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In-Reply-To: <20210305102004.191209-1-hsinyi@chromium.org>
From:   Hsin-Yi Wang <hsinyi@chromium.org>
Date:   Mon, 8 Mar 2021 12:38:50 +0800
Message-ID: <CAJMQK-iDgkETDOnExG3Opuave98q0Nbq2ZK+NpyD_bmB0SrpDA@mail.gmail.com>
Subject: Re: [PATCH] i2c: core: support bus regulator controlling in adapter
To:     Wolfram Sang <wsa@kernel.org>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        linux-i2c@vger.kernel.org
Cc:     Matthias Brugger <matthias.bgg@gmail.com>,
        lkml <linux-kernel@vger.kernel.org>,
        "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@lists.infradead.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@lists.infradead.org>,
        Bibby Hsieh <bibby.hsieh@mediatek.com>,
        Marek Szyprowski <m.szyprowski@samsung.com>
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Precedence: bulk

On Fri, Mar 5, 2021 at 6:20 PM Hsin-Yi Wang <hsinyi@chromium.org> wrote:
>
> From: Bibby Hsieh <bibby.hsieh@mediatek.com>
>
> Although in the most platforms, the bus power of i2c
> are alway on, some platforms disable the i2c bus power
> in order to meet low power request.
>
> We get and enable bulk regulator in i2c adapter device.
>
> Signed-off-by: Bibby Hsieh <bibby.hsieh@mediatek.com>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
> ---
> This patch is squashed from following patch and tested on mt8183 device
> which has eeprom at24 client under i2c, so the fix in [2] is also
> verified.
> [1] https://patchwork.ozlabs.org/project/linux-i2c/cover/20200519072729.7268-1-bibby.hsieh@mediatek.com/
> [2] https://patchwork.ozlabs.org/project/linux-i2c/patch/20200522101327.13456-1-m.szyprowski@samsung.com/
> ---

Sent again with document rebased in v16 here:
https://patchwork.ozlabs.org/project/linux-i2c/cover/20210308043607.957156-1-hsinyi@chromium.org/

