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[185.165.241.34]) by smtp.gmail.com with ESMTPSA id g13-20020aa7d1cd000000b00435a742e350sm1084960edp.75.2022.07.14.07.06.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Jul 2022 07:06:43 -0700 (PDT) Date: Thu, 14 Jul 2022 18:06:32 +0400 From: Yassine Oudjana Subject: Re: [PATCH v2 3/3] media: i2c: ak7375: Add regulator management To: Jacopo Mondi Cc: Lee Jackson , Mauro Carvalho Chehab , Rob Herring , Krzysztof Kozlowski , Tianshu Qiu , Bingbu Cao , Yassine Oudjana , linux-media@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Message-Id: In-Reply-To: <20220713073951.qrg3slmvqbibwc5o@uno.localdomain> References: <20220711144039.232196-1-y.oudjana@protonmail.com> <20220711144039.232196-4-y.oudjana@protonmail.com> <20220713073951.qrg3slmvqbibwc5o@uno.localdomain> X-Mailer: geary/40.0 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Wed, Jul 13 2022 at 09:39:51 +0200, Jacopo Mondi wrote: > Hi Yassine > > On Mon, Jul 11, 2022 at 06:40:39PM +0400, Yassine Oudjana wrote: >> From: Yassine Oudjana >> >> Make the driver get needed regulators on probe and enable/disable >> them on runtime PM callbacks. >> >> Signed-off-by: Yassine Oudjana > > Have you seen this ? > https://github.com/ArduCAM/IMX519_AK7375/blob/main/AK7375/0002-media-i2c-ak7375-driver-add-optional-regulator-suppo.patch#L172 > > It claims > + * Initialisation delay between VDD low->high and the moment > + * when the i2c command is available. > + * From the datasheet, it should be 10ms + 2ms (max power > + * up sequence duration) > > 10ms seems like a long time, it would be nice to have the datasheet to > cross-check. It does seem quite long. I couldn't find a datasheet anywhere so the value I discovered is the best I have. I've added the author of that patch to CC; maybe they have some info to contribute. > > Thanks > j > >> --- >> Changes since v1: >> - Reorganize variable declaration >> - Change the power-on delay range to 3000-3500 microseconds. >> >> drivers/media/i2c/ak7375.c | 39 >> ++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 39 insertions(+) >> >> diff --git a/drivers/media/i2c/ak7375.c b/drivers/media/i2c/ak7375.c >> index 40b1a4aa846c..c2b2542a0056 100644 >> --- a/drivers/media/i2c/ak7375.c >> +++ b/drivers/media/i2c/ak7375.c >> @@ -6,6 +6,7 @@ >> #include >> #include >> #include >> +#include >> #include >> #include >> >> @@ -23,17 +24,32 @@ >> */ >> #define AK7375_CTRL_STEPS 64 >> #define AK7375_CTRL_DELAY_US 1000 >> +/* >> + * The vcm takes around 3 ms to power on and start taking >> + * I2C messages. This value was found experimentally due to >> + * lack of documentation. >> + */ >> +#define AK7375_POWER_DELAY_US 3000 >> >> #define AK7375_REG_POSITION 0x0 >> #define AK7375_REG_CONT 0x2 >> #define AK7375_MODE_ACTIVE 0x0 >> #define AK7375_MODE_STANDBY 0x40 >> >> +static const char * const ak7375_supply_names[] = { >> + "vdd", >> + "vio", >> +}; >> + >> +#define AK7375_NUM_SUPPLIES ARRAY_SIZE(ak7375_supply_names) >> + >> /* ak7375 device structure */ >> struct ak7375_device { >> struct v4l2_ctrl_handler ctrls_vcm; >> struct v4l2_subdev sd; >> struct v4l2_ctrl *focus; >> + struct regulator_bulk_data supplies[AK7375_NUM_SUPPLIES]; >> + >> /* active or standby mode */ >> bool active; >> }; >> @@ -133,12 +149,24 @@ static int ak7375_probe(struct i2c_client >> *client) >> { >> struct ak7375_device *ak7375_dev; >> int ret; >> + int i; >> >> ak7375_dev = devm_kzalloc(&client->dev, sizeof(*ak7375_dev), >> GFP_KERNEL); >> if (!ak7375_dev) >> return -ENOMEM; >> >> + for (i = 0; i < AK7375_NUM_SUPPLIES; i++) >> + ak7375_dev->supplies[i].supply = ak7375_supply_names[i]; >> + >> + ret = devm_regulator_bulk_get(&client->dev, AK7375_NUM_SUPPLIES, >> + ak7375_dev->supplies); >> + if (ret) { >> + dev_err(&client->dev, "Failed to get regulators: %pe", >> + ERR_PTR(ret)); >> + return ret; >> + } >> + >> v4l2_i2c_subdev_init(&ak7375_dev->sd, client, &ak7375_ops); >> ak7375_dev->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE; >> ak7375_dev->sd.internal_ops = &ak7375_int_ops; >> @@ -210,6 +238,10 @@ static int __maybe_unused >> ak7375_vcm_suspend(struct device *dev) >> if (ret) >> dev_err(dev, "%s I2C failure: %d\n", __func__, ret); >> >> + ret = regulator_bulk_disable(AK7375_NUM_SUPPLIES, >> ak7375_dev->supplies); >> + if (ret) >> + return ret; >> + >> ak7375_dev->active = false; >> >> return 0; >> @@ -230,6 +262,13 @@ static int __maybe_unused >> ak7375_vcm_resume(struct device *dev) >> if (ak7375_dev->active) >> return 0; >> >> + ret = regulator_bulk_enable(AK7375_NUM_SUPPLIES, >> ak7375_dev->supplies); >> + if (ret) >> + return ret; >> + >> + /* Wait for vcm to become ready */ >> + usleep_range(AK7375_POWER_DELAY_US, AK7375_POWER_DELAY_US + 500); >> + >> ret = ak7375_i2c_write(ak7375_dev, AK7375_REG_CONT, >> AK7375_MODE_ACTIVE, 1); >> if (ret) { >> -- >> 2.37.0 >>