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SubjectRe: [PATCH 11/27] clocksource: sh_cmt: Add support for multiple channels per device
On Fri, 14 Feb 2014, Laurent Pinchart wrote:
> CMT hardware devices can support multiple channels, with global
> registers and per-channel registers. The sh_cmt driver currently models
> the hardware with one Linux device per channel. This model makes it
> difficult to handle global registers in a clean way.
>
> Add support for a new model that uses one Linux device per timer with
> multiple channels per device. This requires changes to platform data,
> add new channel configuration fields.
>
> Support for the legacy model is kept and will be removed after all
> platforms switch to the new model.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> ---
> drivers/clocksource/sh_cmt.c | 299 +++++++++++++++++++++++++++++++++----------
> include/linux/sh_timer.h | 9 ++
> 2 files changed, 239 insertions(+), 69 deletions(-)
>
> diff --git a/drivers/clocksource/sh_cmt.c b/drivers/clocksource/sh_cmt.c
> index 5280231..8390f0f 100644
> --- a/drivers/clocksource/sh_cmt.c
> +++ b/drivers/clocksource/sh_cmt.c
> @@ -53,7 +53,16 @@ struct sh_cmt_device;
> * channel registers block. All other versions have a shared start/stop register
> * located in the global space.
> *
> - * Note that CMT0 on r8a73a4, r8a7790 and r8a7791, while implementing 32-bit
> + * Channels are indexed from 0 to N-1 in the documentation. The channel index
> + * infers the start/stop bit position in the control register and the channel
> + * registers block address. Some CMT instances have a subset of channels
> + * available, in which case the index in the documentation doesn't match the
> + * "real" index as implemented in hardware. This is for instance the case with
> + * CMT0 on r8a7740, which is a 32-bit variant with a single channel numbered 0
> + * in the documentation but using start/stop bit 5 and having its registers
> + * block at 0x60.
> + *
> + * Similarly CMT0 on r8a73a4, r8a7790 and r8a7791, while implementing 32-bit
> * channels only, is a 48-bit gen2 CMT with the 48-bit channels unavailable.
> */
>
> @@ -85,11 +94,15 @@ struct sh_cmt_info {
>
> struct sh_cmt_channel {
> struct sh_cmt_device *cmt;
> - unsigned int index;
>
> - void __iomem *base;
> + unsigned int index; /* Index in the documentation */
> + unsigned int hwidx; /* Real hardware index */
> +
> + void __iomem *iostart;
> + void __iomem *ioctrl;
> struct irqaction irqaction;

While you are at it, can you please get rid of that irqaction and use
request_irq() ?

Thanks,

tglx


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