On 6/20/2023 3:37 PM, Greg Kroah-Hartman wrote:
On Tue, Jun 20, 2023 at 03:32:37PM +0800, Tao Zhang wrote:
Add the nodes to set value for DSB edge control and DSB edge
control mask. Each DSB subunit TPDM has maximum of n(n<16) EDCR
resgisters to configure edge control. DSB edge detection control
00: Rising edge detection
01: Falling edge detection
10: Rising and falling edge detection (toggle detection)
And each DSB subunit TPDM has maximum of m(m<8) ECDMR registers to
configure mask. Eight 32 bit registers providing DSB interface
edge detection mask control.
Signed-off-by: Tao Zhang <quic_taozha@xxxxxxxxxxx>
---
.../ABI/testing/sysfs-bus-coresight-devices-tpdm | 32 +++++
drivers/hwtracing/coresight/coresight-tpdm.c | 143 ++++++++++++++++++++-
drivers/hwtracing/coresight/coresight-tpdm.h | 22 ++++
3 files changed, 196 insertions(+), 1 deletion(-)
diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
index 2a82cd0..34189e4a 100644
--- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
+++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
@@ -60,3 +60,35 @@ Description:
Bit[3] : Set to 0 for low performance mode.
Set to 1 for high performance mode.
Bit[4:8] : Select byte lane for high performance mode.
+
+What: /sys/bus/coresight/devices/<tpdm-name>/dsb_edge_ctrl
+Date: March 2023
+KernelVersion 6.5
+Contact: Jinlong Mao (QUIC) <quic_jinlmao@xxxxxxxxxxx>, Tao Zhang (QUIC) <quic_taozha@xxxxxxxxxxx>
+Description:
+ Read/Write a set of the edge control registers of the DSB
+ in TPDM.
+
+ Expected format is the following:
+ <integer1> <integer2> <integer3>
sysfs is "one value", not 3. Please never have to parse a sysfs file.
Do you mean sysfs file can only accept "one value"?
I see that more than one value are written to the sysfs file
"trigout_attach".
+static ssize_t dsb_edge_ctrl_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
+ ssize_t size = 0;
+ unsigned long bytes;
+ int i;
+
+ spin_lock(&drvdata->spinlock);
+ for (i = 0; i < TPDM_DSB_MAX_EDCR; i++) {
+ bytes = sysfs_emit_at(buf, size,
+ "Index:0x%x Val:0x%x\n", i,
Again, no, one value, no "string" needed to parse anything.
I also see other sysfs files can be read more than one value in other
drivers.
Is this "one value" limitation the usage rule of Linux sysfs system?
Or am I misunderstanding what you mean?
Best,
Tao
greg k-h
