Re: [PATCH linux dev-4.16 v2] i2c: muxes: pca9641: new driver
2018-04-13 15:27 GMT+08:00 Peter Rosin : > On 2018-04-13 08:59, ChenKenYY 陳永營 TAO wrote: >> Hi Peter, >> >> Sorry for late. Here has some event at my company which needs to pause >> this work. >> >> If the status changed, I will update my patch. > > No worries, I just want to know how to handle my preparatory patches. If > nothing changes, I think I'll push the first two anyway, but will hold > off the third until there is some real need from it. > > Or can you perhaps make time to test a patch adding pca9641 if I adapt > your code to my 3/3 patch? Then I can put these patches behind me. > I think you can push code first, I will test and update when I ready. Thanks, Ken > Cheers, > Peter
Re: [PATCH linux dev-4.16 v2] i2c: muxes: pca9641: new driver
On 2018-04-13 08:59, ChenKenYY 陳永營 TAO wrote: > Hi Peter, > > Sorry for late. Here has some event at my company which needs to pause > this work. > > If the status changed, I will update my patch. No worries, I just want to know how to handle my preparatory patches. If nothing changes, I think I'll push the first two anyway, but will hold off the third until there is some real need from it. Or can you perhaps make time to test a patch adding pca9641 if I adapt your code to my 3/3 patch? Then I can put these patches behind me. Cheers, Peter
Re: [PATCH linux dev-4.16 v2] i2c: muxes: pca9641: new driver
Hi Peter,
Sorry for late. Here has some event at my company which needs to pause
this work.
If the status changed, I will update my patch.
Thanks.
Ken
2018-04-11 17:37 GMT+08:00 Peter Rosin :
> Hi Ken,
>
> It's been a couple of weeks and I wondered if you are making any
> progress? Simple lack of time perhaps, or are you stuck and need
> help?
>
> Cheers,
> Peter
>
> On 2018-03-20 10:31, Peter Rosin wrote:
>> On 2018-03-20 07:19, Ken Chen wrote:
>>> Signed-off-by: Ken Chen
>>
>> Ok, now that you are not adding a new driver, but instead
>> modify an existing driver, the subject I requested in no
>> longer relevant. Now I would like to see:
>>
>> i2c: mux: pca9541: add support for PCA9641 chips
>>
>> Or something like that.
>>
>>> ---
>>> v1->v2
>>> - Merged PCA9641 code into i2c-mux-pca9541.c
>>> - Modified title
>>> - Add PCA9641 detect function
>>> ---
>>> drivers/i2c/muxes/i2c-mux-pca9541.c | 184
>>> ++--
>>> 1 file changed, 174 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/drivers/i2c/muxes/i2c-mux-pca9541.c
>>> b/drivers/i2c/muxes/i2c-mux-pca9541.c
>>> index 6a39ada..493f947 100644
>>> --- a/drivers/i2c/muxes/i2c-mux-pca9541.c
>>> +++ b/drivers/i2c/muxes/i2c-mux-pca9541.c
>>> @@ -1,5 +1,5 @@
>>> /*
>>> - * I2C multiplexer driver for PCA9541 bus master selector
>>> + * I2C multiplexer driver for PCA9541/PCA9641 bus master selector
>>> *
>>> * Copyright (c) 2010 Ericsson AB.
>>> *
>>> @@ -26,8 +26,8 @@
>>> #include
>>>
>>> /*
>>> - * The PCA9541 is a bus master selector. It supports two I2C masters
>>> connected
>>> - * to a single slave bus.
>>> + * The PCA9541/PCA9641 is a bus master selector. It supports two I2C
>>> masters
>>
>> PCA9541 and PCA9641 are bus master selectors. They support two I2C masters
>>
>> And make sure to lose the trailing space.
>>
>>> + * connected to a single slave bus.
>>> *
>>> * Before each bus transaction, a master has to acquire bus ownership.
