From 60162e498e220d1f03bbee5bac0a9ddd6de60ae7 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Tue, 18 Apr 2006 14:11:53 +1000 Subject: [PATCH] [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 Signed-off-by: Paul Mackerras --- arch/powerpc/platforms/powermac/low_i2c.c | 78 ++++++++++------------- 1 file 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", -- 2.30.2