>  drivers/i2c/i2c-core-base.c | 93 +++++++++++++++++++++++++++++++++++++
>  include/linux/i2c.h         |  2 +
>  2 files changed, 95 insertions(+)
>
> diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
> index 63ebf722a424..667f4a4de7cc 100644
> --- a/drivers/i2c/i2c-core-base.c
> +++ b/drivers/i2c/i2c-core-base.c
> @@ -439,12 +439,14 @@ static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
>  static int i2c_device_probe(struct device *dev)
>  {
>         struct i2c_client       *client = i2c_verify_client(dev);
> +       struct i2c_adapter      *adap;
>         struct i2c_driver       *driver;
>         int status;
>
>         if (!client)
>                 return 0;
>
> +       adap = client->adapter;
>         client->irq = client->init_irq;
>
>         if (!client->irq) {
> @@ -510,6 +512,12 @@ static int i2c_device_probe(struct device *dev)
>
>         dev_dbg(dev, "probe\n");
>
> +       status = regulator_enable(adap->bus_regulator);
> +       if (status < 0) {
> +               dev_err(&adap->dev, "Failed to enable power regulator\n");
> +               goto err_clear_wakeup_irq;
> +       }
> +
>         status = of_clk_set_defaults(dev->of_node, false);
>         if (status < 0)
>                 goto err_clear_wakeup_irq;
> @@ -550,8 +558,10 @@ static int i2c_device_probe(struct device *dev)
>  static int i2c_device_remove(struct device *dev)
>  {
>         struct i2c_client       *client = to_i2c_client(dev);
> +       struct i2c_adapter      *adap;
>         struct i2c_driver       *driver;
>
> +       adap = client->adapter;
>         driver = to_i2c_driver(dev->driver);
>         if (driver->remove) {
>                 int status;
> @@ -564,6 +574,8 @@ static int i2c_device_remove(struct device *dev)
>         }
>
>         dev_pm_domain_detach(&client->dev, true);
> +       if (!pm_runtime_status_suspended(&client->dev))
> +               regulator_disable(adap->bus_regulator);
>
>         dev_pm_clear_wake_irq(&client->dev);
>         device_init_wakeup(&client->dev, false);
> @@ -576,6 +588,80 @@ static int i2c_device_remove(struct device *dev)
>         return 0;
>  }
>
> +#ifdef CONFIG_PM_SLEEP
> +static int i2c_resume_early(struct device *dev)
> +{
> +       struct i2c_client *client = i2c_verify_client(dev);
> +       int err;
> +
> +       if (!client)
> +               return 0;
> +
> +       if (!pm_runtime_status_suspended(&client->dev)) {
> +               err = regulator_enable(client->adapter->bus_regulator);
> +               if (err)
> +                       return err;
> +       }
> +
> +       return pm_generic_resume_early(&client->dev);
> +}
> +
> +static int i2c_suspend_late(struct device *dev)
> +{
> +       struct i2c_client *client = i2c_verify_client(dev);
> +       int err;
> +
> +       if (!client)
> +               return 0;
> +
> +       err = pm_generic_suspend_late(&client->dev);
> +       if (err)
> +               return err;
> +
> +       if (!pm_runtime_status_suspended(&client->dev))
> +               return regulator_disable(client->adapter->bus_regulator);
> +
> +       return 0;
> +}
> +#endif
> +
> +#ifdef CONFIG_PM
> +static int i2c_runtime_resume(struct device *dev)
> +{
> +       struct i2c_client *client = i2c_verify_client(dev);
> +       int err;
> +
> +       if (!client)
> +               return 0;
> +
> +       err = regulator_enable(client->adapter->bus_regulator);
> +       if (err)
> +               return err;
> +
> +       return pm_generic_runtime_resume(&client->dev);
> +}
> +
> +static int i2c_runtime_suspend(struct device *dev)
> +{
> +       struct i2c_client *client = i2c_verify_client(dev);
> +       int err;
> +
> +       if (!client)
> +               return 0;
> +
> +       err = pm_generic_runtime_suspend(&client->dev);
> +       if (err)
> +               return err;
> +
> +       return regulator_disable(client->adapter->bus_regulator);
> +}
> +#endif
> +
> +static const struct dev_pm_ops i2c_device_pm = {
> +       SET_LATE_SYSTEM_SLEEP_PM_OPS(i2c_suspend_late, i2c_resume_early)
> +       SET_RUNTIME_PM_OPS(i2c_runtime_suspend, i2c_runtime_resume, NULL)
> +};
> +
>  static void i2c_device_shutdown(struct device *dev)
>  {
>         struct i2c_client *client = i2c_verify_client(dev);
> @@ -633,6 +719,7 @@ struct bus_type i2c_bus_type = {
>         .probe          = i2c_device_probe,
>         .remove         = i2c_device_remove,
>         .shutdown       = i2c_device_shutdown,
> +       .pm             = &i2c_device_pm,
>  };
>  EXPORT_SYMBOL_GPL(i2c_bus_type);
>
> @@ -1446,6 +1533,12 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
>         if (res)
>                 goto out_reg;
>
> +       adap->bus_regulator = devm_regulator_get(&adap->dev, "bus");
> +       if (IS_ERR(adap->bus_regulator)) {
> +               res = PTR_ERR(adap->bus_regulator);
> +               goto out_reg;
> +       }
> +
>         pm_runtime_no_callbacks(&adap->dev);
>         pm_suspend_ignore_children(&adap->dev, true);
>         pm_runtime_enable(&adap->dev);
> diff --git a/include/linux/i2c.h b/include/linux/i2c.h
> index 56622658b215..ec87758d9f40 100644
> --- a/include/linux/i2c.h
> +++ b/include/linux/i2c.h
> @@ -15,6 +15,7 @@
>  #include <linux/device.h>      /* for struct device */
>  #include <linux/sched.h>       /* for completion */
>  #include <linux/mutex.h>
> +#include <linux/regulator/consumer.h>
>  #include <linux/rtmutex.h>
>  #include <linux/irqdomain.h>           /* for Host Notify IRQ */
>  #include <linux/of.h>          /* for struct device_node */
> @@ -721,6 +722,7 @@ struct i2c_adapter {
>         const struct i2c_adapter_quirks *quirks;
>
>         struct irq_domain *host_notify_domain;
> +       struct regulator *bus_regulator;
>  };
>  #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
>
> --
> 2.30.1.766.gb4fecdf3b7-goog
>