On Tue, 4 Jun 2019 07:59:44 +0000 Chuanhua Han <chuanhua....@nxp.com> wrote:
> > -----Original Message----- > > From: Lukasz Majewski <lu...@denx.de> > > Sent: 2019年6月4日 15:56 > > To: Chuanhua Han <chuanhua....@nxp.com> > > Cc: h...@denx.de; u-boot@lists.denx.de; Biwen Li <biwen...@nxp.com> > > Subject: Re: [EXT] Re: [U-Boot] [PATCH 1/2] dm: i2c: Add a flag > > that not call i2c_setup_offset > > > > On Tue, 4 Jun 2019 06:48:59 +0000 > > Chuanhua Han <chuanhua....@nxp.com> wrote: > > > > > > -----Original Message----- > > > > From: Lukasz Majewski <lu...@denx.de> > > > > Sent: 2019年6月4日 14:46 > > > > To: Chuanhua Han <chuanhua....@nxp.com> > > > > Cc: h...@denx.de; u-boot@lists.denx.de; Biwen Li > > > > <biwen...@nxp.com> Subject: Re: [EXT] Re: [U-Boot] [PATCH 1/2] > > > > dm: i2c: Add a flag that not call i2c_setup_offset > > > > > > > > On Tue, 4 Jun 2019 02:20:49 +0000 > > > > Chuanhua Han <chuanhua....@nxp.com> wrote: > > > > > > > > > > -----Original Message----- > > > > > > From: Lukasz Majewski <lu...@denx.de> > > > > > > Sent: 2019年6月4日 6:08 > > > > > > To: Chuanhua Han <chuanhua....@nxp.com> > > > > > > Cc: h...@denx.de; u-boot@lists.denx.de; Biwen Li > > > > > > <biwen...@nxp.com> Subject: [EXT] Re: [U-Boot] [PATCH 1/2] > > > > > > dm: i2c: Add a flag that not call i2c_setup_offset > > > > > > > > > > > > On Thu, 30 May 2019 18:31:48 +0800 Chuanhua Han > > > > > > <chuanhua....@nxp.com> wrote: > > > > > > > > > > > > > Usually the i2c bus needs to write the address of the > > > > > > > register before reading the internal register data of the > > > > > > > device (ignoring the transmission of the slave address). > > > > > > > > > > > > > > Generally, the stop signal is not needed before the > > > > > > > register is read, but there is a special chip that needs > > > > > > > this stop signal (such as pcf2127). However, in the > > > > > > > current i2c general code, the dm_i2c_read api > > > > > > > encapsulates two messages, the first time is to set the > > > > > > > register address message, the second time is a message to > > > > > > > read the register data, so that no stop signal is > > > > > > > generated. > > > > > > > > > > > > > > This patch uses the DM_I2C_CHIP_RD_NO_I2C_SETUP_OFFSET > > > > > > > flag for specific i2c chips, so if the i2c slave requires > > > > > > > a stop signal, chips driver can set this flag, then call > > > > > > > the dm_i2c_write to set the register address (a stop > > > > > > > signal is generated after this API call), then call > > > > > > > dm_i2c_read to read the register data. > > > > > > > > > > > > > > Signed-off-by: Chuanhua Han <chuanhua....@nxp.com> > > > > > > > --- > > > > > > > Changes in v3: > > > > > > > - Use the new flag > > > > > > > DM_I2C_CHIP_RD_NO_I2C_SETUP_OFFSET > > > > > > > > > > > > > > Changes in v2: > > > > > > > - Split the original patch into 3 patches > > > > > > > - Add detailed description information for each > > > > > > > patch > > > > > > > > > > > > > > drivers/i2c/i2c-uclass.c | 6 ++++-- > > > > > > > include/i2c.h | 1 + > > > > > > > 2 files changed, 5 insertions(+), 2 deletions(-) > > > > > > > > > > > > > > diff --git a/drivers/i2c/i2c-uclass.c > > > > > > > b/drivers/i2c/i2c-uclass.c index e47abf1833..9804b5e8c7 > > > > > > > 100644 --- a/drivers/i2c/i2c-uclass.c > > > > > > > +++ b/drivers/i2c/i2c-uclass.c > > > > > > > @@ -135,8 +135,10 @@ int dm_i2c_read(struct udevice *dev, > > > > > > > uint offset, uint8_t *buffer, int len) if (chip->flags & > > > > > > > DM_I2C_CHIP_RD_ADDRESS) return i2c_read_bytewise(dev, > > > > > > > offset, buffer, len); ptr = msg; > > > > > > > - if (!i2c_setup_offset(chip, offset, offset_buf, > > > > > > > ptr)) > > > > > > > - ptr++; > > > > > > > + if (!