linux-kernel - [PATCH v6 7/8] i3c: master: added sysfs key i3c_acquire

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Message-ID: <1587140574-31403-1-git-send-email-pthombar@cadence.com>
Date:   Fri, 17 Apr 2020 18:22:54 +0200
From:   Parshuram Thombare <pthombar@...ence.com>
To:     <bbrezillon@...nel.org>, <vitor.soares@...opsys.com>
CC:     <pgaj@...ence.com>, <linux-i3c@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <mparab@...ence.com>,
        <praneeth@...com>, Parshuram Thombare <pthombar@...ence.com>
Subject: [PATCH v6 7/8] i3c: master: added sysfs key i3c_acquire_bus

This patch add sysfs key 'i3c_acquire_bus'
to acquire I3C bus.

Signed-off-by: Parshuram Thombare <pthombar@...ence.com>
---
 drivers/i3c/master.c | 112 +++++++++++++++++++++++++------------------
 1 file changed, 65 insertions(+), 47 deletions(-)

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 39a412b32c59..c0b6a0c658f0 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -467,6 +467,53 @@ static const char * const i3c_bus_mode_strings[] = {
 	[I3C_BUS_MODE_MIXED_SLOW] = "mixed-slow",
 };
 
+static int i3c_master_enable_mr_events(struct i3c_master_controller *master)
+{
+	int ret;
+
+	master->ops->enable_mr_events(master);
+	i3c_bus_maintenance_lock(&master->bus);
+	ret = i3c_master_enec_locked(master, I3C_BROADCAST_ADDR,
+				     I3C_CCC_EVENT_MR | I3C_CCC_EVENT_HJ);
+	i3c_bus_maintenance_unlock(&master->bus);
+
+	return ret;
+}
+
+/* This function is expected to be called with normaluse_lock */
+int i3c_master_acquire_bus(struct i3c_master_controller *master)
+{
+	int ret = 0;
+
+	if (!master->this || master->this != master->bus.cur_master) {
+		if (master->mr_state == I3C_MR_IDLE) {
+			master->mr_state = I3C_MR_WAIT_DA;
+			init_completion(&master->mr_comp);
+			queue_work(master->wq, &master->sec_mst_work);
+			/*
+			 * Bus acquire procedure may need write lock
+			 * so release read lock before yielding
+			 * to bus acquire state machine
+			 */
+			i3c_bus_normaluse_unlock(&master->bus);
+			wait_for_completion(&master->mr_comp);
+			i3c_bus_normaluse_lock(&master->bus);
+			if (master->mr_state != I3C_MR_DONE)
+				ret = -EAGAIN;
+			master->mr_state = I3C_MR_IDLE;
+		} else {
+			/*
+			 * MR request is already in process for
+			 * this master
+			 */
+			ret = -EAGAIN;
+		}
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(i3c_master_acquire_bus);
+
 static ssize_t mode_show(struct device *dev,
 			 struct device_attribute *da,
 			 char *buf)
@@ -533,6 +580,23 @@ static ssize_t i2c_scl_frequency_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(i2c_scl_frequency);
 
+static ssize_t i3c_acquire_bus_store(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t count)
+{
+	struct i3c_master_controller *master = dev_to_i3cmaster(dev);
+	int ret;
+
+	i3c_bus_normaluse_lock(&master->bus);
+	ret = i3c_master_acquire_bus(master);
+	i3c_bus_normaluse_unlock(&master->bus);
+	if (!ret)
+		i3c_master_enable_mr_events(master);
+
+	return ret ?: count;
+}
+static DEVICE_ATTR_WO(i3c_acquire_bus);
+
 static struct attribute *i3c_masterdev_attrs[] = {
 	&dev_attr_mode.attr,
 	&dev_attr_current_master.attr,
@@ -543,6 +607,7 @@ static struct attribute *i3c_masterdev_attrs[] = {
 	&dev_attr_pid.attr,
 	&dev_attr_dynamic_address.attr,
 	&dev_attr_hdrcap.attr,
+	&dev_attr_i3c_acquire_bus.attr,
 	NULL,
 };
 ATTRIBUTE_GROUPS(i3c_masterdev);
@@ -1244,19 +1309,6 @@ static int i3c_master_get_accmst_locked(struct i3c_master_controller *master,
 	return ret;
 }
 
-static int i3c_master_enable_mr_events(struct i3c_master_controller *master)
-{
-	int ret;
-
-	master->ops->enable_mr_events(master);
-	i3c_bus_maintenance_lock(&master->bus);
-	ret = i3c_master_enec_locked(master, I3C_BROADCAST_ADDR,
-				     I3C_CCC_EVENT_MR | I3C_CCC_EVENT_HJ);
-	i3c_bus_maintenance_unlock(&master->bus);
-
-	return ret;
-}
-
 static int i3c_master_getaccmst(struct i3c_master_controller *master)
 {
 	int ret;
@@ -1792,40 +1844,6 @@ void i3c_sec_mst_mr_dis_event(struct i3c_master_controller *m)
 }
 EXPORT_SYMBOL_GPL(i3c_sec_mst_mr_dis_event);
 
-/* This function is expected to be called with normaluse_lock */
-int i3c_master_acquire_bus(struct i3c_master_controller *master)
-{
-	int ret = 0;
-
-	if (!master->this || master->this != master->bus.cur_master) {
-		if (master->mr_state == I3C_MR_IDLE) {
-			master->mr_state = I3C_MR_WAIT_DA;
-			init_completion(&master->mr_comp);
-			queue_work(master->wq, &master->sec_mst_work);
-			/*
-			 * Bus acquire procedure may need write lock
-			 * so release read lock before yielding
-			 * to bus acquire state machine
-			 */
-			i3c_bus_normaluse_unlock(&master->bus);
-			wait_for_completion(&master->mr_comp);
-			i3c_bus_normaluse_lock(&master->bus);
-			if (master->mr_state != I3C_MR_DONE)
-				ret = -EAGAIN;
-			master->mr_state = I3C_MR_IDLE;
-		} else {
-			/*
-			 * MR request is already in process for
-			 * this master
-			 */
-			ret = -EAGAIN;
-		}
-	}
-
-	return ret;
-}
-EXPORT_SYMBOL_GPL(i3c_master_acquire_bus);
-
 static struct i2c_dev_boardinfo *
 i3c_master_alloc_i2c_boardinfo(struct i3c_master_controller *master,
 			       u16 addr, u8 lvr)
-- 
2.17.1