Hi Peter, Ken,
On 03/20/2018 11:32 AM, Peter Rosin wrote:
> Make the arbitrate and release_bus implementation chip specific.
>
by chance I took a look at the original implementation done by Ken, and
I would say that this 3/3 change is an overkill as a too generic one.
Is there any next observable extension? And do two abstracted (*arbitrate)
and (*release_bus) cover it well? Probably no.
At first it would be simpler to add a new chip id field into struct pca9541
(struct rename would be needed of course), and do a selection of specific
pca9x41_arbitrate() and pca9x41_release_bus() depending on it:
----8<----
diff --git a/drivers/i2c/muxes/i2c-mux-pca9541.c b/drivers/i2c/muxes/i2c-mux-pca9541.c
index 47685eb..a40e6d8 100644
--- a/drivers/i2c/muxes/i2c-mux-pca9541.c
+++ b/drivers/i2c/muxes/i2c-mux-pca9541.c
@@ -70,8 +70,13 @@
#define SELECT_DELAY_SHORT 50
#define SELECT_DELAY_LONG 1000
+enum chip_id {
+ pca9541,
+};
+
struct pca9541 {
struct i2c_client *client;
+ enum chip_id id;
unsigned long select_timeout;
unsigned long arb_timeout;
};
@@ -188,10 +193,13 @@ static int pca9541_reg_read(struct i2c_client *client, u8 command)
*/
/* Release bus. Also reset NTESTON and BUSINIT if it was set. */
-static void pca9541_release_bus(struct i2c_client *client)
+static void pca9541_release_bus(struct i2c_client *client, enum chip_id id)
{
int reg;
+ if (id != pca9541)
+ return;
+
reg = pca9541_reg_read(client, PCA9541_CONTROL);
if (reg >= 0 && !pca9541_busoff(reg) && pca9541_mybus(reg))
pca9541_reg_write(client, PCA9541_CONTROL,
@@ -235,12 +243,15 @@ static const u8 pca9541_control[16] = {
* 0 : bus not acquired
* 1 : bus acquired
*/
-static int pca9541_arbitrate(struct i2c_client *client)
+static int pca9541_arbitrate(struct i2c_client *client, enum chip_id id)
{
struct i2c_mux_core *muxc = i2c_get_clientdata(client);
struct pca9541 *data = i2c_mux_priv(muxc);
int reg;
+ if (id != pca9541)
+ return -EOPNOTSUPP;
+
reg = pca9541_reg_read(client, PCA9541_CONTROL);
if (reg < 0)
return reg;
@@ -318,7 +329,7 @@ static int pca9541_select_chan(struct i2c_mux_core *muxc, u32 chan)
/* force bus ownership after this time */
do {
- ret = pca9541_arbitrate(client);
+ ret = pca9541_arbitrate(client, data->id);
if (ret)
return ret < 0 ? ret : 0;
@@ -336,7 +347,7 @@ static int pca9541_release_chan(struct i2c_mux_core *muxc, u32 chan)
struct pca9541 *data = i2c_mux_priv(muxc);
struct i2c_client *client = data->client;
- pca9541_release_bus(client);
+ pca9541_release_bus(client, data->id);
return 0;
}
@@ -361,7 +372,7 @@ static int pca9541_probe(struct i2c_client *client,
* We have to lock the adapter before releasing the bus.
*/
i2c_lock_adapter(adap);
- pca9541_release_bus(client);
+ pca9541_release_bus(client, pca9541);
i2c_unlock_adapter(adap);
/* Create mux adapter */
@@ -377,6 +388,7 @@ static int pca9541_probe(struct i2c_client *client,
data = i2c_mux_priv(muxc);
data->client = client;
+ data->id = pca9541;
i2c_set_clientdata(client, muxc);
----8<----
> Signed-off-by: Peter Rosin <peda@xxxxxxxxxx>
> ---
> drivers/i2c/muxes/i2c-mux-pca9541.c | 62 +++++++++++++++++++++++++++----------
> 1 file changed, 45 insertions(+), 17 deletions(-)
>
The change above is trivial and it does not cancel any further
extensions similar to your idea, the open question is if there
is a demand right at the moment.
> diff --git a/drivers/i2c/muxes/i2c-mux-pca9541.c b/drivers/i2c/muxes/i2c-mux-pca9541.c
> index 47685eb4e0e9..cac629e36bf8 100644
> --- a/drivers/i2c/muxes/i2c-mux-pca9541.c
> +++ b/drivers/i2c/muxes/i2c-mux-pca9541.c
> @@ -23,6 +23,7 @@
> #include <linux/i2c-mux.h>
> #include <linux/jiffies.h>
> #include <linux/module.h>
> +#include <linux/of_device.h>
> #include <linux/platform_data/pca954x.h>
> #include <linux/slab.h>
>
> @@ -70,26 +71,22 @@
> #define SELECT_DELAY_SHORT 50
> #define SELECT_DELAY_LONG 1000
>
> -struct pca9541 {
> - struct i2c_client *client;
> - unsigned long select_timeout;
> - unsigned long arb_timeout;
> +enum chip_name {
chip_name sound like a string storage, chip_id might be better here.
> + pca9541,
> };
>
--
With best wishes,
Vladimir
