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Message-ID: <b61f5f4a-7931-411d-9519-bbff1b7fd6f9@quicinc.com>
Date: Sun, 10 Mar 2024 22:59:55 +0530
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Subject: Re: [PATCH v1] i3c: master: Enable runtime PM for master controller
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To: <alexandre.belloni@bootlin.com>, <linux-i3c@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>
CC: <andersson@kernel.org>, <vkoul@kernel.org>,
        <manivannan.sadhasivam@linaro.org>
References: <20240228093407.4038399-1-quic_msavaliy@quicinc.com>
From: Mukesh Kumar Savaliya <quic_msavaliy@quicinc.com>
In-Reply-To: <20240228093407.4038399-1-quic_msavaliy@quicinc.com>
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A Gentle reminder ! As i was not part of the linux-i3c group before 
raising this gerrit, might not went into right folder.

On 2/28/2024 3:04 PM, Mukesh Kumar Savaliya wrote:
> Enable runtime PM for i3c master node during master registration time.
> 
> Sometimes i3c client device driver may want to control the PM of the
> parent (master) to perform the transactions and save the power in an
> efficient way by controlling the session. Hence device can call PM
> APIs by passing the parent node.
> 
> Here, I3C target device when calls pm_runtime_get_sync(dev->parent)
> couldn't invoke master drivers runtime PM callback registered by
> the master driver because parent's PM status was disabled in the
> Master node.
> 
> Also call pm_runtime_no_callbacks() and pm_suspend_ignore_children()
> for the master node to not have any callback addition and ignore the
> children to have runtime PM work just locally in the driver. This
> should be generic and common change for all i3c devices and should
> not have any other impact.
> 
> With these changes, I3C client device works and able to invoke
> master driver registered runtime PM callbacks.
> 
> Signed-off-by: Mukesh Kumar Savaliya <quic_msavaliy@quicinc.com>
> ---
>   drivers/i3c/master.c | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
> index 3afa530c5e32..a3dc88974f92 100644
> --- a/drivers/i3c/master.c
> +++ b/drivers/i3c/master.c
> @@ -13,6 +13,7 @@
>   #include <linux/kernel.h>
>   #include <linux/list.h>
>   #include <linux/of.h>
> +#include <linux/pm_runtime.h>
>   #include <linux/slab.h>
>   #include <linux/spinlock.h>
>   #include <linux/workqueue.h>
> @@ -2812,6 +2813,10 @@ int i3c_master_register(struct i3c_master_controller *master,
>   
>   	i3c_bus_notify(i3cbus, I3C_NOTIFY_BUS_ADD);
>   
> +	pm_runtime_no_callbacks(&master->dev);
> +	pm_suspend_ignore_children(&master->dev, true);
> +	pm_runtime_enable(&master->dev);
> +
>   	/*
>   	 * We're done initializing the bus and the controller, we can now
>   	 * register I3C devices discovered during the initial DAA.
> @@ -2849,6 +2854,7 @@ void i3c_master_unregister(struct i3c_master_controller *master)
>   	i3c_master_i2c_adapter_cleanup(master);
>   	i3c_master_unregister_i3c_devs(master);
>   	i3c_master_bus_cleanup(master);
> +	pm_runtime_disable(&master->dev);
>   	device_unregister(&master->dev);
>   }
>   EXPORT_SYMBOL_GPL(i3c_master_unregister);