From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Daney Subject: [PATCH v2 2/2] i2c/of: Automatically populate i2c mux busses from device tree data. Date: Tue, 27 Sep 2011 16:16:24 -0700 Message-ID: <1317165384-20390-3-git-send-email-david.daney@cavium.com> References: <1317165384-20390-1-git-send-email-david.daney@cavium.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1317165384-20390-1-git-send-email-david.daney-YGCgFSpz5w/QT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org Sender: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org To: khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org, ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org, peter.korsgaard-ob4gmnvZ1/cAvxtiuMwx3w@public.gmane.org, guenter.roeck-IzeFyvvaP7pWk0Htik3J/w@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-i2c@vger.kernel.org For 'normal' i2c bus drivers, we can call of_i2c_register_devices() and have the device tree framework automatically populate the bus with the devices specified in the device tree. This patch adds a common code to the i2c mux framework to have the mux sub-busses be populated by the of_i2c_register_devices() too. If the mux device has an of_node, we populate the sub-bus' of_node so that the subsequent call to of_i2c_register_devices() will find the corresponding devices. It seemed better to put this logic in i2c_add_mux_adapter() rather than the individual mux drivers, as they will all probably want to do the same thing. Signed-off-by: David Daney --- Documentation/devicetree/bindings/i2c/mux.txt | 60 +++++++++++++++++++++++++ drivers/i2c/i2c-mux.c | 25 ++++++++++ 2 files changed, 85 insertions(+), 0 deletions(-) create mode 100644 Documentation/devicetree/bindings/i2c/mux.txt diff --git a/Documentation/devicetree/bindings/i2c/mux.txt b/Documentation/devicetree/bindings/i2c/mux.txt new file mode 100644 index 0000000..af84cce --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/mux.txt @@ -0,0 +1,60 @@ +Common i2c bus multiplexer/switch properties. + +An i2c bus multiplexer/switch will have several child busses that are +numbered uniquely in a device dependent manner. The nodes for an i2c bus +multiplexer/switch will have one child node for each child +bus. + +Required properties: +- #address-cells = <1>; +- #size-cells = <0>; + +Required properties for child nodes: +- #address-cells = <1>; +- #size-cells = <0>; +- reg : The sub-bus number. + +Optional properties for child nodes: +- Other properties specific to the multiplexer/switch hardware. +- Child nodes conforming to i2c bus binding + + +Example : + + /* + An NXP pca9548 8 channel I2C multiplexer at address 0x70 + with two NXP pca8574 GPIO expanders attached, one each to + ports 3 and 4. + */ + + mux@70 { + compatible = "nxp,pca9548"; + reg = <0x70>; + #address-cells = <1>; + #size-cells = <0>; + + i2c@3 { + #address-cells = <1>; + #size-cells = <0>; + reg = <3>; + + gpio1: gpio@38 { + compatible = "nxp,pca8574"; + reg = <0x38>; + #gpio-cells = <2>; + gpio-controller; + }; + }; + i2c@4 { + #address-cells = <1>; + #size-cells = <0>; + reg = <4>; + + gpio2: gpio@38 { + compatible = "nxp,pca8574"; + reg = <0x38>; + #gpio-cells = <2>; + gpio-controller; + }; + }; + }; diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c index 26ab31d..bebf94d 100644 --- a/drivers/i2c/i2c-mux.c +++ b/drivers/i2c/i2c-mux.c @@ -24,6 +24,8 @@ #include #include #include +#include +#include /* multiplexer per channel data */ struct i2c_mux_priv { @@ -142,6 +144,29 @@ struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent, dev_info(&parent->dev, "Added multiplexed i2c bus %d\n", i2c_adapter_id(&priv->adap)); +#ifdef CONFIG_OF + /* Try to get populate the mux adapter's of_node */ + if (mux_dev->of_node) { + struct device_node *child = NULL; + const __be32 *reg; + int len; + + for (;;) { + child = of_get_next_child(mux_dev->of_node, child); + if (!child) + break; + reg = of_get_property(child, "reg", &len); + if (!reg || (len < sizeof(__be32))) + continue; + if (chan_id == be32_to_cpup(reg)) { + priv->adap.dev.of_node = child; + break; + } + } + } + of_i2c_register_devices(&priv->adap); +#endif + return &priv->adap; } EXPORT_SYMBOL_GPL(i2c_add_mux_adapter); -- 1.7.2.3