| Message ID | 1439911206-8736-1-git-send-email-ykaneko0929@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Geert Uytterhoeven |
| Headers | show |
On Wed, Aug 19, 2015 at 12:20:06AM +0900, Yoshihiro Kaneko wrote: > From: Ryo Kataoka <ryo.kataoka.wt@renesas.com> > > In case of repeated START condition, the restart has to be kicked > before clear status (MSR register). If it is kicked after clear status, > R-Car I2C may transfer data (TXD register) or receive data (RXD register) > instead of transferring slave address (MAR register). > > Signed-off-by: Ryo Kataoka <ryo.kataoka.wt@renesas.com> > Signed-off-by: Yoshihiro Kaneko <ykaneko0929@gmail.com> I think I could reproduce the issue but changing the order of clearing and kicking did not change anything for me. I have CCed you in my new series regarding the i2c-rcar driver. That made the issue for me go away. Can you kindly check, too? Thanks, Wolfram
Hello Wolfram, 2015-09-04 5:34 GMT+09:00 Wolfram Sang <wsa@the-dreams.de>: > On Wed, Aug 19, 2015 at 12:20:06AM +0900, Yoshihiro Kaneko wrote: >> From: Ryo Kataoka <ryo.kataoka.wt@renesas.com> >> >> In case of repeated START condition, the restart has to be kicked >> before clear status (MSR register). If it is kicked after clear status, >> R-Car I2C may transfer data (TXD register) or receive data (RXD register) >> instead of transferring slave address (MAR register). >> >> Signed-off-by: Ryo Kataoka <ryo.kataoka.wt@renesas.com> >> Signed-off-by: Yoshihiro Kaneko <ykaneko0929@gmail.com> > > I think I could reproduce the issue but changing the order of clearing > and kicking did not change anything for me. I have CCed you in my new > series regarding the i2c-rcar driver. That made the issue for me go > away. Can you kindly check, too? Sure, but I'm not sure about the behavior of the H/W. I would like to learn from your patch series. Best Regards, Kaneko > > Thanks, > > Wolfram > -- To unsubscribe from this list: send the line "unsubscribe linux-sh" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c index d8361da..8cc7bd7 100644 --- a/drivers/i2c/busses/i2c-rcar.c +++ b/drivers/i2c/busses/i2c-rcar.c @@ -2,6 +2,7 @@ * Driver for the Renesas RCar I2C unit * * Copyright (C) 2014 Wolfram Sang <wsa@sang-engineering.com> + * Copyright (C) 2013-2014 Renesas Electronics Corporation * * Copyright (C) 2012-14 Renesas Solutions Corp. * Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> @@ -99,6 +100,7 @@ #define ID_DONE (1 << 2) #define ID_ARBLOST (1 << 3) #define ID_NACK (1 << 4) +#define ID_FIRST_MSG (1 << 5) enum rcar_i2c_type { I2C_RCAR_GEN1, @@ -125,6 +127,7 @@ struct rcar_i2c_priv { #define rcar_i2c_is_recv(p) ((p)->msg->flags & I2C_M_RD) #define rcar_i2c_flags_set(p, f) ((p)->flags |= (f)) +#define rcar_i2c_flags_clr(p, f) ((p)->flags &= ~(f)) #define rcar_i2c_flags_has(p, f) ((p)->flags & (f)) #define LOOP_TIMEOUT 1024 @@ -257,8 +260,14 @@ static void rcar_i2c_prepare_msg(struct rcar_i2c_priv *priv) int read = !!rcar_i2c_is_recv(priv); rcar_i2c_write(priv, ICMAR, (priv->msg->addr << 1) | read); - rcar_i2c_write(priv, ICMSR, 0); - rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_START); + if (rcar_i2c_flags_has(priv, ID_FIRST_MSG)) { /* start */ + rcar_i2c_write(priv, ICMSR, 0); + rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_START); + rcar_i2c_flags_clr(priv, ID_FIRST_MSG); + } else { /* restart */ + rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_START); + rcar_i2c_write(priv, ICMSR, 0); + } rcar_i2c_write(priv, ICMIER, read ? RCAR_IRQ_RECV : RCAR_IRQ_SEND); } @@ -523,6 +532,8 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap, priv->msg = &msgs[i]; priv->pos = 0; priv->flags = 0; + if (i == 0) + rcar_i2c_flags_set(priv, ID_FIRST_MSG); if (i == num - 1) rcar_i2c_flags_set(priv, ID_LAST_MSG);