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authorVitor Soares <Vitor.Soares@synopsys.com>2019-06-19 20:36:32 +0200
committerBoris Brezillon <boris.brezillon@collabora.com>2019-06-20 09:23:22 +0200
commitcbf4f7325a638ced1d815580dfed44ea3b76163c (patch)
tree14967988fe09d6e065c323afe1f47b6f9f87048c
parentecc8fb54bd443bf69996d9d5ddb8d90a50f14936 (diff)
i3c: add mixed limited bus mode
The i3c bus spec defines a bus configuration where i2c devices don't have a 50ns filter but support SCL running at SDR max rate (12.5MHz). This patch introduces the limited bus mode so that users can use a higher speed in presence of i2c devices index 1. Signed-off-by: Vitor Soares <vitor.soares@synopsys.com> Cc: Boris Brezillon <bbrezillon@kernel.org> Cc: <linux-kernel@vger.kernel.org> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
-rw-r--r--drivers/i3c/master.c5
-rw-r--r--include/linux/i3c/master.h5
2 files changed, 10 insertions, 0 deletions
diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 54026be03998..1318adfe0216 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -470,6 +470,7 @@ static int i3c_bus_init(struct i3c_bus *i3cbus)
static const char * const i3c_bus_mode_strings[] = {
[I3C_BUS_MODE_PURE] = "pure",
[I3C_BUS_MODE_MIXED_FAST] = "mixed-fast",
+ [I3C_BUS_MODE_MIXED_LIMITED] = "mixed-limited",
[I3C_BUS_MODE_MIXED_SLOW] = "mixed-slow",
};
@@ -584,6 +585,7 @@ int i3c_bus_set_mode(struct i3c_bus *i3cbus, enum i3c_bus_mode mode,
i3cbus->scl_rate.i3c = I3C_BUS_TYP_I3C_SCL_RATE;
break;
case I3C_BUS_MODE_MIXED_FAST:
+ case I3C_BUS_MODE_MIXED_LIMITED:
if (!i3cbus->scl_rate.i3c)
i3cbus->scl_rate.i3c = I3C_BUS_TYP_I3C_SCL_RATE;
if (!i3cbus->scl_rate.i2c)
@@ -2487,6 +2489,9 @@ int i3c_master_register(struct i3c_master_controller *master,
mode = I3C_BUS_MODE_MIXED_FAST;
break;
case I3C_LVR_I2C_INDEX(1):
+ if (mode < I3C_BUS_MODE_MIXED_LIMITED)
+ mode = I3C_BUS_MODE_MIXED_LIMITED;
+ break;
case I3C_LVR_I2C_INDEX(2):
if (mode < I3C_BUS_MODE_MIXED_SLOW)
mode = I3C_BUS_MODE_MIXED_SLOW;
diff --git a/include/linux/i3c/master.h b/include/linux/i3c/master.h
index eca8337bdaa5..1f08fa8d69d2 100644
--- a/include/linux/i3c/master.h
+++ b/include/linux/i3c/master.h
@@ -250,12 +250,17 @@ struct i3c_device {
* the bus. The only impact in this mode is that the
* high SCL pulse has to stay below 50ns to trick I2C
* devices when transmitting I3C frames
+ * @I3C_BUS_MODE_MIXED_LIMITED: I2C devices without 50ns spike filter are
+ * present on the bus. However they allow
+ * compliance up to the maximum SDR SCL clock
+ * frequency.
* @I3C_BUS_MODE_MIXED_SLOW: I2C devices without 50ns spike filter are present
* on the bus
*/
enum i3c_bus_mode {
I3C_BUS_MODE_PURE,
I3C_BUS_MODE_MIXED_FAST,
+ I3C_BUS_MODE_MIXED_LIMITED,
I3C_BUS_MODE_MIXED_SLOW,
};