From patchwork Thu May 7 21:34:55 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 200920 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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 7D199C54E4B for ; Thu, 7 May 2020 21:35:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4ED1720CC7 for ; Thu, 7 May 2020 21:35:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="e5y1nTJu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726951AbgEGVfb (ORCPT ); Thu, 7 May 2020 17:35:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59210 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726495AbgEGVf2 (ORCPT ); Thu, 7 May 2020 17:35:28 -0400 Received: from mail-pl1-x642.google.com (mail-pl1-x642.google.com [IPv6:2607:f8b0:4864:20::642]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5F8C9C05BD0A for ; Thu, 7 May 2020 14:35:28 -0700 (PDT) Received: by mail-pl1-x642.google.com with SMTP id f8so2610051plt.2 for ; Thu, 07 May 2020 14:35:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=LNGO2aJpJ/k7WS6fZ43tNwyLQEHpwINjX6rCyLagYJg=; b=e5y1nTJuz9KyZAX++ny87kAS4+zpmhWHHmRpEAlvii3XsDxYRax21hzdX/FHDZCuEW MNxDL1UlrgVGba4huvYy398i3gZC7JbZWeGSqZyDeJq1YQhXL0l+XoRBfw4G3/x1sFre 25n3udhOaqw92npu9yFmVEbhVsXs8p6vH8Qms= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=LNGO2aJpJ/k7WS6fZ43tNwyLQEHpwINjX6rCyLagYJg=; b=qVbXdO8/kVxR43CnKYCrNsX785ErGF4cYd91Fs991EGuXz5U6vu1k3ll6F8m9b/xLr VvSsARS0yvrIcnRAal9m5J33axyEEufoLWR8mlQinbr6NuqK8RZPNj+DZcOqcS+xmF3t DvG/muzbpjRf+d8BkHHF4ZLTBJLiuGGu7m6rk1u4aGgKlC9jCFeLLfyhDVn5jxUx9z4M UW0RrKPgS6v6qcARHCZ5JsIFe/xOmqDW8/mOypz5wN3cN3Q8f34Mn4GjhTl5uMgxZmfJ 1CO1XtfQEYhRDVEo4cVultjABe6/mDSjpWSk4P8c0mW/2TPb51IWKzJX1Kbx/YL0rSWM 1m1w== X-Gm-Message-State: AGi0PuYyqyLGBhz5uPM2lmr7TfxbpP1j9BbYeGDVCuUhuw0zA6dRXoqg 6c/NeZHKCinXewYE2xnK9143qg== X-Google-Smtp-Source: APiQypLU3f+NNIXHOyV7Z7a20GXQ9/HormM6jzwth+JcryEB6FOeECEBaWEwsldOpEXYjotwnzZRDA== X-Received: by 2002:a17:902:a513:: with SMTP id s19mr15709090plq.84.1588887327758; Thu, 07 May 2020 14:35:27 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:1:24fa:e766:52c9:e3b2]) by smtp.gmail.com with ESMTPSA id i10sm5884860pfa.166.2020.05.07.14.35.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 07 May 2020 14:35:27 -0700 (PDT) From: Douglas Anderson To: linus.walleij@linaro.org, bgolaszewski@baylibre.com, airlied@linux.ie, daniel@ffwll.ch, robh+dt@kernel.org, narmstrong@baylibre.com, a.hajda@samsung.com, Laurent.pinchart@ideasonboard.com, spanda@codeaurora.org Cc: jonas@kwiboo.se, jeffrey.l.hugo@gmail.com, linux-gpio@vger.kernel.org, bjorn.andersson@linaro.org, swboyd@chromium.org, jernej.skrabec@siol.net, devicetree@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, robdclark@chromium.org, Douglas Anderson , linux-kernel@vger.kernel.org Subject: [PATCH v5 1/6] drm/bridge: ti-sn65dsi86: Export bridge GPIOs to Linux Date: Thu, 7 May 2020 14:34:55 -0700 Message-Id: <20200507143354.v5.1.Ia50267a5549392af8b37e67092ca653a59c95886@changeid> X-Mailer: git-send-email 2.26.2.645.ge9eca65c58-goog In-Reply-To: <20200507213500.241695-1-dianders@chromium.org> References: <20200507213500.241695-1-dianders@chromium.org> MIME-Version: 1.0 Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org The ti-sn65dsi86 MIPI DSI to eDP bridge chip has 4 pins on it that can be used as GPIOs in a