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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2006-04-18 14:11:53 +1000
committerPaul Mackerras <paulus@samba.org>2006-04-21 22:29:46 +1000
commit60162e498e220d1f03bbee5bac0a9ddd6de60ae7 (patch)
tree8cbcbea6060eb2b9f7d39784385efdfc6e947b52 /arch
parent28897731318dc8f63f683eed9091e446916ad706 (diff)
downloadlinux-60162e498e220d1f03bbee5bac0a9ddd6de60ae7.tar.bz2
[PATCH] powermac: Fix i2c on keywest based chips
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>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/platforms/powermac/low_i2c.c78
1 files changed, 35 insertions, 43 deletions
diff --git a/arch/powerpc/platforms/powermac/low_i2c.c b/arch/powerpc/platforms/powermac/low_i2c.c
index e14f9ac55cf4..df2343e1956b 100644
--- a/arch/powerpc/platforms/powermac/low_i2c.c
+++ b/arch/powerpc/platforms/powermac/low_i2c.c
@@ -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",