[PATCH v9 5/5] Input: synaptics-rmi4 - support fallback values for PDT descriptor bytes
From: David Heidelberg via B4 Relay
Date: Fri Jul 31 2026 - 16:39:54 EST
From: Kaustabh Chakraborty <kauschluss@xxxxxxxxxxx>
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)
Signed-off-by: Kaustabh Chakraborty <kauschluss@xxxxxxxxxxx>
[codeflow adjustments, checkpatch fixes, wording]
Signed-off-by: Casey Connolly <casey.connolly@xxxxxxxxxx>
Co-developed-by: David Heidelberg <david@xxxxxxx>
Signed-off-by: David Heidelberg <david@xxxxxxx>
---
drivers/input/rmi4/rmi_driver.c | 64 +++++++++++++++++++++++++++++++++++------
drivers/input/rmi4/rmi_driver.h | 3 ++
include/linux/rmi.h | 3 ++
3 files changed, 62 insertions(+), 8 deletions(-)
diff --git a/drivers/input/rmi4/rmi_driver.c b/drivers/input/rmi4/rmi_driver.c
index 5e7766363aa23..dac26458f0937 100644
--- a/drivers/input/rmi4/rmi_driver.c
+++ b/drivers/input/rmi4/rmi_driver.c
@@ -461,29 +461,45 @@ static int rmi_driver_reset_handler(struct rmi_device *rmi_dev)
error = rmi_driver_process_config_requests(rmi_dev);
if (error < 0)
return error;
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;
error = rmi_read_block(rmi_dev, pdt_address, buf, RMI_PDT_ENTRY_SIZE);
if (error) {
dev_err(&rmi_dev->dev, "Read PDT entry at %#06x failed, code: %d.\n",
pdt_address, error);
return error;
}
+ if (pdata->pdt_fallback_size > state->pdt_count * RMI_OF_PDT_DESC_CELLS + 1) {
+ /* Use the description bytes from the driver */
+ 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];
entry->control_base_addr = buf[2];
entry->data_base_addr = buf[3];
entry->interrupt_source_count = buf[4] & RMI_PDT_INT_SOURCE_COUNT_MASK;
entry->function_version = (buf[4] & RMI_PDT_FUNCTION_VERSION_MASK) >> 5;
entry->function_number = buf[5];
@@ -521,16 +537,17 @@ static bool rmi_pdt_entry_is_valid(struct rmi_device *rmi_dev,
break;
default:
rmi_dbg(RMI_DEBUG_CORE, &rmi_dev->dev,
"PDT has unknown function number %#02x\n", fn);
return false;
}
state->pdts[fn] = true;
+ state->pdt_count++;
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,
@@ -545,17 +562,17 @@ static int rmi_scan_pdt_page(struct rmi_device *rmi_dev,
u16 page_start = RMI4_PAGE_SIZE * page;
u16 pdt_start = page_start + PDT_START_SCAN_LOCATION;
u16 pdt_end = page_start + PDT_END_SCAN_LOCATION;
u16 addr;
int error;
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;
if (RMI4_END_OF_PDT(pdt_entry.function_number))
break;
if (!rmi_pdt_entry_is_valid(rmi_dev, state, pdt_entry.function_number))
continue;
@@ -1062,31 +1079,62 @@ static int rmi_driver_remove(struct device *dev)
irq_domain_remove(data->irqdomain);
data->irqdomain = NULL;
return 0;
}
#ifdef CONFIG_OF
-static int rmi_driver_of_probe(struct device *dev,
- struct rmi_device_platform_data *pdata)
+static const u8 rmi_s3706_fallback_pdt[] = {0x34, 0x41, 0x01,
+ 0x01, 0x12, 0x01};
+
+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,
"syna,reset-delay-ms", 1);
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 driver
+ * may have provide backup PDT entries.
+ */
+
+ 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;
+
+ /* List of known PDT entries per compatible. */
+ if (of_device_is_compatible(dev->of_node, "syna,rmi4-s3706b")) {
+ pdata->pdt_fallback_desc = rmi_s3706_fallback_pdt;
+ pdata->pdt_fallback_size = ARRAY_SIZE(rmi_s3706_fallback_pdt);
+ } else {
+ dev_err(dev, "First PDT entry is empty and no backup values provided.\n");
+ return -EINVAL;
+ }
+
return 0;
}
#else
-static inline int rmi_driver_of_probe(struct device *dev,
- struct rmi_device_platform_data *pdata)
+static inline int rmi_driver_of_probe(struct rmi_device *rmi_dev,
+ struct rmi_device_platform_data *pdata)
{
return -ENODEV;
}
#endif
int rmi_probe_interrupts(struct rmi_driver_data *data)
{
struct rmi_device *rmi_dev = data->rmi_dev;
@@ -1197,17 +1245,17 @@ static int rmi_driver_probe(struct device *dev)
rmi_dev = to_rmi_device(dev);
rmi_driver = to_rmi_driver(dev->driver);
rmi_dev->driver = rmi_driver;
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;
}
data = devm_kzalloc(dev, sizeof(struct rmi_driver_data), GFP_KERNEL);
if (!data)
return -ENOMEM;
diff --git a/drivers/input/rmi4/rmi_driver.h b/drivers/input/rmi4/rmi_driver.h
index 6de8faed08917..f69337510c333 100644
--- a/drivers/input/rmi4/rmi_driver.h
+++ b/drivers/input/rmi4/rmi_driver.h
@@ -26,16 +26,18 @@
#define RMI_PDT_PROPS_HAS_BSR 0x02
#define NAME_BUFFER_SIZE 256
#define RMI_PDT_ENTRY_SIZE 6
#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)
struct pdt_entry {
u16 page_start;
u8 query_base_addr;
u8 command_base_addr;
@@ -48,16 +50,17 @@ struct pdt_entry {
#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;
+ u8 pdt_count;
bool pdts[RMI_PDT_MAX + 1];
};
/* describes a single packet register */
struct rmi_register_desc_item {
u32 reg_size;
u16 reg;
diff --git a/include/linux/rmi.h b/include/linux/rmi.h
index ab7eea01ab427..4ba2cefac8558 100644
--- a/include/linux/rmi.h
+++ b/include/linux/rmi.h
@@ -209,16 +209,19 @@ struct rmi_device_platform_data_spi {
* driver waits a few milliseconds to give the firmware a chance to
* re-initialize. You can override the default wait period here.
* @irq: irq associated with the attn gpio line, or negative
*/
struct rmi_device_platform_data {
int reset_delay_ms;
int irq;
+ unsigned int pdt_fallback_size;
+ const u8 *pdt_fallback_desc;
+
struct rmi_device_platform_data_spi spi_data;
/* function handler pdata */
struct rmi_2d_sensor_platform_data sensor_pdata;
struct rmi_f01_power_management power_management;
struct rmi_gpio_data gpio_data;
};
--
2.53.0