From 904dfbfd67fbdf4562236efb3f0769ecfe7a7e58 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Thu, 14 Jan 2016 14:06:25 +0100 Subject: [PATCH] i2c: mvtwsi: Fix mvtwsi not working on sun6i and newer sunxi SoCs On sun6i and newer IFLG is a write-clear bit which is cleared by writing 1, rather then a normal r/w bit which is cleared by writing 0. Signed-off-by: Hans de Goede applied with fixing 3 checkpatch warnings in drivers/i2c/mvtwsi.c: WARNING: line over 80 characters ERROR: code indent should use tabs where possible WARNING: please, no spaces at the start of a line Signed-off-by: Heiko Schocher --- drivers/i2c/mvtwsi.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) diff --git a/drivers/i2c/mvtwsi.c b/drivers/i2c/mvtwsi.c index 5dc4fbb..30a5b11 100644 --- a/drivers/i2c/mvtwsi.c +++ b/drivers/i2c/mvtwsi.c @@ -73,6 +73,17 @@ struct mvtwsi_registers { #define MVTWSI_CONTROL_INTEN 0x00000080 /* + * On sun6i and newer IFLG is a write-clear bit which is cleared by writing 1, + * on other platforms it is a normal r/w bit which is cleared by writing 0. + */ + +#ifdef CONFIG_SUNXI_GEN_SUN6I +#define MVTWSI_CONTROL_CLEAR_IFLG 0x00000008 +#else +#define MVTWSI_CONTROL_CLEAR_IFLG 0x00000000 +#endif + +/* * Status register values -- only those expected in normal master * operation on non-10-bit-address devices; whatever status we don't * expect in nominal conditions (bus errors, arbitration losses, @@ -189,7 +200,8 @@ static int twsi_start(struct i2c_adapter *adap, int expected_status) /* globally set TWSIEN in case it was not */ twsi_control_flags |= MVTWSI_CONTROL_TWSIEN; /* assert START */ - writel(twsi_control_flags | MVTWSI_CONTROL_START, &twsi->control); + twsi_control_flags |= MVTWSI_CONTROL_START | MVTWSI_CONTROL_CLEAR_IFLG; + writel(twsi_control_flags, &twsi->control); /* wait for controller to process START */ return twsi_wait(adap, expected_status); } @@ -204,7 +216,7 @@ static int twsi_send(struct i2c_adapter *adap, u8 byte, int expected_status) /* put byte in data register for sending */ writel(byte, &twsi->data); /* clear any pending interrupt -- that'll cause sending */ - writel(twsi_control_flags, &twsi->control); + writel(twsi_control_flags | MVTWSI_CONTROL_CLEAR_IFLG, &twsi->control); /* wait for controller to receive byte and check ACK */ return twsi_wait(adap, expected_status); } @@ -224,7 +236,7 @@ static int twsi_recv(struct i2c_adapter *adap, u8 *byte) else expected_status = MVTWSI_STATUS_DATA_R_NAK; /* acknowledge *previous state* and launch receive */ - writel(twsi_control_flags, &twsi->control); + writel(twsi_control_flags | MVTWSI_CONTROL_CLEAR_IFLG, &twsi->control); /* wait for controller to receive byte and assert ACK or NAK */ status = twsi_wait(adap, expected_status); /* if we did receive expected byte then store it */ @@ -246,7 +258,7 @@ static int twsi_stop(struct i2c_adapter *adap, int status) /* assert STOP */ control = MVTWSI_CONTROL_TWSIEN | MVTWSI_CONTROL_STOP; - writel(control, &twsi->control); + writel(control | MVTWSI_CONTROL_CLEAR_IFLG, &twsi->control); /* wait for IDLE; IFLG won't rise so twsi_wait() is no use. */ do { stop_status = readl(&twsi->status); -- 2.7.4