>>> After the
>>> * transaction is complete, bus ownership has to be released. This fits
>>> well
>>> @@ -58,11 +58,43 @@
>>> #define PCA9541_ISTAT_MYTEST(1 << 6)
>>> #define PCA9541_ISTAT_NMYTEST (1 << 7)
>>>
>>> +#define PCA9641_ID 0x00
>>> +#define PCA9641_ID_MAGIC0x38
>>> +
>>> +#define PCA9641_CONTROL 0x01
>>> +#define PCA9641_STATUS 0x02
>>> +#define PCA9641_TIME0x03
>>> +
>>> +#define PCA9641_CTL_LOCK_REQBIT(0)
>>> +#define PCA9641_CTL_LOCK_GRANT BIT(1)
>>> +#define PCA9641_CTL_BUS_CONNECT BIT(2)
>>> +#define PCA9641_CTL_BUS_INITBIT(3)
>>> +#define PCA9641_CTL_SMBUS_SWRST BIT(4)
>>> +#define PCA9641_CTL_IDLE_TIMER_DIS BIT(5)
>>> +#define PCA9641_CTL_SMBUS_DIS BIT(6)
>>> +#define PCA9641_CTL_PRIORITYBIT(7)
>>> +
>>> +#define PCA9641_STS_OTHER_LOCK BIT(0)
>>> +#define PCA9641_STS_BUS_INIT_FAIL BIT(1)
>>> +#define PCA9641_STS_BUS_HUNGBIT(2)
>>> +#define PCA9641_STS_MBOX_EMPTY BIT(3)
>>> +#define PCA9641_STS_MBOX_FULL BIT(4)
>>> +#define PCA9641_STS_TEST_INTBIT(5)
>>> +#define PCA9641_STS_SCL_IO BIT(6)
>>> +#define PCA9641_STS_SDA_IO BIT(7)
>>> +
>>> +#define PCA9641_RES_TIME0x03
>>> +
>>> #define BUSON (PCA9541_CTL_BUSON | PCA9541_CTL_NBUSON)
>>> #define MYBUS (PCA9541_CTL_MYBUS | PCA9541_CTL_NMYBUS)
>>> #define mybus(x)(!((x) & MYBUS) || ((x) & MYBUS) == MYBUS)
>>> #define busoff(x) (!((x) & BUSON) || ((x) & BUSON) == BUSON)
>>>
>>> +#define BUSOFF(x, y)(!((x) & PCA9641_CTL_LOCK_GRANT) && \
>>> +!((y) & PCA9641_STS_OTHER_LOCK))
>>> +#define other_lock(x) ((x) & PCA9641_STS_OTHER_LOCK)
>>> +#define lock_grant(x) ((x) & PCA9641_CTL_LOCK_GRANT)
>> These macro names are now completely hideous. They were bad before,
>> but this is just too much for me. So, instead of adding BUSOFF etc,
>> I would like to see all the macros with a chip prefix. But I think
>> they will get overly long, so I think you should just write trivial
>> pca9541_mybus, pca9541_busoff, pca9641_busoff etc functions. The
>> compiler should inline them just fine.
>>
>> The rename of the existing macros and their conversion to functions
>> should be in the first preparatory patch that I mention below. The
>> new functions should be in the second patch.
>>
>>> +
>>> /* arbitration timeouts, in jiffies */
>>> #define ARB_TIMEOUT (HZ / 8)/* 125 ms until forcing bus ownership
>>> */
>>> #define ARB2_TIMEOUT(HZ / 4)/* 250 ms until acquisition
>>> failure */
>>> @@ -79,6 +111,7 @@ struct pca9541 {
>>>
>>> static const struct i2c_device_id pca9541_id[] = {
>>> {"pca9541", 0},
>>> +{"pca9641", 1},
>>
>> You are actually not using this 0/1 difference. Have a look at
>> e.g. how the i2c-mux-pca954x driver uses this as an index into
>>
Re: [PATCH linux dev-4.16 v2] i2c: muxes: pca9641: new driver
Hi Ken,
It's been a couple of weeks and I wondered if you are making any
progress? Simple lack of time perhaps, or are you stuck and need
help?
Cheers,
Peter
On 2018-03-20 10:31, Peter Rosin wrote:
> On 2018-03-20 07:19, Ken Chen wrote:
>> Signed-off-by: Ken Chen
>
> Ok, now that you are not adding a new driver, but instead
> modify an existing driver, the subject I requested in no
> longer relevant. Now I would like to see:
>
> i2c: mux: pca9541: add support for PCA9641 chips
>
> Or something like that.
