From: Xinpeng Sun <xinpeng.sun@intel.com>

THC supports LTR configuration and runtimely mode switching. There
are two LTR modes: Active LTR and Low Power LTR.

THC hardware layer provides APIs for LTR configuration and mode
switching.

Co-developed-by: Even Xu <even.xu@intel.com>
Signed-off-by: Even Xu <even.xu@intel.com>
Signed-off-by: Xinpeng Sun <xinpeng.sun@intel.com>
Tested-by: Rui Zhang <rui1.zhang@intel.com>
Reviewed-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
 .../intel-thc-hid/intel-thc/intel-thc-dev.c   | 114 ++++++++++++++++++
 .../intel-thc-hid/intel-thc/intel-thc-dev.h   |   3 +
 .../intel-thc-hid/intel-thc/intel-thc-hw.h    |  21 ++++
 3 files changed, 138 insertions(+)

diff --git a/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dev.c b/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dev.c
index 951279ed7765..d9735a8696ac 100644
--- a/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dev.c
+++ b/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dev.c
@@ -552,6 +552,120 @@ void thc_set_pio_interrupt_support(struct thc_device *dev, bool supported)
 }
 EXPORT_SYMBOL_NS_GPL(thc_set_pio_interrupt_support, INTEL_THC);
 
+/**
+ * thc_ltr_config - Configure THC Latency Tolerance Reporting(LTR) settings
+ *
+ * @dev: The pointer of THC private device context
+ * @active_ltr_us: active LTR value, unit is us
+ * @lp_ltr_us: low power LTR value, unit is us
+ */
+void thc_ltr_config(struct thc_device *dev, u32 active_ltr_us, u32 lp_ltr_us)
+{
+	u32 active_ltr_scale, lp_ltr_scale, ltr_ctrl, ltr_mask, orig, tmp;
+
+	if (active_ltr_us >= THC_LTR_MIN_VAL_SCALE_3 &&
+	    active_ltr_us < THC_LTR_MAX_VAL_SCALE_3) {
+		active_ltr_scale = THC_LTR_SCALE_3;
+		active_ltr_us = active_ltr_us >> 5;
+	} else if (active_ltr_us >= THC_LTR_MIN_VAL_SCALE_4 &&
+		   active_ltr_us < THC_LTR_MAX_VAL_SCALE_4) {
+		active_ltr_scale = THC_LTR_SCALE_4;
+		active_ltr_us = active_ltr_us >> 10;
+	} else if (active_ltr_us >= THC_LTR_MIN_VAL_SCALE_5 &&
+		   active_ltr_us < THC_LTR_MAX_VAL_SCALE_5) {
+		active_ltr_scale = THC_LTR_SCALE_5;
+		active_ltr_us = active_ltr_us >> 15;
+	} else {
+		active_ltr_scale = THC_LTR_SCALE_2;
+	}
+
+	if (lp_ltr_us >= THC_LTR_MIN_VAL_SCALE_3 &&
+	    lp_ltr_us < THC_LTR_MAX_VAL_SCALE_3) {
+		lp_ltr_scale = THC_LTR_SCALE_3;
+		lp_ltr_us = lp_ltr_us >> 5;
+	} else if (lp_ltr_us >= THC_LTR_MIN_VAL_SCALE_4 &&
+		   lp_ltr_us < THC_LTR_MAX_VAL_SCALE_4) {
+		lp_ltr_scale = THC_LTR_SCALE_4;
+		lp_ltr_us = lp_ltr_us >> 10;
+	} else if (lp_ltr_us >= THC_LTR_MIN_VAL_SCALE_5 &&
+		   lp_ltr_us < THC_LTR_MAX_VAL_SCALE_5) {
+		lp_ltr_scale = THC_LTR_SCALE_5;
+		lp_ltr_us = lp_ltr_us >> 15;
+	} else {
+		lp_ltr_scale = THC_LTR_SCALE_2;
+	}
+
+	regmap_read(dev->thc_regmap, THC_M_CMN_LTR_CTRL_OFFSET, &orig);
+	ltr_ctrl = FIELD_PREP(THC_M_CMN_LTR_CTRL_ACT_LTR_VAL, active_ltr_us) |
+		   FIELD_PREP(THC_M_CMN_LTR_CTRL_ACT_LTR_SCALE, active_ltr_scale) |
+		   THC_M_CMN_LTR_CTRL_ACTIVE_LTR_REQ |
+		   THC_M_CMN_LTR_CTRL_ACTIVE_LTR_EN |
+		   FIELD_PREP(THC_M_CMN_LTR_CTRL_LP_LTR_VAL, lp_ltr_us) |
+		   FIELD_PREP(THC_M_CMN_LTR_CTRL_LP_LTR_SCALE, lp_ltr_scale) |
+		   THC_M_CMN_LTR_CTRL_LP_LTR_REQ;
+
+	ltr_mask = THC_M_CMN_LTR_CTRL_ACT_LTR_VAL |
+		   THC_M_CMN_LTR_CTRL_ACT_LTR_SCALE |
+		   THC_M_CMN_LTR_CTRL_ACTIVE_LTR_REQ |
+		   THC_M_CMN_LTR_CTRL_ACTIVE_LTR_EN |
+		   THC_M_CMN_LTR_CTRL_LP_LTR_VAL |
+		   THC_M_CMN_LTR_CTRL_LP_LTR_SCALE |
+		   THC_M_CMN_LTR_CTRL_LP_LTR_REQ |
+		   THC_M_CMN_LTR_CTRL_LP_LTR_EN;
+
+	tmp = orig & ~ltr_mask;
+	tmp |= ltr_ctrl & ltr_mask;
+
+	regmap_write(dev->thc_regmap, THC_M_CMN_LTR_CTRL_OFFSET, tmp);
+}
+EXPORT_SYMBOL_NS_GPL(thc_ltr_config, INTEL_THC);
+
+/**
+ * thc_change_ltr_mode - Change THC LTR mode
+ *
+ * @dev: The pointer of THC private device context
+ * @ltr_mode: LTR mode(active or low power)
+ */
+void thc_change_ltr_mode(struct thc_device *dev, u32 ltr_mode)
+{
+	if (ltr_mode == THC_LTR_MODE_ACTIVE) {
+		regmap_write_bits(dev->thc_regmap, THC_M_CMN_LTR_CTRL_OFFSET,
+				  THC_M_CMN_LTR_CTRL_LP_LTR_EN, 0);
+		regmap_write_bits(dev->thc_regmap, THC_M_CMN_LTR_CTRL_OFFSET,
+				  THC_M_CMN_LTR_CTRL_ACTIVE_LTR_EN,
+				  THC_M_CMN_LTR_CTRL_ACTIVE_LTR_EN);
+		return;
+	}
+
+	regmap_write_bits(dev->thc_regmap, THC_M_CMN_LTR_CTRL_OFFSET,
+			  THC_M_CMN_LTR_CTRL_ACTIVE_LTR_EN, 0);
+	regmap_write_bits(dev->thc_regmap, THC_M_CMN_LTR_CTRL_OFFSET,
+			  THC_M_CMN_LTR_CTRL_LP_LTR_EN,
+			  THC_M_CMN_LTR_CTRL_LP_LTR_EN);
+}
+EXPORT_SYMBOL_NS_GPL(thc_change_ltr_mode, INTEL_THC);
+
+/**
+ * thc_ltr_unconfig - Unconfigure THC Latency Tolerance Reporting(LTR) settings
+ *
+ * @dev: The pointer of THC private device context
+ */
+void thc_ltr_unconfig(struct thc_device *dev)
+{
+	u32 ltr_ctrl, bits_clear;
+
+	regmap_read(dev->thc_regmap, THC_M_CMN_LTR_CTRL_OFFSET, &ltr_ctrl);
+	bits_clear = THC_M_CMN_LTR_CTRL_LP_LTR_EN |
+			THC_M_CMN_LTR_CTRL_ACTIVE_LTR_EN |
+			THC_M_CMN_LTR_CTRL_LP_LTR_REQ |
+			THC_M_CMN_LTR_CTRL_ACTIVE_LTR_REQ;
+
+	ltr_ctrl &= ~bits_clear;
+
+	regmap_write(dev->thc_regmap, THC_M_CMN_LTR_CTRL_OFFSET, ltr_ctrl);
+}
+EXPORT_SYMBOL_NS_GPL(thc_ltr_unconfig, INTEL_THC);
+
 MODULE_AUTHOR("Xinpeng Sun <xinpeng.sun@intel.com>");
 MODULE_AUTHOR("Even Xu <even.xu@intel.com>");
 