system. Each pin can be configured as input, output, or a special function for the bridge chip. These are: - GPIO1: SUSPEND Input - GPIO2: DSIA VSYNC - GPIO3: DSIA HSYNC or VSYNC - GPIO4: PWM Let's expose these pins as GPIOs. A few notes: - Access to ti-sn65dsi86 is via i2c so we set "can_sleep". - These pins can't be configured for IRQ. - There are no programmable pulls or other fancy features. - Keeping the bridge chip powered might be expensive. The driver is setup such that if all used GPIOs are only inputs we'll power the bridge chip on just long enough to read the GPIO and then power it off again. Setting a GPIO as output will keep the bridge powered. - If someone releases a GPIO we'll implicitly switch it to an input so we no longer need to keep the bridge powered for it. Because of all of the above limitations we just need to implement a bare-bones GPIO driver. The device tree bindings already account for this device being a GPIO controller so we only need the driver changes for it. NOTE: Despite the fact that these pins are nominally muxable I don't believe it makes sense to expose them through the pinctrl interface as well as the GPIO interface. The special functions are things that the bridge chip driver itself would care about and it can just configure the pins as needed. Signed-off-by: Douglas Anderson Cc: Linus Walleij Cc: Bartosz Golaszewski --- Removed Stephen's review tag in v5 to confirm he's good with the way I implemented of_xlate. Changes in v5: - Use of_xlate so that numbers in dts start at 1, not 0. Changes in v4: - Don't include gpio.h - Use gpiochip_get_data() instead of container_of() to get data. - GPIOF_DIR_XXX => GPIO_LINE_DIRECTION_XXX - Use Linus W's favorite syntax to read a bit from a bitfield. - Define and use SN_GPIO_MUX_MASK. - Add a comment about why we use a bitmap for gchip_output. Changes in v3: - Becaue => Because - Add a kernel-doc to our pdata to clarify double-duty of gchip_output. - More comments about how powering off affects us (get_dir, dir_input). - Cleanup tail of ti_sn_setup_gpio_controller() to avoid one "return". - Use a bitmap rather than rolling my own. Changes in v2: - ("Export...GPIOs") is 1/2 of replacement for ("Allow...bridge GPIOs") drivers/gpu/drm/bridge/ti-sn65dsi86.c | 214 ++++++++++++++++++++++++++ 1 file changed, 214 insertions(+) diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c index 6ad688b320ae..4e8df948b3b8 100644 --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c @@ -4,9 +4,11 @@ * datasheet: http://www.ti.com/lit/ds/symlink/sn65dsi86.pdf */ +#include #include #include #include +#include #include #include #include @@ -54,6 +56,14 @@ #define BPP_18_RGB BIT(0) #define SN_HPD_DISABLE_REG 0x5C #define HPD_DISABLE BIT(0) +#define SN_GPIO_IO_REG 0x5E +#define SN_GPIO_INPUT_SHIFT 4 +#define SN_GPIO_OUTPUT_SHIFT 0 +#define SN_GPIO_CTRL_REG 0x5F +#define SN_GPIO_MUX_INPUT 0 +#define SN_GPIO_MUX_OUTPUT 1 +#define SN_GPIO_MUX_SPECIAL 2 +#define SN_GPIO_MUX_MASK 0x3 #define SN_AUX_WDATA_REG(x) (0x64 + (x)) #define SN_AUX_ADDR_19_16_REG 0x74 #define SN_AUX_ADDR_15_8_REG 0x75 @@ -88,6 +98,35 @@ #define SN_REGULATOR_SUPPLY_NUM 4 +#define SN_NUM_GPIOS 4 +#define SN_GPIO_PHYSICAL_OFFSET 1 + +/** + * struct ti_sn_bridge - Platform data for ti-sn65dsi86 driver. + * @dev: Pointer to our