>
>> ---
>> v1->v2
>> - Merged PCA9641 code into i2c-mux-pca9541.c
>> - Modified title
>> - Add PCA9641 detect function
>> ---
>> drivers/i2c/muxes/i2c-mux-pca9541.c | 184
>> ++--
>> 1 file changed, 174 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/i2c/muxes/i2c-mux-pca9541.c
>> b/drivers/i2c/muxes/i2c-mux-pca9541.c
>> index 6a39ada..493f947 100644
>> --- a/drivers/i2c/muxes/i2c-mux-pca9541.c
>> +++ b/drivers/i2c/muxes/i2c-mux-pca9541.c
>> @@ -1,5 +1,5 @@
>> /*
>> - * I2C multiplexer driver for PCA9541 bus master selector
>> + * I2C multiplexer driver for PCA9541/PCA9641 bus master selector
>> *
>> * Copyright (c) 2010 Ericsson AB.
>> *
>> @@ -26,8 +26,8 @@
>> #include
>>
>> /*
>> - * The PCA9541 is a bus master selector. It supports two I2C masters
>> connected
>> - * to a single slave bus.
>> + * The PCA9541/PCA9641 is a bus master selector. It supports two I2C
>> masters
>
> PCA9541 and PCA9641 are bus master selectors. They support two I2C masters
>
> And make sure to lose the trailing space.
>
>> + * connected to a single slave bus.
>> *
>> * Before each bus transaction, a master has to acquire bus ownership.
>> After the
>> * transaction is complete, bus ownership has to be released. This fits well
>> @@ -58,11 +58,43 @@
>> #define PCA9541_ISTAT_MYTEST(1 << 6)
>> #define PCA9541_ISTAT_NMYTEST (1 << 7)
>>
>> +#define PCA9641_ID 0x00
>> +#define PCA9641_ID_MAGIC0x38
>> +
>> +#define PCA9641_CONTROL 0x01
>> +#define PCA9641_STATUS 0x02
>> +#define PCA9641_TIME0x03
>> +
>> +#define PCA9641_CTL_LOCK_REQBIT(0)
>> +#define PCA9641_CTL_LOCK_GRANT BIT(1)
>> +#define PCA9641_CTL_BUS_CONNECT BIT(2)
>> +#define PCA9641_CTL_BUS_INITBIT(3)
>> +#define PCA9641_CTL_SMBUS_SWRST BIT(4)
>> +#define PCA9641_CTL_IDLE_TIMER_DIS BIT(5)
>> +#define PCA9641_CTL_SMBUS_DIS BIT(6)
>> +#define PCA9641_CTL_PRIORITYBIT(7)
>> +
>> +#define PCA9641_STS_OTHER_LOCK BIT(0)
>> +#define PCA9641_STS_BUS_INIT_FAIL BIT(1)
>> +#define PCA9641_STS_BUS_HUNGBIT(2)
>> +#define PCA9641_STS_MBOX_EMPTY BIT(3)
>> +#define PCA9641_STS_MBOX_FULL BIT(4)
>> +#define PCA9641_STS_TEST_INTBIT(5)
>> +#define PCA9641_STS_SCL_IO BIT(6)
>> +#define PCA9641_STS_SDA_IO BIT(7)
>> +
>> +#define PCA9641_RES_TIME0x03
>> +
>> #define BUSON (PCA9541_CTL_BUSON | PCA9541_CTL_NBUSON)
>> #define MYBUS (PCA9541_CTL_MYBUS | PCA9541_CTL_NMYBUS)
>> #define mybus(x)(!((x) & MYBUS) || ((x) & MYBUS) == MYBUS)
>> #define busoff(x) (!((x) & BUSON) || ((x) & BUSON) == BUSON)
>>
>> +#define BUSOFF(x, y)(!((x) & PCA9641_CTL_LOCK_GRANT) && \
>> +!((y) & PCA9641_STS_OTHER_LOCK))
>> +#define other_lock(x) ((x) & PCA9641_STS_OTHER_LOCK)
>> +#define lock_grant(x) ((x) & PCA9641_CTL_LOCK_GRANT)
> These macro names are now completely hideous. They were bad before,
> but this is just too much for me. So, instead of adding BUSOFF etc,
> I would like to see all the macros with a chip prefix. But I think
> they will get overly long, so I think you should just write trivial
> pca9541_mybus, pca9541_busoff, pca9641_busoff etc functions. The
> compiler should inline them just fine.
>
> The rename of the existing macros and their conversion to functions
> should be in the first preparatory patch that I mention below. The
> new functions should be in the second patch.
