Messages in this thread | | | Date | Mon, 9 Nov 2015 16:25:09 +0200 | Subject | Re: [PATCH v2 1/2] i2c: mediatek: add i2c first write then read optimization | From | Andy Shevchenko <> |
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On Mon, Nov 9, 2015 at 7:43 AM, Liguo Zhang <liguo.zhang@mediatek.com> wrote: > For platform with auto restart support, between every transfer, > i2c controller will trigger an interrupt and SW need to handle > it to start new transfer. When doing write-then-read transfer, > instead of restart mechanism, using WRRD mode to have controller > send both transfer in one request to reduce latency.
> @@ -518,6 +529,16 @@ static int mtk_i2c_transfer(struct i2c_adapter *adap, > if (ret) > return ret; > > + i2c->auto_restart = i2c->dev_comp->auto_restart; > + > + /* checking if we can skip restart and optimize using WRRD mode */ > + if (i2c->auto_restart && num == 2) { > + if (!(msgs[0].flags & I2C_M_RD) && (msgs[1].flags & I2C_M_RD) && > + msgs[0].addr == msgs[1].addr) {
Nitpick (optional):
((msgs[0].flags & msgs[1].flags) & I2C_M_RD) ?
> + i2c->auto_restart = 0; > + } > + }
-- With Best Regards, Andy Shevchenko
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