Re: [PATCH 2/2] drm: adv7511: Add support for i2c_new_secondary_device

[Kieran Bingham]

Hi Archit,

Thank you for your review,

On 29/01/18 04:11, Archit Taneja wrote:
> Hi,
> 
> On 01/22/2018 06:20 PM, Kieran Bingham wrote:
>> The ADV7511 has four 256-byte maps that can be accessed via the main IÂC
>> ports. Each map has it own IÂC address and acts as a standard slave
>> device on the IÂC bus.
>>
>> Allow a device tree node to override the default addresses so that
>> address conflicts with other devices on the same bus may be resolved at
>> the board description level.
>>
>> Signed-off-by: Kieran Bingham <kieran.bingham@xxxxxxxxxxxxxxxx>
>> ---
>> Â .../bindings/display/bridge/adi,adv7511.txtÂÂÂÂÂÂÂ | 10 +++++-
>> Â drivers/gpu/drm/bridge/adv7511/adv7511.hÂÂÂÂÂÂÂÂÂÂ |Â 4 +++
>> Â drivers/gpu/drm/bridge/adv7511/adv7511_drv.cÂÂÂÂÂÂ | 36 ++++++++++++++--------
>> Â 3 files changed, 37 insertions(+), 13 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/display/bridge/adi,adv7511.txt
>> b/Documentation/devicetree/bindings/display/bridge/adi,adv7511.txt
>> index 0047b1394c70..f6bb9f6d3f48 100644
>> --- a/Documentation/devicetree/bindings/display/bridge/adi,adv7511.txt
>> +++ b/Documentation/devicetree/bindings/display/bridge/adi,adv7511.txt
>> @@ -70,6 +70,9 @@ Optional properties:
>> ÂÂÂ rather than generate its own timings for HDMI output.
>> Â - clocks: from common clock binding: reference to the CEC clock.
>> Â - clock-names: from common clock binding: must be "cec".
>> +- reg-names : Names of maps with programmable addresses.
>> +ÂÂÂ It can contain any map needing a non-default address.
>> +ÂÂÂ Possible maps names are : "main", "edid", "cec", "packet"
>> Â Â Required nodes:
>> Â @@ -88,7 +91,12 @@ Example
>> Â ÂÂÂÂÂ adv7511w: hdmi@39 {
>> ÂÂÂÂÂÂÂÂÂ compatible = "adi,adv7511w";
>> -ÂÂÂÂÂÂÂ reg = <39>;
>> +ÂÂÂÂÂÂÂ /*
>> +ÂÂÂÂÂÂÂÂ * The EDID page will be accessible on address 0x66 on the i2c
>> +ÂÂÂÂÂÂÂÂ * bus. All other maps continue to use their default addresses.
>> +ÂÂÂÂÂÂÂÂ */
>> +ÂÂÂÂÂÂÂ reg = <0x39 0x66>;
>> +ÂÂÂÂÂÂÂ reg-names = "main", "edid";
>> ÂÂÂÂÂÂÂÂÂ interrupt-parent = <&gpio3>;
>> ÂÂÂÂÂÂÂÂÂ interrupts = <29 IRQ_TYPE_EDGE_FALLING>;
>> ÂÂÂÂÂÂÂÂÂ clocks = <&cec_clock>;
>> diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511.h
>> b/drivers/gpu/drm/bridge/adv7511/adv7511.h
>> index d034b2cb5eee..7d81ce3808e0 100644
>> --- a/drivers/gpu/drm/bridge/adv7511/adv7511.h
>> +++ b/drivers/gpu/drm/bridge/adv7511/adv7511.h
>> @@ -53,8 +53,10 @@
>> Â #define ADV7511_REG_POWERÂÂÂÂÂÂÂÂÂÂÂ 0x41
>> Â #define ADV7511_REG_STATUSÂÂÂÂÂÂÂÂÂÂÂ 0x42
>> Â #define ADV7511_REG_EDID_I2C_ADDRÂÂÂÂÂÂÂ 0x43
>> +#define ADV7511_REG_EDID_I2C_ADDR_DEFAULTÂÂÂ 0x3f
>> Â #define ADV7511_REG_PACKET_ENABLE1ÂÂÂÂÂÂÂ 0x44ÂÂÂ
>> Â #define ADV7511_REG_PACKET_I2C_ADDRÂÂÂÂÂÂÂ 0x45
>> +#define ADV7511_REG_PACKET_I2C_ADDR_DEFAULTÂÂÂ 0x38
>> Â #define ADV7511_REG_DSD_ENABLEÂÂÂÂÂÂÂÂÂÂÂ 0x46
>> Â #define ADV7511_REG_VIDEO_INPUT_CFG2ÂÂÂÂÂÂÂ 0x48
>> Â #define ADV7511_REG_INFOFRAME_UPDATEÂÂÂÂÂÂÂ 0x4a
>> @@ -89,6 +91,7 @@
>> Â #define ADV7511_REG_TMDS_CLOCK_INVÂÂÂÂÂÂÂ 0xde
>> Â #define ADV7511_REG_ARC_CTRLÂÂÂÂÂÂÂÂÂÂÂ 0xdf
>> Â #define ADV7511_REG_CEC_I2C_ADDRÂÂÂÂÂÂÂ 0xe1
>> +#define ADV7511_REG_CEC_I2C_ADDR_DEFAULTÂÂÂ 0x3c
> 
> Minor comment: The defines above make look like new register
> defines. It would be nice to remove the "REG_" from them, and
> place them somewhere after the register definitions.