>
>> +
>> /* arbitration timeouts, in jiffies */
>> #define ARB_TIMEOUT (HZ / 8)/* 125 ms until forcing bus ownership */
>> #define ARB2_TIMEOUT(HZ / 4)/* 250 ms until acquisition
>> failure */
>> @@ -79,6 +111,7 @@ struct pca9541 {
>>
>> static const struct i2c_device_id pca9541_id[] = {
>> {"pca9541", 0},
>> +{"pca9641", 1},
>
> You are actually not using this 0/1 difference. Have a look at
> e.g. how the i2c-mux-pca954x driver uses this as an index into
> a chip description array. I would like to see something similar
> here...
>
>> {}
>> };
>>
>> @@ -87,6 +120,7 @@ MODULE_DEVICE_TABLE(i2c, pca9541_id);
>> #ifdef CONFIG_OF
>> static const struct of_device_id pca9541_of_match[] = {
>> { .compatible = "nxp,pca9541" },
>> +{ .compatible = "nxp,pca9641"
Re: [PATCH linux dev-4.16 v2] i2c: muxes: pca9641: new driver
On 2018-03-20 07:19, Ken Chen wrote:
> Signed-off-by: Ken Chen
Ok, now that you are not adding a new driver, but instead
modify an existing driver, the subject I requested in no
longer relevant. Now I would like to see:
i2c: mux: pca9541: add support for PCA9641 chips
Or something like that.
> ---
> v1->v2
> - Merged PCA9641 code into i2c-mux-pca9541.c
> - Modified title
> - Add PCA9641 detect function
> ---
> drivers/i2c/muxes/i2c-mux-pca9541.c | 184
> ++--
> 1 file changed, 174 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/i2c/muxes/i2c-mux-pca9541.c
> b/drivers/i2c/muxes/i2c-mux-pca9541.c
> index 6a39ada..493f947 100644
> --- a/drivers/i2c/muxes/i2c-mux-pca9541.c
> +++ b/drivers/i2c/muxes/i2c-mux-pca9541.c
> @@ -1,5 +1,5 @@
> /*
> - * I2C multiplexer driver for PCA9541 bus master selector
> + * I2C multiplexer driver for PCA9541/PCA9641 bus master selector
> *
> * Copyright (c) 2010 Ericsson AB.
> *
> @@ -26,8 +26,8 @@
> #include
>
> /*
> - * The PCA9541 is a bus master selector. It supports two I2C masters
> connected
> - * to a single slave bus.
> + * The PCA9541/PCA9641 is a bus master selector. It supports two I2C masters
PCA9541 and PCA9641 are bus master selectors. They support two I2C masters
And make sure to lose the trailing space.
> + * connected to a single slave bus.
> *
> * Before each bus transaction, a master has to acquire bus ownership. After
> the
> * transaction is complete, bus ownership has to be released. This fits well
> @@ -58,11 +58,43 @@
> #define PCA9541_ISTAT_MYTEST (1 << 6)
> #define PCA9541_ISTAT_NMYTEST(1 << 7)
>
> +#define PCA9641_ID 0x00
> +#define PCA9641_ID_MAGIC 0x38
> +
> +#define PCA9641_CONTROL 0x01
> +#define PCA9641_STATUS 0x02
> +#define PCA9641_TIME 0x03
> +
> +#define PCA9641_CTL_LOCK_REQ BIT(0)
> +#define PCA9641_CTL_LOCK_GRANT BIT(1)
> +#define PCA9641_CTL_BUS_CONNECT BIT(2)
> +#define PCA9641_CTL_BUS_INIT BIT(3)
> +#define PCA9641_CTL_SMBUS_SWRST BIT(4)
> +#define PCA9641_CTL_IDLE_TIMER_DIS BIT(5)
> +#define PCA9641_CTL_SMBUS_DISBIT(6)
> +#define PCA9641_CTL_PRIORITY BIT(7)
> +
> +#define PCA9641_STS_OTHER_LOCK BIT(0)
> +#define PCA9641_STS_BUS_INIT_FAILBIT(1)
> +#define PCA9641_STS_BUS_HUNG BIT(2)
> +#define PCA9641_STS_MBOX_EMPTY BIT(3)
> +#define PCA9641_STS_MBOX_FULLBIT(4)
> +#define PCA9641_STS_TEST_INT BIT(5)
> +#define PCA9641_STS_SCL_IO BIT(6)
> +#define PCA9641_STS_SDA_IO BIT(7)
> +
> +#define PCA9641_RES_TIME 0x03
> +
> #define BUSON(PCA9541_CTL_BUSON | PCA9541_CTL_NBUSON)
> #define MYBUS(PCA9541_CTL_MYBUS | PCA9541_CTL_NMYBUS)
> #define mybus(x) (!((x) & MYBUS) || ((x) & MYBUS) == MYBUS)
> #define busoff(x)(!((x) & BUSON) || ((x) & BUSON) == BUSON)
>
> +#define BUSOFF(x, y) (!((x) & PCA9641_CTL_LOCK_GRANT) && \
> + !((y) & PCA9641_STS_OTHER_LOCK))
> +#define other_lock(x)((x) & PCA9641_STS_OTHER_LOCK)
> +#define lock_grant(x)((x) & PCA9641_CTL_LOCK_GRANT)
These macro names are now completely hideous. They were bad before,
but this is just too much for me. So, instead of adding BUSOFF etc,
I would like to see all the macros with a chip prefix. But I think
they will get overly long, so I think you should just write trivial
pca9541_mybus, pca9541_busoff, pca9641_busoff etc functions. The
compiler should inline them just fine.