(chip->flags & > > > > > > > DM_I2C_CHIP_RD_NO_I2C_SETUP_OFFSET)) { > > > > > > > + if (!i2c_setup_offset(chip, offset, > > > > > > > offset_buf, ptr)) > > > > > > > + ptr++; > > > > > > > + } > > > > > > > > > > > > > > if (len) { > > > > > > > ptr->addr = chip->chip_addr; diff --git > > > > > > > a/include/i2c.h b/include/i2c.h index > > > > > > > a5c760c711..3123cbf280 100644 > > > > > > > --- a/include/i2c.h > > > > > > > +++ b/include/i2c.h > > > > > > > @@ -28,6 +28,7 @@ enum dm_i2c_chip_flags { > > > > > > > DM_I2C_CHIP_10BIT = 1 << 0, > > > > > > > /* Use 10-bit addressing */ > > > > > > > DM_I2C_CHIP_RD_ADDRESS = 1 << 1, > > > > > > > /* Send address for each read byte */ > > > > > > > DM_I2C_CHIP_WR_ADDRESS = 1 << 2, > > > > > > > /* Send address for each write byte */ > > > > > > > > > > > > Aren't those two above flags describe exactly what you need? > > > > > > They send address for each read/written byte. (or do you > > > > > > need to send more than a single byte)? > > > > > This is not what I need. I need to generate a stop signal > > > > > after setting the register address, > > > > > > > > Please correct me if I'm wrong, but the above flag says that you > > > > need to send the I2C stop after you send one byte? > > > > > > > > Would it be possible to send address with I2C stop and then read > > > > data (single byte) with I2C stop? > > > > > > > > > so I need the following flag. > > > > > > > > > > > > > DM_I2C_CHIP_RD_NO_I2C_SETUP_OFFSET = 1 << 3, > > > > > > > > I do find this name as a bit misleading - is the > > > > RD_NO_I2C_SETUP_OFFSET name reflecting the purpose (to send I2C > > > > stop after sending address)? > > > The purpose is to send a stop signal after setting the slave > > > register address. > > > > What I'm trying to point out is that the above description doesn't > > match the flag name. Maybe there is a better, more descriptive > > name? > Because the stop signal is generated by not calling the > i2c_setup_offset function, this flag is used. But the name of the flag shall be not based on particular function name. It shall be a generic description - like presented above: DM_I2C_CHIP_WR_ADDRESS = 1 << 2, /* Send address for each write byte */ With such generic names - there is no problem if we refactor the code and change the function name. I've looked closer into those two flags: git grep -n "DM_I2C_CHIP_WR_ADDRESS" drivers/rtc/ds1307.c:319: drivers/rtc/isl1208.c:173: drivers/rtc/rv3029.c:469: It looks like those above rtc devices use it - so maybe the issue described for pcf2127 is also present on those devices (so those flags have been introduced) ? > > > > Also - what is byte length of send address to this device? One > > byte ? > Yes,one byte > > > > > > > > > > Maybe there would be a better name? > > > > > > > > > > > /* No i2c_setup_offset*/ }; > > > > > > > > > > > > > > struct udevice; > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Best regards, > > > > > > > > > > > > Lukasz Majewski > > > > > > > > > > > > -- > > > > > > > > > > > > DENX Software Engineering GmbH, Managing Director: > > > > > > Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, > > > > > > D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-59 Fax: > > > > > > (+49)-8142-66989-80 Email: lu...@denx.de > > > > > > > > > > > > > > > > > > > > Best regards, > > > > > > > > Lukasz Majewski > > > > > > > > -- > > > > > > > > DENX Software Engineering GmbH, Managing Director: Wolfgang > > > > Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 > > > > Groebenzell, Germany Phone: (+49)-8142-66989-59 Fax: > > > > (+49)-8142-66989-80 Email: lu...@denx.de > > > > > > > > > > Best regards, > > > > Lukasz Majewski > > > > -- > > > > DENX Software Engineering GmbH, Managing Director: Wolfgang > > Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, > > Germany Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: > > lu...@denx.de Best regards, Lukasz Majewski -- DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lu...@denx.de
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