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authorEric Millbrandt <emillbrandt@coldhaus.com>2009-09-03 08:09:44 -0500
committerHeiko Schocher <hs@denx.de>2009-09-06 11:26:04 +0200
commit5da71efa18e8b4eac9afd8bfa13e3c7e7ddde1d0 (patch)
treecc1f409424f382c05c18cf8e6bd452fdc6768a44 /cpu
parent9f23ca42b3ba19b24e66fade572f2b86d929b6e8 (diff)
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Reset i2c slave devices during init on mpc5xxx cpus
Reset any i2c devices that may have been interrupted during a system reset. Normally this would be accomplished by clocking the line until SCL and SDA are released and then sending a start condtiion (From an Atmel datasheet). There is no direct access to the i2c pins so instead create start commands through the i2c interface. Send a start command then delay for the SDA Hold time, repeat this by disabling/enabling the bus a total of 9 times. Signed-off-by: Eric Millbrandt <emillbrandt@dekaresearch.com>
Diffstat (limited to 'cpu')
-rw-r--r--cpu/mpc5xxx/i2c.c49
1 files changed, 49 insertions, 0 deletions
diff --git a/cpu/mpc5xxx/i2c.c b/cpu/mpc5xxx/i2c.c
index 2341932..4f7f716 100644
--- a/cpu/mpc5xxx/i2c.c
+++ b/cpu/mpc5xxx/i2c.c
@@ -207,6 +207,52 @@ static int receive_bytes(uchar chip, char *buf, int len)
return 0;
}
+#if defined(CONFIG_SYS_I2C_INIT_MPC5XXX)
+
+#define FDR510(x) (u8) (((x & 0x20) >> 3) | (x & 0x3))
+#define FDR432(x) (u8) ((x & 0x1C) >> 2)
+/*
+ * Reset any i2c devices that may have been interrupted during a system reset.
+ * Normally this would be accomplished by clocking the line until SCL and SDA
+ * are released and then sending a start condtiion (From an Atmel datasheet).
+ * There is no direct access to the i2c pins so instead create start commands
+ * through the i2c interface. Send a start command then delay for the SDA Hold
+ * time, repeat this by disabling/enabling the bus a total of 9 times.
+ */
+static void send_reset(void)
+{
+ struct mpc5xxx_i2c *regs = (struct mpc5xxx_i2c *)I2C_BASE;
+ int i;
+ u32 delay;
+ u8 fdr;
+ int SDA_Tap[] = { 3, 3, 4, 4, 1, 1, 2, 2};
+ struct mpc5xxx_i2c_tap scltap[] = {
+ {4, 1},
+ {4, 2},
+ {6, 4},
+ {6, 8},
+ {14, 16},
+ {30, 32},
+ {62, 64},
+ {126, 128}
+ };
+
+ fdr = (u8)mpc_reg_in(&regs->mfdr);
+
+ delay = scltap[FDR432(fdr)].scl2tap + ((SDA_Tap[FDR510(fdr)] - 1) * \
+ scltap[FDR432(fdr)].tap2tap) + 3;
+
+ for (i = 0; i < 9; i++) {
+ mpc_reg_out(&regs->mcr, I2C_EN|I2C_STA|I2C_TX, I2C_INIT_MASK);
+ udelay(delay);
+ mpc_reg_out(&regs->mcr, 0, I2C_INIT_MASK);
+ udelay(delay);
+ }
+
+ mpc_reg_out(&regs->mcr, I2C_EN, I2C_INIT_MASK);
+}
+#endif /* CONFIG_SYS_I2c_INIT_MPC5XXX */
+
/**************** I2C API ****************/
void i2c_init(int speed, int saddr)
@@ -225,6 +271,9 @@ void i2c_init(int speed, int saddr)
mpc_reg_out(&regs->mcr, I2C_EN, I2C_INIT_MASK);
mpc_reg_out(&regs->msr, 0, I2C_IF);
+#if defined(CONFIG_SYS_I2C_INIT_MPC5XXX)
+ send_reset();
+#endif
return;
}