From patchwork Wed May 29 09:17:39 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bastien Curutchet X-Patchwork-Id: 800361 Received: from relay2-d.mail.gandi.net (relay2-d.mail.gandi.net [217.70.183.194]) (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 7EDFD16A375; Wed, 29 May 2024 09:17:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.183.194 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716974275; cv=none; b=jzDvHMKmJwQDatC+GOCUmzYzlcCr3P0IbcdugnXv4Vm2bT9RYetYz2YCoIqzeEB/4N9n7BSyA0aiD6h9IT5fPmz3IfjQ74k9Ft7oDgwNbKcVXJdAegXnar4/Y5YLQC0J2kTzfC/dWVGUTEP/vzKYAyWv6yK6ZC+FrPoLB2+ybdg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716974275; c=relaxed/simple; bh=rAquyJjGl8AvRSJGDILkpKhh6ptv3dUO3G5M0U8rfq4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Z5+maAOZGZl46JWZclXq75OTkL10LVPByac2XVAMsSatWBDxKGdxdoGIzthf2p8S2O1gZldLTVyyoNezoDXB4Ey6rjFeipXLfj1/N4g/drqM2OuAJakRVz/hdL+KHqYQ0GYA6L8rQvVbJtjQlpN5C0MKrPUlDd1EPlrVkky3rtI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=H0r7cZOl; arc=none smtp.client-ip=217.70.183.194 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="H0r7cZOl" Received: by mail.gandi.net (Postfix) with ESMTPA id C6BE740009; Wed, 29 May 2024 09:17:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1716974266; 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=avFH+TZR+wV/3lFdLJG11Lahbf9QsDr/KQUzB649vpc=; b=H0r7cZOlg4xUHgNF6KRBu97q0RWPV3zMDpjmjiulr6EXDEx6COUcc3lg9xIFuVgh2VSavM gmc8kRdvwLGhIuv2r3BIjci74MoiNRvmyaHCT4Vb3thdGVp8ZxfjJMJaAFEPMmAVa87/3q e2icDhz1jZ/B+C1kUeJZk+C1SMksPhIIs5ZcRJvLoCs2jJsNqX9eSLZi77E1ZhBNfNekhR G9wmNVj5Onn+u6wxN/yx+mdNd64sPFiAKkwmkE9gsFBhZ/nAJzOCfGcMkTJ7vHqZgAjYz0 ucQHGCC1flZTO6ft8JxV3hgffAu4ruTLIIy0uwLJ47b2crTb6QfquWIywBlyfw== From: Bastien Curutchet To: Peter Rosin , Andi Shyti , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Peter Korsgaard , Wolfram Sang Cc: linux-i2c@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Thomas Petazzoni , Herve Codina , Christopher Cordahi , Bastien Curutchet Subject: [PATCH v2 3/3] i2c: mux: gpio: Add support for the 'transition-delay-us' property Date: Wed, 29 May 2024 11:17:39 +0200 Message-ID: <20240529091739.10808-4-bastien.curutchet@bootlin.com> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240529091739.10808-1-bastien.curutchet@bootlin.com> References: <20240529091739.10808-1-bastien.curutchet@bootlin.com> Precedence: bulk X-Mailing-List: linux-i2c@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-GND-Sasl: bastien.curutchet@bootlin.com Some hardware need some time to switch from a bus to another. This can cause the first transfers following the selection of a bus to fail. There is no way to configure this kind of waiting time in the driver. Add support for the 'transition-delay-us' device-tree property. When set, the i2c_mux_gpio_select() applies a delay before returning, leaving enough time to the hardware to switch to the new bus. Signed-off-by: Bastien Curutchet --- drivers/i2c/muxes/i2c-mux-gpio.c | 6 ++++++ include/linux/platform_data/i2c-mux-gpio.h | 2 ++ 2 files changed, 8 insertions(+) diff --git a/drivers/i2c/muxes/i2c-mux-gpio.c b/drivers/i2c/muxes/i2c-mux-gpio.c index c61e9d9ea695..b9cfc80660e2 100644 --- a/drivers/i2c/muxes/i2c-mux-gpio.c +++ b/drivers/i2c/muxes/i2c-mux-gpio.c @@ -6,6 +6,7 @@ */ #include +#include #include #include #include @@ -37,6 +38,9 @@ static int i2c_mux_gpio_select(struct i2c_mux_core *muxc, u32 chan) i2c_mux_gpio_set(mux, chan); + if (mux->data.transition_delay) + udelay(mux->data.transition_delay); + return 0; } @@ -116,6 +120,8 @@ static int i2c_mux_gpio_probe_fw(struct gpiomux *mux, if (device_property_read_u32(dev, "idle-state", &mux->data.idle)) mux->data.idle = I2C_MUX_GPIO_NO_IDLE; + device_property_read_u32(dev, "transition-delay-us", &mux->data.transition_delay); + return 0; } diff --git a/include/linux/platform_data/i2c-mux-gpio.h b/include/linux/platform_data/i2c-mux-gpio.h index 816a4cd3ccb5..c449f714d32b 100644 --- a/include/linux/platform_data/i2c-mux-gpio.h +++ b/include/linux/platform_data/i2c-mux-gpio.h @@ -19,6 +19,7 @@ * position * @n_values: Number of multiplexer positions (busses to instantiate) * @idle: Bitmask to write to MUX when idle or GPIO_I2CMUX_NO_IDLE if not used + * @transition_delay: Delay to wait when a new bus is selected */ struct i2c_mux_gpio_platform_data { int parent; @@ -26,6 +27,7 @@ struct i2c_mux_gpio_platform_data { const unsigned *values; int n_values; unsigned idle; + int transition_delay; }; #endif /* _LINUX_I2C_MUX_GPIO_H */