From patchwork Mon Sep 21 13:45:48 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Kleine-Budde X-Patchwork-Id: 260479 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=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, 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 51E28C43466 for ; Mon, 21 Sep 2020 13:46:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 24E8420888 for ; Mon, 21 Sep 2020 13:46:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727559AbgIUNqg (ORCPT ); Mon, 21 Sep 2020 09:46:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34704 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727468AbgIUNqc (ORCPT ); Mon, 21 Sep 2020 09:46:32 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DB933C0613B0 for ; Mon, 21 Sep 2020 06:46:15 -0700 (PDT) Received: from heimdall.vpn.pengutronix.de ([2001:67c:670:205:1d::14] helo=blackshift.org) by metis.ext.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1kKM8z-0003ED-2F; Mon, 21 Sep 2020 15:46:13 +0200 From: Marc Kleine-Budde To: netdev@vger.kernel.org Cc: davem@davemloft.net, linux-can@vger.kernel.org, kernel@pengutronix.de, Tim Harvey , Marc Kleine-Budde Subject: [PATCH 29/38] can: mcp251x: add support for half duplex controllers Date: Mon, 21 Sep 2020 15:45:48 +0200 Message-Id: <20200921134557.2251383-30-mkl@pengutronix.de> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200921134557.2251383-1-mkl@pengutronix.de> References: <20200921134557.2251383-1-mkl@pengutronix.de> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2001:67c:670:205:1d::14 X-SA-Exim-Mail-From: mkl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: netdev@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Tim Harvey Some SPI host controllers do not support full-duplex SPI and are marked as such via the SPI_CONTROLLER_HALF_DUPLEX controller flag. For such controllers use half duplex transactions but retain full duplex transactions for the controllers that can handle those. Signed-off-by: Tim Harvey Link: https://lore.kernel.org/r/1595516275-1179-1-git-send-email-tharvey@gateworks.com Signed-off-by: Marc Kleine-Budde --- drivers/net/can/spi/mcp251x.c | 34 +++++++++++++++++++++++++++------- 1 file changed, 27 insertions(+), 7 deletions(-) diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c index 3bf57bc9b3ff..22d814ae4edc 100644 --- a/drivers/net/can/spi/mcp251x.c +++ b/drivers/net/can/spi/mcp251x.c @@ -322,8 +322,12 @@ static u8 mcp251x_read_reg(struct spi_device *spi, u8 reg) priv->spi_tx_buf[0] = INSTRUCTION_READ; priv->spi_tx_buf[1] = reg; - mcp251x_spi_trans(spi, 3); - val = priv->spi_rx_buf[2]; + if (spi->controller->flags & SPI_CONTROLLER_HALF_DUPLEX) { + spi_write_then_read(spi, priv->spi_tx_buf, 2, &val, 1); + } else { + mcp251x_spi_trans(spi, 3); + val = priv->spi_rx_buf[2]; + } return val; } @@ -335,10 +339,18 @@ static void mcp251x_read_2regs(struct spi_device *spi, u8 reg, u8 *v1, u8 *v2) priv->spi_tx_buf[0] = INSTRUCTION_READ; priv->spi_tx_buf[1] = reg; - mcp251x_spi_trans(spi, 4); + if (spi->controller->flags & SPI_CONTROLLER_HALF_DUPLEX) { + u8 val[2] = { 0 }; - *v1 = priv->spi_rx_buf[2]; - *v2 = priv->spi_rx_buf[3]; + spi_write_then_read(spi, priv->spi_tx_buf, 2, val, 2); + *v1 = val[0]; + *v2 = val[1]; + } else { + mcp251x_spi_trans(spi, 4); + + *v1 = priv->spi_rx_buf[2]; + *v2 = priv->spi_rx_buf[3]; + } } static void mcp251x_write_reg(struct spi_device *spi, u8 reg, u8 val) @@ -657,8 +669,16 @@ static void mcp251x_hw_rx_frame(struct spi_device *spi, u8 *buf, buf[i] = mcp251x_read_reg(spi, RXBCTRL(buf_idx) + i); } else { priv->spi_tx_buf[RXBCTRL_OFF] = INSTRUCTION_READ_RXB(buf_idx); - mcp251x_spi_trans(spi, SPI_TRANSFER_BUF_LEN); - memcpy(buf, priv->spi_rx_buf, SPI_TRANSFER_BUF_LEN); + if (spi->controller->flags & SPI_CONTROLLER_HALF_DUPLEX) { + spi_write_then_read(spi, priv->spi_tx_buf, 1, + priv->spi_rx_buf, + SPI_TRANSFER_BUF_LEN); + memcpy(buf + 1, priv->spi_rx_buf, + SPI_TRANSFER_BUF_LEN - 1); + } else { + mcp251x_spi_trans(spi, SPI_TRANSFER_BUF_LEN); + memcpy(buf, priv->spi_rx_buf, SPI_TRANSFER_BUF_LEN); + } } }