When going to suspend, the I2C registers may be lost because the power to
VDDcore is cut. Save them and restore them when resuming.
Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-at91.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c
index 0b86c6173e07..633bdd899952 100644
--- a/drivers/i2c/busses/i2c-at91.c
+++ b/drivers/i2c/busses/i2c-at91.c
@@ -140,6 +140,12 @@ struct at91_twi_dev {
unsigned transfer_status;
struct i2c_adapter adapter;
unsigned twi_cwgr_reg;
+ struct {
+ u32 mmr;
+ u32 imr;
+ u32 fmr;
+ u32 fimr;
+ } cache;
struct at91_twi_pdata *pdata;
bool use_dma;
bool use_alt_cmd;
@@ -1172,6 +1178,15 @@ static int at91_twi_runtime_resume(struct device *dev)
static int at91_twi_suspend_noirq(struct device *dev)
{
+ struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
+
+ twi_dev->cache.mmr = at91_twi_read(twi_dev, AT91_TWI_MMR);
+ twi_dev->cache.imr = at91_twi_read(twi_dev, AT91_TWI_IMR);
+ if (twi_dev->fifo_size) {
+ twi_dev->cache.fmr = at91_twi_read(twi_dev, AT91_TWI_FMR);
+ twi_dev->cache.fimr = at91_twi_read(twi_dev, AT91_TWI_FIMR);
+ }
+
if (!pm_runtime_status_suspended(dev))
at91_twi_runtime_suspend(dev);
@@ -1180,6 +1195,7 @@ 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)) {
@@ -1191,6 +1207,14 @@ 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);
+ at91_twi_write(twi_dev, AT91_TWI_MMR, twi_dev->cache.mmr);
+ at91_twi_write(twi_dev, AT91_TWI_IER, twi_dev->cache.imr);
+ if (twi_dev->fifo_size) {
+ at91_twi_write(twi_dev, AT91_TWI_FMR, twi_dev->cache.fmr);
+ at91_twi_write(twi_dev, AT91_TWI_FIER, twi_dev->cache.fimr);
+ }
+
return 0;
}
--
2.11.0
--
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