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SubjectRe: [PATCH v2 2/2] drm/bridge: sii902x: add optional power supplies
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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 <philippe.cornu@st.com>
>> ---
>> 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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