diff --git a/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dev.h b/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dev.h
index f775b972b4f5..c25f2fd57c76 100644
--- a/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dev.h
+++ b/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dev.h
@@ -68,5 +68,8 @@ void thc_int_trigger_type_select(struct thc_device *dev, bool edge_trigger);
 void thc_interrupt_enable(struct thc_device *dev, bool int_enable);
 void thc_set_pio_interrupt_support(struct thc_device *dev, bool supported);
 int thc_interrupt_quiesce(const struct thc_device *dev, bool int_quiesce);
+void thc_ltr_config(struct thc_device *dev, u32 active_ltr_us, u32 lp_ltr_us);
+void thc_change_ltr_mode(struct thc_device *dev, u32 ltr_mode);
+void thc_ltr_unconfig(struct thc_device *dev);
 
 #endif /* _INTEL_THC_DEV_H_ */
diff --git a/drivers/hid/intel-thc-hid/intel-thc/intel-thc-hw.h b/drivers/hid/intel-thc-hid/intel-thc/intel-thc-hw.h
index d4b67b81e954..4a1153022605 100644
--- a/drivers/hid/intel-thc-hid/intel-thc/intel-thc-hw.h
+++ b/drivers/hid/intel-thc-hid/intel-thc/intel-thc-hw.h
@@ -653,6 +653,27 @@
 /* Interrupt Quiesce default timeout value */
 #define THC_QUIESCE_EN_TIMEOUT_US		USEC_PER_SEC /* 1s */
 
+/* LTR definition */
+/*
+ * THC uses scale to calcualte final LTR value.
+ * Scale is geometric progression of 2^5 step, starting from 2^0.
+ * For example, THC_LTR_SCALE_2(2) means 2^(5 * 2) = 1024, unit is ns.
+ */
+#define THC_LTR_SCALE_0				0
+#define THC_LTR_SCALE_1				1
+#define THC_LTR_SCALE_2				2
+#define THC_LTR_SCALE_3				3
+#define THC_LTR_SCALE_4				4
+#define THC_LTR_SCALE_5				5
+#define THC_LTR_MODE_ACTIVE			0
+#define THC_LTR_MODE_LP				1
+#define THC_LTR_MIN_VAL_SCALE_3			BIT(10)
+#define THC_LTR_MAX_VAL_SCALE_3			BIT(15)
+#define THC_LTR_MIN_VAL_SCALE_4			BIT(15)
+#define THC_LTR_MAX_VAL_SCALE_4			BIT(20)
+#define THC_LTR_MIN_VAL_SCALE_5			BIT(20)
+#define THC_LTR_MAX_VAL_SCALE_5			BIT(25)
+
 /*
  * THC PIO opcode default value
  * @THC_PIO_OP_SPI_TIC_READ: THC opcode for SPI PIO read
-- 
2.40.1