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Message-ID: <20210416074307.mtd7bcv3yj6zekt6@uno.localdomain>
Date: Fri, 16 Apr 2021 09:43:07 +0200
From: Jacopo Mondi <jacopo@...ndi.org>
To: Laurent Pinchart <laurent.pinchart@...asonboard.com>
Cc: Jacopo Mondi <jacopo+renesas@...ndi.org>,
Geert Uytterhoeven <geert+renesas@...der.be>,
Magnus Damm <magnus.damm@...il.com>,
Kieran Bingham <kieran.bingham@...asonboard.com>,
Rob Herring <robh+dt@...nel.org>,
linux-renesas-soc@...r.kernel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/5] media: i2c: max9286: Use "maxim,gpio-poc" property
Hi Laurent,
On Thu, Apr 15, 2021 at 10:14:05PM +0300, Laurent Pinchart wrote:
> > > > + /* GPIO values default to high */
> > > > + priv->gpio_state = BIT(0) | BIT(1);
> > >
> > > Why is that ?
> > >
> > As the set/get functions of gpiochip use the gpio_state and I wanted
> > to use the same functions for the internal gpio handling I used
> > gpio_state in gpio_set(). My thinking was that in this way altering
> > the gpio line would be visibile to gpio consumers... which we don't
> > have as I won't register the gpio-controller :)
>
> My question was why they default to high here, when they default to low
> when there's a gpio-controller property.
>
Oh, got it now... the two output lines are high by default :)
Why do you say "they default to low when there's a gpio-controller
property" ? When does that requirement come from ?
Thanks
j
> > > > + priv->regulator = NULL;
> > >
> > > As priv is initialized to 0, you can skip this.
> >
> > Yes, I liked it explicit as it is used as flag, but it is not
> > required...
> >
> > > > +
> > > > + return 0;
> > > > + }
> > > > +
> > > > + ret = max9286_register_gpio(priv);
> > > > + if (ret)
> > > > + return ret;
> > > > +
> > > > + priv->regulator = devm_regulator_get(dev, "poc");
> > > > + if (IS_ERR(priv->regulator)) {
> > > > + if (PTR_ERR(priv->regulator) != -EPROBE_DEFER)
> > > > + dev_err(dev, "Unable to get PoC regulator (%ld)\n",
> > > > + PTR_ERR(priv->regulator));
> > > > + return PTR_ERR(priv->regulator);
> > > > + }
> > > > +
> > > > + return 0;
> > > > +}
> > > > +
> > > > +static int max9286_poc_enable(struct max9286_priv *priv, bool enable)
> > > > +{
> > > > + int ret;
> > > > +
> > > > + /* If "poc-gpio" is used, toggle the line and do not use regulator. */
> > > > + if (!priv->regulator)
> > > > + return max9286_gpio_set(priv, priv->gpio_poc,
> > > > + enable ^ priv->gpio_poc_flags);
> > > > +
> > > > + /* Otherwise PoC is controlled using a regulator. */
> > > > + if (enable) {
> > > > + ret = regulator_enable(priv->regulator);
> > > > + if (ret < 0) {
> > > > + dev_err(&priv->client->dev, "Unable to turn PoC on\n");
> > >
> > > As error message when max9286_gpio_set() fails (at least in the enable
> > > case) would be good too. Bonus points if there's a single dev_err()
> > > call.
> >
> > I'll see how it looks like
> >
> > > > + return ret;
> > > > + }
> > > > +
> > > > + return 0;
> > > > + }
> > > > +
> > > > + return regulator_disable(priv->regulator);
> > > > +}
> > > > +
> > > > static int max9286_init(struct device *dev)
> > > > {
> > > > struct max9286_priv *priv;
> > > > @@ -1078,17 +1158,14 @@ static int max9286_init(struct device *dev)
> > > > client = to_i2c_client(dev);
> > > > priv = i2c_get_clientdata(client);
> > > >
> > > > - /* Enable the bus power. */
> > > > - ret = regulator_enable(priv->regulator);
> > > > - if (ret < 0) {
> > > > - dev_err(&client->dev, "Unable to turn PoC on\n");
> > > > + ret = max9286_poc_enable(priv, true);
> > > > + if (ret)
> > > > return ret;
> > > > - }
> > > >
> > > > ret = max9286_setup(priv);
> > > > if (ret) {
> > > > dev_err(dev, "Unable to setup max9286\n");
> > > > - goto err_regulator;
> > > > + goto err_poc_disable;
> > > > }
> > > >
> > > > /*
> > > > @@ -1098,7 +1175,7 @@ static int max9286_init(struct device *dev)
> > > > ret = max9286_v4l2_register(priv);
> > > > if (ret) {
> > > > dev_err(dev, "Failed to register with V4L2\n");
> > > > - goto err_regulator;
> > > > + goto err_poc_disable;
> > > > }
> > > >
> > > > ret = max9286_i2c_mux_init(priv);
> > > > @@ -1114,8 +1191,8 @@ static int max9286_init(struct device *dev)
> > > >
> > > > err_v4l2_register:
> > > > max9286_v4l2_unregister(priv);
> > > > -err_regulator:
> > > > - regulator_disable(priv->regulator);
> > > > +err_poc_disable:
> > > > + max9286_poc_enable(priv, false);
> > > >
> > > > return ret;
> > > > }
> > > > @@ -1286,20 +1363,10 @@ static int max9286_probe(struct i2c_client *client)
> > > > */
> > > > max9286_configure_i2c(priv, false);
> > > >
> > > > - ret = max9286_register_gpio(priv);
> > > > + ret = max9286_parse_gpios(priv);
> > > > if (ret)
> > > > goto err_powerdown;
> > > >
> > > > - priv->regulator = devm_regulator_get(&client->dev, "poc");
> > > > - if (IS_ERR(priv->regulator)) {
> > > > - if (PTR_ERR(priv->regulator) != -EPROBE_DEFER)
> > > > - dev_err(&client->dev,
> > > > - "Unable to get PoC regulator (%ld)\n",
> > > > - PTR_ERR(priv->regulator));
> > > > - ret = PTR_ERR(priv->regulator);
> > > > - goto err_powerdown;
> > > > - }
> > > > -
> > > > ret = max9286_parse_dt(priv);
> > > > if (ret)
> > > > goto err_powerdown;
> > > > @@ -1326,7 +1393,7 @@ static int max9286_remove(struct i2c_client *client)
> > > >
> > > > max9286_v4l2_unregister(priv);
> > > >
> > > > - regulator_disable(priv->regulator);
> > > > + max9286_poc_enable(priv, false);
> > > >
> > > > gpiod_set_value_cansleep(priv->gpiod_pwdn, 0);
> > > >
>
> --
> Regards,
>
> Laurent Pinchart
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