From: Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
To: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>,
devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
Rob Landley <rob-VoJi6FS/r0vR7s880joybQ@public.gmane.org>,
linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: [PATCH 01/17] Documentation: i2c: describe devicetree method for instantiating devices
Date: Mon, 10 Feb 2014 11:03:55 +0100 [thread overview]
Message-ID: <1392026654-5343-2-git-send-email-wsa@the-dreams.de> (raw)
In-Reply-To: <1392026654-5343-1-git-send-email-wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
Signed-off-by: Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
---
Documentation/i2c/instantiating-devices | 34 +++++++++++++++++++++++++++++++--
1 file changed, 32 insertions(+), 2 deletions(-)
diff --git a/Documentation/i2c/instantiating-devices b/Documentation/i2c/instantiating-devices
index c70e7a7..6df095a 100644
--- a/Documentation/i2c/instantiating-devices
+++ b/Documentation/i2c/instantiating-devices
@@ -8,8 +8,8 @@ reason, the kernel code must instantiate I2C devices explicitly. There are
several ways to achieve this, depending on the context and requirements.
-Method 1: Declare the I2C devices by bus number
------------------------------------------------
+Method 1a: Declare the I2C devices by bus number
+------------------------------------------------
This method is appropriate when the I2C bus is a system bus as is the case
for many embedded systems. On such systems, each I2C bus has a number
@@ -51,6 +51,36 @@ The devices will be automatically unbound and destroyed when the I2C bus
they sit on goes away (if ever.)
+Method 1b: Declare the I2C devices via devicetree
+-------------------------------------------------
+
+This method has the same implications as method 1a. The declaration of I2C
+devices is here done via devicetree as subnodes of the master controller.
+
+Example:
+
+ i2c1: i2c@400a0000 {
+ /* ... master properties skipped ... */
+ clock-frequency = <100000>;
+
+ flash@50 {
+ compatible = "atmel,24c256";
+ reg = <0x50>;
+ };
+
+ pca9532: gpio@60 {
+ compatible = "nxp,pca9532";
+ gpio-controller;
+ #gpio-cells = <2>;
+ reg = <0x60>;
+ };
+ };
+
+Here, two devices are attached to the bus using a speed of 100kHz. For
+additional properties which might be needed to set up the device, please refer
+to its devicetree documentation in Documentation/devicetree/bindings/.
+
+
Method 2: Instantiate the devices explicitly
--------------------------------------------
--
1.8.5.1
next parent reply other threads:[~2014-02-10 10:03 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1392026654-5343-1-git-send-email-wsa@the-dreams.de>
[not found] ` <1392026654-5343-1-git-send-email-wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
2014-02-10 10:03 ` Wolfram Sang [this message]
2014-02-10 18:21 ` [PATCH 01/17] Documentation: i2c: describe devicetree method for instantiating devices linux
[not found] ` <20140210122119.115858a7ntu4lr40-S15kz1ZIOvSoVoj5zvVkGw@public.gmane.org>
2014-02-12 15:15 ` Wolfram Sang
2014-02-15 14:48 ` Wolfram Sang
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