diff options
| author | Jeremy Kerr <jk@ozlabs.org> | 2017-06-06 16:08:58 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-06-09 11:52:09 +0200 |
| commit | 4af889b0ff78a71a0d5e3d4ce62515eca2ba4939 (patch) | |
| tree | b43c2330baee78a4f92242f031e7cc0c1681acbf /drivers/fsi | |
| parent | 7f9e8f767030e9d588ffc71e50ebf5164c86c8a9 (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>
Diffstat (limited to 'drivers/fsi')
| -rw-r--r-- | drivers/fsi/fsi-core.c | 22 | ||||
| -rw-r--r-- | drivers/fsi/fsi-master-gpio.c | 1 | ||||
| -rw-r--r-- | drivers/fsi/fsi-master.h | 2 |
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; |