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i2c-designware: Don't use the IC_CLR_INTR register to clear interrupts 

We're strongly discouraged from using the IC_CLR_INTR register because
it clears all software-clearable interrupts asserted at the moment.

  stat = readl(IC_INTR_STAT);
    :
    :  <=== Interrupts asserted during this period will be lost
    :
  readl(IC_CLR_INTR);

Instead, use the separately-prepared IC_CLR_* registers.

At the same time, this patch adds all remaining interrupt definitions
available in the DesignWare I2C hardware.

Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi@necel.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This commit is contained in:
Shinya Kuribayashi 2009-11-06 21:44:37 +09:00 committed by Ben Dooks
parent ed5e1dd5f2
commit e28000a38d
1 changed files with 79 additions and 5 deletions
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84
drivers/i2c/busses/i2c-designware.c
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@ -49,7 +49,18 @@
#define DW_IC_FS_SCL_LCNT 0x20
#define DW_IC_INTR_STAT 0x2c
#define DW_IC_INTR_MASK 0x30
#define DW_IC_RAW_INTR_STAT 0x34
#define DW_IC_CLR_INTR 0x40
#define DW_IC_CLR_RX_UNDER 0x44
#define DW_IC_CLR_RX_OVER 0x48
#define DW_IC_CLR_TX_OVER 0x4c
#define DW_IC_CLR_RD_REQ 0x50
#define DW_IC_CLR_TX_ABRT 0x54
#define DW_IC_CLR_RX_DONE 0x58
#define DW_IC_CLR_ACTIVITY 0x5c
#define DW_IC_CLR_STOP_DET 0x60
#define DW_IC_CLR_START_DET 0x64
#define DW_IC_CLR_GEN_CALL 0x68
#define DW_IC_ENABLE 0x6c
#define DW_IC_STATUS 0x70
#define DW_IC_TXFLR 0x74
@ -64,9 +75,18 @@
#define DW_IC_CON_RESTART_EN 0x20
#define DW_IC_CON_SLAVE_DISABLE 0x40
#define DW_IC_INTR_TX_EMPTY 0x10
#define DW_IC_INTR_TX_ABRT 0x40
#define DW_IC_INTR_RX_UNDER 0x001
#define DW_IC_INTR_RX_OVER 0x002
#define DW_IC_INTR_RX_FULL 0x004
#define DW_IC_INTR_TX_OVER 0x008
#define DW_IC_INTR_TX_EMPTY 0x010
#define DW_IC_INTR_RD_REQ 0x020
#define DW_IC_INTR_TX_ABRT 0x040
#define DW_IC_INTR_RX_DONE 0x080
#define DW_IC_INTR_ACTIVITY 0x100
#define DW_IC_INTR_STOP_DET 0x200
#define DW_IC_INTR_START_DET 0x400
#define DW_IC_INTR_GEN_CALL 0x800
#define DW_IC_STATUS_ACTIVITY 0x1
@ -439,6 +459,61 @@ static void dw_i2c_pump_msg(unsigned long data)
writel(intr_mask, dev->base + DW_IC_INTR_MASK);
}
static u32 i2c_dw_read_clear_intrbits(struct dw_i2c_dev *dev)
{
u32 stat;
/*
* The IC_INTR_STAT register just indicates "enabled" interrupts.
* Ths unmasked raw version of interrupt status bits are available
* in the IC_RAW_INTR_STAT register.
*
* That is,
* stat = readl(IC_INTR_STAT);
* equals to,
* stat = readl(IC_RAW_INTR_STAT) & readl(IC_INTR_MASK);
*
* The raw version might be useful for debugging purposes.
*/
stat = readl(dev->base + DW_IC_INTR_STAT);
/*
* Do not use the IC_CLR_INTR register to clear interrupts, or
* you'll miss some interrupts, triggered during the period from
* readl(IC_INTR_STAT) to readl(IC_CLR_INTR).
*
* Instead, use the separately-prepared IC_CLR_* registers.
*/
if (stat & DW_IC_INTR_RX_UNDER)
readl(dev->base + DW_IC_CLR_RX_UNDER);
if (stat & DW_IC_INTR_RX_OVER)
readl(dev->base + DW_IC_CLR_RX_OVER);
if (stat & DW_IC_INTR_TX_OVER)
readl(dev->base + DW_IC_CLR_TX_OVER);
if (stat & DW_IC_INTR_RD_REQ)
readl(dev->base + DW_IC_CLR_RD_REQ);
if (stat & DW_IC_INTR_TX_ABRT) {
/*
* The IC_TX_ABRT_SOURCE register is cleared whenever
* the IC_CLR_TX_ABRT is read. Preserve it beforehand.
*/
dev->abort_source = readl(dev->base + DW_IC_TX_ABRT_SOURCE);
readl(dev->base + DW_IC_CLR_TX_ABRT);
}
if (stat & DW_IC_INTR_RX_DONE)
readl(dev->base + DW_IC_CLR_RX_DONE);
if (stat & DW_IC_INTR_ACTIVITY)
readl(dev->base + DW_IC_CLR_ACTIVITY);
if (stat & DW_IC_INTR_STOP_DET)
readl(dev->base + DW_IC_CLR_STOP_DET);
if (stat & DW_IC_INTR_START_DET)
readl(dev->base + DW_IC_CLR_START_DET);
if (stat & DW_IC_INTR_GEN_CALL)
readl(dev->base + DW_IC_CLR_GEN_CALL);
return stat;
}
/*
* Interrupt service routine. This gets called whenever an I2C interrupt
* occurs.
@ -448,16 +523,15 @@ static irqreturn_t i2c_dw_isr(int this_irq, void *dev_id)
struct dw_i2c_dev *dev = dev_id;
u32 stat;
stat = readl(dev->base + DW_IC_INTR_STAT);
stat = i2c_dw_read_clear_intrbits(dev);
dev_dbg(dev->dev, "%s: stat=0x%x\n", __func__, stat);
if (stat & DW_IC_INTR_TX_ABRT) {
dev->abort_source = readl(dev->base + DW_IC_TX_ABRT_SOURCE);
dev->cmd_err |= DW_IC_ERR_TX_ABRT;
dev->status = STATUS_IDLE;
} else if (stat & DW_IC_INTR_TX_EMPTY)
tasklet_schedule(&dev->pump_msg);
readl(dev->base + DW_IC_CLR_INTR); /* clear interrupts */
writel(0, dev->base + DW_IC_INTR_MASK); /* disable interrupts */
if (stat & (DW_IC_INTR_TX_ABRT | DW_IC_INTR_STOP_DET))
complete(&dev->cmd_complete);