[PATCH v3 6/8] HID: logitech: Add function to enable HID++ 1.0 "scrolling acceleration"

From: Peter Hutterer
Date: Tue Dec 04 2018 - 19:43:15 EST


From: Harry Cutts <hcutts@xxxxxxxxxxxx>

"Scrolling acceleration" is a bit of a misnomer: it doesn't deal with
acceleration at all. However, that's the name used in Logitech's spec,
so I used it here.

Signed-off-by: Harry Cutts <hcutts@xxxxxxxxxxxx>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
Signed-off-by: Peter Hutterer <peter.hutterer@xxxxxxxxx>
---
Unchanged since v1

drivers/hid/hid-logitech-hidpp.c | 47 +++++++++++++++++++++++---------
1 file changed, 34 insertions(+), 13 deletions(-)

diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index 22b37a3844d1..95ba9db6e613 100644
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c
@@ -400,32 +400,53 @@ static void hidpp_prefix_name(char **name, int name_length)
#define HIDPP_SET_LONG_REGISTER 0x82
#define HIDPP_GET_LONG_REGISTER 0x83

-#define HIDPP_REG_GENERAL 0x00
-
-static int hidpp10_enable_battery_reporting(struct hidpp_device *hidpp_dev)
+/**
+ * hidpp10_set_register_bit() - Sets a single bit in a HID++ 1.0 register.
+ * @hidpp_dev: the device to set the register on.
+ * @register_address: the address of the register to modify.
+ * @byte: the byte of the register to modify. Should be less than 3.
+ * Return: 0 if successful, otherwise a negative error code.
+ */
+static int hidpp10_set_register_bit(struct hidpp_device *hidpp_dev,
+ u8 register_address, u8 byte, u8 bit)
{
struct hidpp_report response;
int ret;
u8 params[3] = { 0 };

ret = hidpp_send_rap_command_sync(hidpp_dev,
- REPORT_ID_HIDPP_SHORT,
- HIDPP_GET_REGISTER,
- HIDPP_REG_GENERAL,
- NULL, 0, &response);
+ REPORT_ID_HIDPP_SHORT,
+ HIDPP_GET_REGISTER,
+ register_address,
+ NULL, 0, &response);
if (ret)
return ret;

memcpy(params, response.rap.params, 3);

- /* Set the battery bit */
- params[0] |= BIT(4);
+ params[byte] |= BIT(bit);

return hidpp_send_rap_command_sync(hidpp_dev,
- REPORT_ID_HIDPP_SHORT,
- HIDPP_SET_REGISTER,
- HIDPP_REG_GENERAL,
- params, 3, &response);
+ REPORT_ID_HIDPP_SHORT,
+ HIDPP_SET_REGISTER,
+ register_address,
+ params, 3, &response);
+}
+
+
+#define HIDPP_REG_GENERAL 0x00
+
+static int hidpp10_enable_battery_reporting(struct hidpp_device *hidpp_dev)
+{
+ return hidpp10_set_register_bit(hidpp_dev, HIDPP_REG_GENERAL, 0, 4);
+}
+
+#define HIDPP_REG_FEATURES 0x01
+
+/* On HID++ 1.0 devices, high-res scroll was called "scrolling acceleration". */
+static int hidpp10_enable_scrolling_acceleration(struct hidpp_device *hidpp_dev)
+{
+ return hidpp10_set_register_bit(hidpp_dev, HIDPP_REG_FEATURES, 0, 6);
}

#define HIDPP_REG_BATTERY_STATUS 0x07
--
2.19.2