Hello Geert, Wolfram, Do you have any feedback on version 2 of this patch, that was submitted after your review comments below? https://lore.kernel.org/all/20211006182314.10585-1-andrew_gabbasov@xxxxxxxxxx/ Thanks! Best regards, Andrew > -----Original Message----- > From: Andrew Gabbasov <andrew_gabbasov@xxxxxxxxxx> > Sent: Wednesday, October 06, 2021 9:12 PM > To: 'Geert Uytterhoeven' <geert@xxxxxxxxxxxxxx> > Cc: Linux-Renesas <linux-renesas-soc@xxxxxxxxxxxxxxx>; Linux I2C <linux-i2c@xxxxxxxxxxxxxxx>; Linux Kernel > Mailing List <linux-kernel@xxxxxxxxxxxxxxx>; Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>; Surachari, > Bhuvanesh <Bhuvanesh_Surachari@xxxxxxxxxx> > Subject: RE: [PATCH] i2c: rcar: add SMBus block read support > > Hi Geert, > > Thank you for your review! > > > -----Original Message----- > > From: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> > > Sent: Tuesday, October 05, 2021 4:32 PM > > To: Gabbasov, Andrew <Andrew_Gabbasov@xxxxxxxxxx> > > Cc: Linux-Renesas <linux-renesas-soc@xxxxxxxxxxxxxxx>; Linux I2C <linux-i2c@xxxxxxxxxxxxxxx>; Linux Kernel > > Mailing List <linux-kernel@xxxxxxxxxxxxxxx>; Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>; Surachari, > > Bhuvanesh <Bhuvanesh_Surachari@xxxxxxxxxx> > > Subject: Re: [PATCH] i2c: rcar: add SMBus block read support > > > > Hi Andrew, > > > > On Wed, Sep 22, 2021 at 6:14 PM Andrew Gabbasov > > <andrew_gabbasov@xxxxxxxxxx> wrote: > > > The smbus block read is not currently supported for rcar i2c devices. > > > This patchset adds the support to rcar i2c bus so that blocks of data > > > can be read using SMbus block reads.(using i2c_smbus_read_block_data() > > > function from the i2c-core-smbus.c). > > > > > > Inspired by commit 8e8782c71595 ("i2c: imx: add SMBus block read support") > > > > > > This patch (adapted) was tested with v4.14, but due to lack of real > > > hardware with SMBus block read operations support, using "simulation", > > > that is manual analysis of data, read from plain I2C devices with > > > SMBus block read request. > > > > > > Signed-off-by: Bhuvanesh Surachari <bhuvanesh_surachari@xxxxxxxxxx> > > > Signed-off-by: Andrew Gabbasov <andrew_gabbasov@xxxxxxxxxx> > > > > Thanks for your patch! > > > > > --- a/drivers/i2c/busses/i2c-rcar.c > > > +++ b/drivers/i2c/busses/i2c-rcar.c > > > @@ -429,9 +431,16 @@ static bool rcar_i2c_dma(struct rcar_i2c_priv *priv) > > > /* > > > * The last two bytes needs to be fetched using PIO in > > > * order for the STOP phase to work. > > > + * > > > + * For SMBus block read the first byte was received using PIO. > > > > So it might be easier to read, and more maintainable, to keep the > > old assignments: > > > > buf = priv->msg->buf; > > len = priv->msg->len - 2; > > > > and adjust them for SMBus afterwards: > > > > if (block_data) { > > /* For SMBus block read the first byte was received using PIO */ > > buf++; > > len--; > > } > > > > ? > > > > > */ > > > - buf = priv->msg->buf; > > > - len = priv->msg->len - 2; > > > + if (block_data) { > > > + buf = priv->msg->buf + 1; > > > + len = priv->msg->len - 3; > > > + } else { > > > + buf = priv->msg->buf; > > > + len = priv->msg->len - 2; > > > + } > > > } else { > > > /* > > > * First byte in message was sent using PIO. > > > > And below we have another case handling buf and len :-( > > > > So perhaps: > > > > buf = priv->msg->buf; > > len = priv->msg->len; > > > > if (read) { > > /* > > * The last two bytes needs to be fetched using PIO in > > * order for the STOP phase to work. > > */ > > len -= 2; > > } > > if (!read || block_data) { > > /* First byte in message was sent using PIO * > > buf++; > > len--; > > } > > Probably I was trying to minimize the changes ;-) > > However, I agree with you that the whole code fragment can be simplified > and your variant indeed looks more clean and understandable. > Thank you for your suggestion, I'll submit version 2 of the patch > with this fragment changed. > > Thanks! > > Best regards, > Andrew
