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linux-raspberrypi: Fix i2c issues

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I was having intermittent i2c issues on the device until I applied this kernel patch
which I found online.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
This commit is contained in:
Richard Purdie 2013-04-21 15:23:59 +01:00 committed by Andrei Gherzan
parent 808f5e54f8
commit 7b6aa02efe
3 changed files with 34 additions and 0 deletions
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32
recipes-kernel/linux/linux-raspberrypi/sl030raspberrypii2ckernel.patch Normal file
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@ -0,0 +1,32 @@
Fix i2c timing errors.
When Transmitting: Make SDA valid quarter of a cycle after the falling edge of SCL.
When Receiving: Sample SDA Quarter of a cycle after the rising edge of SCL.
Upstream-Status: Pending
RP 2013/04/21
Index: git/drivers/i2c/busses/i2c-bcm2708.c
===================================================================
--- git.orig/drivers/i2c/busses/i2c-bcm2708.c 2013-01-06 17:15:00.754954587 +0000
+++ git/drivers/i2c/busses/i2c-bcm2708.c 2013-01-06 17:50:09.794905741 +0000
@@ -150,6 +150,7 @@
unsigned long bus_hz;
u32 cdiv;
u32 c = BSC_C_I2CEN | BSC_C_INTD | BSC_C_ST | BSC_C_CLEAR_1;
+ u32 cdel;
bus_hz = clk_get_rate(bi->clk);
cdiv = bus_hz / baudrate;
@@ -163,6 +164,10 @@
bcm2708_wr(bi, BSC_A, bi->msg->addr);
bcm2708_wr(bi, BSC_DLEN, bi->msg->len);
bcm2708_wr(bi, BSC_C, c);
+
+ cdel = (cdiv / 4) & 0xffff;
+ cdel = cdel << 16 | cdel;
+ bcm2708_wr(bi, BSC_DEL, cdel);
}
static irqreturn_t bcm2708_i2c_interrupt(int irq, void *dev_id)

1
recipes-kernel/linux/linux-raspberrypi_3.2.27.bb
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@ -8,6 +8,7 @@ PV_append = "+git${SRCREV}"
SRCREV = "10182a3bc434b27740f81c2b836a1af943060241"
SRC_URI = "git://github.com/raspberrypi/linux.git;protocol=git;branch=rpi-3.2.27 \
file://sl030raspberrypii2ckernel.patch \
"
S = "${WORKDIR}/git"

1
recipes-kernel/linux/linux-raspberrypi_3.6.11.bb
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@ -8,6 +8,7 @@ PV_append = "+git${SRCREV}"
SRCREV = "31a951046155b27361127d9cf85a1f58719fe9b3"
SRC_URI = "git://github.com/raspberrypi/linux.git;protocol=git;branch=rpi-3.6.y \
file://sl030raspberrypii2ckernel.patch \
"
S = "${WORKDIR}/git"