i2c: rcar: improve bus busy detection (9374ed1d) · Commits · 戴 / test

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>

drivers/i2c/busses/i2c-rcar.c

+10 −9

Original line number	Diff line number	Diff line
		@@ -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;

		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);
		}
		int ret;
		u32 val;

		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;
		return i2c_recover_bus(&priv->adap);
		ret = i2c_recover_bus(&priv->adap);
		}

		return ret;
		}

		static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv)

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