[PATCH 04/10] soundwire: bus: add PM/no-PM versions of read/write functions - Pierre-Louis Bossart

From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
To: alsa-devel@alsa-project.org
Cc: linux-kernel@vger.kernel.org, tiwai@suse.de, broonie@kernel.org,
	vkoul@kernel.org, gregkh@linuxfoundation.org, jank@cadence.com,
	srinivas.kandagatla@linaro.org, slawomir.blauciak@intel.com,
	Bard liao <yung-chuan.liao@linux.intel.com>,
	Rander Wang <rander.wang@linux.intel.com>,
	Ranjani Sridharan <ranjani.sridharan@linux.intel.com>,
	Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>,
	Sanyog Kale <sanyog.r.kale@intel.com>
Subject: [PATCH 04/10] soundwire: bus: add PM/no-PM versions of read/write functions
Date: Tue, 14 Jan 2020 18:08:38 -0600	[thread overview]
Message-ID: <20200115000844.14695-5-pierre-louis.bossart@linux.intel.com> (raw)
In-Reply-To: <20200115000844.14695-1-pierre-louis.bossart@linux.intel.com>

Add support for pm_runtime with the appropriate error checks for
sdw_write/read functions, e.g. when pm_runtime is not supported.

Also expose internal functions without pm_runtime support, which are
required to perform any sort of suspend/resume operation, as well as
any enumeration tasks.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 drivers/soundwire/bus.c | 68 +++++++++++++++++++++++++++++++----------
 1 file changed, 52 insertions(+), 16 deletions(-)

diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
index ea04cf5f5bdc..c525b9b50453 100644
--- a/drivers/soundwire/bus.c
+++ b/drivers/soundwire/bus.c
@@ -317,6 +317,46 @@ int sdw_fill_msg(struct sdw_msg *msg, struct sdw_slave *slave,
 	return 0;
 }
 
+/*
+ * Read/Write IO functions.
+ * no_pm versions can only be called by the bus, e.g. while enumerating or
+ * handling suspend-resume sequences.
+ * all clients need to use the pm versions
+ */
+
+static int
+sdw_nread_no_pm(struct sdw_slave *slave, u32 addr, size_t count, u8 *val)
+{
+	struct sdw_msg msg;
+	int ret;
+
+	ret = sdw_fill_msg(&msg, slave, addr, count,
+			   slave->dev_num, SDW_MSG_FLAG_READ, val);
+	if (ret < 0)
+		return ret;
+
+	return sdw_transfer(slave->bus, &msg);
+}
+
+static int
+sdw_nwrite_no_pm(struct sdw_slave *slave, u32 addr, size_t count, u8 *val)
+{
+	struct sdw_msg msg;
+	int ret;
+
+	ret = sdw_fill_msg(&msg, slave, addr, count,
+			   slave->dev_num, SDW_MSG_FLAG_WRITE, val);
+	if (ret < 0)
+		return ret;
+
+	return sdw_transfer(slave->bus, &msg);
+}
+
+static int sdw_write_no_pm(struct sdw_slave *slave, u32 addr, u8 value)
+{
+	return sdw_nwrite_no_pm(slave, addr, 1, &value);
+}
+
 /**
  * sdw_nread() - Read "n" contiguous SDW Slave registers
  * @slave: SDW Slave
@@ -326,19 +366,17 @@ int sdw_fill_msg(struct sdw_msg *msg, struct sdw_slave *slave,
  */
 int sdw_nread(struct sdw_slave *slave, u32 addr, size_t count, u8 *val)
 {
-	struct sdw_msg msg;
 	int ret;
 
-	ret = sdw_fill_msg(&msg, slave, addr, count,
-			   slave->dev_num, SDW_MSG_FLAG_READ, val);
-	if (ret < 0)
-		return ret;
-
 	ret = pm_runtime_get_sync(slave->bus->dev);
-	if (ret < 0)
+	if (ret < 0 && ret != -EACCES) {
+		pm_runtime_put_noidle(slave->bus->dev);
 		return ret;
+	}
+
+	ret = sdw_nread_no_pm(slave, addr, count, val);
 
-	ret = sdw_transfer(slave->bus, &msg);
+	pm_runtime_mark_last_busy(slave->bus->dev);
 	pm_runtime_put(slave->bus->dev);
 
 	return ret;
@@ -354,19 +392,17 @@ EXPORT_SYMBOL(sdw_nread);
  */
 int sdw_nwrite(struct sdw_slave *slave, u32 addr, size_t count, u8 *val)
 {
-	struct sdw_msg msg;
 	int ret;
 
-	ret = sdw_fill_msg(&msg, slave, addr, count,
-			   slave->dev_num, SDW_MSG_FLAG_WRITE, val);
-	if (ret < 0)
-		return ret;
-
 	ret = pm_runtime_get_sync(slave->bus->dev);
-	if (ret < 0)
+	if (ret < 0 && ret != -EACCES) {
+		pm_runtime_put_noidle(slave->bus->dev);
 		return ret;
+	}
+
+	ret = sdw_nwrite_no_pm(slave, addr, count, val);
 
-	ret = sdw_transfer(slave->bus, &msg);
+	pm_runtime_mark_last_busy(slave->bus->dev);
 	pm_runtime_put(slave->bus->dev);
 
 	return ret;
-- 
2.20.1

