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Message-Id: <20250514061944.125857-5-even.xu@intel.com>
Date: Wed, 14 May 2025 14:19:41 +0800
From: Even Xu <even.xu@...el.com>
To: jikos@...nel.org,
bentiss@...nel.org
Cc: srinivas.pandruvada@...ux.intel.com,
linux-input@...r.kernel.org,
linux-kernel@...r.kernel.org,
linux-doc@...r.kernel.org,
Even Xu <even.xu@...el.com>,
Chong Han <chong.han@...el.com>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: [PATCH v1 4/7] HID: Intel-thc-hid: Intel-thc: Introduce interrupt delay control
This patch adds support for a new feature, named "Interrupt Delay",
allowing driver to set a specific delay time for next interrupt
detection. It gives driver a capability to control THC waiting time for
the next interrupt, to reduce the likelihood of spurious readings.
APIs added:
- thc_i2c_set_rx_int_delay(): Set I2C Rx input interrupt delay value
- thc_i2c_rx_int_delay_enable(): Enable or disable I2C Rx interrupt delay
As this interrupt delay feature is only applicable to RxDMA and must
remain disabled during SWDMA operations, it also involves a change
in SWDMA code to record the max input size control feature state
before SWDMA and restore the state after SWDMA.
Signed-off-by: Even Xu <even.xu@...el.com>
Tested-by: Chong Han <chong.han@...el.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
---
Documentation/hid/intel-thc-hid.rst | 13 ++++
.../intel-thc-hid/intel-thc/intel-thc-dev.c | 71 +++++++++++++++++++
.../intel-thc-hid/intel-thc/intel-thc-dev.h | 6 ++
.../intel-thc-hid/intel-thc/intel-thc-dma.c | 18 +++++
.../intel-thc-hid/intel-thc/intel-thc-dma.h | 3 +
.../intel-thc-hid/intel-thc/intel-thc-hw.h | 2 +
6 files changed, 113 insertions(+)
diff --git a/Documentation/hid/intel-thc-hid.rst b/Documentation/hid/intel-thc-hid.rst
index 52b80f06f744..9f86164e7356 100644
--- a/Documentation/hid/intel-thc-hid.rst
+++ b/Documentation/hid/intel-thc-hid.rst
@@ -202,6 +202,19 @@ input packet size with the given max size:
This feature is used to avoid data corruption which will cause RxDMA buffer overrun issue for
I2C bus, and enhance whole system stability.
+2.4 Interrupt delay
+-------------------
+
+Because of MCU performance limitation, some touch devices cannot de-assert interrupt pin
+immediately after input data is transferred, which cause an interrupt toggle delay. But THC
+always detects next interrupt immediately after last input interrupt is handled. In this
+case, the delayed interrupt de-assertion will be recognized as a new interrupt signal by THC,
+and causes THC to start an input report reading spuriously.
+
+In order to avoid this situation, THC introduced interrupt delay new feature in Panther Lake
+platform, where THC allows driver to set an interrupt delay. After this feature is enabled,
+THC will delay this given time for next interrupt detection.
+
3. High level concept
=====================
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 9b92437a298f..e1c25fad6409 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
@@ -2,6 +2,7 @@
/* Copyright (c) 2024 Intel Corporation */
#include <linux/bitfield.h>
+#include <linux/math.h>
#include <linux/regmap.h>
#include "intel-thc-dev.h"
@@ -1640,6 +1641,76 @@ int thc_i2c_rx_max_size_enable(struct thc_device *dev, bool enable)
}
EXPORT_SYMBOL_NS_GPL(thc_i2c_rx_max_size_enable, "INTEL_THC");
+/**
+ * thc_i2c_set_rx_int_delay - Set I2C Rx input interrupt delay value
+ * @dev: The pointer of THC private device context
+ * @delay_us: Interrupt delay value, unit is us
+ *
+ * Set @delay_us for I2C RxDMA input interrupt delay feature.
+ *
+ * Return: 0 on success, other error codes on failure.
+ */
+int thc_i2c_set_rx_int_delay(struct thc_device *dev, u32 delay_us)
+{
+ u32 val;
+ int ret;
+
+ if (!dev)
+ return -EINVAL;
+
+ if (!delay_us)
+ return -EOPNOTSUPP;
+
+ ret = regmap_read(dev->thc_regmap, THC_M_PRT_SW_SEQ_STS_OFFSET, &val);
+ if (ret)
+ return ret;
+
+ /* THC hardware counts at 10us unit */
+ val |= FIELD_PREP(THC_M_PRT_SPI_ICRRD_OPCODE_I2C_INTERVAL, DIV_ROUND_UP(delay_us, 10));
+
+ ret = regmap_write(dev->thc_regmap, THC_M_PRT_SPI_ICRRD_OPCODE_OFFSET, val);
+ if (ret)
+ return ret;
+
+ dev->i2c_int_delay_us = delay_us;
+
+ return 0;
+}
+EXPORT_SYMBOL_NS_GPL(thc_i2c_set_rx_int_delay, "INTEL_THC");
+
+/**
+ * thc_i2c_rx_int_delay_enable - Enable I2C Rx interrupt delay
+ * @dev: The pointer of THC private device context
+ * @enable: Enable interrupt delay or not
+ *
+ * Enable or disable I2C RxDMA input interrupt delay feature.
+ * Input interrupt delay can only be enabled after interrupt delay value
+ * was set by thc_i2c_set_rx_int_delay().
+ *
+ * Return: 0 on success, other error codes on failure.
