From patchwork Sun Feb 27 10:00:34 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 12761596 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 75D90C433FE for ; Sun, 27 Feb 2022 10:01:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229900AbiB0KBp (ORCPT ); Sun, 27 Feb 2022 05:01:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47874 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229922AbiB0KBn (ORCPT ); Sun, 27 Feb 2022 05:01:43 -0500 Received: from pegase2.c-s.fr (pegase2.c-s.fr [93.17.235.10]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CB5FE5B8AA; Sun, 27 Feb 2022 02:01:06 -0800 (PST) Received: from localhost (mailhub3.si.c-s.fr [172.26.127.67]) by localhost (Postfix) with ESMTP id 4K5zY51grbz9sSf; Sun, 27 Feb 2022 11:00:57 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase2.c-s.fr ([172.26.127.65]) by localhost (pegase2.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id t_JPdnIHkgKu; Sun, 27 Feb 2022 11:00:57 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase2.c-s.fr (Postfix) with ESMTP id 4K5zY25c6pz9sSN; Sun, 27 Feb 2022 11:00:54 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id E960F8B763; Sun, 27 Feb 2022 11:00:53 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id W5oqlttZPhHn; Sun, 27 Feb 2022 11:00:53 +0100 (CET) Received: from PO20335.IDSI0.si.c-s.fr (unknown [192.168.232.62]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 9C6348B770; Sun, 27 Feb 2022 11:00:53 +0100 (CET) Received: from PO20335.IDSI0.si.c-s.fr (localhost [127.0.0.1]) by PO20335.IDSI0.si.c-s.fr (8.17.1/8.16.1) with ESMTPS id 21RA0kq1262871 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Sun, 27 Feb 2022 11:00:46 +0100 Received: (from chleroy@localhost) by PO20335.IDSI0.si.c-s.fr (8.17.1/8.17.1/Submit) id 21RA0jEV262870; Sun, 27 Feb 2022 11:00:45 +0100 X-Authentication-Warning: PO20335.IDSI0.si.c-s.fr: chleroy set sender to christophe.leroy@csgroup.eu using -f From: Christophe Leroy To: Mark Brown , Rob Herring , Pratyush Yadav Cc: Christophe Leroy , linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org, devicetree@vger.kernel.org Subject: [PATCH v1 1/2] spi: Add new mode to generate additional clock cycles Date: Sun, 27 Feb 2022 11:00:34 +0100 Message-Id: <2bbe791f1c2b3c809c8863020184cdcfdadd1510.1645950971.git.christophe.leroy@csgroup.eu> X-Mailer: git-send-email 2.34.1 In-Reply-To: References: MIME-Version: 1.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1645956034; l=3649; s=20211009; h=from:subject:message-id; bh=UpeHInRYCMHgzsyoIq8kRNojKZE72iMXwQWDi6TVlqk=; b=i7tLSbR8+v/1DDEB7oHUwrjhbyyYwOlVlN7xPMNsiAn38Kos0bN0rLigbxvlYhudGKbSnVcnTJZ/ 88DH2DlGBtaT8bSNK2VYgRFBbbqRak9QIi4/ffocP1++9xXPfk11 X-Developer-Key: i=christophe.leroy@csgroup.eu; a=ed25519; pk=HIzTzUj91asvincQGOFx6+ZF5AoUuP9GdOtQChs7Mm0= Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org Some components require a few clock cycles with chipselect off before or/and after the data transfer done with CS on. Typically IDT 801034 QUAD PCM CODEC datasheet states "Note *: CCLK should have one cycle before CS goes low, and two cycles after CS goes high". The cycles "before" are implicitely provided by all previous activity on the SPI bus. But the cycles "after" must be provided in order to achieve the SPI transfer. In order to use that kind of component, implement a new option for SPI slaves in order to implement a trailing clock of a few bits with ChipSelect off at the end of the transfer. Signed-off-by: Christophe Leroy --- .../devicetree/bindings/spi/spi-peripheral-props.yaml | 4 ++++ drivers/spi/spi.c | 5 ++++- include/uapi/linux/spi/spi.h | 3 ++- 3 files changed, 10 insertions(+), 2 deletions(-) diff --git a/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml b/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml index 5dd209206e88..4e4fc357d667 100644 --- a/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml +++ b/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml @@ -82,6 +82,10 @@ properties: description: Delay, in microseconds, after a write transfer. + spi-trailing-clock: + description: + Add a few clock cycles (minimum 2) with chipselect OFF after transfers. + # The controller specific properties go here. allOf: - $ref: cdns,qspi-nor-peripheral-props.yaml# diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 4599b121d744..1b943e112751 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -2109,6 +2109,8 @@ static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi, spi->mode |= SPI_LSB_FIRST; if (of_property_read_bool(nc, "spi-cs-high")) spi->mode |= SPI_CS_HIGH; + if (of_property_read_bool(nc, "spi-trailing-clock")) + spi->mode |= SPI_TRAILING; /* Device DUAL/QUAD mode */ if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) { @@ -3538,12 +3540,13 @@ int spi_setup(struct spi_device *spi) trace_spi_setup(spi, status); - dev_dbg(&spi->dev, "setup mode %lu, %s%s%s%s%u bits/w, %u Hz max --> %d\n", + dev_dbg(&spi->dev, "setup mode %lu, %s%s%s%s%s%u bits/w, %u Hz max --> %d\n", spi->mode & SPI_MODE_X_MASK, (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "", (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "", (spi->mode & SPI_3WIRE) ? "3wire, " : "", (spi->mode & SPI_LOOP) ? "loopback, " : "", + (spi->mode & SPI_TRAILING) ? "trailing clock, " : "", spi->bits_per_word, spi->max_speed_hz, status); diff --git a/include/uapi/linux/spi/spi.h b/include/uapi/linux/spi/spi.h index 236a85f08ded..0933a619a154 100644 --- a/include/uapi/linux/spi/spi.h +++ b/include/uapi/linux/spi/spi.h @@ -27,6 +27,7 @@ #define SPI_TX_OCTAL _BITUL(13) /* transmit with 8 wires */ #define SPI_RX_OCTAL _BITUL(14) /* receive with 8 wires */ #define SPI_3WIRE_HIZ _BITUL(15) /* high impedance turnaround */ +#define SPI_TRAILING _BITUL(16) /* trailing clock needed */ /* * All the bits defined above should be covered by SPI_MODE_USER_MASK. @@ -36,6 +37,6 @@ * These bits must not overlap. A static assert check should make sure of that. * If adding extra bits, make sure to increase the bit index below as well. */ -#define SPI_MODE_USER_MASK (_BITUL(16) - 1) +#define SPI_MODE_USER_MASK (_BITUL(17) - 1) #endif /* _UAPI_SPI_H */