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 B72D2C433F5 for ; Tue, 12 Apr 2022 16:28:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357648AbiDLQbF (ORCPT ); Tue, 12 Apr 2022 12:31:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57446 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1357558AbiDLQaV (ORCPT ); Tue, 12 Apr 2022 12:30:21 -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 D4C925D5F3 for ; Tue, 12 Apr 2022 09:27:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1649780876; 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=fiitAF+obi/0SZz4a7WRaAtgx4DdchhRvhz/qzB643E=; b=iz2g3j/dKCHQR1egfrYrnvjEGFUkYXJaglzyx+SNiMXu5YOx40zCipj4JLc39UZnV8emOI vJmduLqpCb9P94zubTimxF2tWOpydOwOR4y/nGk7iDvie5lhtNv2ofp+RugcjQ0phRREqy w2CB3qiLuxND8QiV3BpFlHNY+8KKL+c= Received: from mail-wr1-f72.google.com (mail-wr1-f72.google.com [209.85.221.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-663-ip6bh1ORMUqndWm_mHA6Hg-1; Tue, 12 Apr 2022 12:27:55 -0400 X-MC-Unique: ip6bh1ORMUqndWm_mHA6Hg-1 Received: by mail-wr1-f72.google.com with SMTP id a12-20020a5d6cac000000b002079e81d09eso1741541wra.4 for ; Tue, 12 Apr 2022 09:27:55 -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=fiitAF+obi/0SZz4a7WRaAtgx4DdchhRvhz/qzB643E=; b=Itx2DIiyR2wFKGDHcxp+DCMMMsySZH4RQIoWtgp3rGTR6pfvJIj95BkZ5RvBdrKRgR INVu8ACm4czCN7OItIeYbVrjRb+a59VJk3Xs0VPqJXY2ciSpWD9U5OLnX4vt3GIedA2J vUeJCR2jax9nfJ8UCVgBTpSlP6ia/jFgYa7BRxL5IjSNKh2aRoQ3vvGWL8JNUUL++Mun HXnZVHZnwbkdrKui9GJw+wd7IM3muB8xkgNafs6z52dRWLeVv7o/cNX/1fHCbd96SYEf iNOXsvZFIV8tUMm6QzzLTgnNKMRVNtp/bal3z0fDJ/WUZMV90lbe/3ZoMe7ZmeQ0xJkP PgsA== X-Gm-Message-State: AOAM53203FwWcYk2WQpVOlGQLJlpp0sazmUBH3xAi0PYSNvpCstHHaGm ned5Hb1LV26uneLzRZd3FC5OB+pn7meEcKCkUYrdsH6C89LrpRUOafnibU3gXG2E/HREWjzqywm 3gruUAxia3/tUok8FivlTNUwi7WVb3ZUqTtW7GrHDJ01hFPm+x2G5xXQqRmfHVX/BU+Vciatms1 E= X-Received: by 2002:a05:6000:1566:b0:204:20d9:a5b0 with SMTP id 6-20020a056000156600b0020420d9a5b0mr31136660wrz.207.1649780874037; Tue, 12 Apr 2022 09:27:54 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzZk0MWTuuvHqtVROhBDnTpdj23O58Hyyzt/iYLuFJGH3Qm6i0aohCcnZ+MQb5YSi1vkdpJ4w== X-Received: by 2002:a05:6000:1566:b0:204:20d9:a5b0 with SMTP id 6-20020a056000156600b0020420d9a5b0mr31136615wrz.207.1649780873653; Tue, 12 Apr 2022 09:27:53 -0700 (PDT) Received: from minerva.home ([92.176.231.205]) by smtp.gmail.com with ESMTPSA id g8-20020a5d4888000000b00207a49fa6a1sm7700358wrq.81.2022.04.12.09.27.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 12 Apr 2022 09:27:53 -0700 (PDT) From: Javier Martinez Canillas To: linux-kernel@vger.kernel.org Cc: Geert Uytterhoeven , Neil Armstrong , Rob Herring , Andy Shevchenko , dri-devel@lists.freedesktop.org, Mark Brown , Chen-Yu Tsai , Javier Martinez Canillas , Chen-Yu Tsai , Daniel Vetter , David Airlie , Maxime Ripard , YueHaibing Subject: [PATCH v3 5/5] drm/solomon: Add SSD130x OLED displays SPI support Date: Tue, 12 Apr 2022 18:27:29 +0200 Message-Id: <20220412162729.184783-6-javierm@redhat.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220412162729.184783-1-javierm@redhat.com> References: <20220412162729.184783-1-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 --- Changes in v3: - Drop ssd130x_spi_get_dc() helper and open code it (Geert Uytterhoeven) - Export variants array and use &info[ID] in device table (Andy Shevchenko) Changes in v2: - Add the same compatible strings than I2C (Geert Uytterhoeven) drivers/gpu/drm/solomon/Kconfig | 9 ++ drivers/gpu/drm/solomon/Makefile | 1 + drivers/gpu/drm/solomon/ssd130x-spi.c | 177 ++++++++++++++++++++++++++ 3 files changed, 187 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..4fda420ae0a6 --- /dev/null +++ b/drivers/gpu/drm/solomon/ssd130x-spi.c @@ -0,0 +1,177 @@ +// 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 int ssd130x_spi_probe(struct spi_device *spi) +{ + struct ssd130x_spi_transport *t; + struct ssd130x_device *ssd130x; + struct regmap *regmap; + struct gpio_desc *dc; + struct device *dev = &spi->dev; + + dc = devm_gpiod_get(dev, "dc", GPIOD_OUT_LOW); + if (IS_ERR(dc)) + return dev_err_probe(dev, PTR_ERR(dc), + "Failed to get dc gpio\n"); + + 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 = 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 = &ssd130x_variants[SH1106_ID], + }, + { + .compatible = "solomon,ssd1305", + .data = &ssd130x_variants[SSD1305_ID], + }, + { + .compatible = "solomon,ssd1306", + .data = &ssd130x_variants[SSD1306_ID], + }, + { + .compatible = "solomon,ssd1307", + .data = &ssd130x_variants[SSD1307_ID], + }, + { + .compatible = "solomon,ssd1309", + .data = &ssd130x_variants[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