From ad448378825f5746c5fa37718724bc8f4e7b6945 Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Tue, 20 Mar 2018 15:07:38 +0200 Subject: scsi: ufs: Add support for Auto-Hibernate Idle Timer UFS host controllers may support an autonomous power management feature called the Auto-Hibernate Idle Timer. The timer is set to the number of microseconds of idle time before the UFS host controller will autonomously put the link into Hibernate state. That will save power at the expense of increased latency. Any access to the host controller interface registers will automatically put the link out of Hibernate state. So once configured, the feature is transparent to the driver. Expose the Auto-Hibernate Idle Timer value via SysFS to allow users to choose between power efficiency or lower latency. Set a default value of 150 ms. Signed-off-by: Adrian Hunter Acked-by: Stanislav Nijnikov Signed-off-by: Martin K. Petersen --- Documentation/ABI/testing/sysfs-driver-ufs | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'Documentation/ABI') diff --git a/Documentation/ABI/testing/sysfs-driver-ufs b/Documentation/ABI/testing/sysfs-driver-ufs index 83735f79e572..016724ec26d5 100644 --- a/Documentation/ABI/testing/sysfs-driver-ufs +++ b/Documentation/ABI/testing/sysfs-driver-ufs @@ -1,3 +1,17 @@ +What: /sys/bus/*/drivers/ufshcd/*/auto_hibern8 +Date: March 2018 +Contact: linux-scsi@vger.kernel.org +Description: + This file contains the auto-hibernate idle timer setting of a + UFS host controller. A value of '0' means auto-hibernate is not + enabled. Otherwise the value is the number of microseconds of + idle time before the UFS host controller will autonomously put + the link into hibernate state. That will save power at the + expense of increased latency. Note that the hardware supports + 10-bit values with a power-of-ten multiplier which allows a + maximum value of 102300000. Refer to the UFS Host Controller + Interface specification for more details. + What: /sys/bus/platform/drivers/ufshcd/*/device_descriptor/device_type Date: February 2018 Contact: Stanislav Nijnikov -- cgit v1.2.1