device. + * @regmap: Regmap for accessing i2c. + * @aux: Our aux channel. + * @bridge: Our bridge. + * @connector: Our connector. + * @debugfs: Used for managing our debugfs. + * @host_node: Remote DSI node. + * @dsi: Our MIPI DSI source. + * @refclk: Our reference clock. + * @panel: Our panel. + * @enable_gpio: The GPIO we toggle to enable the bridge. + * @supplies: Data for bulk enabling/disabling our regulators. + * @dp_lanes: Count of dp_lanes we're using. + * + * @gchip: If we expose our GPIOs, this is used. + * @gchip_output: A cache of whether we've set GPIOs to output. This + * serves double-duty of keeping track of the direction and + * also keeping track of whether we've incremented the + * pm_runtime reference count for this pin, which we do + * whenever a pin is configured as an output. This is a + * bitmap so we can do atomic ops on it without an extra + * lock so concurrent users of our 4 GPIOs don't stomp on + * each other's read-modify-write. + */ struct ti_sn_bridge { struct device *dev; struct regmap *regmap; @@ -102,6 +141,9 @@ struct ti_sn_bridge { struct gpio_desc *enable_gpio; struct regulator_bulk_data supplies[SN_REGULATOR_SUPPLY_NUM]; int dp_lanes; + + struct gpio_chip gchip; + DECLARE_BITMAP(gchip_output, SN_NUM_GPIOS); }; static const struct regmap_range ti_sn_bridge_volatile_ranges[] = { @@ -874,6 +916,172 @@ static int ti_sn_bridge_parse_dsi_host(struct ti_sn_bridge *pdata) return 0; } +static int tn_sn_bridge_of_xlate(struct gpio_chip *chip, + const struct of_phandle_args *gpiospec, + u32 *flags) +{ + if (WARN_ON(gpiospec->args_count < chip->of_gpio_n_cells)) + return -EINVAL; + + if (gpiospec->args[0] > chip->ngpio || gpiospec->args[0] < 1) + return -EINVAL; + + if (flags) + *flags = gpiospec->args[1]; + + return gpiospec->args[0] - SN_GPIO_PHYSICAL_OFFSET; +} + +static int ti_sn_bridge_gpio_get_direction(struct gpio_chip *chip, + unsigned int offset) +{ + struct ti_sn_bridge *pdata = gpiochip_get_data(chip); + + /* + * We already have to keep track of the direction because we use + * that to figure out whether we've powered the device. We can + * just return that rather than (maybe) powering up the device + * to ask its direction. + */ + return test_bit(offset, pdata->gchip_output) ? + GPIO_LINE_DIRECTION_OUT : GPIO_LINE_DIRECTION_IN; +} + +static int ti_sn_bridge_gpio_get(struct gpio_chip *chip, unsigned int offset) +{ + struct ti_sn_bridge *pdata = gpiochip_get_data(chip); + unsigned int val; + int ret; + + /* + * When the pin is an input we don't forcibly keep the bridge + * powered--we just power it on to read the pin. NOTE: part of + * the reason this works is that the bridge defaults (when + * powered back on) to all 4 GPIOs being configured as GPIO input. + * Also note that if something else is keeping the chip powered the + * pm_runtime functions are lightweight increments of a refcount. + */ + pm_runtime_get_sync(pdata->dev); + ret = regmap_read(pdata->regmap, SN_GPIO_IO_REG, &val); + pm_runtime_put(pdata->dev); + + if (ret) + return ret; + + return !!