Re: Howto read I2C on MPC5200 Lite
From: Domen Puncer <hidden>
Date: 2007-03-15 09:58:06
Subsystem:
freescale mpc i2c driver, i2c subsystem, i2c subsystem host drivers, the rest · Maintainers:
Chris Packham, Andi Shyti, Linus Torvalds
On 11/03/07 01:55 +0100, Matthias Fechner wrote:
Hi, * Matthias Fechner [off-list ref] [10-03-07 00:42]:quoted
It seems now that everything works fine. I will check it for the next days. And will give some feedback.ok, I checked now the driver some time at it failed. So it seems that that the patch had not solved the problem. I have attached the programm to check it.
But not for built-in eeprom :-P Anyway, I managed to reproduce some problems, and hopefully "fix" them. One problem seems to be fixed by disabling i2c on stop, another looks like it's: http://ozlabs.org/pipermail/linuxppc-embedded/2005-July/019038.html Can you please try following patch. Domen
diff --git a/drivers/i2c/busses/i2c-mpc.c b/drivers/i2c/busses/i2c-mpc.c
index ee65aa1..522f485 100644
--- a/drivers/i2c/busses/i2c-mpc.c
+++ b/drivers/i2c/busses/i2c-mpc.c@@ -75,6 +75,20 @@ static irqreturn_t mpc_i2c_isr(int irq, return IRQ_HANDLED; } +static void mpc_i2c_fixup(struct mpc_i2c *i2c) +{ + writeccr(i2c, 0); + udelay(30); + writeccr(i2c, CCR_MEN); + udelay(30); + writeccr(i2c, CCR_MSTA | CCR_MTX); + udelay(30); + writeccr(i2c, CCR_MSTA | CCR_MTX | CCR_MEN); + udelay(30); + writeccr(i2c, CCR_MEN); + udelay(30); +} + static int i2c_wait(struct mpc_i2c *i2c, unsigned timeout, int writing) { unsigned long orig_jiffies = jiffies;
@@ -154,6 +168,9 @@ static void mpc_i2c_start(struct mpc_i2c static void mpc_i2c_stop(struct mpc_i2c *i2c) { writeccr(i2c, CCR_MEN); + mb(); + writeccr(i2c, 0); + mb(); } static int mpc_write(struct mpc_i2c *i2c, int target,
@@ -246,6 +263,8 @@ static int mpc_xfer(struct i2c_adapter * } if (time_after(jiffies, orig_jiffies + HZ)) { pr_debug("I2C: timeout\n"); + if (readb(i2c->base + MPC_I2C_SR) == (CSR_MCF | CSR_MBB | CSR_RXAK)) + mpc_i2c_fixup(i2c); return -EIO; } schedule();