client->addr == SMBUS_ALERT_RESPONSE_ADDRESS) { + i2c_smbus_read_byte(client); + return -ENODEV; + } + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*cm32181)); if (!indio_dev) { dev_err(&client->dev, "devm_iio_device_alloc failed\n");