[PATCH 11/27] clocksource: sh_cmt: Add support for multiple channels per device

Hi Magnus,

On Monday 17 February 2014 10:41:31 Magnus Damm wrote:

On Mon, Feb 17, 2014 at 3:18 AM, Laurent Pinchart wrote:

quoted

On Saturday 15 February 2014 13:46:54 Thomas Gleixner wrote:

quoted

On Fri, 14 Feb 2014, Laurent Pinchart wrote:

quoted

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
[off-list ref]
---

 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

[snip]

quoted

quoted

quoted

@@ -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() ?

The driver claims it can't use request_irq() because the function is not
available for early platform devices. If the situation has changed I'd
gladly get rid of irqaction.

With the risk of stating the obvious, this depends on how early the
early platform device stuff is being run. The actual location may not
be the same on SH and ARM for instance.

On ARM we are doing all we can to initialize these devices as late as
ever possible in the MULTIPLAFORM (DT reference) case. Once we manage
to remove the legacy ARM case then there is one less user of early
platform timers.

One perhaps reasonable way forward could be to use request_irq() in
case of DT and leave the legacy platform data case to rely on
irqaction.

The whole point of switching from setup_irq() to request_irq() is to simplify 
the code. Adding request_irq() as an option would go in the opposite 
direction.

-- 
Regards,

Laurent Pinchart