When we query the device let's also read the descriptor from the device.
This tells us useful information, including the version, which we use to
determine a generation.
This is based on the driver from Wacom.
Signed-off-by: Alistair Francis <alistair@xxxxxxxxxxxxx>
---
drivers/input/touchscreen/wacom_i2c.c | 64 +++++++++++++++++++++++++++
1 file changed, 64 insertions(+)
diff --git a/drivers/input/touchscreen/wacom_i2c.c b/drivers/input/touchscreen/wacom_i2c.c
index 28255c77d426..72ba4a36459b 100644
--- a/drivers/input/touchscreen/wacom_i2c.c
+++ b/drivers/input/touchscreen/wacom_i2c.c
@@ -16,6 +16,7 @@
#include <linux/of.h>
#include <asm/unaligned.h>
+#define WACOM_DESC_REG 0x01
#define WACOM_CMD_QUERY0 0x04
#define WACOM_CMD_QUERY1 0x00
#define WACOM_CMD_QUERY2 0x33
@@ -24,11 +25,46 @@
#define WACOM_CMD_THROW1 0x00
#define WACOM_QUERY_SIZE 19
+#define WACOM_MAX_DATA_SIZE_BG9 10
+#define WACOM_MAX_DATA_SIZE_G12 15
+#define WACOM_MAX_DATA_SIZE_AG14 17
+#define WACOM_MAX_DATA_SIZE 22
+
+/* Generation selction */
+/* Before and at G9 generation */
+#define WACOM_BG9 0
+/* G12 generation the IC supports "height"*/
+#define WACOM_G12 1
+/* After and at G14 generation the IC supports "height" and
+ * it is defined as "Z" axis
+ */
+#define WACOM_AG14 2
+
+struct wacom_desc {
+ u16 descLen;
+ u16 version;
+ u16 reportLen;
+ u16 reportReg;
+ u16 inputReg;
+ u16 maxInputLen;
+ u16 outputReg;
+ u16 maxOutputLen;
+ u16 commReg;
+ u16 dataReg;
+ u16 vendorID;
+ u16 productID;
+ u16 fwVersion;
+ u16 misc_high;
+ u16 misc_low;
+};
+
struct wacom_features {
+ struct wacom_desc desc;
int x_max;
int y_max;
int pressure_max;
char fw_version;
+ unsigned char generation;
};
struct wacom_i2c {
@@ -45,6 +81,7 @@ static int wacom_query_device(struct i2c_client *client,
struct wacom_features *features)
{
int ret;
+ u8 cmd_wac_desc[] = {WACOM_DESC_REG, 0x00};
u8 cmd1[] = { WACOM_CMD_QUERY0, WACOM_CMD_QUERY1,
WACOM_CMD_QUERY2, WACOM_CMD_QUERY3 };
u8 cmd2[] = { WACOM_CMD_THROW0, WACOM_CMD_THROW1 };
@@ -70,6 +107,33 @@ static int wacom_query_device(struct i2c_client *client,
},
};
+ /* Read the description register */
+ ret = i2c_master_send(client, cmd_wac_desc, sizeof(cmd_wac_desc));
+ if (ret < 0)
+ return ret;
+ ret = i2c_master_recv(client, (char *)&features->desc, sizeof(features->desc));
+ if (ret < 0)
+ return ret;
+
+ switch (features->desc.maxInputLen) {
+ case WACOM_MAX_DATA_SIZE_BG9:
+ features->generation = WACOM_BG9;
+ break;
+
+ case WACOM_MAX_DATA_SIZE_G12:
+ features->generation = WACOM_G12;
+ break;
+
+ case WACOM_MAX_DATA_SIZE_AG14:
+ features->generation = WACOM_AG14;
+ break;
+
+ default:
+ /* Cover all generations possible */
+ features->generation = WACOM_AG14;
+ break;
+ }
+
ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
if (ret < 0)
return ret;
--
2.31.1
