W dniu 2014-09-08 20:33, Marek Vasut pisze:
On Monday, September 08, 2014 at 08:06:12 PM, Janusz Użycki wrote:
Subject: [PATCH 2/2] i2c-mxs: fixed PIO NACK error instead of timeout
(1000ms)
i2cdetect scanned i2c bus very slow if address was not occupied by any
device.
Shouldn't this check be used only after the 'SELECT' command ?
It looks |||mxs_i2c_isr()| for DMA transfer does not differentiate
commands also
and does not mask irqs for each command.
|STAT_GOT_A_NAK| is a separate bit.|CTRL1_NO_SLAVE_ACK_IRQ can be set
both after SELECT and WRITE command. Should we differentiate?
|
|Checking CTRL1_NO_SLAVE_ACK_IRQ |bit for SELECT command will increase
code size only
without special profit. Current PIO implementation also gathers all errors
together and reads them on the end by mxs_i2c_pio_check_error_state().
Probably mxs_i2c_pio_check_error_state() call or
enabling interrupt masks for PIO could be better than
direct |CTRL1_NO_SLAVE_ACK_IRQ |bit checking for clear code.
It also could support multimaster for PIO (MASTER_LOSS).
best regards
Janusz
Signed-off-by: Janusz Uzycki <j.uzycki@xxxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-mxs.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/i2c/busses/i2c-mxs.c b/drivers/i2c/busses/i2c-mxs.c
index 87ee72d..b498708 100644
--- a/drivers/i2c/busses/i2c-mxs.c
+++ b/drivers/i2c/busses/i2c-mxs.c
@@ -307,6 +307,9 @@ static int mxs_i2c_pio_wait_xfer_end(struct
mxs_i2c_dev *i2c)
unsigned long timeout = jiffies + msecs_to_jiffies(1000);
while (readl(i2c->regs + MXS_I2C_CTRL0) & MXS_I2C_CTRL0_RUN) {
+ /*int ret = mxs_i2c_pio_check_error_state(i2c);*/
+ if (readl(i2c->regs + MXS_I2C_CTRL1) & MXS_I2C_CTRL1_NO_SLAVE_ACK_IRQ)
+ return -ENXIO;
if (time_after(jiffies, timeout))
return -ETIMEDOUT;
cond_resched();
--
1.7.11.3
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