Sure.


>> Â #define ADV7511_REG_CEC_CTRLÂÂÂÂÂÂÂÂÂÂÂ 0xe2
>> Â #define ADV7511_REG_CHIP_ID_HIGHÂÂÂÂÂÂÂ 0xf5
>> Â #define ADV7511_REG_CHIP_ID_LOWÂÂÂÂÂÂÂÂÂÂÂ 0xf6
>> @@ -322,6 +325,7 @@ struct adv7511 {
>> ÂÂÂÂÂ struct i2c_client *i2c_main;
>> ÂÂÂÂÂ struct i2c_client *i2c_edid;
>> ÂÂÂÂÂ struct i2c_client *i2c_cec;
>> +ÂÂÂ struct i2c_client *i2c_packet;
>> Â ÂÂÂÂÂ struct regmap *regmap;
>> ÂÂÂÂÂ struct regmap *regmap_cec;
>> diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
>> b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
>> index efa29db5fc2b..7ec33837752b 100644
>> --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
>> +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
>> @@ -969,8 +969,8 @@ static int adv7511_init_cec_regmap(struct adv7511 *adv)
>> Â {
>> ÂÂÂÂÂ int ret;
>> Â -ÂÂÂ adv->i2c_cec = i2c_new_dummy(adv->i2c_main->adapter,
>> -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ adv->i2c_main->addr - 1);
> 
> This patch avoids deriving the CEC/EDID map addresses from the main map. I think
> this would break what the original patch tried to do:

That was intentional.

The ADV7511 data-sheet defines default addresses for these maps.
 (or rather the hardware does)

> 
> d25a4cbba4b9da7c2d674b2f8ecf84af1b24988e
> "drm/bridge: adv7511: add support for the 2nd chip"
> 
> Maybe the default macros can be a function of the main address?

I'm loathed to do that, because then intrinsic knowledge must be known that if I
define a device at address X ... it will also use magic offset A B and C.

IMO - the driver should define the defaults to match the hardware.

Anything else is an override ...


<Welcoming comments, and arguments here>


>> +ÂÂÂ adv->i2c_cec = i2c_new_secondary_device(adv->i2c_main, "cec",
>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ ADV7511_REG_CEC_I2C_ADDR_DEFAULT);
> 
> Also, I'm a bit unclear on the default address values. For example, previously,
> the CEC
> address was calculated as "adv->i2c_main->addr - 1", which is 0x38. The new
> CEC_I2C_ADDR_DEFAULT
> define sets it to 0x3c.


The registers defined in the programming guide [0] define default addresses
which is set by the hardware (and noteworthy, reset to; at low power mode!)

Page : Register : Default   : Purpose

165  : 0x43     : 0x3f << 1 : EDID Memory Address
166  : 0x45     : 0x38 << 1 : Packet Memory I2C Map Address
181  : 0xE1     : 0x3c << 1 : CEC ID

Actually - I've just seen there's a good table at page 16 :D

The ADV7511 main register map can appear at either 0x39 or 0x3D depending on the
input to a pull-up/down pin.

Thus - that implies that perhaps Sergei must have been working on a device
located at 0x3D, to determine the offset of -1 ... but we have two values for
computing the offset depending on whether you start at 0x39 or 0x3D.

And also - I can't even be sure that I can infer the starting address, as the
offsets for the EDID and Packet do not correlate here.

[0]
http://www.analog.com/media/en/technical-documentation/user-guides/ADV7511_Programming_Guide.pdf

> Thanks,
> Archit
> 
>> ÂÂÂÂÂ if (!adv->i2c_cec)
>> ÂÂÂÂÂÂÂÂÂ return -ENOMEM;
>> ÂÂÂÂÂ i2c_set_clientdata(adv->i2c_cec, adv);
>> @@ -1082,8 +1082,6 @@ static int adv7511_probe(struct i2c_client *i2c, const
>> struct i2c_device_id *id)
>> ÂÂÂÂÂ struct adv7511_link_config link_config;
>> ÂÂÂÂÂ struct adv7511 *adv7511;
>> ÂÂÂÂÂ struct device *dev = &i2c->dev;
>> -ÂÂÂ unsigned int main_i2c_addr = i2c->addr << 1;
>> -ÂÂÂ unsigned int edid_i2c_addr = main_i2c_addr + 4;

This computation doesn't correspond to anything except a random (perhaps
platform specific) offset.


