i2c: at91: ensure state is restored after suspending

[ Upstream commit e3ccc921b7d8fd1fcd10a00720e09823d8078666 ]

When going to suspend, the I2C registers may be lost because the power to
VDDcore is cut. Restore them when resuming.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c
index 10835d1..dee0fc4 100644 (file)
--- a/drivers/i2c/busses/i2c-at91.c
+++ b/drivers/i2c/busses/i2c-at91.c
@@ -1131,6 +1131,7 @@ static int at91_twi_suspend_noirq(struct device *dev)
 
 static int at91_twi_resume_noirq(struct device *dev)
 {
+       struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
        int ret;
 
        if (!pm_runtime_status_suspended(dev)) {
@@ -1142,6 +1143,8 @@ static int at91_twi_resume_noirq(struct device *dev)
        pm_runtime_mark_last_busy(dev);
        pm_request_autosuspend(dev);
 
+       at91_init_twi_bus(twi_dev);
+
        return 0;
 }