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

Frank Li
2025-12-16T17:16:44Z

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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