HID: rmi: Set F01 interrupt enable register when not set

A firmware bug in some touchpads causes the F01 interrupt enable register
to be cleared on reset. This register controls which RMI functions generate
interrupts and when it is cleared, the touchpad stops reporting all data.
This patch looks for the cleared F01 control register and writes the
correct value based on interrupt mask computed while scanning the PDT.

Fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=91102
Signed-off-by: Andrew Duggan <aduggan@synaptics.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>

drivers/hid/hid-rmi.c

@@ -141,6 +141,8 @@ struct rmi_data {
 	unsigned long firmware_id;
 
 	u8 f01_ctrl0;
+	u8 interrupt_enable_mask;
+	bool restore_interrupt_mask;
 };
 
 #define RMI_PAGE(addr) (((addr) >> 8) & 0xff)
@@ -361,13 +363,34 @@ static void rmi_f11_process_touch(struct rmi_data *hdata, int slot,
 	}
 }
 
+static int rmi_reset_attn_mode(struct hid_device *hdev)
+{
+	struct rmi_data *data = hid_get_drvdata(hdev);
+	int ret;
+
+	ret = rmi_set_mode(hdev, RMI_MODE_ATTN_REPORTS);
+	if (ret)
+		return ret;
+
+	if (data->restore_interrupt_mask) {
+		ret = rmi_write(hdev, data->f01.control_base_addr + 1,
+				&data->interrupt_enable_mask);
+		if (ret) {
+			hid_err(hdev, "can not write F01 control register\n");
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
 static void rmi_reset_work(struct work_struct *work)
 {
 	struct rmi_data *hdata = container_of(work, struct rmi_data,
 						reset_work);
 
 	/* switch the device to RMI if we receive a generic mouse report */
-	rmi_set_mode(hdata->hdev, RMI_MODE_ATTN_REPORTS);
+	rmi_reset_attn_mode(hdata->hdev);
 }
 
 static inline int rmi_schedule_reset(struct hid_device *hdev)
@@ -590,7 +613,7 @@ static int rmi_post_reset(struct hid_device *hdev)
 	struct rmi_data *data = hid_get_drvdata(hdev);
 	int ret;
 
-	ret = rmi_set_mode(hdev, RMI_MODE_ATTN_REPORTS);
+	ret = rmi_reset_attn_mode(hdev);
 	if (ret) {
 		hid_err(hdev, "can not set rmi mode\n");
 		return ret;
@@ -617,7 +640,7 @@ static int rmi_post_reset(struct hid_device *hdev)
 
 static int rmi_post_resume(struct hid_device *hdev)
 {
-	return rmi_set_mode(hdev, RMI_MODE_ATTN_REPORTS);
+	return rmi_reset_attn_mode(hdev);
 }
 #endif /* CONFIG_PM */
 
@@ -673,6 +696,7 @@ static void rmi_register_function(struct rmi_data *data,
 		f->interrupt_count = pdt_entry->interrupt_source_count;
 		f->irq_mask = rmi_gen_mask(f->interrupt_base,
 						f->interrupt_count);
+		data->interrupt_enable_mask |= f->irq_mask;
 	}
 }
 
@@ -810,12 +834,35 @@ static int rmi_populate_f01(struct hid_device *hdev)
 		data->firmware_id += info[2] * 65536;
 	}
 
-	ret = rmi_read(hdev, data->f01.control_base_addr, &data->f01_ctrl0);
+	ret = rmi_read_block(hdev, data->f01.control_base_addr, info,
+				2);
 
 	if (ret) {
-		hid_err(hdev, "can not read f01 ctrl0\n");
+		hid_err(hdev, "can not read f01 ctrl registers\n");
 		return ret;
 	}
+
+	data->f01_ctrl0 = info[0];
+
+	if (!info[1]) {
+		/*
+		 * Do to a firmware bug in some touchpads the F01 interrupt
+		 * enable control register will be cleared on reset.
+		 * This will stop the touchpad from reporting data, so
+		 * if F01 CTRL1 is 0 then we need to explicitly enable
+		 * interrupts for the functions we want data for.
+		 */
+		data->restore_interrupt_mask = true;
+
+		ret = rmi_write(hdev, data->f01.control_base_addr + 1,
+				&data->interrupt_enable_mask);
+		if (ret) {
+			hid_err(hdev, "can not write to control reg 1: %d.\n",
+				ret);
+			return ret;
+		}
+	}
+
 	return 0;
 }