+ */
+int thc_i2c_rx_int_delay_enable(struct thc_device *dev, bool enable)
+{
+ u32 mask = THC_M_PRT_SPI_ICRRD_OPCODE_I2C_INTERVAL_EN;
+ u32 val = enable ? mask : 0;
+ int ret;
+
+ if (!dev)
+ return -EINVAL;
+
+ if (!dev->i2c_int_delay_us)
+ return -EOPNOTSUPP;
+
+ ret = regmap_write_bits(dev->thc_regmap, THC_M_PRT_SPI_ICRRD_OPCODE_OFFSET, mask, val);
+ if (ret)
+ return ret;
+
+ dev->i2c_int_delay_en = enable;
+
+ return 0;
+}
+EXPORT_SYMBOL_NS_GPL(thc_i2c_rx_int_delay_enable, "INTEL_THC");
+
MODULE_AUTHOR("Xinpeng Sun <xinpeng.sun@...el.com>");
MODULE_AUTHOR("Even Xu <even.xu@...el.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 3e0bb0b31ed9..8666e2362e32 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
@@ -63,7 +63,9 @@ enum thc_int_type {
* @perf_limit: The delay between read operation and write operation
* @i2c_subip_regs: The copy of THC I2C sub-system registers for resuming restore
* @i2c_max_rx_size: I2C Rx transfer max input size
+ * @i2c_int_delay_us: I2C input interrupt delay, unit is us
* @i2c_max_rx_size_en: Bool value that indicates I2C max input size control enabled or not
+ * @i2c_int_delay_en: Bool value that indicates I2C input interrupt delay enabled or not
*/
struct thc_device {
struct device *dev;
@@ -85,7 +87,9 @@ struct thc_device {
u32 *i2c_subip_regs;
u32 i2c_max_rx_size;
+ u32 i2c_int_delay_us;
bool i2c_max_rx_size_en;
+ bool i2c_int_delay_en;
};
struct thc_device *thc_dev_init(struct device *device, void __iomem *mem_addr);
@@ -119,5 +123,7 @@ int thc_i2c_subip_regs_save(struct thc_device *dev);
int thc_i2c_subip_regs_restore(struct thc_device *dev);
int thc_i2c_set_rx_max_size(struct thc_device *dev, u32 max_rx_size);
int thc_i2c_rx_max_size_enable(struct thc_device *dev, bool enable);
+int thc_i2c_set_rx_int_delay(struct thc_device *dev, u32 delay_us);
+int thc_i2c_rx_int_delay_enable(struct thc_device *dev, bool enable);
#endif /* _INTEL_THC_DEV_H_ */
diff --git a/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.c b/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.c
index 5bef342cd738..82b8854843e0 100644
--- a/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.c
+++ b/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.c
@@ -725,6 +725,15 @@ static int thc_swdma_read_start(struct thc_device *dev, void *write_buff,
dev->dma_ctx->rx_max_size_en = true;
}
+ /*
+ * Interrupt delay feature is in the same situation with max input size control feature,
+ * needs record feature state before SWDMA.
+ */
+ if (dev->i2c_int_delay_en) {
+ thc_i2c_rx_int_delay_enable(dev, false);
+ dev->dma_ctx->rx_int_delay_en = true;
+ }
+
mask = THC_M_PRT_RPRD_CNTRL_SW_THC_SWDMA_I2C_WBC |
THC_M_PRT_RPRD_CNTRL_SW_THC_SWDMA_I2C_RX_DLEN_EN;
val = FIELD_PREP(THC_M_PRT_RPRD_CNTRL_SW_THC_SWDMA_I2C_WBC, write_len) |
@@ -776,6 +785,15 @@ static int thc_swdma_read_completion(struct thc_device *dev)
dev->dma_ctx->rx_max_size_en = false;
}
+ /*
+ * Restore input interrupt delay feature to previous state after SWDMA if it was
+ * enabled before SWDMA, and reset temp rx_int_delay_en variable for next time.
+ */
+ if (dev->dma_ctx->rx_int_delay_en) {
+ thc_i2c_rx_int_delay_enable(dev, true);
+ dev->dma_ctx->rx_int_delay_en = false;
+ }
+
thc_reset_dma_settings(dev);
dma_set_start_bit(dev, &dev->dma_ctx->dma_config[THC_RXDMA2]);
diff --git a/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.h b/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.h
index 42cfd55c3e2c..78917400492c 100644
--- a/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.h
+++ b/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.h
@@ -123,12 +123,15 @@ struct thc_dma_configuration {
* @use_write_interrupts: Indicate TxDMA using interrupt or polling
* @rx_max_size_en: Temp flag to indicate THC I2C Rx max input size control feature
* enabled or not, only be used during SWDMA operation.
+ * @rx_int_delay_en: Temp flag to indicate THC I2C Rx interrupt delay feature
+ * enabled or not, only be used during SWDMA operation.
*/
struct thc_dma_context {
struct thc_dma_configuration dma_config[MAX_THC_DMA_CHANNEL];
u8 use_write_interrupts;
bool rx_max_size_en;
+ bool rx_int_delay_en;
};
struct thc_device;
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 ed8e28858e0c..413730f8e3f7 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
@@ -400,6 +400,8 @@
#define THC_M_PRT_SPI_ICRRD_OPCODE_SPI_QIO GENMASK(15, 8)
#define THC_M_PRT_SPI_ICRRD_OPCODE_I2C_MAX_SIZE GENMASK(15, 0)
+#define THC_M_PRT_SPI_ICRRD_OPCODE_I2C_INTERVAL GENMASK(23, 16)
+#define THC_M_PRT_SPI_ICRRD_OPCODE_I2C_INTERVAL_EN BIT(30)
#define THC_M_PRT_SPI_ICRRD_OPCODE_I2C_MAX_SIZE_EN BIT(31)
#define THC_M_PRT_INT_EN_SIPE BIT(0)
--
2.40.1
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