The rename of the existing macros and their conversion to functions
should be in the first preparatory patch that I mention below. The
new functions should be in the second patch.
> +
> /* arbitration timeouts, in jiffies */
> #define ARB_TIMEOUT (HZ / 8)/* 125 ms until forcing bus ownership */
> #define ARB2_TIMEOUT (HZ / 4)/* 250 ms until acquisition failure */
> @@ -79,6 +111,7 @@ struct pca9541 {
>
> static const struct i2c_device_id pca9541_id[] = {
> {"pca9541", 0},
> + {"pca9641", 1},
You are actually not using this 0/1 difference. Have a look at
e.g. how the i2c-mux-pca954x driver uses this as an index into
a chip description array. I would like to see something similar
here...
> {}
> };
>
> @@ -87,6 +120,7 @@ MODULE_DEVICE_TABLE(i2c, pca9541_id);
> #ifdef CONFIG_OF
> static const struct of_device_id pca9541_of_match[] = {
> { .compatible = "nxp,pca9541" },
> + { .compatible = "nxp,pca9641" },
...including pointers to the above chip descriptions here, just
like the pca954x driver.
> {}
> };
> MODULE_DEVICE_TABLE(of, pca9541_of_match);
> @@ -328,6 +362,125 @@ static int pca9541_release_chan(struct i2c_mux_core
> *muxc, u32 chan)
> }
>
> /*
> + * Arbitration management functions
> + */
> +static void pca9641_release_bus(struct i2c_client *client)
> +{
> + pca9541_r
Re: [PATCH linux dev-4.16 v2] i2c: muxes: pca9641: new driver
Hi Ken,
A note on your subject line: we use the "linux dev-4.16" style tags in
OpenBMC to indicate which branch you're targetting, but in upstream
Linux we always target the next release, so you don't need to use
--subject-prefix at all.
On Tue, Mar 20, 2018 at 4:49 PM, Ken Chen wrote:
> Signed-off-by: Ken Chen
Try to add some words to the commit message describing why you're
making the change.
I'll leave it to Peter and Guneter to review the implementation.
Cheers,
Joel
>
> ---
> v1->v2
> - Merged PCA9641 code into i2c-mux-pca9541.c
> - Modified title
> - Add PCA9641 detect function
> ---
> drivers/i2c/muxes/i2c-mux-pca9541.c | 184
> ++--
> 1 file changed, 174 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/i2c/muxes/i2c-mux-pca9541.c
> b/drivers/i2c/muxes/i2c-mux-pca9541.c
> index 6a39ada..493f947 100644
> --- a/drivers/i2c/muxes/i2c-mux-pca9541.c
> +++ b/drivers/i2c/muxes/i2c-mux-pca9541.c
> @@ -1,5 +1,5 @@
> /*
> - * I2C multiplexer driver for PCA9541 bus master selector
> + * I2C multiplexer driver for PCA9541/PCA9641 bus master selector
> *
> * Copyright (c) 2010 Ericsson AB.
> *
> @@ -26,8 +26,8 @@
> #include
>
> /*
> - * The PCA9541 is a bus master selector. It supports two I2C masters
> connected
> - * to a single slave bus.
> + * The PCA9541/PCA9641 is a bus master selector. It supports two I2C masters
> + * connected to a single slave bus.
