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SubjectRe: [RFC PATCH 2/2] HISI LPC: Add PNP device support
On Fri, Apr 20, 2018 at 06:07:26PM +0800, John Garry wrote:
> Currently the driver creates an per-ACPI device mfd_cell
> for child devices. This does not suit devices which are
> PNP-compatible, as we expect PNP-compatible devices to
> derive PNP devices.
>
> To add PNP device support, we continue to allow the PNP
> scan code to create the PNP device (which have the
> enumeration_by_parent flag set), but expect the PNP
> scan to defer adding the device to allow the host probe
> code to do this. In addition, no longer do we create an
> mfd_cell (platform_device) for PNP-compatible devices.
>
> We take this approach so that host probe code can
> translate the IO resources of the PNP device prior
> to adding the device.
>
> Signed-off-by: John Garry <john.garry@huawei.com>
> ---
> drivers/bus/hisi_lpc.c | 38 +++++++++++++++++++++++++++++++++++++-
> 1 file changed, 37 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/bus/hisi_lpc.c b/drivers/bus/hisi_lpc.c
> index 2d4611e..d228bc5 100644
> --- a/drivers/bus/hisi_lpc.c
> +++ b/drivers/bus/hisi_lpc.c
> @@ -17,8 +17,11 @@
> #include <linux/of_address.h>
> #include <linux/of_platform.h>
> #include <linux/pci.h>
> +#include <linux/pnp.h>
> #include <linux/slab.h>
>
> +#include "../pnp/base.h"
> +
> #define DRV_NAME "hisi-lpc"
>
> /*
> @@ -469,8 +472,11 @@ static int hisi_lpc_acpi_probe(struct device *hostdev)
> struct acpi_device *child;
> int size, ret, count = 0, cell_num = 0;
>
> - list_for_each_entry(child, &adev->children, node)
> + list_for_each_entry(child, &adev->children, node) {
> + if (acpi_is_pnp_device(child))
> + continue;
> cell_num++;
> + }
>
> /* allocate the mfd cell and companion ACPI info, one per child */
> size = sizeof(*mfd_cells) + sizeof(*hisi_lpc_mfd_cells);
> @@ -492,6 +498,9 @@ static int hisi_lpc_acpi_probe(struct device *hostdev)
> .pnpid = pnpid,
> };
>
> + if (acpi_is_pnp_device(child))
> + continue;
> +
> /*
> * For any instances of this host controller (Hip06 and Hip07
> * are the only chipsets), we would not have multiple slaves
> @@ -523,6 +532,33 @@ static int hisi_lpc_acpi_probe(struct device *hostdev)
> return ret;
> }
>
> + list_for_each_entry(child, &adev->children, node) {
> + struct pnp_resource *pnp_res;
> + struct pnp_dev *pnp_dev;
> + int rc;
> +
> + if (!acpi_is_pnp_device(child))
> + continue;
> +
> + pnp_dev = child->driver_data;

...or better yet a PNP helper function that makes this more
understandable.

> +
> + /*
> + * Prior to adding the device, we need to translate the
> + * resources to logical PIO addresses.
> + */
> + list_for_each_entry(pnp_res, &pnp_dev->resources, list) {
> + struct resource *res = &pnp_res->res;
> +
> + if (res->flags | IORESOURCE_IO)

I think you should use

if (resource_type(res) == IORESOURCE_IO)

instead.

> + hisi_lpc_acpi_xlat_io_res(child, adev, res);
> + }
> + rc = pnp_add_device(pnp_dev);
> + if (rc) {
> + put_device(&pnp_dev->dev);
> + return rc;
> + }
> + }
> +
> return 0;
> }
>
> --
> 1.9.1

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