From patchwork Thu Apr 30 19:46:12 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 11521383 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9716815E6 for ; Thu, 30 Apr 2020 19:47:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7773D207DD for ; Thu, 30 Apr 2020 19:47:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="XkUJdR8V" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726871AbgD3TrC (ORCPT ); Thu, 30 Apr 2020 15:47:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54378 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726788AbgD3Tq3 (ORCPT ); Thu, 30 Apr 2020 15:46:29 -0400 Received: from mail-pg1-x541.google.com (mail-pg1-x541.google.com [IPv6:2607:f8b0:4864:20::541]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0C1F0C035494 for ; Thu, 30 Apr 2020 12:46:28 -0700 (PDT) Received: by mail-pg1-x541.google.com with SMTP id n11so3350566pgl.9 for ; Thu, 30 Apr 2020 12:46:28 -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=NxGWym6M39FpWdScigAXkwBmrVrNXh+0LWhd39ynj6c=; b=XkUJdR8V1C3am+EJyt9UZIe3TO+QKdIR5fwICpZC4ZHIh7XC6dK2m/2frGsFFmVF4+ XFvFRZDs/uKFuBsrAMBeFg/o5gbGXanTomcJTZ9gpykF5Op/zXbfwstVNm9poKskcXUU D4k5+FuOjdrHtSTiIAZzl4puSjm+lATNc65ww= 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=NxGWym6M39FpWdScigAXkwBmrVrNXh+0LWhd39ynj6c=; b=CWxDDWKW3PzhdLvhceNUHNzo4DLWIvQoqIY75RdQwbTaenNLXReD35XtysovnrOeyo eE53dRErTgtZKriLDRWQnYunYaCQonGtLokQ6BzDDQg6cg+riEejvOf17BvuEiDN/gz/ qWsqWXrzIrWGipiDNeyct+pxCK26Q8jcUs5AOoJxrHG0C+sUgGgAqGj9jnaDpKdONUKt kVAZAcdhQRJWO1o2n8k8Ux85l8vuGtUPAX29lmX9IPl/omnHSj92CjWPizk56hm7wph3 JbYQG4nhHmpCGNYxitvz8c/Ke8SIAmOkJ0/aSH2HTtLa11YzkkPJ/iwSeRKjx4tiOYiw 2cNg== X-Gm-Message-State: AGi0PuYjSpzGNgQY7CAEeXBxeQDBpu6q6WFqnHtrDFqxWpy6y6GwHcNX gIlaLrBivGL1BuqjUhZqdA046Q== X-Google-Smtp-Source: APiQypI8SL4AfT1E4wyLsRXT6pVJShj3Chcf1e1fcW4Z6r9ohTrqxNdAMX2KVlkj3fEWUtQ5+gqT5Q== X-Received: by 2002:a62:f247:: with SMTP id y7mr387808pfl.200.1588275987416; Thu, 30 Apr 2020 12:46:27 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:1:24fa:e766:52c9:e3b2]) by smtp.gmail.com with ESMTPSA id u3sm495993pfb.105.2020.04.30.12.46.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Apr 2020 12:46:26 -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: linux-gpio@vger.kernel.org, jonas@kwiboo.se, robdclark@chromium.org, bjorn.andersson@linaro.org, jeffrey.l.hugo@gmail.com, jernej.skrabec@siol.net, dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org, swboyd@chromium.org, Douglas Anderson , linux-kernel@vger.kernel.org Subject: [PATCH v4 1/6] drm/bridge: ti-sn65dsi86: Export bridge GPIOs to Linux Date: Thu, 30 Apr 2020 12:46:12 -0700 Message-Id: <20200430124442.v4.1.Ia50267a5549392af8b37e67092ca653a59c95886@changeid> X-Mailer: git-send-email 2.26.2.526.g744177e7f7-goog In-Reply-To: <20200430194617.197510-1-dianders@chromium.org> References: <20200430194617.197510-1-dianders@chromium.org> MIME-Version: 1.0 Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@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 Reviewed-by: Stephen Boyd --- 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 | 195 ++++++++++++++++++++++++++ 1 file changed, 195 insertions(+) diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c index 6ad688b320ae..1a125423eb07 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 +98,34 @@ #define SN_REGULATOR_SUPPLY_NUM 4 +#define SN_NUM_GPIOS 4 + +/** + * 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 +140,9 @@ 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 +915,154 @@ static int ti_sn_bridge_parse_dsi_host(struct ti_sn_bridge *pdata) return 0; } +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.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 +1126,12 @@ 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";