> *
> * Before each bus transaction, a master has to acquire bus ownership. After
> the
> * transaction is complete, bus ownership has to be released. This fits well
> @@ -58,11 +58,43 @@
> #define PCA9541_ISTAT_MYTEST (1 << 6)
> #define PCA9541_ISTAT_NMYTEST (1 << 7)
>
> +#define PCA9641_ID 0x00
> +#define PCA9641_ID_MAGIC 0x38
> +
> +#define PCA9641_CONTROL0x01
> +#define PCA9641_STATUS 0x02
> +#define PCA9641_TIME 0x03
> +
> +#define PCA9641_CTL_LOCK_REQ BIT(0)
> +#define PCA9641_CTL_LOCK_GRANT BIT(1)
> +#define PCA9641_CTL_BUS_CONNECTBIT(2)
> +#define PCA9641_CTL_BUS_INIT BIT(3)
> +#define PCA9641_CTL_SMBUS_SWRSTBIT(4)
> +#define PCA9641_CTL_IDLE_TIMER_DIS BIT(5)
> +#define PCA9641_CTL_SMBUS_DIS BIT(6)
> +#define PCA9641_CTL_PRIORITY BIT(7)
> +
> +#define PCA9641_STS_OTHER_LOCK BIT(0)
> +#define PCA9641_STS_BUS_INIT_FAIL BIT(1)
> +#define PCA9641_STS_BUS_HUNG BIT(2)
> +#define PCA9641_STS_MBOX_EMPTY BIT(3)
> +#define PCA9641_STS_MBOX_FULL BIT(4)
> +#define PCA9641_STS_TEST_INT BIT(5)
> +#define PCA9641_STS_SCL_IO BIT(6)
> +#define PCA9641_STS_SDA_IO BIT(7)
> +
> +#define PCA9641_RES_TIME 0x03
> +
> #define BUSON (PCA9541_CTL_BUSON | PCA9541_CTL_NBUSON)
> #define MYBUS (PCA9541_CTL_MYBUS | PCA9541_CTL_NMYBUS)
> #define mybus(x) (!((x) & MYBUS) || ((x) & MYBUS) == MYBUS)
> #define busoff(x) (!((x) & BUSON) || ((x) & BUSON) == BUSON)
>
> +#define BUSOFF(x, y) (!((x) & PCA9641_CTL_LOCK_GRANT) && \
> + !((y) & PCA9641_STS_OTHER_LOCK))
> +#define other_lock(x) ((x) & PCA9641_STS_OTHER_LOCK)
> +#define lock_grant(x) ((x) & PCA9641_CTL_LOCK_GRANT)
> +
> /* arbitration timeouts, in jiffies */
> #define ARB_TIMEOUT(HZ / 8)/* 125 ms until forcing bus ownership
> */
> #define ARB2_TIMEOUT (HZ / 4)/* 250 ms until acquisition failure */
> @@ -79,6 +111,7 @@ struct pca9541 {
>
> static const struct i2c_device_id pca9541_id[] = {
> {"pca9541", 0},
> + {"pca9641", 1},
> {}
> };
>
> @@ -87,6 +120,7 @@ MODULE_DEVICE_TABLE(i2c, pca9541_id);
> #ifdef CONFIG_OF
> static const struct of_device_id pca9541_of_match[] = {
> { .compatible = "nxp,pca9541" },
> + { .compatible = "nxp,pca9641" },
> {}
> };
> MODULE_DEVICE_TABLE(of, pca9541_of_match);
> @@ -328,6 +362,125 @@ static int pca9541_release_chan(struct i2c_mux_core
> *muxc, u32 chan)
> }
>
> /*
> + * Arbitration management functions
> + */
> +static void pca9641_release_bus(struct i2c_client *client)
> +{
> + pca9541_reg_write(client, PCA9641_CONTROL, 0);
> +}
> +
> +/*
> + * Channel arbitration
> + *
> + * Return values:
> + * <0: error
> + * 0 : bus not acquired
> + * 1 : bus acquired
> + */
> +static int pca9641_arbitrate(struct i2c_client *client)
> +{
> + struct i2c_mux_core *muxc = i2c_get_clientdata(client);
> + struct pca9541 *data = i2c_mux_priv(muxc);
> + int reg_ctl, reg_sts;
> +
> + reg_ctl = pca9541_reg_read(client, PCA9641_CONTROL);
> + if (reg_ctl < 0)
> + return reg_ctl;
> + reg_sts = pca9541_reg_read(client, PCA9641_STATUS);
> +
> + if (BUSOFF(reg_ctl, reg_sts)) {
> + /*
> +* Bus is off. Request ownership or turn it on unless
> +* other master requested ownership.
> +
