From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C0EE6C43387 for ; Mon, 17 Dec 2018 04:06:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8F6D6217F5 for ; Mon, 17 Dec 2018 04:06:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731418AbeLQEFM (ORCPT ); Sun, 16 Dec 2018 23:05:12 -0500 Received: from mirror2.csie.ntu.edu.tw ([140.112.30.76]:53260 "EHLO wens.csie.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731377AbeLQEFM (ORCPT ); Sun, 16 Dec 2018 23:05:12 -0500 Received: by wens.csie.org (Postfix, from userid 1000) id 8670C5FDB8; Mon, 17 Dec 2018 12:05:03 +0800 (CST) From: Chen-Yu Tsai To: Marcel Holtmann , Johan Hedberg , Rob Herring , Mark Rutland , Maxime Ripard Cc: Chen-Yu Tsai , Loic Poulain , linux-bluetooth@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Ondrej Jirman Subject: [PATCH v3 10/15] Bluetooth: hci_bcm: Wait for device to come out of reset after power on Date: Mon, 17 Dec 2018 12:04:44 +0800 Message-Id: <20181217040449.31437-11-wens@csie.org> X-Mailer: git-send-email 2.20.0 In-Reply-To: <20181217040449.31437-1-wens@csie.org> References: <20181217040449.31437-1-wens@csie.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-bluetooth-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org The datasheets for BCM20702 and BCM43438 both have power up time sequence graphs, however they are slightly different. Both chips also have an internal power-on-reset, which holds the chip in reset for a short time after the regulators are enabled. For the BCM20702, the time period from when the regulators are enabled, until the chip settles and comes out of sleep state, is 6564 ~ 8171 us. For the BCM43438, the graph only shows the time period from when the regulators are enabled until the chip responds by driving the host's CTS line low, assuming the host has already driven its RTS line low. This is shown to be 6.5 sleep cycles, with the sleep clock at 32.768 kHz. This is around 2 ms. Wait a full 10 ms after the regulators are enabled to account for signal rising times. Tested-by: Ondrej Jirman Signed-off-by: Chen-Yu Tsai --- drivers/bluetooth/hci_bcm.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/bluetooth/hci_bcm.c b/drivers/bluetooth/hci_bcm.c index f2101038284e..538ce8059bff 100644 --- a/drivers/bluetooth/hci_bcm.c +++ b/drivers/bluetooth/hci_bcm.c @@ -256,6 +256,9 @@ static int bcm_gpio_set_power(struct bcm_device *dev, bool powered) regulator_bulk_disable(BCM_NUM_SUPPLIES, dev->supplies); } + /* wait for device to power on and come out of reset */ + usleep_range(10000, 20000); + dev->res_enabled = powered; return 0; -- 2.20.0