>> ÂÂÂÂÂ unsigned int val;
>> ÂÂÂÂÂ int ret;
>> Â @@ -1153,24 +1151,35 @@ static int adv7511_probe(struct i2c_client *i2c,
>> const struct i2c_device_id *id)
>> ÂÂÂÂÂ if (ret)
>> ÂÂÂÂÂÂÂÂÂ goto uninit_regulators;
>> Â -ÂÂÂ regmap_write(adv7511->regmap, ADV7511_REG_EDID_I2C_ADDR, edid_i2c_addr);
>> -ÂÂÂ regmap_write(adv7511->regmap, ADV7511_REG_PACKET_I2C_ADDR,
>> -ÂÂÂÂÂÂÂÂÂÂÂÂ main_i2c_addr - 0xa);


Packet address here is written as an offset of -0x0a, which gives 0x2f or 0x33 ... ?

I think these current offsets are platform specific to a specific platform :)

--
Regards

Kieran


>> -ÂÂÂ regmap_write(adv7511->regmap, ADV7511_REG_CEC_I2C_ADDR,
>> -ÂÂÂÂÂÂÂÂÂÂÂÂ main_i2c_addr - 2);
>> -
>> ÂÂÂÂÂ adv7511_packet_disable(adv7511, 0xffff);
>> Â -ÂÂÂ adv7511->i2c_edid = i2c_new_dummy(i2c->adapter, edid_i2c_addr >> 1);
>> +ÂÂÂ adv7511->i2c_edid = i2c_new_secondary_device(i2c, "edid",
>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ ADV7511_REG_EDID_I2C_ADDR_DEFAULT);
>> ÂÂÂÂÂ if (!adv7511->i2c_edid) {
>> ÂÂÂÂÂÂÂÂÂ ret = -ENOMEM;
>> ÂÂÂÂÂÂÂÂÂ goto uninit_regulators;
>> ÂÂÂÂÂ }
>> Â +ÂÂÂ regmap_write(adv7511->regmap, ADV7511_REG_EDID_I2C_ADDR,
>> +ÂÂÂÂÂÂÂÂÂÂÂÂ adv7511->i2c_edid->addr << 1);
>> +
>> ÂÂÂÂÂ ret = adv7511_init_cec_regmap(adv7511);
>> ÂÂÂÂÂ if (ret)
>> ÂÂÂÂÂÂÂÂÂ goto err_i2c_unregister_edid;
>> Â +ÂÂÂ regmap_write(adv7511->regmap, ADV7511_REG_CEC_I2C_ADDR,
>> +ÂÂÂÂÂÂÂÂÂÂÂÂ adv7511->i2c_cec->addr << 1);
>> +
>> +ÂÂÂ adv7511->i2c_packet = i2c_new_secondary_device(i2c, "packet",
>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ ADV7511_REG_PACKET_I2C_ADDR_DEFAULT);
>> +ÂÂÂ if (!adv7511->i2c_packet) {
>> +ÂÂÂÂÂÂÂ ret = -ENOMEM;
>> +ÂÂÂÂÂÂÂ goto err_unregister_cec;
>> +ÂÂÂ }
>> +
>> +ÂÂÂ regmap_write(adv7511->regmap, ADV7511_REG_PACKET_I2C_ADDR,
>> +ÂÂÂÂÂÂÂÂÂÂÂÂ adv7511->i2c_packet->addr << 1);
>> +
>> ÂÂÂÂÂ INIT_WORK(&adv7511->hpd_work, adv7511_hpd_work);
>> Â ÂÂÂÂÂ if (i2c->irq) {
>> @@ -1181,7 +1190,7 @@ static int adv7511_probe(struct i2c_client *i2c, const
>> struct i2c_device_id *id)
>> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ IRQF_ONESHOT, dev_name(dev),
>> ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ adv7511);
>> ÂÂÂÂÂÂÂÂÂ if (ret)
>> -ÂÂÂÂÂÂÂÂÂÂÂ goto err_unregister_cec;
>> +ÂÂÂÂÂÂÂÂÂÂÂ goto err_unregister_packet;
>> ÂÂÂÂÂ }
>> Â ÂÂÂÂÂ adv7511_power_off(adv7511);
>> @@ -1203,6 +1212,8 @@ static int adv7511_probe(struct i2c_client *i2c, const
>> struct i2c_device_id *id)
>> ÂÂÂÂÂ adv7511_audio_init(dev, adv7511);
>> ÂÂÂÂÂ return 0;
>> Â +err_unregister_packet:
>> +ÂÂÂ i2c_unregister_device(adv7511->i2c_packet);
>> Â err_unregister_cec:
>> ÂÂÂÂÂ i2c_unregister_device(adv7511->i2c_cec);
>> ÂÂÂÂÂ if (adv7511->cec_clk)
>> @@ -1234,6 +1245,7 @@ static int adv7511_remove(struct i2c_client *i2c)
>> ÂÂÂÂÂ cec_unregister_adapter(adv7511->cec_adap);
>> Â ÂÂÂÂÂ i2c_unregister_device(adv7511->i2c_edid);
>> +ÂÂÂ i2c_unregister_device(adv7511->i2c_packet);
>> Â ÂÂÂÂÂ return 0;
>> Â }
>>
>