linux-kernel - [PATCH v7 06/23] drivers/fsi: Set up links for slave communication

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Message-Id: <20170511210101.78409-7-cbostic@linux.vnet.ibm.com>
Date:   Thu, 11 May 2017 16:00:43 -0500
From:   Christopher Bostic <cbostic@...ux.vnet.ibm.com>
To:     robh+dt@...nel.org, mark.rutland@....com, linux@...linux.org.uk,
        rostedt@...dmis.org, mingo@...hat.com, gregkh@...uxfoundation.org,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Cc:     Christopher Bostic <cbostic@...ux.vnet.ibm.com>, joel@....id.au,
        linux-kernel@...r.kernel.org, andrew@...id.au,
        alistair@...ple.id.au, benh@...nel.crashing.org
Subject: [PATCH v7 06/23] drivers/fsi: Set up links for slave communication

Enable each link and send a break command, and try to detect a slave by
reading from the SMODE register.

Signed-off-by: Christopher Bostic <cbostic@...ux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@....id.au>
---
 drivers/fsi/fsi-core.c | 37 +++++++++++++++++++++++++++++++++++--
 1 file changed, 35 insertions(+), 2 deletions(-)

diff --git a/drivers/fsi/fsi-core.c b/drivers/fsi/fsi-core.c
index 1ec9790..235f17a 100644
--- a/drivers/fsi/fsi-core.c
+++ b/drivers/fsi/fsi-core.c
@@ -133,12 +133,45 @@ static int fsi_master_write(struct fsi_master *master, int link,
 	return master->write(master, link, slave_id, addr, val, size);
 }
 
+static int fsi_master_link_enable(struct fsi_master *master, int link)
+{
+	if (master->link_enable)
+		return master->link_enable(master, link);
+
+	return 0;
+}
+
+/*
+ * Issue a break command on this link
+ */
+static int fsi_master_break(struct fsi_master *master, int link)
+{
+	if (master->send_break)
+		return master->send_break(master, link);
+
+	return 0;
+}
+
 static int fsi_master_scan(struct fsi_master *master)
 {
-	int link;
+	int link, rc;
+
+	for (link = 0; link < master->n_links; link++) {
+		rc = fsi_master_link_enable(master, link);
+		if (rc) {
+			dev_dbg(&master->dev,
+				"enable link %d failed: %d\n", link, rc);
+			continue;
+		}
+		rc = fsi_master_break(master, link);
+		if (rc) {
+			dev_dbg(&master->dev,
+				"break to link %d failed: %d\n", link, rc);
+			continue;
+		}
 
-	for (link = 0; link < master->n_links; link++)
 		fsi_slave_init(master, link, 0);
+	}
 
 	return 0;
 }
-- 
1.8.2.2