From mboxrd@z Thu Jan 1 00:00:00 1970 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 30C97C433EF for ; Mon, 11 Apr 2022 21:13:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350118AbiDKVPg (ORCPT ); Mon, 11 Apr 2022 17:15:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42330 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350095AbiDKVPR (ORCPT ); Mon, 11 Apr 2022 17:15:17 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 66B672AE20 for ; Mon, 11 Apr 2022 14:13:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1649711580; 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=M95WJfrMn4Zy07mhQ4y0daSPzPIFGxeBWEMZH1/VxdI=; b=QgELhwWFbcU4vYpe/o7yxGGsLEpFy5FjCsLGuFLA/nXklRiEb2iMkKZ9y1OSaM16E2Qy6G Av9FLh2xTl4WdXC/pnO53k71d9jdk4kNNft7HWxRHW6qzJV7pUQLU2gbvsGKsMjm3ToGbF 1VEQ53CbNVQgQtZrP4WInr4F85mJNXk= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-115-t6T5vSp-PUiUm895dDoEWw-1; Mon, 11 Apr 2022 17:12:57 -0400 X-MC-Unique: t6T5vSp-PUiUm895dDoEWw-1 Received: by mail-wm1-f71.google.com with SMTP id z16-20020a05600c0a1000b0038bebbd8548so212992wmp.3 for ; Mon, 11 Apr 2022 14:12:57 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=M95WJfrMn4Zy07mhQ4y0daSPzPIFGxeBWEMZH1/VxdI=; b=sCzIqJm9YYLgYkGiH7hjEHp8NjC6HYBSJ7aWqobw6dH+KQrAcSJ5OMNq9e6qA3Q+CP iWt669wludt+1ddvhmjYhT5GGaeQIhReBJngt6AWqExxhhXgE15tDroEnzqMWaJBHLCK ejC7c1hiEW4T+H2zdjwDn1j7AiCLQP2G2Ry/bp2XmAV+lot1NdctTVg2iMVLasJwfkyA hGKaO+l7YwGcUixQaBr2lSk2Q4XK+0r2cS+ESJNUhOtzIT4Tk2+Jw8madwOvTHHXdCIY yK9pmYfuSpdJpARA/7fncCyLqFsRh8YnFoZNQHKloUMlOxOZQewPQDpS9+vObTfz4x5h 6zow== X-Gm-Message-State: AOAM531y2kbs7vY4P+vK1P8ctaEv7VU2jfWbR0u9kmcgsAxHR+iqbBIY ebBSSAEdPpNYW2lrvYNY9SA4Q7AfFp7ibPAhm9yle3N0G+nAOx7YVUctld3YrGIVGqG0EZejOYF cQHOZSDofdJoqH/VQ9RyFtrerjAqsX/RacxtVbPJmRK3iYY/t2MXdMiBpr7SbIAXIgtxdnypkkl Q= X-Received: by 2002:adf:eb86:0:b0:1e6:8c92:af6b with SMTP id t6-20020adfeb86000000b001e68c92af6bmr26342349wrn.116.1649711575908; Mon, 11 Apr 2022 14:12:55 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwxvx0POEPQt1rNQq1OQWSMr6MX6jGMvV5y/3zA8cOpvVB60dnM/YE1MmkCed4WruaERKY1fQ== X-Received: by 2002:adf:eb86:0:b0:1e6:8c92:af6b with SMTP id t6-20020adfeb86000000b001e68c92af6bmr26342319wrn.116.1649711575506; Mon, 11 Apr 2022 14:12:55 -0700 (PDT) Received: from minerva.home ([92.176.231.205]) by smtp.gmail.com with ESMTPSA id l9-20020a5d6d89000000b00203d62072c4sm28723722wrs.43.2022.04.11.14.12.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Apr 2022 14:12:55 -0700 (PDT) From: Javier Martinez Canillas To: linux-kernel@vger.kernel.org Cc: Rob Herring , dri-devel@lists.freedesktop.org, Neil Armstrong , Geert Uytterhoeven , Mark Brown , Andy Shevchenko , Chen-Yu Tsai , Javier Martinez Canillas , Chen-Yu Tsai , Daniel Vetter , David Airlie , Maxime Ripard , YueHaibing Subject: [PATCH v2 5/5] drm/solomon: Add SSD130x OLED displays SPI support Date: Mon, 11 Apr 2022 23:12:43 +0200 Message-Id: <20220411211243.11121-6-javierm@redhat.