[PATCH 3/4] msm-bus: Define the msm-bus skeleton

[Grant Likely]

On Wed, Aug 18, 2010 at 1:15 PM, Patrick Pannuto
<ppannuto at codeaurora.org> wrote:
> This defines the msm_bus_type and adds 3 bus
> devices (msm-apps, msm-system, msm-mmss) to it.
>
> With this new model it is trivial to move devices and
> drivers onto the msm_bus, simply
>
>        s/platform_device_register/msm_device_register
>        s/platform_driver_register/msm_driver_register
>
> This is not the final architecture of msm_bus /devices/,
> rather a demonstration of the API usage to define and
> utilize the msm_bus_type. Architecture will likely be
> specified in board files or perhaps OF.
>
> The resulting bus structure is (snipped):
>
> /sys/bus
> |-- msm-bus-type
> |   |-- devices
> |   |   |-- msm-apps -> ../../../devices/msm-apps
> |   |   |-- msm-mmss -> ../../../devices/msm-mmss
> |   |   |-- msm-system -> ../../../devices/msm-system
> |   |   |-- some-msm-dev -> ../../../devices/msm-system/some-msm-dev
> |   |-- drivers
> |   |   |-- some-msm-drv
>
> /sys/devices
> |-- msm-apps
> |-- msm-mmss
> |-- msm-system
> |   |-- some-msm-dev
>
> Which maps the desired topology
>
> QUICK COMMENT
>
> It is worth noting that this patch is a fairly minimal implementation,
> that is, it does not yet have any functionality that makes it differ
> from the platform bus - it just shows how it would be done.

Okay, so that's the core point.  without the differentiated behaviour,
you can do exactly the same thing, with the same topology, without the
new bus types.

So, the question remains, what is the new functionality that needs to
be supported that platform_bus_type doesn't implement?  That is the
example that I'm really keen to see!  :-)

Cheers,
g.

>
> Also, it only implements the part of the API it needs to, which could
> be confusing - you register devices with msm_device_register, yet
> unregister them with platform_device_unregister; although it would
> be perfectly valid to add
>
>   #define msm_device_unregister platform_device_unregister
>   (...etc)
>
> to msm_device.h to "complete the API".
>
> This patch and the following are a /proof of concept/, not the acutal
> patches for MSM; physical bus devices vary, and will not be defined as
> statically as shown here
>
> Change-Id: I0f4cd8eb515726ef1945d8ea972f0f8a5e145a7b
> Signed-off-by: Patrick Pannuto <ppannuto at codeaurora.org>
> ---
>  arch/arm/mach-msm/Makefile                  |    1 +
>  arch/arm/mach-msm/include/mach/msm_device.h |   28 +++++++
>  arch/arm/mach-msm/msm_bus.c                 |  105 +++++++++++++++++++++++++++
>  3 files changed, 134 insertions(+), 0 deletions(-)
>  create mode 100644 arch/arm/mach-msm/include/mach/msm_device.h
>  create mode 100644 arch/arm/mach-msm/msm_bus.c
>
> diff --git a/arch/arm/mach-msm/Makefile b/arch/arm/mach-msm/Makefile
> index 7046106..977ba89 100644
> --- a/arch/arm/mach-msm/Makefile
> +++ b/arch/arm/mach-msm/Makefile
> @@ -4,6 +4,7 @@ obj-y += vreg.o
>  obj-y += acpuclock-arm11.o
>  obj-y += clock.o clock-pcom.o
>  obj-y += gpio.o
> +obj-y += msm_bus.o
>
>  ifdef CONFIG_MSM_VIC
>  obj-y += irq-vic.o
> diff --git a/arch/arm/mach-msm/include/mach/msm_device.h b/arch/arm/mach-msm/include/mach/msm_device.h
> new file mode 100644
> index 0000000..f46a2d0
> --- /dev/null
> +++ b/arch/arm/mach-msm/include/mach/msm_device.h
> @@ -0,0 +1,28 @@
> +/* Copyright (c) 2010, Code Aurora Forum. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 and
> + * only version 2 as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
> + * 02110-1301, USA.
> + */
> +
> +#ifndef _MSM_DEVICE_H
> +#define _MSM_DEVICE_H
> +
> +#include <linux/platform_device.h>
> +
> +extern int msm_device_register(struct platform_device *pdev);
> +extern int msm_driver_register(struct platform_driver *pdrv);
> +extern int msm_driver_probe(struct platform_driver *pdrv,
> +               int (*probe)(struct platform_device *));
> +
> +#endif
> diff --git a/arch/arm/mach-msm/msm_bus.c b/arch/arm/mach-msm/msm_bus.c
> new file mode 100644
> index 0000000..f32942c
> --- /dev/null
> +++ b/arch/arm/mach-msm/msm_bus.c
> @@ -0,0 +1,105 @@
> +/* Copyright (c) 2010, Code Aurora Forum. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 and
> + * only version 2 as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
> + * 02110-1301, USA.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +
> +#include <mach/msm_device.h>
> +
> +const struct dev_pm_ops msm_pm_ops = {
> +       PLATFORM_PM_OPS_TEMPLATE,
> +       .prepare        = NULL,
> +};
> +
> +struct bus_type msm_bus_type = {
> +       PLATFORM_BUS_TEMPLATE,
> +       .name           = "msm-bus-type",
> +       .dev_attrs      = NULL,
> +       .pm             = &msm_pm_ops,
> +};
> +
> +static struct platform_device msm_apps_bus = {
> +       .name                   = "msm-apps",
> +       .id                     = -1,
> +};
> +
> +static struct platform_device msm_system_bus = {
> +       .name                   = "msm-system",
> +       .id                     = -1,
> +};
> +
> +static struct platform_device msm_mmss_bus = {
> +       .name                   = "msm-mmss",
> +       .id                     = -1,
> +};
> +
> +int msm_device_register(struct platform_device *pdev)
> +{
> +       pdev->dev.bus = &msm_bus_type;
> +       /* XXX: Use platform_data to assign pdev->dev.parent */
> +
> +       device_initialize(&pdev->dev);
> +       return __platform_device_add(pdev);
> +}
> +
> +int msm_driver_register(struct platform_driver *pdrv)
> +{
> +       pdrv->driver.bus = &msm_bus_type;
> +
> +       return __platform_driver_register(pdrv);
> +}
> +
> +int msm_driver_probe(struct platform_driver *pdrv,
> +               int (*probe)(struct platform_device *))
> +{
> +       return __platform_driver_probe(pdrv, probe, &msm_driver_register);
> +}
> +
> +static int __init msm_bus_init(void)
> +{
> +       int error;
> +
> +       error = bus_register(&msm_bus_type);
> +       if (error)
> +               return error;
> +
> +       error = msm_device_register(&msm_apps_bus);
> +       if (error)
> +               goto fail_apps_bus;
> +
> +       error = msm_device_register(&msm_system_bus);
> +       if (error)
> +               goto fail_system_bus;
> +
> +       error = msm_device_register(&msm_mmss_bus);
> +       if (error)
> +               goto fail_mmss_bus;
> +
> +       return error;
> +
> +       /* platform_device_unregister(&msm_mmss_bus); */
> +fail_mmss_bus:
> +       platform_device_unregister(&msm_system_bus);
> +fail_system_bus:
> +       platform_device_unregister(&msm_apps_bus);
> +fail_apps_bus:
> +       bus_unregister(&msm_bus_type);
> +
> +       return error;
> +}
> +postcore_initcall(msm_bus_init);
> --
> 1.7.2.1
>
>



-- 
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.