Re: [PATCH V3 07/11] i3c: mipi-i3c-hci: Allow for Multi-Bus Instances

Frank Li
2025-12-16T17:10:21Z

On Tue, Dec 16, 2025 at 06:56:38PM +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.
>
> A separate platform device will represent each instance, but it is
> necessary to allow for shared resources.
>
> Multi-bus instances share the same MMIO address space, but the ranges are
> not guaranteed to be contiguous. To avoid overlapping mappings, pass
> base_regs from the parent mapping to child devices.
>
> Allow the IRQ to be shared among instances.
>
> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
> ---

Reviewed-by: Frank Li <Frank.Li@nxp.com>

>
>
> Changes in V3:
>
> Enhance commit message
>
> Changes in V2:
>
> None
>
>
> drivers/i3c/master/mipi-i3c-hci/core.c | 21 +++++++++++++++++----
> include/linux/platform_data/mipi-i3c-hci.h | 15 +++++++++++++++
> 2 files changed, 32 insertions(+), 4 deletions(-)
> create mode 100644 include/linux/platform_data/mipi-i3c-hci.h
>
> diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c b/drivers/i3c/master/mipi-i3c-hci/core.c
> index 3d6544a64188..6da5daf18166 100644
> --- a/drivers/i3c/master/mipi-i3c-hci/core.c
> +++ b/drivers/i3c/master/mipi-i3c-hci/core.c
> @@ -14,6 +14,7 @@
> #include <linux/interrupt.h>
> #include <linux/iopoll.h>
> #include <linux/module.h>
> +#include <linux/platform_data/mipi-i3c-hci.h>
> #include <linux/platform_device.h>
>
> #include "hci.h"
> @@ -737,15 +738,27 @@ static int i3c_hci_init(struct i3c_hci *hci)
>
> static int i3c_hci_probe(struct platform_device *pdev)
> {
> + const struct mipi_i3c_hci_platform_data *pdata = pdev->dev.platform_data;
> struct i3c_hci *hci;
> int irq, ret;
>
> hci = devm_kzalloc(&pdev->dev, sizeof(*hci), GFP_KERNEL);
> if (!hci)
> return -ENOMEM;
> - hci->base_regs = devm_platform_ioremap_resource(pdev, 0);
> - if (IS_ERR(hci->base_regs))
> - return PTR_ERR(hci->base_regs);
> +
> + /*
> + * Multi-bus instances share the same MMIO address range, but not
> + * necessarily in separate contiguous sub-ranges. To avoid overlapping
> + * mappings, provide base_regs from the parent mapping.
> + */
> + if (pdata)
> + hci->base_regs = pdata->base_regs;
> +
> + if (!hci->base_regs) {
> + hci->base_regs = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(hci->base_regs))
> + return PTR_ERR(hci->base_regs);
> + }
>
> platform_set_drvdata(pdev, hci);
> /* temporary for dev_printk's, to be replaced in i3c_master_register */
> @@ -759,7 +772,7 @@ static int i3c_hci_probe(struct platform_device *pdev)
>
> irq = platform_get_irq(pdev, 0);
> ret = devm_request_irq(&pdev->dev, irq, i3c_hci_irq_handler,
> - 0, NULL, hci);
> + IRQF_SHARED, NULL, hci);
> if (ret)
> return ret;
>
> diff --git a/include/linux/platform_data/mipi-i3c-hci.h b/include/linux/platform_data/mipi-i3c-hci.h
> new file mode 100644
> index 000000000000..ab7395f455f9
> --- /dev/null
> +++ b/include/linux/platform_data/mipi-i3c-hci.h
> @@ -0,0 +1,15 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef INCLUDE_PLATFORM_DATA_MIPI_I3C_HCI_H
> +#define INCLUDE_PLATFORM_DATA_MIPI_I3C_HCI_H
> +
> +#include <linux/compiler_types.h>
> +
> +/**
> + * struct mipi_i3c_hci_platform_data - Platform-dependent data for mipi_i3c_hci
> + * @base_regs: Register set base address (to support multi-bus instances)
> + */
> +struct mipi_i3c_hci_platform_data {
> + void __iomem *base_regs;
> +};
> +
> +#endif
> --
> 2.51.0
>
>
> --
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