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220411211243.11121-1-javierm@redhat.com> References: <20220411211243.11121-1-javierm@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The ssd130x driver only provides the core support for these devices but it does not have any bus transport logic. Add a driver to interface over SPI. There is a difference in the communication protocol when using 4-wire SPI instead of I2C. For the latter, a control byte that contains a D/C# field has to be sent. This field tells the controller whether the data has to be written to the command register or to the graphics display data memory. But for 4-wire SPI that control byte is not used, instead a real D/C# line must be pulled HIGH for commands data and LOW for graphics display data. For this reason the standard SPI regmap can't be used and a custom .write bus handler is needed. Signed-off-by: Javier Martinez Canillas Acked-by: Mark Brown --- (no changes since v1) drivers/gpu/drm/solomon/Kconfig | 9 ++ drivers/gpu/drm/solomon/Makefile | 1 + drivers/gpu/drm/solomon/ssd130x-spi.c | 184 ++++++++++++++++++++++++++ 3 files changed, 194 insertions(+) create mode 100644 drivers/gpu/drm/solomon/ssd130x-spi.c diff --git a/drivers/gpu/drm/solomon/Kconfig b/drivers/gpu/drm/solomon/Kconfig index 8c0a0c788385..e170716d976b 100644 --- a/drivers/gpu/drm/solomon/Kconfig +++ b/drivers/gpu/drm/solomon/Kconfig @@ -20,3 +20,12 @@ config DRM_SSD130X_I2C I2C bus. If M is selected the module will be called ssd130x-i2c. + +config DRM_SSD130X_SPI + tristate "DRM support for Solomon SSD130X OLED displays (SPI bus)" + depends on DRM_SSD130X && SPI + select REGMAP + help + Say Y here if the SSD130x OLED display is connected via SPI bus. + + If M is selected the module will be called ssd130x-spi. diff --git a/drivers/gpu/drm/solomon/Makefile b/drivers/gpu/drm/solomon/Makefile index 4bfc5acb0447..b5fc792257d7 100644 --- a/drivers/gpu/drm/solomon/Makefile +++ b/drivers/gpu/drm/solomon/Makefile @@ -1,2 +1,3 @@ obj-$(CONFIG_DRM_SSD130X) += ssd130x.o obj-$(CONFIG_DRM_SSD130X_I2C) += ssd130x-i2c.o +obj-$(CONFIG_DRM_SSD130X_SPI) += ssd130x-spi.o diff --git a/drivers/gpu/drm/solomon/ssd130x-spi.c b/drivers/gpu/drm/solomon/ssd130x-spi.c new file mode 100644 index 000000000000..b6fee66a0c01 --- /dev/null +++ b/drivers/gpu/drm/solomon/ssd130x-spi.c @@ -0,0 +1,184 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * DRM driver for Solomon SSD130X OLED displays (SPI bus) + * + * Copyright 2022 Red Hat Inc. + * Authors: Javier Martinez Canillas + */ +#include +#include + +#include "ssd130x.h" + +#define DRIVER_NAME "ssd130x-spi" +#define DRIVER_DESC "DRM driver for Solomon SSD130X OLED displays (SPI)" + +struct ssd130x_spi_transport { + struct spi_device *spi; + struct gpio_desc *dc; +}; + +static const struct regmap_config ssd130x_spi_regmap_config = { + .reg_bits = 8, + .val_bits = 8, +}; + +/* + * The regmap bus .write handler, it is just a wrapper around spi_write() + * but toggling the Data/Command control pin (D/C#). Since for 4-wire SPI + * a D/C# pin is used, in contrast with I2C where a control byte is sent, + * prior to every data byte, that contains a bit with the D/C# value. + * + * These control bytes are considered registers by the ssd130x core driver + * and can be used by the ssd130x SPI driver to determine if the data sent + * is for a command register or for the Graphic Display Data RAM (GDDRAM). + */ +static int ssd130x_spi_write(void *context, const void *data, size_t count) +{ + struct ssd130x_spi_transport *t = context; + struct spi_device *spi = t->spi; + const u8 *reg = data; + + if (*reg == SSD130X_COMMAND) + gpiod_set_value_cansleep(t->dc, 0); + + if (*reg == SSD130X_DATA) + gpiod_set_value_cansleep(t->dc, 1); + + /* Remove the control byte since is not used by the 4-wire SPI */ + return spi_write(spi, ((u8 *)data) + 1, count - 1); +} + +/* The ssd130x driver does not read registers but regmap expects a .read */ +static int ssd130x_spi_read(void *context, const void *reg, size_t reg_size, + void *val, size_t val_size) +{ + return -EOPNOTSUPP; +} + +/* + * A custom bus is needed due the special write that toggles a D/C# pin, + * another option could be to just have a .reg_write() callback but that + * will prevent to do data writes in bulk. + * + * Once the regmap API is extended to support defining a bulk write handler + * in the struct regmap_config, this can be simplified and the bus dropped. + */ +static struct regmap_bus regmap_ssd130x_spi_bus = { + .write = ssd130x_spi_write, + .read = ssd130x_spi_read, +}; + +static struct gpio_desc *ssd130x_spi_get_dc(struct device *dev) +{ + struct gpio_desc *dc = devm_gpiod_get(dev, "dc", GPIOD_OUT_LOW); + + if (IS_ERR(dc)) + return ERR_PTR(dev_err_probe(dev, PTR_ERR(dc), "Failed to get dc gpio\n")); + + return dc; +} + +static int ssd130x_spi_probe(struct spi_device *spi) +{ + struct ssd130x_spi_transport *t; + struct ssd130x_device *ssd130x; + struct regmap *regmap; + struct device *dev = &spi->dev; + + t = devm_kzalloc(dev, sizeof(*t), GFP_KERNEL); + if (!t) + return dev_err_probe(dev, -ENOMEM, + "Failed to allocate SPI transport data\n"); + + t->spi = spi; + + t->dc = ssd130x_spi_get_dc(&spi->dev); + if (IS_ERR(t->dc)) + return PTR_ERR(t->dc); + + regmap = devm_regmap_init(dev, ®map_ssd130x_spi_bus, t, + &ssd130x_spi_regmap_config); + if (IS_ERR(regmap)) + return PTR_ERR(regmap); + + ssd130x = ssd130x_probe(dev, regmap); + if (IS_ERR(ssd130x)) + return PTR_ERR(ssd130x); + + spi_set_drvdata(spi, ssd130x); + + return 0; +} + +static void ssd130x_spi_remove(struct spi_device *spi) +{ + struct ssd130x_device *ssd130x = spi_get_drvdata(spi); + + ssd130x_remove(ssd130x); +} + +static void ssd130x_spi_shutdown(struct spi_device *spi) +{ + struct ssd130x_device *ssd130x = spi_get_drvdata(spi); + + ssd130x_shutdown(ssd130x); +} + +static const struct of_device_id ssd130x_of_match[] = { + { + .compatible = "sinowealth,sh1106", + .data = (void *)SH1106_ID, + }, + { + .compatible = "solomon,ssd1305", + .data = (void *)SSD1305_ID, + }, + { + .compatible = "solomon,ssd1306", + .data = (void *)SSD1306_ID, + }, + { + .compatible = "solomon,ssd1307", + .data = (void *)SSD1307_ID, + }, + { + .compatible = "solomon,ssd1309", + .data = (void *)SSD1309_ID, + }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, ssd130x_of_match); + +/* + * The SPI core always reports a MODALIAS uevent of the form "spi:", even + * if the device was registered via OF. This means that the module will not be + * auto loaded, unless it contains an alias that matches the MODALIAS reported. + * + * To workaround this issue, add a SPI device ID table. Even when this should + * not be needed for this driver to match the registered SPI devices. + */ +static const struct spi_device_id ssd130x_spi_table[] = { + { "sh1106", SH1106_ID }, + { "ssd1305", SSD1305_ID }, + { "ssd1306", SSD1306_ID }, + { "ssd1307", SSD1307_ID }, + { "ssd1309", SSD1309_ID }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(spi, ssd130x_spi_table); + +static struct spi_driver ssd130x_spi_driver = { + .driver = { + .name = DRIVER_NAME, + .of_match_table = ssd130x_of_match, + }, + .probe = ssd130x_spi_probe, + .remove = ssd130x_spi_remove, + .shutdown = ssd130x_spi_shutdown, +}; +module_spi_driver(ssd130x_spi_driver); + +MODULE_DESCRIPTION(DRIVER_DESC); +MODULE_AUTHOR("Javier Martinez Canillas "); +MODULE_LICENSE("GPL"); -- 2.35.1