Hi Vladimir,
On 2016-08-15 15:55, Vladimir Zapolskiy wrote:
> Hi Peter,
>
> On 08/15/2016 04:40 PM, Peter Rosin wrote:
>> Backwards compatibility is preserved; the subnodes are in practice
>> optional.
>>
>> However, the mux core needs to know what subnode it should examine, so add
>> a couple of new flags for i2c_mux_alloc for this purpose.
>>
>> The rule is that if the mux core finds a 'reg' property in the appropriate
>> subnode, e.g. if 'reg' exists in the 'i2c-mux' subnode, then the mux core
>> will assume that this is an old style entry and not an i2c-mux subnode
>> (correspondingly for arbitrators and gates with 'i2c-arb' and 'i2c-gate').
>>
>> Signed-off-by: Peter Rosin <[email protected]>
>> ---
>> drivers/i2c/i2c-mux.c | 44 ++++++++++++++++++++++++++++++++++++--------
>> include/linux/i2c-mux.h | 8 ++++++--
>> 2 files changed, 42 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c
>> index 8eee98634cda..c1ae719d1a7a 100644
>> --- a/drivers/i2c/i2c-mux.c
>> +++ b/drivers/i2c/i2c-mux.c
>> @@ -255,6 +255,10 @@ struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter
>> *parent,
>> muxc->dev = dev;
>> if (flags & I2C_MUX_LOCKED)
>> muxc->mux_locked = true;
>> + if (flags & I2C_MUX_ARBITRATOR)
>> + muxc->arbitrator = true;
>> + if (flags & I2C_MUX_GATE)
>> + muxc->gate = true;
>> muxc->select = select;
>> muxc->deselect = deselect;
>> muxc->max_adapters = max_adapters;
>> @@ -335,18 +339,42 @@ int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
>> * nothing if !CONFIG_OF.
>> */
>> if (muxc->dev->of_node) {
>> - struct device_node *child;
>> + struct device_node *dev_node = muxc->dev->of_node;
>> + struct device_node *mux_node, *child = NULL;
>> u32 reg;
>>
>> - for_each_child_of_node(muxc->dev->of_node, child) {
>> - ret = of_property_read_u32(child, "reg", ®);
>> - if (ret)
>> - continue;
>> - if (chan_id == reg) {
>> - priv->adap.dev.of_node = child;
>> - break;
>
> missing of_node_put(child);
Note, you are commenting on the old code that is removed, but I don't think
there was any bug. A reference is stored away for later use, so better not
of_node_put(child) or it might disappear from under us. Or do I have a
fundamental misunderstanding?
> Also adding an empty line would be perfect.
Strange comment for the split between removing and adding lines. What do you
mean? I certainly don't miss any empty lines here...
>> + if (muxc->arbitrator)
>> + mux_node = of_get_child_by_name(dev_node, "i2c-arb");
>> + else if (muxc->gate)
>> + mux_node = of_get_child_by_name(dev_node, "i2c-gate");
>> + else
>> + mux_node = of_get_child_by_name(dev_node, "i2c-mux");
>> +
>> + if (mux_node) {
>> + /* A "reg" property indicates an old-style DT entry */
>> + if (!of_property_read_u32(mux_node, "reg", ®)) {
>> + of_node_put(mux_node);
>> + mux_node = NULL;
>> + }
>> + }
>> +
>> + if (!mux_node)
>> + mux_node = of_node_get(dev_node);
>> + else if (muxc->arbitrator || muxc->gate)
>> + child = of_node_get(mux_node);
>> +
>> + if (!child) {
>> + for_each_child_of_node(mux_node, child) {
>> + ret = of_property_read_u32(child, "reg", ®);
>> + if (ret)
>> + continue;
>> + if (chan_id == reg)
>> + break;
>
> missing of_node_put(child);
Here you are commenting on the new code, but I think the same argument
holds here as well. The reference to the child node is stored away...
>> }
>> }
>> +
>> + priv->adap.dev.of_node = child;
...here, for later use (by i2c_add_adapter).
Anyway, IF the of node really should be put, this is orthogonal to what
I'm doing here, and the problem exists in other places as well (just grep
for "dev.of_node = of_node_get". So, that would be fodder for future
patches.
Cheers,
Peter
>> + of_node_put(mux_node);
>> }
>>
>> /*
>> diff --git a/include/linux/i2c-mux.h b/include/linux/i2c-mux.h
>> index d4c1d12f900d..bd74d5706f3b 100644
>> --- a/include/linux/i2c-mux.h
>> +++ b/include/linux/i2c-mux.h
>> @@ -32,7 +32,9 @@
>> struct i2c_mux_core {
>> struct i2c_adapter *parent;
>> struct device *dev;
>> - bool mux_locked;
>> + unsigned int mux_locked:1;
>> + unsigned int arbitrator:1;
>> + unsigned int gate:1;
>>
>> void *priv;
>>
>> @@ -51,7 +53,9 @@ struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter
>> *parent,
>> int (*deselect)(struct i2c_mux_core *, u32));
>>
>> /* flags for i2c_mux_alloc */
>> -#define I2C_MUX_LOCKED BIT(0)
>> +#define I2C_MUX_LOCKED BIT(0)
>> +#define I2C_MUX_ARBITRATOR BIT(1)
>> +#define I2C_MUX_GATE BIT(2)
>>
>> static inline void *i2c_mux_priv(struct i2c_mux_core *muxc)
>> {
>>
