linux-kernel - RE: [PATCH v3] i2c: cadence: Add shutdown handler

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Message-ID:
 <LV2PR12MB5869A142217C335B89EA02218B1FA@LV2PR12MB5869.namprd12.prod.outlook.com>
Date: Thu, 25 Sep 2025 12:30:42 +0000
From: "Neeli, Ajay" <Ajay.Neeli@....com>
To: "andi.shyti@...nel.org" <andi.shyti@...nel.org>, "Simek, Michal"
	<michal.simek@....com>
CC: "Goud, Srinivas" <srinivas.goud@....com>, "Pandey, Radhey Shyam"
	<radhey.shyam.pandey@....com>, "Neeli, Ajay" <Ajay.Neeli@....com>, "git
 (AMD-Xilinx)" <git@....com>, "linux-arm-kernel@...ts.infradead.org"
	<linux-arm-kernel@...ts.infradead.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, "linux-i2c@...r.kernel.org"
	<linux-i2c@...r.kernel.org>
Subject: RE: [PATCH v3] i2c: cadence: Add shutdown handler

[Public]

Ping!

> -----Original Message-----
> From: Ajay Neeli <ajay.neeli@....com>
> Sent: Wednesday, July 30, 2025 5:59 PM
> To: git (AMD-Xilinx) <git@....com>; andi.shyti@...nel.org; linux-arm-kernel@...ts.infradead.org; linux-i2c@...r.kernel.org;
> linux-kernel@...r.kernel.org
> Cc: Simek, Michal <michal.simek@....com>; Goud, Srinivas <srinivas.goud@....com>; Pandey, Radhey Shyam
> <radhey.shyam.pandey@....com>; Neeli, Ajay <Ajay.Neeli@....com>
> Subject: [PATCH v3] i2c: cadence: Add shutdown handler
>
> Implement shutdown function for Cadence I2C driver to suspend the bus
> during system "reboot" or "shutdown".
>
> Interrupts are disabled in the handler to avoid spurious events when the
> driver is in slave mode.
>
> Signed-off-by: Ajay Neeli <ajay.neeli@....com>
> ---
> Changes v2->v3:
> Corrected a typo that caused a build error in v2
>
> Changes in v1->v2:
> Disable interrupts
> ---
>  drivers/i2c/busses/i2c-cadence.c | 34 +++++++++++++++++++++++++++-------
>  1 file changed, 27 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-cadence.c b/drivers/i2c/busses/i2c-cadence.c
> index 8df63aa..4f033a6 100644
> --- a/drivers/i2c/busses/i2c-cadence.c
> +++ b/drivers/i2c/busses/i2c-cadence.c
> @@ -192,6 +192,7 @@ enum cdns_i2c_slave_state {
>   * @transfer_size:   The maximum number of bytes in one transfer
>   * @atomic:          Mode of transfer
>   * @err_status_atomic:       Error status in atomic mode
> + * @irq:             IRQ Number
>   */
>  struct cdns_i2c {
>       struct device           *dev;
> @@ -224,6 +225,7 @@ struct cdns_i2c {
>       unsigned int transfer_size;
>       bool atomic;
>       int err_status_atomic;
> +     int irq;
>  };
>
>  struct cdns_platform_data {
> @@ -1495,7 +1497,7 @@ static int cdns_i2c_probe(struct platform_device *pdev)
>  {
>       struct resource *r_mem;
>       struct cdns_i2c *id;
> -     int ret, irq;
> +     int ret;
>       const struct of_device_id *match;
>
>       id = devm_kzalloc(&pdev->dev, sizeof(*id), GFP_KERNEL);
> @@ -1526,9 +1528,9 @@ static int cdns_i2c_probe(struct platform_device *pdev)
>       if (IS_ERR(id->membase))
>               return PTR_ERR(id->membase);
>
> -     irq = platform_get_irq(pdev, 0);
> -     if (irq < 0)
> -             return irq;
> +     id->irq = platform_get_irq(pdev, 0);
> +     if (id->irq < 0)
> +             return id->irq;
>
>       id->adap.owner = THIS_MODULE;
>       id->adap.dev.of_node = pdev->dev.of_node;
> @@ -1590,10 +1592,10 @@ static int cdns_i2c_probe(struct platform_device *pdev)
>               goto err_clk_notifier_unregister;
>       }
>
> -     ret = devm_request_irq(&pdev->dev, irq, cdns_i2c_isr, 0,
> +     ret = devm_request_irq(&pdev->dev, id->irq, cdns_i2c_isr, 0,
>                                DRIVER_NAME, id);
>       if (ret) {
> -             dev_err(&pdev->dev, "cannot get irq %d\n", irq);
> +             dev_err(&pdev->dev, "cannot get irq %d\n", id->irq);
>               goto err_clk_notifier_unregister;
>       }
>       cdns_i2c_init(id);
> @@ -1603,7 +1605,7 @@ static int cdns_i2c_probe(struct platform_device *pdev)
>               goto err_clk_notifier_unregister;
>
>       dev_info(&pdev->dev, "%u kHz mmio %08lx irq %d\n",
> -              id->i2c_clk / 1000, (unsigned long)r_mem->start, irq);
> +              id->i2c_clk / 1000, (unsigned long)r_mem->start, id->irq);
>
>       return 0;
>
> @@ -1636,6 +1638,23 @@ static void cdns_i2c_remove(struct platform_device *pdev)
>       reset_control_assert(id->reset);
>  }
>
> +/**
> + * cdns_i2c_shutdown - Shutdown the i2c device
> + * @pdev:    Handle to the platform device structure
> + *
> + * This function handles shutdown sequence
> + */
> +static void cdns_i2c_shutdown(struct platform_device *pdev)
> +{
> +     struct cdns_i2c *id = platform_get_drvdata(pdev);
> +
> +     /* Disable interrupts */
> +     disable_irq(id->irq);
> +
> +     /* Initiate failure of client i2c transfers */
> +     i2c_mark_adapter_suspended(&id->adap);
> +}
> +
>  static struct platform_driver cdns_i2c_drv = {
>       .driver = {
>               .name  = DRIVER_NAME,
> @@ -1644,6 +1663,7 @@ static void cdns_i2c_remove(struct platform_device *pdev)
>       },
>       .probe  = cdns_i2c_probe,
>       .remove = cdns_i2c_remove,
> +     .shutdown = cdns_i2c_shutdown,
>  };
>
>  module_platform_driver(cdns_i2c_drv);
> --
> 1.8.3.1