[PATCH v2 1/4] i2c: mux-pinctrl: Rework to honor disabled child nodes
Sebastian Hesselbarth
sebastian.hesselbarth at gmail.com
Fri Feb 27 04:24:42 PST 2015
I2C mux pinctrl driver currently determines the number of sub-busses by
counting available pinctrl-names. Unfortunately, this requires each
incarnation of the devicetree node with different available sub-busses
to be rewritten.
This patch reworks i2c-mux-pinctrl driver to count the number of
available sub-nodes instead. The rework should be compatible to the old
way of probing for sub-busses and additionally allows to disable unused
sub-busses with standard DT property status = "disabled".
This also amends the corresponding devicetree binding documentation to
reflect the new functionality to disable unused sub-nodes. While at it,
also fix two references to binding documentation files that miss an "i2c-"
prefix.
Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth at gmail.com>
Tested-by: Stephen Warren <swarren at nvidia.com>
---
Cc: Jason Cooper <jason at lakedaemon.net>
Cc: Andrew Lunn <andrew at lunn.ch>
Cc: Gregory Clement <gregory.clement at free-electrons.com>
Cc: Gabriel Dobato <dobatog at gmail.com>
Cc: Wolfram Sang <wsa at the-dreams.de>
Cc: Stephen Warren <swarren at wwwdotorg.org>
Cc: linux-i2c at vger.kernel.org
Cc: devicetree at vger.kernel.org
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-kernel at vger.kernel.org
---
.../devicetree/bindings/i2c/i2c-mux-pinctrl.txt | 25 ++++----
drivers/i2c/muxes/i2c-mux-pinctrl.c | 70 ++++++++++++++--------
2 files changed, 59 insertions(+), 36 deletions(-)
diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-pinctrl.txt b/Documentation/devicetree/bindings/i2c/i2c-mux-pinctrl.txt
index ae8af1694e95..40cf6d86f935 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-mux-pinctrl.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-mux-pinctrl.txt
@@ -28,21 +28,21 @@ Also required are:
* Standard pinctrl properties that specify the pin mux state for each child
bus. See ../pinctrl/pinctrl-bindings.txt.
-* Standard I2C mux properties. See mux.txt in this directory.
+* Standard I2C mux properties. See i2c-mux.txt in this directory.
-* I2C child bus nodes. See mux.txt in this directory.
+* I2C child bus nodes. See i2c-mux.txt in this directory.
-For each named state defined in the pinctrl-names property, an I2C child bus
-will be created. I2C child bus numbers are assigned based on the index into
-the pinctrl-names property.
+For each enabled child node an I2C child bus will be created. I2C child bus
+numbers are assigned based on the order of child nodes.
-The only exception is that no bus will be created for a state named "idle". If
-such a state is defined, it must be the last entry in pinctrl-names. For
-example:
+There must be a corresponding pinctrl-names entry for each enabled child
+node at the position of the child node's "reg" property. Also, there can be
+an idle pinctrl state defined at the end of possible pinctrl states. If such
+a state is defined, it must be the last entry in pinctrl-names. For example:
- pinctrl-names = "ddc", "pta", "idle" -> ddc = bus 0, pta = bus 1
- pinctrl-names = "ddc", "idle", "pta" -> Invalid ("idle" not last)
- pinctrl-names = "idle", "ddc", "pta" -> Invalid ("idle" not last)
+ pinctrl-names = "ddc", "pta", "idle" -> ddc = bus 0, pta = bus 1
+ pinctrl-names = "ddc", "idle", "pta" -> Invalid ("idle" not last)
+ pinctrl-names = "idle", "ddc", "pta" -> Invalid ("idle" not last)
Whenever an access is made to a device on a child bus, the relevant pinctrl
state will be programmed into hardware.
