Applied "regmap: Apply optional delay in multi_reg_write/register_patch" to the regmap tree

Mark Brown
2015-07-16T21:08:03Z

The patch

regmap: Apply optional delay in multi_reg_write/register_patch

has been applied to the regmap tree at

git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap.git

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 2de9d6006c190bb0f706e8404de94cd94293801f Mon Sep 17 00:00:00 2001
From: Nariman Poushin <nariman@opensource.wolfsonmicro.com>
Date: Thu, 16 Jul 2015 16:36:22 +0100
Subject: [PATCH] regmap: Apply optional delay in
multi_reg_write/register_patch

Add an optional delay_us field in reg_sequence to allow the client to
specify a delay (in microseconds) to be applied after any given write
in a sequence of writes.

We treat a delay in a sequence the same way we treat a page change as
they are logically similar in that you can coalesce all write before
a delay (in the same way you can coalesce all writes before a page
change is needed)

Signed-off-by: Nariman Poushin <nariman@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
---
drivers/base/regmap/regmap.c | 54 +++++++++++++++++++++++++++++++++++++++-----
include/linux/regmap.h | 5 +++-
2 files changed, 52 insertions(+), 7 deletions(-)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 2cbb4502747d..b3a5aa5cd580 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -18,6 +18,7 @@
#include <linux/of.h>
#include <linux/rbtree.h>
#include <linux/sched.h>
+#include <linux/delay.h>

#define CREATE_TRACE_POINTS
#include "trace.h"
@@ -1807,10 +1808,12 @@ static int _regmap_range_multi_paged_reg_write(struct regmap *map,
int i, n;
struct reg_sequence *base;
unsigned int this_page = 0;
+ unsigned int page_change = 0;
/*
* the set of registers are not neccessarily in order, but
* since the order of write must be preserved this algorithm
- * chops the set each time the page changes
+ * chops the set each time the page changes. This also applies
+ * if there is a delay required at any point in the sequence.
*/
base = regs;
for (i = 0, n = 0; i < num_regs; i++, n++) {
@@ -1826,16 +1829,48 @@ static int _regmap_range_multi_paged_reg_write(struct regmap *map,
this_page = win_page;
if (win_page != this_page) {
this_page = win_page;
+ page_change = 1;
+ }
+ }
+
+ /* If we have both a page change and a delay make sure to
+ * write the regs and apply the delay before we change the
+ * page.
+ */
+
+ if (page_change || regs[i].delay_us) {
+
+ /* For situations where the first write requires
+ * a delay we need to make sure we don't call
+ * raw_multi_reg_write with n=0
+ * This can't occur with page breaks as we
+ * never write on the first iteration
+ */
+ if (regs[i].delay_us && i == 0)
+ n = 1;
+
ret = _regmap_raw_multi_reg_write(map, base, n);
if (ret != 0)
return ret;
+
+ if (regs[i].delay_us)
+ udelay(regs[i].delay_us);
+
base += n;
n = 0;
- }
- ret = _regmap_select_page(map, &base[n].reg, range, 1);
- if (ret != 0)
- return ret;
+
+ if (page_change) {
+ ret = _regmap_select_page(map,
+ &base[n].reg,
+ range, 1);
+ if (ret != 0)
+ return ret;
+
+ page_change = 0;
+ }
+
}
+
}
if (n > 0)
return _regmap_raw_multi_reg_write(map, base, n);
@@ -1854,6 +1889,9 @@ static int _regmap_multi_reg_write(struct regmap *map,
ret = _regmap_write(map, regs[i].reg, regs[i].def);
if (ret != 0)
return ret;
+
+ if (regs[i].delay_us)
+ udelay(regs[i].delay_us);
}
return 0;
}
@@ -1893,8 +1931,12 @@ static int _regmap_multi_reg_write(struct regmap *map,
for (i = 0; i < num_regs; i++) {
unsigned int reg = regs[i].reg;
struct regmap_range_node *range;
+
+ /* Coalesce all the writes between a page break or a delay
+ * in a sequence
+ */
range = _regmap_range_lookup(map, reg);
- if (range) {
+ if (range || regs[i].delay_us) {
size_t len = sizeof(struct reg_sequence)*num_regs;
struct reg_sequence *base = kmemdup(regs, len,
GFP_KERNEL);
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index c9ef2ec69142..5a7cf2136c81 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -51,14 +51,17 @@ struct reg_default {
};

/**
- * Register/value pairs for sequences of writes
+ * Register/value pairs for sequences of writes with an optional delay in
+ * microseconds to be applied after each write.
*
* @reg: Register address.
* @def: Register value.
+ * @delay_us: Delay to be applied after the register write in microseconds
*/
struct reg_sequence {
unsigned int reg;
unsigned int def;
+ unsigned int delay_us;