From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752074AbeBDVc3 (ORCPT ); Sun, 4 Feb 2018 16:32:29 -0500 Received: from mx07-00178001.pphosted.com ([62.209.51.94]:55983 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751724AbeBDVcV (ORCPT ); Sun, 4 Feb 2018 16:32:21 -0500 From: Philippe Cornu To: Archit Taneja , Andrzej Hajda , Laurent Pinchart , David Airlie , Philippe Cornu , Brian Norris , Benjamin Gaignard , Bhumika Goyal , , , "Sandy Huang" , Heiko Stubner , , CC: Yannick Fertre , Vincent Abriou , Alexandre Torgue Subject: [PATCH] drm/bridge/synopsys: dsi: Add read feature Date: Sun, 4 Feb 2018 22:31:04 +0100 Message-ID: <20180204213104.17834-1-philippe.cornu@st.com> X-Mailer: git-send-email 2.15.1 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.129.5.167] X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-02-04_05:,, signatures=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch adds the DCS/GENERIC DSI read feature. Signed-off-by: Philippe Cornu --- Extra notes: DSI read tests have been performed with DCS & GENERIC, short & long commands, on two different panels. The maximum fifo size (32*32-bit = 128 bytes on stm32) has been verified too. drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 58 +++++++++++++++++++++------ 1 file changed, 45 insertions(+), 13 deletions(-) diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c index e9422d05e897..65aeb3f78b48 100644 --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c @@ -397,18 +397,46 @@ static int dw_mipi_dsi_write(struct dw_mipi_dsi *dsi, return dw_mipi_dsi_gen_pkt_hdr_write(dsi, le32_to_cpu(word)); } +static int dw_mipi_dsi_read(struct dw_mipi_dsi *dsi, + const struct mipi_dsi_msg *msg) +{ + int i, j, ret, len = msg->rx_len; + u8 *buf = msg->rx_buf; + u32 val; + + /* Wait end of the read operation */ + ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS, + val, !(val & GEN_RD_CMD_BUSY), + 1000, CMD_PKT_STATUS_TIMEOUT_US); + if (ret) { + dev_err(dsi->dev, "Timeout during read operation\n"); + return ret; + } + + for (i = 0; i < len; i += 4) { + /* Read fifo must not be empty before all bytes are read */ + ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS, + val, !(val & GEN_PLD_R_EMPTY), + 1000, CMD_PKT_STATUS_TIMEOUT_US); + if (ret) { + dev_err(dsi->dev, "Read payload FIFO is empty\n"); + return ret; + } + + val = dsi_read(dsi, DSI_GEN_PLD_DATA); + for (j = 0; j < 4 && j + i < len; j++) + buf[i + j] = val >> (8 * j); + } + + return ret; +} + static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host, const struct mipi_dsi_msg *msg) { struct dw_mipi_dsi *dsi = host_to_dsi(host); struct mipi_dsi_packet packet; - int ret; - - if (msg->rx_buf || msg->rx_len) { - /* TODO dw drv improvements: implement read feature */ - dev_warn(dsi->dev, "read operations not yet implemented\n"); - return -EINVAL; - } + int ret, nb_bytes; ret = mipi_dsi_create_packet(&packet, msg); if (ret) { @@ -422,12 +450,16 @@ static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host, if (ret) return ret; - /* - * TODO Only transmitted size is returned as actual driver does - * not support dcs/generic reads. Please update return value when - * delivering the read feature. - */ - return packet.size; + if (msg->rx_buf && msg->rx_len) { + ret = dw_mipi_dsi_read(dsi, msg); + if (ret) + return ret; + nb_bytes = msg->rx_len; + } else { + nb_bytes = packet.size; + } + + return nb_bytes; } static const struct mipi_dsi_host_ops dw_mipi_dsi_host_ops = { -- 2.15.1