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[PATCH] powermac: Fix i2c on keywest based chips

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The new i2c implementation for PowerMac has a regression that causes the
hardware to go out of state when probing non-existent devices. While
fixing that, I also found & fixed a couple of other corner cases. This
fixes booting with a pbbuttons version that scans the i2c bus for an LMU
controller among others. Tested on a dual G5 with thermal control (which
has heavy i2c activity) with no problem so far.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
Benjamin Herrenschmidt 2006-04-18 14:11:53 +10:00 committed by Paul Mackerras
parent 2889773131
commit 60162e498e
1 changed files with 35 additions and 43 deletions
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78
arch/powerpc/platforms/powermac/low_i2c.c
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@ -231,6 +231,14 @@ static u8 kw_i2c_wait_interrupt(struct pmac_i2c_host_kw *host)
return isr;
}
static void kw_i2c_do_stop(struct pmac_i2c_host_kw *host, int result)
{
kw_write_reg(reg_control, KW_I2C_CTL_STOP);
host->state = state_stop;
host->result = result;
}
static void kw_i2c_handle_interrupt(struct pmac_i2c_host_kw *host, u8 isr)
{
u8 ack;
@ -246,42 +254,36 @@ static void kw_i2c_handle_interrupt(struct pmac_i2c_host_kw *host, u8 isr)
}
if (isr == 0) {
printk(KERN_WARNING "low_i2c: Timeout in i2c transfer"
" on keywest !\n");
if (host->state != state_stop) {
DBG_LOW("KW: Timeout !\n");
host->result = -EIO;
goto stop;
}
if (host->state == state_stop) {
ack = kw_read_reg(reg_status);
if (ack & KW_I2C_STAT_BUSY)
kw_write_reg(reg_status, 0);
host->state = state_idle;
kw_write_reg(reg_ier, 0x00);
if (!host->polled)
complete(&host->complete);
kw_i2c_do_stop(host, -EIO);
return;
}
ack = kw_read_reg(reg_status);
if (ack & KW_I2C_STAT_BUSY)
kw_write_reg(reg_status, 0);
host->state = state_idle;
kw_write_reg(reg_ier, 0x00);
if (!host->polled)
complete(&host->complete);
return;
}
if (isr & KW_I2C_IRQ_ADDR) {
ack = kw_read_reg(reg_status);
if (host->state != state_addr) {
kw_write_reg(reg_isr, KW_I2C_IRQ_ADDR);
WRONG_STATE("KW_I2C_IRQ_ADDR");
host->result = -EIO;
goto stop;
kw_i2c_do_stop(host, -EIO);
}
if ((ack & KW_I2C_STAT_LAST_AAK) == 0) {
host->result = -ENODEV;
DBG_LOW("KW: NAK on address\n");
host->result = -ENXIO;
host->state = state_stop;
return;
DBG_LOW("KW: NAK on address\n");
} else {
if (host->len == 0) {
kw_write_reg(reg_isr, KW_I2C_IRQ_ADDR);
goto stop;
}
if (host->rw) {
if (host->len == 0)
kw_i2c_do_stop(host, 0);
else if (host->rw) {
host->state = state_read;
if (host->len > 1)
kw_write_reg(reg_control,
@ -308,25 +310,19 @@ static void kw_i2c_handle_interrupt(struct pmac_i2c_host_kw *host, u8 isr)
ack = kw_read_reg(reg_status);
if ((ack & KW_I2C_STAT_LAST_AAK) == 0) {
DBG_LOW("KW: nack on data write\n");
host->result = -EIO;
goto stop;
host->result = -EFBIG;
host->state = state_stop;
} else if (host->len) {
kw_write_reg(reg_data, *(host->data++));
host->len--;
} else {
kw_write_reg(reg_control, KW_I2C_CTL_STOP);
host->state = state_stop;
host->result = 0;
}
kw_write_reg(reg_isr, KW_I2C_IRQ_DATA);
} else
kw_i2c_do_stop(host, 0);
} else {
kw_write_reg(reg_isr, KW_I2C_IRQ_DATA);
WRONG_STATE("KW_I2C_IRQ_DATA");
if (host->state != state_stop) {
host->result = -EIO;
goto stop;
}
if (host->state != state_stop)
kw_i2c_do_stop(host, -EIO);
}
kw_write_reg(reg_isr, KW_I2C_IRQ_DATA);
}
if (isr & KW_I2C_IRQ_STOP) {
@ -340,14 +336,10 @@ static void kw_i2c_handle_interrupt(struct pmac_i2c_host_kw *host, u8 isr)
complete(&host->complete);
}
/* Below should only happen in manual mode which we don't use ... */
if (isr & KW_I2C_IRQ_START)
kw_write_reg(reg_isr, KW_I2C_IRQ_START);
return;
stop:
kw_write_reg(reg_control, KW_I2C_CTL_STOP);
host->state = state_stop;
return;
}
/* Interrupt handler */
@ -544,11 +536,11 @@ static struct pmac_i2c_host_kw *__init kw_i2c_host_init(struct device_node *np)
return NULL;
}
/* Make sure IRA is disabled */
/* Make sure IRQ is disabled */
kw_write_reg(reg_ier, 0);
/* Request chip interrupt */
if (request_irq(host->irq, kw_i2c_irq, SA_SHIRQ, "keywest i2c", host))
if (request_irq(host->irq, kw_i2c_irq, 0, "keywest i2c", host))
host->irq = NO_IRQ;
printk(KERN_INFO "KeyWest i2c @0x%08x irq %d %s\n",