From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932678AbdJYB6p (ORCPT ); Tue, 24 Oct 2017 21:58:45 -0400 Received: from fldsmtpe03.verizon.com ([140.108.26.142]:9344 "EHLO fldsmtpe03.verizon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932278AbdJYB5O (ORCPT ); Tue, 24 Oct 2017 21:57:14 -0400 From: "Levin, Alexander (Sasha Levin)" Cc: Lars-Peter Clausen , Hans Verkuil , Mauro Carvalho Chehab , "Levin, Alexander (Sasha Levin)" X-Host: mariner.tdc.vzwcorp.com To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" Subject: [PATCH AUTOSEL for 4.4 01/25] [media] adv7604: Initialize drive strength to default when using DT Thread-Topic: [PATCH AUTOSEL for 4.4 01/25] [media] adv7604: Initialize drive strength to default when using DT Thread-Index: AQHTTTRvyhbX1VXjuk+FK7FhLTd53g== Date: Wed, 25 Oct 2017 01:56:13 +0000 Message-ID: <20171025015607.24625-1-alexander.levin@verizon.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.144.60.250] Content-Type: text/plain; charset="utf-8" Content-ID: <9293F667CEA1C942BC5DC66B7018D6C4@vzwcorp.com> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by nfs id v9P1wnkj012073 From: Lars-Peter Clausen [ Upstream commit da8892d410db224d9a24104529794e6e37e0c100 ] The adv7604 driver platform data contains fields for configuring the drive strength of the output pins. When probing the driver through DT these fields are not explicitly initialized, which means they are left at 0. This is a reserved setting for the drive strength configuration though and can cause signal integrity issues. Whether these signal integrity issues are visible depends on the PCB specifics (e.g. the higher the load capacitance for the output the more visible the issue). But it has been observed on existing solutions at high pixel clock rates. Initialize the drive strength settings to the power-on-reset value of the device when probing through devicetree to avoid this issue. Fixes: 0e158be0162b ("adv7604: Add DT support") Signed-off-by: Lars-Peter Clausen Reviewed-by: Laurent Pinchart Tested-by: Niklas Söderlund Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Sasha Levin --- drivers/media/i2c/adv7604.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/media/i2c/adv7604.c b/drivers/media/i2c/adv7604.c index 01adcdc52346..a9e2722f5e22 100644 --- a/drivers/media/i2c/adv7604.c +++ b/drivers/media/i2c/adv7604.c @@ -2856,6 +2856,9 @@ static int adv76xx_parse_dt(struct adv76xx_state *state) state->pdata.alt_data_sat = 1; state->pdata.op_format_mode_sel = ADV7604_OP_FORMAT_MODE0; state->pdata.bus_order = ADV7604_BUS_ORDER_RGB; + state->pdata.dr_str_data = ADV76XX_DR_STR_MEDIUM_HIGH; + state->pdata.dr_str_clk = ADV76XX_DR_STR_MEDIUM_HIGH; + state->pdata.dr_str_sync = ADV76XX_DR_STR_MEDIUM_HIGH; return 0; } -- 2.11.0