Re: [PATCH V3 10/11] i3c: mipi-i3c-hci-pci: Add support for Multi-Bus Instances

[Frank Li <Frank.li@nxp.com>]

On Tue, Dec 16, 2025 at 06:56:41PM +0200, Adrian Hunter wrote:
> Add support for MIPI I3C Host Controllers with the Multi-Bus Instance
> capability.  These controllers can host multiple I3C buses (up to 15)
> within a single hardware function (e.g., PCIe B/D/F), providing one
> indepedent HCI register set and corresponding I3C bus controller logic
> per bus.
>
> Create an MFD cell for each instance and use platform_data to pass the
> starting address of the instance's register set.
>
> The MIPI I3C HCI specification defines an Extended Capability that holds
> the offset of each instance register set.  Parsing this information is
> relatively complex, so include the offsets in driver data for now.
>
> Driver data for additional instances beyond instance 0 will be added in a
> subsequent patch.
>
> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
> ---

Reviewed-by: Frank Li <Frank.Li@nxp.com>
>
>
> Changes in V3:
>
> 	Make hci a parameter of mipi_i3c_hci_pci_alloc()
> 	Adjust for doing away with dynamic devid allocation
> 	Enhance commit message
>
> Changes in V2:
> 	Conversion to MFD split into separate patch
> 	Simplify ID allocation / free
> 	Correct use of __free()
> 	Also define instance 0 in driver_data
>
>
>  .../master/mipi-i3c-hci/mipi-i3c-hci-pci.c    | 36 +++++++++++++------
>  1 file changed, 26 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c b/drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c
> index 7ef17255c312..782f46989423 100644
> --- a/drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c
> +++ b/drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c
> @@ -19,6 +19,12 @@
>  #include <linux/platform_device.h>
>  #include <linux/pm_qos.h>
>
> +/*
> + * There can up to 15 instances, but implementations have at most 2 at this
> + * time.
> + */
> +#define INST_MAX 2
> +
>  struct mipi_i3c_hci_pci {
>  	struct pci_dev *pci;
>  	void __iomem *base;
> @@ -30,7 +36,9 @@ struct mipi_i3c_hci_pci_info {
>  	int (*init)(struct mipi_i3c_hci_pci *hci);
>  	void (*exit)(struct mipi_i3c_hci_pci *hci);
>  	const char *name;
> -	int id;
> +	int id[INST_MAX];
> +	u32 instance_offset[INST_MAX];
> +	int instance_count;
>  };
>
>  #define INTEL_PRIV_OFFSET		0x2b0
> @@ -177,14 +185,18 @@ static const struct mipi_i3c_hci_pci_info intel_1_info = {
>  	.init = intel_i3c_init,
>  	.exit = intel_i3c_exit,
>  	.name = "intel-lpss-i3c",
> -	.id = 0,
> +	.id = {0},
> +	.instance_offset = {0},
> +	.instance_count = 1,
>  };
>
>  static const struct mipi_i3c_hci_pci_info intel_2_info = {
>  	.init = intel_i3c_init,
>  	.exit = intel_i3c_exit,
>  	.name = "intel-lpss-i3c",
> -	.id = 2,
> +	.id = {2},
> +	.instance_offset = {0},
> +	.instance_count = 1,
>  };
>
>  struct mipi_i3c_hci_pci_cell_data {
> @@ -192,34 +204,38 @@ struct mipi_i3c_hci_pci_cell_data {
>  	struct resource res;
>  };
>
> -static void mipi_i3c_hci_pci_setup_cell(struct mipi_i3c_hci_pci *hci,
> +static void mipi_i3c_hci_pci_setup_cell(struct mipi_i3c_hci_pci *hci, int idx,
>  					struct mipi_i3c_hci_pci_cell_data *data,
>  					struct mfd_cell *cell)
>  {
> -	data->pdata.base_regs = hci->base;
> +	data->pdata.base_regs = hci->base + hci->info->instance_offset[idx];
>
>  	data->res = DEFINE_RES_IRQ(0);
>
>  	cell->name = hci->info->name;
> -	cell->id = hci->info->id;
> +	cell->id = hci->info->id[idx];
>  	cell->platform_data = &data->pdata;
>  	cell->pdata_size = sizeof(data->pdata);
>  	cell->num_resources = 1;
>  	cell->resources = &data->res;
>  }
>
> +#define mipi_i3c_hci_pci_alloc(h, x) kcalloc((h)->info->instance_count, sizeof(*(x)), GFP_KERNEL)
> +
>  static int mipi_i3c_hci_pci_add_instances(struct mipi_i3c_hci_pci *hci)
>  {
> -	struct mipi_i3c_hci_pci_cell_data *data __free(kfree) = kzalloc(sizeof(*data), GFP_KERNEL);
> -	struct mfd_cell *cells __free(kfree) = kzalloc(sizeof(*cells), GFP_KERNEL);
> +	struct mipi_i3c_hci_pci_cell_data *data __free(kfree) = mipi_i3c_hci_pci_alloc(hci, data);
> +	struct mfd_cell *cells __free(kfree) = mipi_i3c_hci_pci_alloc(hci, cells);
>  	int irq = pci_irq_vector(hci->pci, 0);
> +	int nr = hci->info->instance_count;
>
>  	if (!cells || !data)
>  		return -ENOMEM;
>
> -	mipi_i3c_hci_pci_setup_cell(hci, data, cells);
> +	for (int i = 0; i < nr; i++)
> +		mipi_i3c_hci_pci_setup_cell(hci, i, data + i, cells + i);
>
> -	return mfd_add_devices(&hci->pci->dev, 0, cells, 1, NULL, irq, NULL);
> +	return mfd_add_devices(&hci->pci->dev, 0, cells, nr, NULL, irq, NULL);
>  }
>
>  static int mipi_i3c_hci_pci_probe(struct pci_dev *pci,
> --
> 2.51.0
>
>
> --
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