From: Matthias Schwarzott <zzam@gentoo.org>
To: Antti Palosaari <crope@iki.fi>,
linux-media@vger.kernel.org, mchehab@osg.samsung.com
Subject: Re: [PATCH V2 08/13] cx231xx: remember status of i2c port_3 switch
Date: Wed, 01 Oct 2014 23:02:33 +0200 [thread overview]
Message-ID: <542C6BE9.40309@gentoo.org> (raw)
In-Reply-To: <542C57D4.4000004@iki.fi>
On 01.10.2014 21:36, Antti Palosaari wrote:
> I don't understand that patch. Commit message should explain it likely
> better details.
>
> You added flag 'port_3_switch_enabled' to device state. That is for I2C
> mux, but what it means? Does it means mux is currently switched to to
> port 3? Later you will use that flag to avoid unnecessary mux switching?
>
You are right, it should be described better.
Basically it is to be able to query the state of the mux.
This is in the next patch used for the hack that detects if a specific
tuner on a specific bus is accessed.
It is not used to suppress unnecessary switching.
The switching function explicitly reads the switch register and only
writes it if the value is different.
But maybe it would be more consistent if in this case the code also
reads the register.
Regards
Matthias
> regards
> Antti
>
>
>
> On 10/01/2014 08:20 AM, Matthias Schwarzott wrote:
>> If remembering is not stable enough, this must be changed to query
>> from the register when needed.
>>
>> Signed-off-by: Matthias Schwarzott <zzam@gentoo.org>
>> ---
>> drivers/media/usb/cx231xx/cx231xx-avcore.c | 3 +++
>> drivers/media/usb/cx231xx/cx231xx.h | 1 +
>> 2 files changed, 4 insertions(+)
>>
>> diff --git a/drivers/media/usb/cx231xx/cx231xx-avcore.c
>> b/drivers/media/usb/cx231xx/cx231xx-avcore.c
>> index 40a6987..4c85b6f 100644
>> --- a/drivers/media/usb/cx231xx/cx231xx-avcore.c
>> +++ b/drivers/media/usb/cx231xx/cx231xx-avcore.c
>> @@ -1294,6 +1294,9 @@ int cx231xx_enable_i2c_port_3(struct cx231xx
>> *dev, bool is_port_3)
>> status = cx231xx_write_ctrl_reg(dev, VRT_SET_REGISTER,
>> PWR_CTL_EN, value, 4);
>>
>> + if (status >= 0)
>> + dev->port_3_switch_enabled = is_port_3;
>> +
>> return status;
>>
>> }
>> diff --git a/drivers/media/usb/cx231xx/cx231xx.h
>> b/drivers/media/usb/cx231xx/cx231xx.h
>> index f03338b..8a3c97b 100644
>> --- a/drivers/media/usb/cx231xx/cx231xx.h
>> +++ b/drivers/media/usb/cx231xx/cx231xx.h
>> @@ -629,6 +629,7 @@ struct cx231xx {
>> /* I2C adapters: Master 1 & 2 (External) & Master 3 (Internal
>> only) */
>> struct cx231xx_i2c i2c_bus[3];
>> unsigned int xc_fw_load_done:1;
>> + unsigned int port_3_switch_enabled:1;
>> /* locks */
>> struct mutex gpio_i2c_lock;
>> struct mutex i2c_lock;
>>
>
next prev parent reply other threads:[~2014-10-01 21:02 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-01 5:20 [PATCH V2 00/13] cx231xx: Use muxed i2c adapters instead of custom switching Matthias Schwarzott
2014-10-01 5:20 ` [PATCH V2 01/13] cx231xx: let i2c bus scanning use its own i2c_client Matthias Schwarzott
2014-10-01 5:20 ` [PATCH V2 02/13] cx231xx: use own i2c_client for eeprom access Matthias Schwarzott
2014-10-01 5:20 ` [PATCH V2 03/13] cx231xx: delete i2c_client per bus Matthias Schwarzott
2014-10-01 5:20 ` [PATCH V2 04/13] cx231xx: give each master i2c bus a seperate name Matthias Schwarzott
2014-10-01 19:22 ` Antti Palosaari
2014-10-02 5:16 ` Matthias Schwarzott
2014-10-01 5:20 ` [PATCH V2 05/13] cx231xx: Modifiy the symbolic constants for i2c ports and describe Matthias Schwarzott
2014-10-01 19:12 ` Antti Palosaari
2014-10-01 5:20 ` [PATCH V2 06/13] cx231xx: Use symbolic constants for i2c ports instead of numbers Matthias Schwarzott
2014-10-01 5:20 ` [PATCH V2 07/13] cx231xx: add wrapper to get the i2c_adapter pointer Matthias Schwarzott
2014-10-01 19:28 ` Antti Palosaari
2014-10-01 5:20 ` [PATCH V2 08/13] cx231xx: remember status of i2c port_3 switch Matthias Schwarzott
2014-10-01 19:36 ` Antti Palosaari
2014-10-01 21:02 ` Matthias Schwarzott [this message]
2014-10-01 5:20 ` [PATCH V2 09/13] cx231xx: let is_tuner check the real i2c port and not the i2c master number Matthias Schwarzott
2014-10-01 5:20 ` [PATCH V2 10/13] cx231xx: change usage of I2C_1 to the real i2c port Matthias Schwarzott
2014-10-01 19:40 ` Antti Palosaari
2014-10-01 5:20 ` [PATCH V2 11/13] cx231xx: register i2c mux adapters for master1 and use as I2C_1_MUX_1 and I2C_1_MUX_3 Matthias Schwarzott
2014-10-01 19:43 ` Antti Palosaari
2014-10-01 5:20 ` [PATCH V2 12/13] cx231xx: drop unconditional port3 switching Matthias Schwarzott
2014-10-01 5:20 ` [PATCH V2 13/13] cx231xx: scan all four existing i2c busses instead of the 3 masters Matthias Schwarzott
2014-10-01 19:47 ` Antti Palosaari
2014-10-02 4:31 ` Matthias Schwarzott
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