From patchwork Mon Jun 19 15:59:58 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miquel Raynal X-Patchwork-Id: 13284791 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id F0460EB64D9 for ; Mon, 19 Jun 2023 16:00:33 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0A51E10E21C; Mon, 19 Jun 2023 16:00:33 +0000 (UTC) Received: from relay8-d.mail.gandi.net (relay8-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::228]) by gabe.freedesktop.org (Postfix) with ESMTPS id E797810E21C for ; Mon, 19 Jun 2023 16:00:13 +0000 (UTC) X-GND-Sasl: miquel.raynal@bootlin.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1687190412; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Buq07FqJfA/AX33oYkO9+19k+nw9EBL40YqYi/2S1zA=; b=MqmSJXwFMQUJ0+ITTGObDe7ebaLEanre/zOZMGTslduGxomaCDFwfTw2Hw6s64CDmlrbzF Bk/E3E1xa1YdECnamvtYaCxiYaYN5ppdECv2fQ6SD5M2dSzUc2uYwKaHb9bWGABLQyg+tu 7FlXXPPYsoxJqj+Ui5Po8n9lJnmC5src5h9GP7MmJqlkoXlKWlFuf7Ca5AUmUVSFL+vR8r 4xEe53ecC7Fms4/JJyFKet92PKKPU9Ph6b/H11eA8ElyFHg0TBrINEIDiFipDhuHtWB+4o niLqbjJUrGhAXQYnvz8oo349nAYMY46u86pP7m54RVJpuO661l9HWRmW7F219Q== X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com Received: by mail.gandi.net (Postfix) with ESMTPSA id 31DDC1BF205; Mon, 19 Jun 2023 16:00:11 +0000 (UTC) From: Miquel Raynal To: David Airlie , Daniel Vetter , Thierry Reding , Sam Ravnborg , dri-devel@lists.freedesktop.org Subject: [PATCH v3 6/6] drm/panel: sitronix-st7789v: Check display ID Date: Mon, 19 Jun 2023 17:59:58 +0200 Message-Id: <20230619155958.3119181-7-miquel.raynal@bootlin.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230619155958.3119181-1-miquel.raynal@bootlin.com> References: <20230619155958.3119181-1-miquel.raynal@bootlin.com> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, Krzysztof Kozlowski , Maxime Ripard , Rob Herring , Maxime Ripard , Thomas Petazzoni , Miquel Raynal Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" A very basic debugging rule when a device is connected for the first time is to access a read-only register which contains known data in order to ensure the communication protocol is properly working. This driver lacked any read helper which is often a critical piece for speeding-up bring-ups. Add a read helper and use it to verify the communication with the panel is working as soon as possible in order to inform the user early if this is not the case. As this panel may work with no MISO line, the check is discarded in this case. Upon error, we do not fail probing but just warn the user, in case the DT description would be lacking the Rx bus width (which is likely on old descriptions) in order to avoid breaking existing devices. Signed-off-by: Miquel Raynal Acked-by: Sam Ravnborg Acked-by: Maxime Ripard --- .../gpu/drm/panel/panel-sitronix-st7789v.c | 81 +++++++++++++++++++ 1 file changed, 81 insertions(+) diff --git a/drivers/gpu/drm/panel/panel-sitronix-st7789v.c b/drivers/gpu/drm/panel/panel-sitronix-st7789v.c index 8649966ceae8..205de179f7f2 100644 --- a/drivers/gpu/drm/panel/panel-sitronix-st7789v.c +++ b/drivers/gpu/drm/panel/panel-sitronix-st7789v.c @@ -110,6 +110,9 @@ return val; \ } while (0) +#define ST7789V_IDS { 0x85, 0x85, 0x52 } +#define ST7789V_IDS_SIZE 3 + struct st7789_panel_info { const struct drm_display_mode *mode; u32 bus_format; @@ -157,6 +160,76 @@ static int st7789v_write_data(struct st7789v *ctx, u8 cmd) return st7789v_spi_write(ctx, ST7789V_DATA, cmd); } +static int st7789v_read_data(struct st7789v *ctx, u8 cmd, u8 *buf, + unsigned int len) +{ + struct spi_transfer xfer[2] = { }; + struct spi_message msg; + u16 txbuf = ((ST7789V_COMMAND & 1) << 8) | cmd; + u16 rxbuf[4] = {}; + u8 bit9 = 0; + int ret, i; + + switch (len) { + case 1: + case 3: + case 4: + break; + default: + return -EOPNOTSUPP; + } + + spi_message_init(&msg); + + xfer[0].tx_buf = &txbuf; + xfer[0].len = sizeof(txbuf); + spi_message_add_tail(&xfer[0], &msg); + + xfer[1].rx_buf = rxbuf; + xfer[1].len = len * 2; + spi_message_add_tail(&xfer[1], &msg); + + ret = spi_sync(ctx->spi, &msg); + if (ret) + return ret; + + for (i = 0; i < len; i++) { + buf[i] = rxbuf[i] >> i | (bit9 << (9 - i)); + if (i) + bit9 = rxbuf[i] & GENMASK(i - 1, 0); + } + + return 0; +} + +static int st7789v_check_id(struct drm_panel *panel) +{ + const u8 st7789v_ids[ST7789V_IDS_SIZE] = ST7789V_IDS; + struct st7789v *ctx = panel_to_st7789v(panel); + bool invalid_ids = false; + int ret, i; + u8 ids[3]; + + if (ctx->spi->mode & SPI_NO_RX) + return 0; + + ret = st7789v_read_data(ctx, MIPI_DCS_GET_DISPLAY_ID, ids, ST7789V_IDS_SIZE); + if (ret) + return ret; + + for (i = 0; i < ST7789V_IDS_SIZE; i++) { + if (ids[i] != st7789v_ids[i]) { + invalid_ids = true; + break; + } + } + + if (invalid_ids) + return -EIO; + + return 0; +} + static const struct drm_display_mode default_mode = { .clock = 7000, .hdisplay = 240, @@ -295,6 +368,14 @@ static int st7789v_prepare(struct drm_panel *panel) gpiod_set_value(ctx->reset, 0); msleep(120); + /* + * Avoid failing if the IDs are invalid in case the Rx bus width + * description is missing. + */ + ret = st7789v_check_id(panel); + if (ret) + dev_warn(panel->dev, "Unrecognized panel IDs"); + ST7789V_TEST(ret, st7789v_write_command(ctx, MIPI_DCS_EXIT_SLEEP_MODE)); /* We need to wait 120ms after a sleep out command */