i2c: Blackfin I2C Driver: Functional power management support

PM_SUSPEND_MEM: Blackfin does not maintain register state through
Hibernate. Save and restore peripheral base initialization during
PM transitions.
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

drivers/i2c/busses/i2c-bfin-twi.c

@@ -49,6 +49,8 @@ struct bfin_twi_iface {
 	struct i2c_msg 		*pmsg;
 	int			msg_num;
 	int			cur_msg;
+	u16			saved_clkdiv;
+	u16			saved_control;
 	void __iomem		*regs_base;
 };
 
@@ -565,32 +567,43 @@ static u32 bfin_twi_functionality(struct i2c_adapter *adap)
 	       I2C_FUNC_I2C;
 }
 
-
 static struct i2c_algorithm bfin_twi_algorithm = {
 	.master_xfer   = bfin_twi_master_xfer,
 	.smbus_xfer    = bfin_twi_smbus_xfer,
 	.functionality = bfin_twi_functionality,
 };
 
-
-static int i2c_bfin_twi_suspend(struct platform_device *dev, pm_message_t state)
+static int i2c_bfin_twi_suspend(struct platform_device *pdev, pm_message_t state)
 {
-	struct bfin_twi_iface *iface = platform_get_drvdata(dev);
+	struct bfin_twi_iface *iface = platform_get_drvdata(pdev);
+
+	iface->saved_clkdiv = read_CLKDIV(iface);
+	iface->saved_control = read_CONTROL(iface);
+
+	free_irq(iface->irq, iface);
 
 	/* Disable TWI */
-	write_CONTROL(iface, read_CONTROL(iface) & ~TWI_ENA);
-	SSYNC();
+	write_CONTROL(iface, iface->saved_control & ~TWI_ENA);
 
 	return 0;
 }
 
-static int i2c_bfin_twi_resume(struct platform_device *dev)
+static int i2c_bfin_twi_resume(struct platform_device *pdev)
 {
-	struct bfin_twi_iface *iface = platform_get_drvdata(dev);
+	struct bfin_twi_iface *iface = platform_get_drvdata(pdev);
 
-	/* Enable TWI */
-	write_CONTROL(iface, read_CONTROL(iface) | TWI_ENA);
-	SSYNC();
+	int rc = request_irq(iface->irq, bfin_twi_interrupt_entry,
+		IRQF_DISABLED, pdev->name, iface);
+	if (rc) {
+		dev_err(&pdev->dev, "Can't get IRQ %d !\n", iface->irq);
+		return -ENODEV;
+	}
+
+	/* Resume TWI interface clock as specified */
+	write_CLKDIV(iface, iface->saved_clkdiv);
+
+	/* Resume TWI */
+	write_CONTROL(iface, iface->saved_control);
 
 	return 0;
 }