CBUS: Tahvo: add atomic set and clear register bits function

Signed-off-by: Imre Deak <imre.deak@solidboot.com>
Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com>

drivers/cbus/tahvo.c

@@ -91,6 +91,26 @@ void tahvo_write_reg(int reg, u16 val)
 	cbus_write_reg(cbus_host, TAHVO_ID, reg, val);
 }
 
+/**
+ * tahvo_set_clear_reg_bits - set and clear register bits atomically
+ * @reg: the register to write to
+ * @bits: the bits to set
+ *
+ * This function sets and clears the specified Tahvo register bits atomically
+ */
+void tahvo_set_clear_reg_bits(int reg, u16 set, u16 clear)
+{
+	unsigned long flags;
+	u16 w;
+
+	spin_lock_irqsave(&tahvo_lock, flags);
+	w = tahvo_read_reg(reg);
+	w &= ~clear;
+	w |= set;
+	tahvo_write_reg(reg, w);
+	spin_unlock_irqrestore(&tahvo_lock, flags);
+}
+
 /*
  * Disable given TAHVO interrupt
  */

drivers/cbus/tahvo.h

@@ -41,6 +41,7 @@
 
 int tahvo_read_reg(int reg);
 void tahvo_write_reg(int reg, u16 val);
+void tahvo_set_clear_reg_bits(int reg, u16 set, u16 clear);
 int tahvo_request_irq(int id, void *irq_handler, unsigned long arg, char *name);
 void tahvo_free_irq(int id);
 void tahvo_enable_irq(int id);