On 14.05.2018 11:38, Philippe CORNU wrote:
> Hi Laurent, Archit, Andrzej & Yannick,
>
> Do you have any comments on this v2 driver part?
> (more details regarding v1/v2 differences in the cover letter 
> https://www.spinics.net/lists/dri-devel/msg174137.html)
>
> Thank you,
> Philippe :-)
>
>
> On 04/25/2018 09:53 AM, Philippe Cornu wrote:
>> Add the optional power supplies using the description found in
>> "SiI9022A/SiI9024A HDMI Transmitter Data Sheet (August 2016)".
>>
>> The sii902x input IOs are not "io safe" so it is important to
>> enable/disable voltage regulators during probe/remove phases to
>> avoid damages.

What exactly does it mean? Ie I understand that the chip has some
limitations, but why enabling/disabling regulators in probe/remove
should solve it?

Regards
Andrzej

>>
>> Signed-off-by: Philippe Cornu <[email protected]>
>> ---
>>   drivers/gpu/drm/bridge/sii902x.c | 38 
>> ++++++++++++++++++++++++++++++++++----
>>   1 file changed, 34 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/sii902x.c 
>> b/drivers/gpu/drm/bridge/sii902x.c
>> index 60373d7eb220..c367d7b91ade 100644
>> --- a/drivers/gpu/drm/bridge/sii902x.c
>> +++ b/drivers/gpu/drm/bridge/sii902x.c
>> @@ -24,6 +24,7 @@
>>   #include <linux/i2c.h>
>>   #include <linux/module.h>
>>   #include <linux/regmap.h>
>> +#include <linux/regulator/consumer.h>
>>   
>>   #include <drm/drmP.h>
>>   #include <drm/drm_atomic_helper.h>
>> @@ -86,6 +87,7 @@ struct sii902x {
>>      struct drm_bridge bridge;
>>      struct drm_connector connector;
>>      struct gpio_desc *reset_gpio;
>> +    struct regulator_bulk_data supplies[2];
>>   };
>>   
>>   static inline struct sii902x *bridge_to_sii902x(struct drm_bridge *bridge)
>> @@ -392,23 +394,42 @@ static int sii902x_probe(struct i2c_client *client,
>>              return PTR_ERR(sii902x->reset_gpio);
>>      }
>>   
>> +    sii902x->supplies[0].supply = "iovcc";
>> +    sii902x->supplies[1].supply = "vcc12";
>> +    ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(sii902x->supplies),
>> +                                  sii902x->supplies);
>> +    if (ret) {
>> +            dev_err(dev, "Failed to get power supplies: %d\n", ret);
>> +            return ret;
>> +    }
>> +
>> +    ret = regulator_bulk_enable(ARRAY_SIZE(sii902x->supplies),
>> +                                sii902x->supplies);
>> +    if (ret) {
>> +            dev_err(dev, "Failed to enable power supplies: %d\n", ret);
>> +            return ret;
>> +    }
>> +
>> +    usleep_range(10000, 20000);
>> +
>>      sii902x_reset(sii902x);
>>   
>>      ret = regmap_write(sii902x->regmap, SII902X_REG_TPI_RQB, 0x0);
>>      if (ret)
>> -            return ret;
>> +            goto err_disable_regulator;
>>   
>>      ret = regmap_bulk_read(sii902x->regmap, SII902X_REG_CHIPID(0),
>>                             &chipid, 4);
>>      if (ret) {
>>              dev_err(dev, "regmap_read failed %d\n", ret);
>> -            return ret;
>> +            goto err_disable_regulator;
>>      }
>>   
>>      if (chipid[0] != 0xb0) {
>>              dev_err(dev, "Invalid chipid: %02x (expecting 0xb0)\n",
>>                      chipid[0]);
>> -            return -EINVAL;
>> +            ret = -EINVAL;
>> +            goto err_disable_regulator;
>>      }
>>   
>>      /* Clear all pending interrupts */
>> @@ -424,7 +445,7 @@ static int sii902x_probe(struct i2c_client *client,
>>                                              IRQF_ONESHOT, dev_name(dev),
>>                                              sii902x);
>>              if (ret)
>> -                    return ret;
>> +                    goto err_disable_regulator;
>>      }
>>   
>>      sii902x->bridge.funcs = &sii902x_bridge_funcs;
>> @@ -434,6 +455,12 @@ static int sii902x_probe(struct i2c_client *client,
>>      i2c_set_clientdata(client, sii902x);
>>   
>>      return 0;
>> +
>> +err_disable_regulator:
>> +    regulator_bulk_disable(ARRAY_SIZE(sii902x->supplies),
>> +                           sii902x->supplies);
>> +
>> +    return ret;
>>   }
>>   
>>   static int sii902x_remove(struct i2c_client *client)
>> @@ -443,6 +470,9 @@ static int sii902x_remove(struct i2c_client *client)
>>   
>>      drm_bridge_remove(&sii902x->bridge);
>>   
>> +    regulator_bulk_disable(ARRAY_SIZE(sii902x->supplies),
>> +                           sii902x->supplies);
>> +
>>      return 0;
>>   }
>>   


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