A syscon device may need to be taken out of reset before functioning -
this change adds a facility to attach a reset control to a mmio regmap,
and performs the necessary deassert/assert operations on the reset
controller on attach/detach.
Signed-off-by: Jeremy Kerr <[email protected]>
---
drivers/base/regmap/regmap-mmio.c | 22 ++++++++++++++++++++++
include/linux/regmap.h | 3 +++
2 files changed, 25 insertions(+)
diff --git a/drivers/base/regmap/regmap-mmio.c b/drivers/base/regmap/regmap-mmio.c
index 3ccdd86a97e7..e2611de73b42 100644
--- a/drivers/base/regmap/regmap-mmio.c
+++ b/drivers/base/regmap/regmap-mmio.c
@@ -8,6 +8,7 @@
#include <linux/err.h>
#include <linux/io.h>
#include <linux/module.h>
+#include <linux/reset.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include <linux/swab.h>
@@ -22,6 +23,8 @@ struct regmap_mmio_context {
bool attached_clk;
struct clk *clk;
+ struct reset_control *reset;
+
void (*reg_write)(struct regmap_mmio_context *ctx,
unsigned int reg, unsigned int val);
unsigned int (*reg_read)(struct regmap_mmio_context *ctx,
@@ -633,4 +636,23 @@ void regmap_mmio_detach_clk(struct regmap *map)
}
EXPORT_SYMBOL_GPL(regmap_mmio_detach_clk);
+int regmap_mmio_attach_reset(struct regmap *map, struct reset_control *reset)
+{
+ struct regmap_mmio_context *ctx = map->bus_context;
+
+ ctx->reset = reset;
+
+ return reset_control_deassert(ctx->reset);
+}
+EXPORT_SYMBOL_GPL(regmap_mmio_attach_reset);
+
+void regmap_mmio_detach_reset(struct regmap *map)
+{
+ struct regmap_mmio_context *ctx = map->bus_context;
+
+ reset_control_assert(ctx->reset);
+ ctx->reset = NULL;
+}
+EXPORT_SYMBOL_GPL(regmap_mmio_detach_reset);
+
MODULE_LICENSE("GPL v2");
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index ca3434dca3a0..b0c7a747c06f 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -34,6 +34,7 @@ struct spmi_device;
struct regmap;
struct regmap_range_cfg;
struct regmap_field;
+struct reset_control;
struct snd_ac97;
struct sdw_slave;
@@ -1150,6 +1151,8 @@ bool regmap_ac97_default_volatile(struct device *dev, unsigned int reg);
int regmap_mmio_attach_clk(struct regmap *map, struct clk *clk);
void regmap_mmio_detach_clk(struct regmap *map);
+int regmap_mmio_attach_reset(struct regmap *map, struct reset_control *reset);
+void regmap_mmio_detach_reset(struct regmap *map);
void regmap_exit(struct regmap *map);
int regmap_reinit_cache(struct regmap *map,
const struct regmap_config *config);
--
2.35.1
On Fri, Dec 09, 2022 at 09:33:08AM +0800, Jeremy Kerr wrote:
> A syscon device may need to be taken out of reset before functioning -
> this change adds a facility to attach a reset control to a mmio regmap,
> and performs the necessary deassert/assert operations on the reset
> controller on attach/detach.
Managment of reset feels like something that should be done at a higher
level - typically reset also implies losing all the register contents
which means it should be somewhere above the cache layer.
Hi Mark,
> > A syscon device may need to be taken out of reset before functioning
> > - this change adds a facility to attach a reset control to a mmio
> > regmap, and performs the necessary deassert/assert operations on the
> > reset controller on attach/detach.
>
> Managment of reset feels like something that should be done at a
> higher level - typically reset also implies losing all the register
> contents which means it should be somewhere above the cache layer.
Yep, that makes sense. I'll rework to do the reset controller handling
in the syscon layer instead - unless there are any objections to that?
Cheers,
Jeremy