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i2c: rcar: improve bus busy detection 

I2C doesn't define a timeout for bus busy, so an arbitrary value like
LOOP_TIMEOUT is not a good idea. Let's use the timeout value in struct
adapter which is meant for such cases and is user-configurable (via
IOCTL). To reduce the load, wait 10us instead of 1us which is good
enough for the slow frequencies used by I2C. Finally, use the
poll_timeout helper instead of open coding it.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
This commit is contained in:
Wolfram Sang 2020-08-29 22:38:09 +02:00 committed by Wolfram Sang
parent 6af0771946
commit 9374ed1dfe
1 changed files with 10 additions and 9 deletions
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19
drivers/i2c/busses/i2c-rcar.c
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@ -19,6 +19,7 @@
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/i2c.h>
#include <linux/kernel.h>
#include <linux/module.h>
@ -221,18 +222,18 @@ static void rcar_i2c_init(struct rcar_i2c_priv *priv)
static int rcar_i2c_bus_barrier(struct rcar_i2c_priv *priv)
{
int i;
int ret;
u32 val;
for (i = 0; i < LOOP_TIMEOUT; i++) {
/* make sure that bus is not busy */
if (!(rcar_i2c_read(priv, ICMCR) & FSDA))
return 0;
udelay(1);
ret = readl_poll_timeout(priv->io + ICMCR, val, !(val & FSDA), 10,
priv->adap.timeout);
if (ret) {
/* Waiting did not help, try to recover */
priv->recovery_icmcr = MDBS | OBPC | FSDA | FSCL;
ret = i2c_recover_bus(&priv->adap);
}
/* Waiting did not help, try to recover */
priv->recovery_icmcr = MDBS | OBPC | FSDA | FSCL;
return i2c_recover_bus(&priv->adap);
return ret;
}
static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv)