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[7/7] Input: synaptics-rmi4 - support fallback values for PDT descriptor bytes

Message ID 20230929-caleb-rmi4-quirks-v1-7-cc3c703f022d@linaro.org (mailing list archive)
State Superseded
Headers show
Series Input: synaptics-rmi4: add quirks for third party touchscreen controllers | expand

Commit Message

Caleb Connolly Sept. 30, 2023, 5:08 p.m. UTC 
From: methanal <baclofen@tuta.io>

Some replacement displays include third-party touch ICs which do not
expose the function number and the interrupt status in its PDT entries.

OnePlus 6 (original touch IC)
  rmi4_i2c 12-0020: read 6 bytes at 0x00e3: 0 (2b 22 0d 06 01 01)

OnePlus 6 (aftermarket touch IC)
  rmi4_i2c 12-0020: read 6 bytes at 0x00e3: 0 (2c 23 0d 06 00 00)

Introduce a new devicetree property `syna,pdt-desc` which can be used to
provide platform-specific fallback values for users with a replacement
display with an aftermarket touch IC.

Signed-off-by: methanal <baclofen@tuta.io>
[codeflow adjustments, checkpatch fixes, wording]
Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
---
 drivers/input/rmi4/rmi_driver.c | 67 ++++++++++++++++++++++++++++++++++++++---
 drivers/input/rmi4/rmi_driver.h |  2 ++
 include/linux/rmi.h             |  3 ++
 3 files changed, 67 insertions(+), 5 deletions(-)
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Patch

diff --git a/drivers/input/rmi4/rmi_driver.c b/drivers/input/rmi4/rmi_driver.c
index 58bf3dfbf81c..5e1e3d5dd800 100644
--- a/drivers/input/rmi4/rmi_driver.c
+++ b/drivers/input/rmi4/rmi_driver.c
@@ -461,9 +461,10 @@  static int rmi_driver_reset_handler(struct rmi_device *rmi_dev)
 	return 0;
 }
 
-static int rmi_read_pdt_entry(struct rmi_device *rmi_dev,
-			      struct pdt_entry *entry, u16 pdt_address)
+static int rmi_read_pdt_entry(struct rmi_device *rmi_dev, struct pdt_entry *entry,
+			      struct pdt_scan_state *state, u16 pdt_address)
 {
+	const struct rmi_device_platform_data *pdata = rmi_get_platform_data(rmi_dev);
 	u8 buf[RMI_PDT_ENTRY_SIZE];
 	int error;
 
@@ -474,6 +475,21 @@  static int rmi_read_pdt_entry(struct rmi_device *rmi_dev,
 		return error;
 	}
 
+	if (pdata->pdt_fallback_size > state->pdt_count * RMI_OF_PDT_DESC_CELLS + 1) {
+		/* Use the description bytes from DT */
+		buf[5] = pdata->pdt_fallback_desc[state->pdt_count * RMI_OF_PDT_DESC_CELLS];
+		buf[4] = pdata->pdt_fallback_desc[state->pdt_count * RMI_OF_PDT_DESC_CELLS + 1];
+
+		error = rmi_read_block(rmi_dev, pdt_address, buf,
+				RMI_PDT_ENTRY_SIZE - 2);
+		if (error) {
+			dev_err(&rmi_dev->dev,
+					"Read PDT entry at %#06x failed, code: %d.\n",
+					pdt_address, error);
+			return error;
+		}
+	}
+
 	entry->page_start = pdt_address & RMI4_PAGE_MASK;
 	entry->query_base_addr = buf[0];
 	entry->command_base_addr = buf[1];
@@ -551,7 +567,7 @@  static int rmi_scan_pdt_page(struct rmi_device *rmi_dev,
 	int retval;
 
 	for (addr = pdt_start; addr >= pdt_end; addr -= RMI_PDT_ENTRY_SIZE) {
-		error = rmi_read_pdt_entry(rmi_dev, &pdt_entry, addr);
+		error = rmi_read_pdt_entry(rmi_dev, &pdt_entry, state, addr);
 		if (error)
 			return error;
 
