From patchwork Mon Dec 7 21:15:24 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Sakari Ailus X-Patchwork-Id: 339336 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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 13596C2BBCD for ; Mon, 7 Dec 2020 21:25:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B948C2395A for ; Mon, 7 Dec 2020 21:25:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726998AbgLGVZK (ORCPT ); Mon, 7 Dec 2020 16:25:10 -0500 Received: from retiisi.eu ([95.216.213.190]:34636 "EHLO hillosipuli.retiisi.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726761AbgLGVZK (ORCPT ); Mon, 7 Dec 2020 16:25:10 -0500 Received: from lanttu.localdomain (lanttu-e.localdomain [192.168.1.64]) by hillosipuli.retiisi.eu (Postfix) with ESMTP id 912CD634CA4; Mon, 7 Dec 2020 23:23:13 +0200 (EET) From: Sakari Ailus To: linux-media@vger.kernel.org Cc: mchehab@kernel.org Subject: [PATCH 18/24] ccs: Hardware requires a delay after starting the clock of lifting reset Date: Mon, 7 Dec 2020 23:15:24 +0200 Message-Id: <20201207211530.21180-19-sakari.ailus@linux.intel.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201207211530.21180-1-sakari.ailus@linux.intel.com> References: <20201207211530.21180-1-sakari.ailus@linux.intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org A CCS compliant device requires a delay before the first I²C transaction after pulling xshutdown up or starting the external clock. This is what the driver does. However, if neither is actually there, there's no need for the delay. This also has the effect of removing an unnecessary delay on ACPI systems where ACPI is responsible for the power-up sequence. Signed-off-by: Sakari Ailus --- drivers/media/i2c/ccs/ccs-core.c | 29 ++++++++++++++++------------- 1 file changed, 16 insertions(+), 13 deletions(-) diff --git a/drivers/media/i2c/ccs/ccs-core.c b/drivers/media/i2c/ccs/ccs-core.c index e1b3c5693e01..fae8ceded861 100644 --- a/drivers/media/i2c/ccs/ccs-core.c +++ b/drivers/media/i2c/ccs/ccs-core.c @@ -1515,7 +1515,6 @@ static int ccs_power_on(struct device *dev) struct ccs_sensor *sensor = container_of(ssd, struct ccs_sensor, ssds[0]); const struct ccs_device *ccsdev = device_get_match_data(dev); - unsigned int sleep; int rval; rval = regulator_bulk_enable(ARRAY_SIZE(ccs_regulators), @@ -1525,21 +1524,25 @@ static int ccs_power_on(struct device *dev) return rval; } - rval = clk_prepare_enable(sensor->ext_clk); - if (rval < 0) { - dev_dbg(dev, "failed to enable xclk\n"); - goto out_xclk_fail; - } + if (sensor->reset || sensor->xshutdown || sensor->ext_clk) { + unsigned int sleep; + + rval = clk_prepare_enable(sensor->ext_clk); + if (rval < 0) { + dev_dbg(dev, "failed to enable xclk\n"); + goto out_xclk_fail; + } - gpiod_set_value(sensor->reset, 0); - gpiod_set_value(sensor->xshutdown, 1); + gpiod_set_value(sensor->reset, 0); + gpiod_set_value(sensor->xshutdown, 1); - if (ccsdev->flags & CCS_DEVICE_FLAG_IS_SMIA) - sleep = SMIAPP_RESET_DELAY(sensor->hwcfg.ext_clk); - else - sleep = 5000; + if (ccsdev->flags & CCS_DEVICE_FLAG_IS_SMIA) + sleep = SMIAPP_RESET_DELAY(sensor->hwcfg.ext_clk); + else + sleep = 5000; - usleep_range(sleep, sleep); + usleep_range(sleep, sleep); + } /* * Failures to respond to the address change command have been noticed.