3 files changed, 24 insertions, 1 deletions

diff --git a/drivers/fsi/fsi-core.c b/drivers/fsi/fsi-core.c
index c9ff8d3b3f03..b56f4ed5c488 100644
--- a/drivers/fsi/fsi-core.c
+++ b/drivers/fsi/fsi-core.c
@@ -49,6 +49,7 @@ static const int engine_page_size = 0x400;
 #define FSI_SMODE               0x0     /* R/W: Mode register */
 #define FSI_SISC                0x8     /* R/W: Interrupt condition */
 #define FSI_SSTAT               0x14    /* R  : Slave status */
+#define FSI_LLMODE              0x100   /* R/W: Link layer mode register */
 
 /*
  * SMODE fields
@@ -64,6 +65,11 @@ static const int engine_page_size = 0x400;
 #define FSI_SMODE_LBCRR_SHIFT   8               /* Clk ratio shift */
 #define FSI_SMODE_LBCRR_MASK    0xf             /* Clk ratio mask */
 
+/*
+ * LLMODE fields
+ */
+#define FSI_LLMODE_ASYNC        0x1
+
 #define FSI_SLAVE_SIZE_23b              0x800000
 
 static DEFINE_IDA(master_ida);
@@ -557,8 +563,8 @@ static void fsi_slave_release(struct device *dev)
 
 static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
 {
+        uint32_t chip_id, llmode;
         struct fsi_slave *slave;
-        uint32_t chip_id;
         uint8_t crc;
         int rc;
 
@@ -594,6 +600,20 @@ static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
                 return -ENODEV;
         }
 
+        /* If we're behind a master that doesn't provide a self-running bus
+         * clock, put the slave into async mode
+         */
+        if (master->flags & FSI_MASTER_FLAG_SWCLOCK) {
+                llmode = cpu_to_be32(FSI_LLMODE_ASYNC);
+                rc = fsi_master_write(master, link, id,
+                                FSI_SLAVE_BASE + FSI_LLMODE,
+                                &llmode, sizeof(llmode));
+                if (rc)
+                        dev_warn(&master->dev,
+                                "can't set llmode on slave:%02x:%02x %d\n",
+                                link, id, rc);
+        }
+
         /* We can communicate with a slave; create the slave device and
          * register.
          */
diff --git a/drivers/fsi/fsi-master-gpio.c b/drivers/fsi/fsi-master-gpio.c
index a5d6e705b3c5..ae2618768508 100644
--- a/drivers/fsi/fsi-master-gpio.c
+++ b/drivers/fsi/fsi-master-gpio.c
@@ -554,6 +554,7 @@ static int fsi_master_gpio_probe(struct platform_device *pdev)
         master->gpio_mux = gpio;
 
         master->master.n_links = 1;
+        master->master.flags = FSI_MASTER_FLAG_SWCLOCK;
         master->master.read = fsi_master_gpio_read;
         master->master.write = fsi_master_gpio_write;
         master->master.term = fsi_master_gpio_term;
diff --git a/drivers/fsi/fsi-master.h b/drivers/fsi/fsi-master.h
index 7764b0079d28..12f7b119567d 100644
--- a/drivers/fsi/fsi-master.h
+++ b/drivers/fsi/fsi-master.h
@@ -19,6 +19,8 @@
 
 #include <linux/device.h>
 
+#define FSI_MASTER_FLAG_SWCLOCK         0x1
+
 struct fsi_master {
         struct device   dev;
         int             idx;