@@ -1028,9 +1044,11 @@  static int rmi_driver_remove(struct device *dev)
 }
 
 #ifdef CONFIG_OF
-static int rmi_driver_of_probe(struct device *dev,
+static int rmi_driver_of_probe(struct rmi_device *rmi_dev,
 				struct rmi_device_platform_data *pdata)
 {
+	struct device *dev = rmi_dev->xport->dev;
+	u8 buf[RMI_PDT_ENTRY_SIZE];
 	int retval;
 
 	retval = rmi_of_property_read_u32(dev, &pdata->reset_delay_ms,
@@ -1038,6 +1056,45 @@  static int rmi_driver_of_probe(struct device *dev,
 	if (retval)
 		return retval;
 
+	/*
+	 * In some aftermerket touch ICs, the first PDT entry is empty and
+	 * the function number register is 0. If so, the platform
+	 * may have provided backup PDT entries in the device tree.
+	 */
+
+	retval = rmi_read_block(rmi_dev, PDT_START_SCAN_LOCATION,
+			buf, RMI_PDT_ENTRY_SIZE);
+	if (retval) {
+		dev_err(dev, "Read PDT entry at %#06x failed, code: %d.\n",
+			PDT_START_SCAN_LOCATION, retval);
+		return retval;
+	}
+
+	if (!RMI4_END_OF_PDT(buf[5]))
+		return 0;
+
+	pdata->pdt_fallback_size = of_property_count_u8_elems(dev->of_node,
+						  "syna,pdt-fallback-desc");
+
+	/* The rmi4 driver would fail later anyway, so just error out now. */
+	if (pdata->pdt_fallback_size == -EINVAL) {
+		dev_err(dev, "First PDT entry is empty and no backup values provided\n");
+		return -EINVAL;
+	}
+
+	if (pdata->pdt_fallback_size < 0) {
+		dev_err(dev, "syna,ptd-desc property was not specified properly: %d\n",
+			pdata->pdt_fallback_size);
+		return pdata->pdt_fallback_size;
+	}
+
+	pdata->pdt_fallback_desc = devm_kzalloc(dev, pdata->pdt_fallback_size, GFP_KERNEL);
+
+	retval = of_property_read_u8_array(dev->of_node, "syna,pdt-fallback-desc",
+		pdata->pdt_fallback_desc, pdata->pdt_fallback_size);
+	if (retval < 0)
+		return retval;
+
 	return 0;
 }
 #else
@@ -1163,7 +1220,7 @@  static int rmi_driver_probe(struct device *dev)
 	pdata = rmi_get_platform_data(rmi_dev);
 
 	if (rmi_dev->xport->dev->of_node) {
-		retval = rmi_driver_of_probe(rmi_dev->xport->dev, pdata);
+		retval = rmi_driver_of_probe(rmi_dev, pdata);
 		if (retval)
 			return retval;
 	}
diff --git a/drivers/input/rmi4/rmi_driver.h b/drivers/input/rmi4/rmi_driver.h
index e1a5412f2f8f..2531c32d6163 100644
--- a/drivers/input/rmi4/rmi_driver.h
+++ b/drivers/input/rmi4/rmi_driver.h
@@ -31,6 +31,8 @@ 
 #define RMI_PDT_FUNCTION_VERSION_MASK   0x60
 #define RMI_PDT_INT_SOURCE_COUNT_MASK   0x07
 
+#define RMI_OF_PDT_DESC_CELLS 2
+
 #define PDT_START_SCAN_LOCATION 0x00e9
 #define PDT_END_SCAN_LOCATION	0x0005
 #define RMI4_END_OF_PDT(id) ((id) == 0x00 || (id) == 0xff)
diff --git a/include/linux/rmi.h b/include/linux/rmi.h
index ab7eea01ab42..974597960b5e 100644
--- a/include/linux/rmi.h
+++ b/include/linux/rmi.h
@@ -214,6 +214,9 @@  struct rmi_device_platform_data {
 	int reset_delay_ms;
 	int irq;
 
+	u8 *pdt_fallback_desc;
+	int pdt_fallback_size;
+
 	struct rmi_device_platform_data_spi spi_data;
 
 	/* function handler pdata */