On Tue, Nov 08, 2016 at 11:51:29AM +0100, Jean-Francois Moine wrote:
On Mon, 7 Nov 2016 21:05:05 +0100 Maxime Ripard maxime.ripard@free-electrons.com wrote:
Hi,
On Sun, Nov 06, 2016 at 07:02:48PM +0100, Jean-Francois Moine wrote:
On Sun, 23 Oct 2016 09:33:16 +0800 Chen-Yu Tsai wens@csie.org wrote:
On Fri, Oct 21, 2016 at 4:36 PM, Jean-Francois Moine moinejf@free.fr wrote:
This patch adds I2S support to sun8i SoCs as the A83T and H3.
Signed-off-by: Jean-Francois Moine moinejf@free.fr
Note: This driver is closed to the sun4i-i2s except that:
- it handles the H3
If it's close to sun4i-i2s, you should probably rework that one to support the newer SoCs.
I started to add the H3 into the sun4i-i2s, but I am blocked with regmap. Many H3 registers are common with the A10, but some of them have more or less fields, the fields may be at different offsets. And, finally, some registers are completely different. This would not raise any problem, except with regmap which is really painful.
That's weird, because regmap's regmap_field should make that much easier.
#define field_relaxed(addr, mask, val) \ writel_relaxed((readl_relaxed(addr) & mask) | val, addr)
I'm not sure what you mean here.
As I may understood, regmap is used to simplify suspend/resume, but, is it useful to save the I2S register on suspend? Practically, I am streaming some tune on my device. I suspend it for any reason. The next morning, I resume it. Are you sure I want to continue to hear the end of the tune?
I better think that streaming should be simply stopped on suspend.
You're mistaken. The code in there is for *runtime* suspend, ie when the device is no longer used, so that case shouldn't even happen at all.
(And real suspend isn't supported anyway)
Is it time to remove this useless code?
Which useless code?
Then, there is no need to save the playing registers, and, here I am, there is no need to use regmap.
May I go this way?
No, please don't. regmap is also providing very useful features, such as access to all the registers through debugfs, or tracing. What exactly feels painful to you?
When the I/O registers are in memory (that's the case), you may access them (read and write) thru /dev/mem.
For all the registers if you want to dump all of them. It needs scripting, it needs root access, and it needs some tool (either devmem or a custom one) to dump the values. And this is if you have the right kernel configuration options (devmem enabled, with the protection against mapped devices disabled).
It just works with debugfs.
Also, is a register access trace really needed in this driver?
Yes.
The pain is to define the regmap_config (which registers can be read/write/volatile and which can be the values the u-boot let us in the registers at startup time), and the lot of code which is run instead of simple load/store machine instructions.
This is only needed if you want to use caching, and caching is optional.
Maxime