[PATCH linux v4 16/20] drivers/fsi: Set up links for slave communication

[christopher.lee.bostic at gmail.com]

From: Chris Bostic <cbostic at us.ibm.com>

Enable each link and send a break command in preparation
for scanning each link for slaves.

V3 - Remove definition of BREAK command from fsi-master.h

   - Remove definitions of fsi_master_fake for set_smode
     and break

   - Remove master->set_smode master dependent function and
     moved to a generic base master set_smode.

   - Add fsi_master_link_enable with master type dependencies

V4 - Remove all references to set smode

   - Remove file fsi-slave.h

   - Move link break and enable up into master scan

   - Change rc = func(); return rc; coding to return func();
     Note this is still in place in fsi_master_send_break in
     anticipation of changes coming up in next patch of this
     series.

   - Fix comment spelling error

   - Use dev_dbg instead of dev_info when link enable or break
     fails

   - Remove explicit set of master->break and
     master->link_enable to NULL due to kzalloc

Signed-off-by: Chris Bostic <cbostic at us.ibm.com>
---
 drivers/fsi/fsi-core.c        | 43 ++++++++++++++++++++++++++++++++++++++++---
 drivers/fsi/fsi-master-gpio.c | 31 +++++++++++++++++++++++++++++++
 drivers/fsi/fsi-master.h      |  2 ++
 3 files changed, 73 insertions(+), 3 deletions(-)

diff --git a/drivers/fsi/fsi-core.c b/drivers/fsi/fsi-core.c
index 5cbe78d..0195373 100644
--- a/drivers/fsi/fsi-core.c
+++ b/drivers/fsi/fsi-core.c
@@ -287,16 +287,53 @@ static int fsi_slave_init(struct fsi_master *master,
 
 /* FSI master support */
 
+static int fsi_master_link_enable(struct fsi_master *master, int link)
+{
+	if (master->link_enable)
+		return master->link_enable(master, link);
+
+	return -EINVAL;
+}
+
+/*
+ * Issue a break command on this link
+ */
+static int fsi_master_break(struct fsi_master *master, int link)
+{
+	int rc;
+
+	if (!master->send_break)
+		return -EINVAL;
+
+	rc =  master->send_break(master, link);
+	if (rc)
+		dev_info(master->dev, "break failed with:%d\n", rc);
+
+	return rc;
+}
+
 static int fsi_master_scan(struct fsi_master *master)
 {
-	int link, slave_id;
+	int link, slave_id, rc;
 
-	for (link = 0; link < master->n_links; link++)
+	for (link = 0; link < master->n_links; link++) {
+		rc = fsi_master_link_enable(master, link);
+		if (rc) {
+			dev_dbg(master->dev,
+				"Enable of link:%d failed with:%d\n", link, rc);
+			continue;
+		}
+		rc = fsi_master_break(master, link);
+		if (rc) {
+			dev_dbg(master->dev,
+				"break to link:%d failed with:%d\n", link, rc);
+			continue;
+		}
 		for (slave_id = 0; slave_id < FSI_N_SLAVES; slave_id++)
 			fsi_slave_init(master, link, slave_id);
+	}
 
 	return 0;
-
 }
 
 int fsi_master_register(struct fsi_master *master)
diff --git a/drivers/fsi/fsi-master-gpio.c b/drivers/fsi/fsi-master-gpio.c
index 5c3d5cd..f8e5ca4 100644
--- a/drivers/fsi/fsi-master-gpio.c
+++ b/drivers/fsi/fsi-master-gpio.c
@@ -50,6 +50,35 @@ static int fsi_master_gpio_write(struct fsi_master *_master, int link,
 	return 0;
 }
 
+/*
+ * Issue a break command on link
+ */
+static int fsi_master_gpio_break(struct fsi_master *_master, int link)
+{
+	struct fsi_master_gpio *master = to_fsi_master_gpio(_master);
+
+	if (link != 0)
+		return -ENODEV;
+
+	/* todo: send the break pattern over gpio */
+	(void)master;
+
+	return 0;
+}
+
+static int fsi_master_gpio_link_enable(struct fsi_master *_master, int link)
+{
+	struct fsi_master_gpio *master = to_fsi_master_gpio(_master);
+
+	if (link != 0)
+		return -ENODEV;
+
+	/* todo: set the enable pin */
+	(void)master;
+
+	return 0;
+}
+
 static int fsi_master_gpio_probe(struct platform_device *pdev)
 {
 	struct fsi_master_gpio *master;
@@ -71,6 +100,8 @@ static int fsi_master_gpio_probe(struct platform_device *pdev)
 
 	master->master.read = fsi_master_gpio_read;
 	master->master.write = fsi_master_gpio_write;
+	master->master.send_break = fsi_master_gpio_break;
+	master->master.link_enable = fsi_master_gpio_link_enable;
 
 	return fsi_master_register(&master->master);
 }
diff --git a/drivers/fsi/fsi-master.h b/drivers/fsi/fsi-master.h
index cafb433..56aad0e 100644
--- a/drivers/fsi/fsi-master.h
+++ b/drivers/fsi/fsi-master.h
@@ -29,6 +29,8 @@ struct fsi_master {
 	int		(*write)(struct fsi_master *, int link,
 				uint8_t slave, uint32_t addr,
 				const void *val, size_t size);
+	int		(*send_break)(struct fsi_master *, int link);
+	int		(*link_enable)(struct fsi_master *, int link);
 };
 
 extern int fsi_master_register(struct fsi_master *master);
-- 
1.8.2.2