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authorJeremy Kerr <jk@ozlabs.org>2017-06-06 16:08:58 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-06-09 11:52:09 +0200
commit4af889b0ff78a71a0d5e3d4ce62515eca2ba4939 (patch)
treeb43c2330baee78a4f92242f031e7cc0c1681acbf
parent7f9e8f767030e9d588ffc71e50ebf5164c86c8a9 (diff)
drivers/fsi: Use asynchronous slave mode
For slaves that are behind a software-clocked master, we want FSI CFAMs to run asynchronously to the FSI clock, so set up our slaves to be in async mode. Signed-off-by: Jeremy Kerr <jk@ozlabs.org> Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/fsi/fsi-core.c22
-rw-r--r--drivers/fsi/fsi-master-gpio.c1
-rw-r--r--drivers/fsi/fsi-master.h2
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;

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