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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>
This commit is contained in:
Jeremy Kerr 2017-06-06 16:08:58 -05:00 committed by Greg Kroah-Hartman
parent 7f9e8f7670
commit 4af889b0ff
3 changed files with 24 additions and 1 deletions
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22
drivers/fsi/fsi-core.c
View File

@ -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.
*/

1
drivers/fsi/fsi-master-gpio.c
View File

@ -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;

2
drivers/fsi/fsi-master.h
View File

@ -19,6 +19,8 @@
#include <linux/device.h>
#define FSI_MASTER_FLAG_SWCLOCK 0x1
struct fsi_master {
struct device dev;
int idx;