(val & BIT(SN_GPIO_INPUT_SHIFT + offset)); +} + +static void ti_sn_bridge_gpio_set(struct gpio_chip *chip, unsigned int offset, + int val) +{ + struct ti_sn_bridge *pdata = gpiochip_get_data(chip); + int ret; + + if (!test_bit(offset, pdata->gchip_output)) { + dev_err(pdata->dev, "Ignoring GPIO set while input\n"); + return; + } + + val &= 1; + ret = regmap_update_bits(pdata->regmap, SN_GPIO_IO_REG, + BIT(SN_GPIO_OUTPUT_SHIFT + offset), + val << (SN_GPIO_OUTPUT_SHIFT + offset)); +} + +static int ti_sn_bridge_gpio_direction_input(struct gpio_chip *chip, + unsigned int offset) +{ + struct ti_sn_bridge *pdata = gpiochip_get_data(chip); + int shift = offset * 2; + int ret; + + if (!test_and_clear_bit(offset, pdata->gchip_output)) + return 0; + + ret = regmap_update_bits(pdata->regmap, SN_GPIO_CTRL_REG, + SN_GPIO_MUX_MASK << shift, + SN_GPIO_MUX_INPUT << shift); + if (ret) { + set_bit(offset, pdata->gchip_output); + return ret; + } + + /* + * NOTE: if nobody else is powering the device this may fully power + * it off and when it comes back it will have lost all state, but + * that's OK because the default is input and we're now an input. + */ + pm_runtime_put(pdata->dev); + + return 0; +} + +static int ti_sn_bridge_gpio_direction_output(struct gpio_chip *chip, + unsigned int offset, int val) +{ + struct ti_sn_bridge *pdata = gpiochip_get_data(chip); + int shift = offset * 2; + int ret; + + if (test_and_set_bit(offset, pdata->gchip_output)) + return 0; + + pm_runtime_get_sync(pdata->dev); + + /* Set value first to avoid glitching */ + ti_sn_bridge_gpio_set(chip, offset, val); + + /* Set direction */ + ret = regmap_update_bits(pdata->regmap, SN_GPIO_CTRL_REG, + SN_GPIO_MUX_MASK << shift, + SN_GPIO_MUX_OUTPUT << shift); + if (ret) { + clear_bit(offset, pdata->gchip_output); + pm_runtime_put(pdata->dev); + } + + return ret; +} + +static void ti_sn_bridge_gpio_free(struct gpio_chip *chip, unsigned int offset) +{ + /* We won't keep pm_runtime if we're input, so switch there on free */ + ti_sn_bridge_gpio_direction_input(chip, offset); +} + +static const char * const ti_sn_bridge_gpio_names[SN_NUM_GPIOS] = { + "GPIO1", "GPIO2", "GPIO3", "GPIO4" +}; + +static int ti_sn_setup_gpio_controller(struct ti_sn_bridge *pdata) +{ + int ret; + + /* Only init if someone is going to use us as a GPIO controller */ + if (!of_property_read_bool(pdata->dev->of_node, "gpio-controller")) + return 0; + + pdata->gchip.label = dev_name(pdata->dev); + pdata->gchip.parent = pdata->dev; + pdata->gchip.owner = THIS_MODULE; + pdata->gchip.of_xlate = tn_sn_bridge_of_xlate; + pdata->gchip.of_gpio_n_cells = 2; + pdata->gchip.free = ti_sn_bridge_gpio_free; + pdata->gchip.get_direction = ti_sn_bridge_gpio_get_direction; + pdata->gchip.direction_input = ti_sn_bridge_gpio_direction_input; + pdata->gchip.direction_output = ti_sn_bridge_gpio_direction_output; + pdata->gchip.get = ti_sn_bridge_gpio_get; + pdata->gchip.set = ti_sn_bridge_gpio_set; + pdata->gchip.can_sleep = true; + pdata->gchip.names = ti_sn_bridge_gpio_names; + pdata->gchip.ngpio = SN_NUM_GPIOS; + ret = devm_gpiochip_add_data(pdata->dev, &pdata->gchip, pdata); + if (ret) + dev_err(pdata->dev, "can't add gpio chip\n"); + + return ret; +} + static int ti_sn_bridge_probe(struct i2c_client *client, const struct i2c_device_id *id) { @@ -937,6 +1145,12 @@ static int ti_sn_bridge_probe(struct i2c_client *client, pm_runtime_enable(pdata->dev); + ret = ti_sn_setup_gpio_controller(pdata); + if (ret) { + pm_runtime_disable(pdata->dev); + return ret; + } + i2c_set_clientdata(client, pdata); pdata->aux.name = "ti-sn65dsi86-aux";