[PATCH v9 1/5] Input: synaptics-rmi4 - handle duplicate/unknown PDT entries

From: Casey Connolly <[email protected]>

Some third party rmi4-compatible ICs don't expose their PDT entries
very well. Add a few checks to skip duplicate entries as well as entries
for unsupported functions.

This is required to support some phones with third party displays.

Validated on a stock OnePlus 6T (original parts):
manufacturer: Synaptics, product: S3706B, fw id: 2852315

Co-developed-by: Kaustabh Chakraborty <[email protected]>
Signed-off-by: Kaustabh Chakraborty <[email protected]>
Signed-off-by: Casey Connolly <[email protected]>
Co-developed-by: David Heidelberg <[email protected]>
Signed-off-by: David Heidelberg <[email protected]>
---
 drivers/input/rmi4/rmi_driver.c | 41 +++++++++++++++++++++++++++++++++++------
 drivers/input/rmi4/rmi_driver.h |  7 +++++++
 2 files changed, 42 insertions(+), 6 deletions(-)

diff --git a/drivers/input/rmi4/rmi_driver.c b/drivers/input/rmi4/rmi_driver.c
index 5d49a9021c7d0..3edec5ae1f8c9 100644
--- a/drivers/input/rmi4/rmi_driver.c
+++ b/drivers/input/rmi4/rmi_driver.c
@@ -493,22 +493,48 @@ static void rmi_driver_copy_pdt_to_fd(const struct pdt_entry *pdt,
 	fd->command_base_addr = pdt->command_base_addr + pdt->page_start;
 	fd->control_base_addr = pdt->control_base_addr + pdt->page_start;
 	fd->data_base_addr = pdt->data_base_addr + pdt->page_start;
 	fd->function_number = pdt->function_number;
 	fd->interrupt_source_count = pdt->interrupt_source_count;
 	fd->function_version = pdt->function_version;
 }
 
+static bool rmi_pdt_entry_is_valid(struct rmi_device *rmi_dev,
+				   struct pdt_scan_state *state, u8 fn)
+{
+	switch (fn) {
+	case 0x01:
+	case 0x03:
+	case 0x11:
+	case 0x12:
+	case 0x30:
+	case 0x34:
+	case 0x3a:
+	case 0x54:
+	case 0x55:
+		if (state->pdts[fn] == true)
+			return false;
+		break;
+	default:
+		rmi_dbg(RMI_DEBUG_CORE, &rmi_dev->dev,
+			"PDT has unknown function number %#02x\n", fn);
+		return false;
+	}
+
+	state->pdts[fn] = true;
+	return true;
+}
+
 #define RMI_SCAN_CONTINUE	0
 #define RMI_SCAN_DONE		1
 
 static int rmi_scan_pdt_page(struct rmi_device *rmi_dev,
 			     int page,
-			     int *empty_pages,
+			     struct pdt_scan_state *state,
 			     void *ctx,
 			     int (*callback)(struct rmi_device *rmi_dev,
 					     void *ctx,
 					     const struct pdt_entry *entry))
 {
 	struct rmi_driver_data *data = dev_get_drvdata(&rmi_dev->dev);
 	struct pdt_entry pdt_entry;
 	u16 page_start = RMI4_PAGE_SIZE * page;
@@ -521,44 +547,47 @@ static int rmi_scan_pdt_page(struct rmi_device *rmi_dev,
 	for (addr = pdt_start; addr >= pdt_end; addr -= RMI_PDT_ENTRY_SIZE) {
 		error = rmi_read_pdt_entry(rmi_dev, &pdt_entry, addr);
 		if (error)
 			return error;
 
 		if (RMI4_END_OF_PDT(pdt_entry.function_number))
 			break;
 
+		if (!rmi_pdt_entry_is_valid(rmi_dev, state, pdt_entry.function_number))
+			continue;
+
 		retval = callback(rmi_dev, ctx, &pdt_entry);
 		if (retval != RMI_SCAN_CONTINUE)
 			return retval;
 	}
 
 	/*
 	 * Count number of empty PDT pages. If a gap of two pages
 	 * or more is found, stop scanning.
 	 */
 	if (addr == pdt_start)
-		++*empty_pages;
+		++state->empty_pages;
 	else
-		*empty_pages = 0;
+		state->empty_pages = 0;
 
-	return (data->bootloader_mode || *empty_pages >= 2) ?
+	return (data->bootloader_mode || state->empty_pages >= 2) ?
 					RMI_SCAN_DONE : RMI_SCAN_CONTINUE;
 }
 
 int rmi_scan_pdt(struct rmi_device *rmi_dev, void *ctx,
 		 int (*callback)(struct rmi_device *rmi_dev,
 		 void *ctx, const struct pdt_entry *entry))
 {
 	int page;
-	int empty_pages = 0;
+	struct pdt_scan_state state = {0, 0, {0}};
 	int retval = RMI_SCAN_DONE;
 
 	for (page = 0; page <= RMI4_MAX_PAGE; page++) {
-		retval = rmi_scan_pdt_page(rmi_dev, page, &empty_pages,
+		retval = rmi_scan_pdt_page(rmi_dev, page, &state,
 					   ctx, callback);
 		if (retval != RMI_SCAN_CONTINUE)
 			break;
 	}
 
 	return retval < 0 ? retval : 0;
 }
 
diff --git a/drivers/input/rmi4/rmi_driver.h b/drivers/input/rmi4/rmi_driver.h
index abeafb77a4838..6de8faed08917 100644
--- a/drivers/input/rmi4/rmi_driver.h
+++ b/drivers/input/rmi4/rmi_driver.h
@@ -44,16 +44,23 @@ struct pdt_entry {
 	u8 interrupt_source_count;
 	u8 function_version;
 	u8 function_number;
 };
 
 #define RMI_REG_DESC_PRESENCE_BITS	(32 * BITS_PER_BYTE)
 #define RMI_REG_DESC_PRESENCE_REGS_MAX	(3 + RMI_REG_DESC_PRESENCE_BITS / 8)
 #define RMI_REG_DESC_SUBPACKET_BITS	(37 * BITS_PER_BYTE)
+#define RMI_PDT_MAX 0x55
+
+struct pdt_scan_state {
+	u8 empty_pages;
+	bool pdts[RMI_PDT_MAX + 1];
+};
+
 
 /* describes a single packet register */
 struct rmi_register_desc_item {
 	u32 reg_size;
 	u16 reg;
 	u16 num_subpackets;
 	DECLARE_BITMAP(subpacket_map, RMI_REG_DESC_SUBPACKET_BITS);
 };

-- 
2.53.0