@@ -68,6 +68,7 @@ Example:
pinctrl-1 = <&state_i2cmux_pta>;
pinctrl-2 = <&state_i2cmux_idle>;
+ /* Enabled child bus 0 */
i2c at 0 {
reg = <0>;
#address-cells = <1>;
@@ -79,10 +80,12 @@ Example:
};
};
+ /* Disabled child bus 1 */
i2c at 1 {
reg = <1>;
#address-cells = <1>;
#size-cells = <0>;
+ status = "disabled";
eeprom {
compatible = "eeprom";
diff --git a/drivers/i2c/muxes/i2c-mux-pinctrl.c b/drivers/i2c/muxes/i2c-mux-pinctrl.c
index b48378c4b40d..033dacfabfdf 100644
--- a/drivers/i2c/muxes/i2c-mux-pinctrl.c
+++ b/drivers/i2c/muxes/i2c-mux-pinctrl.c
@@ -56,9 +56,12 @@ static int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux,
struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
- int num_names, i, ret;
+ struct device_node *child;
+ struct property *prop;
+ int num_names, num_children, ret;
struct device_node *adapter_np;
struct i2c_adapter *adapter;
+ const char *state;
if (!np)
return 0;
@@ -77,32 +80,16 @@ static int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux,
return num_names;
}
- mux->pdata->pinctrl_states = devm_kzalloc(&pdev->dev,
- sizeof(*mux->pdata->pinctrl_states) * num_names,
- GFP_KERNEL);
- if (!mux->pdata->pinctrl_states) {
- dev_err(mux->dev, "Cannot allocate pinctrl_states\n");
- return -ENOMEM;
+ num_children = of_get_available_child_count(np);
+ if (num_children < 0) {
+ dev_err(mux->dev, "Unable to count available children: %d\n",
+ num_children);
+ return num_children;
}
- for (i = 0; i < num_names; i++) {
- ret = of_property_read_string_index(np, "pinctrl-names", i,
- &mux->pdata->pinctrl_states[mux->pdata->bus_count]);
- if (ret < 0) {
- dev_err(mux->dev, "Cannot parse pinctrl-names: %d\n",
- ret);
- return ret;
- }
- if (!strcmp(mux->pdata->pinctrl_states[mux->pdata->bus_count],
- "idle")) {
- if (i != num_names - 1) {
- dev_err(mux->dev, "idle state must be last\n");
- return -EINVAL;
- }
- mux->pdata->pinctrl_state_idle = "idle";
- } else {
- mux->pdata->bus_count++;
- }
+ if (num_names < num_children) {
+ dev_err(mux->dev, "Found less pinctrl states than children\n");
+ return -EINVAL;
}
adapter_np = of_parse_phandle(np, "i2c-parent", 0);
@@ -118,6 +105,39 @@ static int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux,
mux->pdata->parent_bus_num = i2c_adapter_id(adapter);
put_device(&adapter->dev);
+ mux->pdata->pinctrl_states = devm_kzalloc(&pdev->dev,
+ sizeof(*mux->pdata->pinctrl_states) * num_children,
+ GFP_KERNEL);
+ if (!mux->pdata->pinctrl_states) {
+ dev_err(mux->dev, "Cannot allocate pinctrl_states\n");
+ return -ENOMEM;
+ }
+
+ of_property_for_each_string(np, "pinctrl-names", prop, state)
+ if (!strcmp(state, "idle"))
+ mux->pdata->pinctrl_state_idle = "idle";
+
+ for_each_available_child_of_node(np, child) {
+ u32 reg;
+
+ ret = of_property_read_u32(child, "reg", ®);
+ if (ret < 0) {
+ dev_err(mux->dev, "Missing reg property for child node: %d\n",
+ ret);
+ return ret;
+ }
+
+ ret = of_property_read_string_index(np,
+ "pinctrl-names", reg, &state);
+ if (ret < 0) {
+ dev_err(mux->dev, "Cannot parse pinctrl-names for mux %d: %d\n",
+ reg, ret);
+ return ret;
+ }
+
+ mux->pdata->pinctrl_states[mux->pdata->bus_count++] = state;
+ }
+
return 0;
}
#else
--
2.1.0
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