From patchwork Fri Feb 21 10:14:27 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Quentin Schulz X-Patchwork-Id: 867217 Received: from smtp-190e.mail.infomaniak.ch (smtp-190e.mail.infomaniak.ch [185.125.25.14]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0CF541F4299 for ; Fri, 21 Feb 2025 10:14:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.125.25.14 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740132886; cv=none; b=OqWlcB+0+KqdqohpVX/Ml/vG1g2fxG69ZWBIuKyft34uzv63K9YSXTE3dvKcF61BM0GgHWvg1lpP06D4JKnnfpWYorTjwdLHVUTK1Ro7xwAM49SAK/LyGapl3SXoZqx7VDXLqkQl+6ET3xDK6g2CE5VFO/nS2UjWa69UTlOfK4s= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740132886; c=relaxed/simple; bh=btnEhaUwYw0VeLK58faU2JxTUUH8+nVhoaz8xfFivsc=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=C6j6Ji/Yz79oF9Iu6nAZW+uBivcnSAbj+iIw1Kvqvtddrnk1372cgjdQzBPPoxHJ6u5DGHQp2qykStjXHy80SJ2MkYcZ78PgUN3clXII6saiQ2vqDaRWQy+VDBAj8POYJbJk1jXN0L4l0lTwH1+45iuwoL39DgtfIyVrYWoCQ3E= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=0leil.net; spf=pass smtp.mailfrom=0leil.net; arc=none smtp.client-ip=185.125.25.14 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=0leil.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=0leil.net Received: from smtp-3-0000.mail.infomaniak.ch (unknown [IPv6:2001:1600:4:17::246b]) by smtp-3-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4YzmFs17Mdz4G2; Fri, 21 Feb 2025 11:14:41 +0100 (CET) Received: from unknown by smtp-3-0000.mail.infomaniak.ch (Postfix) with ESMTPA id 4YzmFr4LKKzM2N; Fri, 21 Feb 2025 11:14:40 +0100 (CET) From: Quentin Schulz Date: Fri, 21 Feb 2025 11:14:27 +0100 Subject: [PATCH v2 2/2] gpio: pcf857x: add support for reset-gpios on (most) PCA967x Precedence: bulk X-Mailing-List: linux-gpio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20250221-pca976x-reset-driver-v2-2-a2bcb9fdc256@cherry.de> References: <20250221-pca976x-reset-driver-v2-0-a2bcb9fdc256@cherry.de> In-Reply-To: <20250221-pca976x-reset-driver-v2-0-a2bcb9fdc256@cherry.de> To: Linus Walleij , Bartosz Golaszewski , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Laurent Pinchart Cc: Heiko Stuebner , linux-gpio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Quentin Schulz X-Mailer: b4 0.14.2 X-Infomaniak-Routing: alpha From: Quentin Schulz The PCA9670, PCA9671, PCA9672 and PCA9673 all have a RESETN input pin that is used to reset the I2C GPIO expander. One needs to hold this pin low for at least 4us and the reset should be finished after about 100us according to the datasheet[1]. Once the reset is done, the "registers and I2C-bus state machine will be held in their default state until the RESET input is once again HIGH.". Because the logic is reset, the latch values eventually provided in the Device Tree via lines-initial-states property are inapplicable so they are simply ignored if a reset GPIO is provided. [1] https://www.nxp.com/docs/en/data-sheet/PCA9670.pdf 8.5 and fig 22. Tested-by: Heiko Stuebner # RK3588 Tiger Haikou Video Demo Signed-off-by: Quentin Schulz --- drivers/gpio/gpio-pcf857x.c | 29 +++++++++++++++++++++++++++-- 1 file changed, 27 insertions(+), 2 deletions(-) diff --git a/drivers/gpio/gpio-pcf857x.c b/drivers/gpio/gpio-pcf857x.c index 7c57eaeb0afeba8953d998d8eec60a65b40efb6d..2e5f5d7f886598318b753304e7e0efca54ff8b69 100644 --- a/drivers/gpio/gpio-pcf857x.c +++ b/drivers/gpio/gpio-pcf857x.c @@ -5,6 +5,8 @@ * Copyright (C) 2007 David Brownell */ +#include +#include #include #include #include @@ -272,12 +274,11 @@ static const struct irq_chip pcf857x_irq_chip = { static int pcf857x_probe(struct i2c_client *client) { + struct gpio_desc *reset_gpio; struct pcf857x *gpio; unsigned int n_latch = 0; int status; - device_property_read_u32(&client->dev, "lines-initial-states", &n_latch); - /* Allocate, initialize, and register this gpio_chip. */ gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL); if (!gpio) @@ -297,6 +298,30 @@ static int pcf857x_probe(struct i2c_client *client) gpio->chip.direction_output = pcf857x_output; gpio->chip.ngpio = (uintptr_t)i2c_get_match_data(client); + reset_gpio = devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH); + if (IS_ERR(reset_gpio)) + return dev_err_probe(&client->dev, PTR_ERR(reset_gpio), + "failed to get reset GPIO\n"); + + if (reset_gpio) { + /* Reset already held with devm_gpiod_get_optional with GPIOD_OUT_HIGH */ + fsleep(4); /* tw(rst) > 4us */ + gpiod_set_value_cansleep(reset_gpio, 0); + fsleep(100); /* trst > 100uS */ + + /* + * Performing a reset means "The PCA9670 registers and I2C-bus + * state machine will be held in their default state until the + * RESET input is once again HIGH". + * + * This is the same as writing 1 for all pins, which is the same + * as n_latch=0, the default value of the variable. + */ + } else { + device_property_read_u32(&client->dev, "lines-initial-states", + &n_latch); + } + /* NOTE: the OnSemi jlc1562b is also largely compatible with * these parts, notably for output. It has a low-resolution * DAC instead of pin change IRQs; and its inputs can be the