Re: [PATCH V3 13/14] i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()

[Mukesh Savaliya]

Hi Adrian,

On 8/4/2026 7:08 PM, Adrian Hunter wrote:

[...]

> @@ -117,6 +118,17 @@ static inline struct i3c_hci *to_i3c_hci(struct i3c_master_controller *m)
>   	return container_of(m, struct i3c_hci, master);
>   }
>   
> +/*
> + * Determine the device that does PM / DMA and has IOMMU setup done for it in
> + * case of enabled IOMMU (for use with the DMA API).
> + * Such device is either "mipi-i3c-hci" platform device (OF/ACPI enumeration)
> + * parent or grandparent (PCI enumeration).
> + */
I was kind of confused and could not understand much (excuse me!). But 
could draft below from function definition. I know comments removed from 
below function and kept here.

Hope this can be simplified or improved further if possible.

/**
* i3c_hci_sysdev() - Get the device used for system PM and DMA
* operations
* @dev: HCI device
*
* Return the PCI parent device when the HCI controller is attached
* through PCI, otherwise return @dev itself. The returned device can
* be used for system power management and wakeup configuration.
*
* Return: Device to use for system PM and wakeup handling.
*/
> +struct device *i3c_hci_sysdev(struct device *dev)
> +{
> +	return dev->parent && dev_is_pci(dev->parent) ? dev->parent : dev;
> +}
> +
>   static void i3c_hci_set_master_dyn_addr(struct i3c_hci *hci)
>   {
>   	reg_write(MASTER_DEVICE_ADDR,
> diff --git a/drivers/i3c/master/mipi-i3c-hci/dma.c b/drivers/i3c/master/mipi-i3c-hci/dma.c
> index 0672ed1132f8..7c2b20474130 100644
> --- a/drivers/i3c/master/mipi-i3c-hci/dma.c
> +++ b/drivers/i3c/master/mipi-i3c-hci/dma.c
> @@ -15,7 +15,6 @@
>   #include <linux/errno.h>
>   #include <linux/i3c/master.h>
>   #include <linux/io.h>
> -#include <linux/pci.h>
>   
>   #include "hci.h"
>   #include "cmd.h"
> @@ -301,23 +300,11 @@ static int hci_dma_init(struct i3c_hci *hci)
>   {
>   	struct hci_rings_data *rings;
>   	struct hci_rh_data *rh;
> -	struct device *sysdev;
>   	u32 regval;
>   	unsigned int i, nr_rings, xfers_sz, resps_sz;
>   	unsigned int ibi_status_ring_sz, ibi_data_ring_sz;
>   	int ret;
>   
> -	/*
> -	 * Set pointer to a physical device that does DMA and has IOMMU setup
> -	 * done for it in case of enabled IOMMU and use it with the DMA API.
> -	 * Here such device is either
> -	 * "mipi-i3c-hci" platform device (OF/ACPI enumeration) parent or
> -	 * grandparent (PCI enumeration).
> -	 */
> -	sysdev = hci->master.dev.parent;
> -	if (sysdev->parent && dev_is_pci(sysdev->parent))
> -		sysdev = sysdev->parent;
> -
>   	regval = rhs_reg_read(CONTROL);
>   	nr_rings = FIELD_GET(MAX_HEADER_COUNT_CAP, regval);
>   	dev_dbg(&hci->master.dev, "%d DMA rings available\n", nr_rings);
> @@ -332,7 +319,7 @@ static int hci_dma_init(struct i3c_hci *hci)
>   		return -ENOMEM;
>   	hci->io_data = rings;
>   	rings->total = nr_rings;
> -	rings->sysdev = sysdev;
> +	rings->sysdev = i3c_hci_sysdev(hci->master.dev.parent);
>   
>   	for (i = 0; i < rings->total; i++) {
>   		u32 offset = rhs_reg_read(RHn_OFFSET(i));
> diff --git a/drivers/i3c/master/mipi-i3c-hci/hci.h b/drivers/i3c/master/mipi-i3c-hci/hci.h
> index b3d9803b1968..b8d2a3d680f8 100644
> --- a/drivers/i3c/master/mipi-i3c-hci/hci.h
> +++ b/drivers/i3c/master/mipi-i3c-hci/hci.h
> @@ -184,6 +184,8 @@ void amd_set_resp_buf_thld(struct i3c_hci *hci);
>   void i3c_hci_sync_irq_inactive(struct i3c_hci *hci);
>   int i3c_hci_process_xfer(struct i3c_hci *hci, struct hci_xfer *xfer, int n);
>   
> +struct device *i3c_hci_sysdev(struct device *dev);
> +
>   #define DEFAULT_AUTOSUSPEND_DELAY_MS 1000
>   
>   int i3c_hci_rpm_suspend(struct device *dev);