Messages in this thread | | | Subject | Re: [PATCH v2 1/1] Input: atmel_mxt_ts - implement I2C retries | From | "Wang, Jiada" <> | Date | Sat, 12 Sep 2020 09:50:22 +0900 |
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Hi Andy
Thanks for your comment
On 2020/09/06 3:02, Andy Shevchenko wrote: > > > On Thursday, September 3, 2020, Jiada Wang <jiada_wang@mentor.com > <mailto:jiada_wang@mentor.com>> wrote: > > From: Nick Dyer <nick.dyer@itdev.co.uk <mailto:nick.dyer@itdev.co.uk>> > > Some maXTouch chips (eg mXT1386) will not respond on the first I2C > request > when they are in a sleep state. It must be retried after a delay for the > chip to wake up. > > Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk > <mailto:nick.dyer@itdev.co.uk>> > Acked-by: Yufeng Shen <miletus@chromium.org > <mailto:miletus@chromium.org>> > > > (cherry picked from ndyer/linux/for-upstream commit > 63fd7a2cd03c3a572a5db39c52f4856819e1835d) > > > It’s a noise for upstream. > sure, I will remove it
> [gdavis: Forward port and fix conflicts.] > Signed-off-by: George G. Davis <george_davis@mentor.com > <mailto:george_davis@mentor.com>> > [jiada: return exact errno when i2c_transfer & i2c_master_send fails] > Signed-off-by: Jiada Wang <jiada_wang@mentor.com > <mailto:jiada_wang@mentor.com>> > --- > drivers/input/touchscreen/atmel_mxt_ts.c | 45 ++++++++++++++++-------- > 1 file changed, 30 insertions(+), 15 deletions(-) > > diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c > b/drivers/input/touchscreen/atmel_mxt_ts.c > index a2189739e30f..5d4cb15d21dc 100644 > --- a/drivers/input/touchscreen/atmel_mxt_ts.c > +++ b/drivers/input/touchscreen/atmel_mxt_ts.c > @@ -196,6 +196,7 @@ enum t100_type { > #define MXT_CRC_TIMEOUT 1000 /* msec */ > #define MXT_FW_RESET_TIME 3000 /* msec */ > #define MXT_FW_CHG_TIMEOUT 300 /* msec */ > +#define MXT_WAKEUP_TIME 25 /* msec */ > > > Can we simple add _MS unit suffix to the definition? As Dmitry commented, I'd like to keep it as-is, probably a separate patch to update all these together. > > > /* Command to unlock bootloader */ > #define MXT_UNLOCK_CMD_MSB 0xaa > @@ -626,6 +627,7 @@ static int __mxt_read_reg(struct i2c_client *client, > struct i2c_msg xfer[2]; > u8 buf[2]; > int ret; > + bool retry = false; > > > Keep this ordered by length. I will move "retry" upper. > > > buf[0] = reg & 0xff; > buf[1] = (reg >> 8) & 0xff; > @@ -642,17 +644,22 @@ static int __mxt_read_reg(struct i2c_client > *client, > xfer[1].len = len; > xfer[1].buf = val; > > - ret = i2c_transfer(client->adapter, xfer, 2); > - if (ret == 2) { > - ret = 0; > - } else { > - if (ret >= 0) > - ret = -EIO; > - dev_err(&client->dev, "%s: i2c transfer failed (%d)\n", > - __func__, ret); > +retry_read: > + ret = i2c_transfer(client->adapter, xfer, ARRAY_SIZE(xfer)); > + if (ret != ARRAY_SIZE(xfer)) { > + if (!retry) { > > > Why not positive conditional? to me, it's not much different either positive or negative conditional, can you elaborate more about this?
> > + dev_dbg(&client->dev, "%s: i2c retry\n", > __func__); > > > __func__ is redundant for dev_dbg(). > > + msleep(MXT_WAKEUP_TIME); > + retry = true; > + goto retry_read; > > + } else { > > > Redundant in either case of conditional. Allows to drop indentation level. I will remove the redundant conditional
Thanks, Jiada > > + dev_err(&client->dev, "%s: i2c transfer > failed (%d)\n", > + __func__, ret); > + return ret < 0 ? ret : -EIO; > + } > } > > - return ret; > + return 0; > } > > > Same comments about below. > > static int __mxt_write_reg(struct i2c_client *client, u16 reg, u16 > len, > @@ -661,6 +668,7 @@ static int __mxt_write_reg(struct i2c_client > *client, u16 reg, u16 len, > u8 *buf; > size_t count; > int ret; > + bool retry = false; > > count = len + 2; > buf = kmalloc(count, GFP_KERNEL); > @@ -671,14 +679,21 @@ static int __mxt_write_reg(struct i2c_client > *client, u16 reg, u16 len, > buf[1] = (reg >> 8) & 0xff; > memcpy(&buf[2], val, len); > > +retry_write: > ret = i2c_master_send(client, buf, count); > - if (ret == count) { > - ret = 0; > + if (ret != count) { > + if (!retry) { > + dev_dbg(&client->dev, "%s: i2c retry\n", > __func__); > + msleep(MXT_WAKEUP_TIME); > + retry = true; > + goto retry_write; > + } else { > + dev_err(&client->dev, "%s: i2c send failed > (%d)\n", > + __func__, ret); > + ret = ret < 0 ? ret : -EIO; > + } > } else { > - if (ret >= 0) > - ret = -EIO; > - dev_err(&client->dev, "%s: i2c send failed (%d)\n", > - __func__, ret); > + ret = 0; > } > > kfree(buf); > -- > 2.17.1 > > > > -- > With Best Regards, > Andy Shevchenko > >
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