From: Sander Vanheule <sander@svanheule.net>
To: Pavel Machek <pavel@ucw.cz>, Rob Herring <robh+dt@kernel.org>,
Lee Jones <lee.jones@linaro.org>, Mark Brown <broonie@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J . Wysocki" <rafael@kernel.org>,
Michael Walle <michael@walle.cc>,
Linus Walleij <linus.walleij@linaro.org>,
Bartosz Golaszewski <bgolaszewski@baylibre.com>,
linux-leds@vger.kernel.org, devicetree@vger.kernel.org,
linux-gpio@vger.kernel.org
Cc: Andrew Lunn <andrew@lunn.ch>,
Andy Shevchenko <andy.shevchenko@gmail.com>,
linux-kernel@vger.kernel.org,
Sander Vanheule <sander@svanheule.net>
Subject: [PATCH v5 1/8] regmap: Support atomic forced uncached reads
Date: Sat, 12 Jun 2021 23:12:31 +0200 [thread overview]
Message-ID: <e1be20bb92cff2688153125b534b738b71c3a743.1623532208.git.sander@svanheule.net> (raw)
In-Reply-To: <cover.1623532208.git.sander@svanheule.net>
When a user wants to read a single uncached register, cache bypassing
can be enabled. However, this is not atomic unless an external lock is
used for the regmap. When using regcache_cache_bypass, the original
bypass state also cannot be restored.
Add support to atomically read a single uncached value, bypassing any
regmap cache.
Signed-off-by: Sander Vanheule <sander@svanheule.net>
---
drivers/base/regmap/regmap.c | 33 +++++++++++++++++++++++++++++++++
include/linux/regmap.h | 8 ++++++++
2 files changed, 41 insertions(+)
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index fe3e38dd5324..a828f05535b7 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -2745,6 +2745,39 @@ int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val)
}
EXPORT_SYMBOL_GPL(regmap_read);
+/**
+ * regmap_read_bypassed() - Read a value from a single register, bypassing the cache
+ *
+ * @map: Register map to read from
+ * @reg: Register to be read from
+ * @val: Pointer to store read value
+ *
+ * A value of zero will be returned on success, a negative errno will
+ * be returned in error cases.
+ */
+int regmap_read_bypassed(struct regmap *map, unsigned int reg, unsigned int *val)
+{
+ bool bypass;
+ int ret;
+
+ if (!IS_ALIGNED(reg, map->reg_stride))
+ return -EINVAL;
+
+ map->lock(map->lock_arg);
+
+ bypass = map->cache_bypass;
+ map->cache_bypass = true;
+
+ ret = _regmap_read(map, reg, val);
+
+ map->cache_bypass = bypass;
+
+ map->unlock(map->lock_arg);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(regmap_read_bypassed);
+
/**
* regmap_raw_read() - Read raw data from the device
*
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index f5f08dd0a116..a54dc00326ba 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -1133,6 +1133,7 @@ int regmap_multi_reg_write_bypassed(struct regmap *map,
int regmap_raw_write_async(struct regmap *map, unsigned int reg,
const void *val, size_t val_len);
int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val);
+int regmap_read_bypassed(struct regmap *map, unsigned int reg, unsigned int *val);
int regmap_raw_read(struct regmap *map, unsigned int reg,
void *val, size_t val_len);
int regmap_noinc_read(struct regmap *map, unsigned int reg,
@@ -1607,6 +1608,13 @@ static inline int regmap_read(struct regmap *map, unsigned int reg,
return -EINVAL;
}
+static inline int regmap_read_bypassed(struct regmap *map, unsigned int reg,
+ unsigned int *val)
+{
+ WARN_ONCE(1, "regmap API is disabled");
+ return -EINVAL;
+}
+
static inline int regmap_raw_read(struct regmap *map, unsigned int reg,
void *val, size_t val_len)
{
--
2.31.1
next prev parent reply other threads:[~2021-06-12 21:13 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-12 21:12 [PATCH v5 0/8] RTL8231 GPIO expander support Sander Vanheule
2021-06-12 21:12 ` Sander Vanheule [this message]
2021-06-12 21:23 ` [PATCH v5 1/8] regmap: Support atomic forced uncached reads Andy Shevchenko
2021-06-14 10:33 ` Mark Brown
2021-06-12 21:12 ` [PATCH v5 2/8] gpio: regmap: Add quirk for aliased data registers Sander Vanheule
2021-06-12 21:29 ` Andy Shevchenko
2021-07-07 20:53 ` Sander Vanheule
2021-07-08 14:23 ` Mark Brown
2021-06-12 21:12 ` [PATCH v5 3/8] dt-bindings: leds: Binding for RTL8231 scan matrix Sander Vanheule
2021-06-12 21:12 ` [PATCH v5 4/8] dt-bindings: mfd: Binding for RTL8231 Sander Vanheule
2021-06-12 21:12 ` [PATCH v5 5/8] mfd: Add RTL8231 core device Sander Vanheule
2021-06-12 21:12 ` [PATCH v5 6/8] pinctrl: Add RTL8231 pin control and GPIO support Sander Vanheule
2021-06-12 21:12 ` [PATCH v5 7/8] leds: Add support for RTL8231 LED scan matrix Sander Vanheule
2021-06-12 21:12 ` [PATCH v5 8/8] MAINTAINERS: Add RTL8231 MFD driver Sander Vanheule
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