From 904dfbfd67fbdf4562236efb3f0769ecfe7a7e58 Mon Sep 17 00:00:00 2001
From: Hans de Goede <hdegoede@redhat.com>
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 <hdegoede@redhat.com>
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 <hs@denx.de>
---
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 5dc4fbba1f..30a5b11f9f 100644
--- a/drivers/i2c/mvtwsi.c
+++ b/drivers/i2c/mvtwsi.c
@@ -72,6 +72,17 @@ struct mvtwsi_registers {
#define MVTWSI_CONTROL_TWSIEN 0x00000040
#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
@@ -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);
--
2.39.5