| Message ID | 20200225155012.22764-1-codrin.ciubotariu@microchip.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v4,1/4] i2c: at91: Send bus clear command if SDA is down | expand |
On 2/25/2020 4:50 PM, Codrin Ciubotariu wrote: > After a transfer timeout, some faulty I2C slave devices might hold down > the SDA pin. We can generate a bus clear command, hoping that the slave > might release the pins. > If the CLEAR command is not supported, we will use gpio recovery, if > available, to reset the bus. > > Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com> Sounds good so Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com> Wolfram, you have accepted the v3 of the recovery support and requested these changes. It has been sent as a v4, but, in fact, this patch goes on top on v3. It could, should, have been a new patch. Regards Ludovic > --- > > Changes in v4: > - moved the HW bus clear command in a recover_bus() function, to be able > to just call i2c_recover_bus() if a transfer fails; > - recovery gpios are no longer taken if HW bus clear command is > supported; > > Changes in v3: > - removed unnecessary condition from info print; > - removed unneded declarations; > > Changes in v2: > - called i2c_recover_bus() after an error occurs, if SDA is down; > - release gpios if recovery information is incomplete; > > drivers/i2c/busses/i2c-at91-core.c | 2 ++ > drivers/i2c/busses/i2c-at91-master.c | 49 ++++++++++++++++++++++++---- > drivers/i2c/busses/i2c-at91.h | 7 +++- > 3 files changed, 50 insertions(+), 8 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-at91-core.c b/drivers/i2c/busses/i2c-at91-core.c > index 3da1a8acecb5..e14edd236108 100644 > --- a/drivers/i2c/busses/i2c-at91-core.c > +++ b/drivers/i2c/busses/i2c-at91-core.c > @@ -131,6 +131,7 @@ static struct at91_twi_pdata sama5d2_config = { > .has_dig_filtr = true, > .has_adv_dig_filtr = true, > .has_ana_filtr = true, > + .has_clear_cmd = false, /* due to errata, CLEAR cmd is not working */ > }; > > static struct at91_twi_pdata sam9x60_config = { > @@ -142,6 +143,7 @@ static struct at91_twi_pdata sam9x60_config = { > .has_dig_filtr = true, > .has_adv_dig_filtr = true, > .has_ana_filtr = true, > + .has_clear_cmd = true, > }; > > static const struct of_device_id atmel_twi_dt_ids[] = { > diff --git a/drivers/i2c/busses/i2c-at91-master.c b/drivers/i2c/busses/i2c-at91-master.c > index 0aba51a7df32..776e95962ab6 100644 > --- a/drivers/i2c/busses/i2c-at91-master.c > +++ b/drivers/i2c/busses/i2c-at91-master.c > @@ -480,7 +480,6 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev) > unsigned long time_left; > bool has_unre_flag = dev->pdata->has_unre_flag; > bool has_alt_cmd = dev->pdata->has_alt_cmd; > - struct i2c_bus_recovery_info *rinfo = &dev->rinfo; > > /* > * WARNING: the TXCOMP bit in the Status Register is NOT a clear on > @@ -641,11 +640,12 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev) > AT91_TWI_THRCLR | AT91_TWI_LOCKCLR); > } > > - if (rinfo->get_sda && !(rinfo->get_sda(&dev->adapter))) { > - dev_dbg(dev->dev, > - "SDA is down; clear bus using gpio\n"); > - i2c_recover_bus(&dev->adapter); > - } > + /* > + * some faulty I2C slave devices might hold SDA down; > + * we can send a bus clear command, hoping that the pins will be > + * released > + */ > + i2c_recover_bus(&dev->adapter); > > return ret; > } > @@ -830,7 +830,7 @@ static void at91_unprepare_twi_recovery(struct i2c_adapter *adap) > pinctrl_select_state(dev->pinctrl, dev->pinctrl_pins_default); > } > > -static int at91_init_twi_recovery_info(struct platform_device *pdev, > +static int at91_init_twi_recovery_gpio(struct platform_device *pdev, > struct at91_twi_dev *dev) > { > struct i2c_bus_recovery_info *rinfo = &dev->rinfo; > @@ -880,6 +880,41 @@ static int at91_init_twi_recovery_info(struct platform_device *pdev, > return 0; > } > > +static int at91_twi_recover_bus_cmd(struct i2c_adapter *adap) > +{ > + struct at91_twi_dev *dev = i2c_get_adapdata(adap); > + > + dev->transfer_status |= at91_twi_read(dev, AT91_TWI_SR); > + if (!(dev->transfer_status & AT91_TWI_SDA)) { > + dev_dbg(dev->dev, "SDA is down; sending bus clear command\n"); > + if (dev->use_alt_cmd) { > + unsigned int acr; > + > + acr = at91_twi_read(dev, AT91_TWI_ACR); > + acr &= ~AT91_TWI_ACR_DATAL_MASK; > + at91_twi_write(dev, AT91_TWI_ACR, acr); > + } > + at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_CLEAR); > + } > + > + return 0; > +} > + > +static int at91_init_twi_recovery_info(struct platform_device *pdev, > + struct at91_twi_dev *dev) > +{ > + struct i2c_bus_recovery_info *rinfo = &dev->rinfo; > + bool has_clear_cmd = dev->pdata->has_clear_cmd; > + > + if (!has_clear_cmd) > + return at91_init_twi_recovery_gpio(pdev, dev); > + > + rinfo->recover_bus = at91_twi_recover_bus_cmd; > + dev->adapter.bus_recovery_info = rinfo; > + > + return 0; > +} > + > int at91_twi_probe_master(struct platform_device *pdev, > u32 phy_addr, struct at91_twi_dev *dev) > { > diff --git a/drivers/i2c/busses/i2c-at91.h b/drivers/i2c/busses/i2c-at91.h > index f57a6cab96b4..7e7b4955ca7f 100644 > --- a/drivers/i2c/busses/i2c-at91.h > +++ b/drivers/i2c/busses/i2c-at91.h > @@ -36,6 +36,7 @@ > #define AT91_TWI_SVDIS BIT(5) /* Slave Transfer Disable */ > #define AT91_TWI_QUICK BIT(6) /* SMBus quick command */ > #define AT91_TWI_SWRST BIT(7) /* Software Reset */ > +#define AT91_TWI_CLEAR BIT(15) /* Bus clear command */ > #define AT91_TWI_ACMEN BIT(16) /* Alternative Command Mode Enable */ > #define AT91_TWI_ACMDIS BIT(17) /* Alternative Command Mode Disable */ > #define AT91_TWI_THRCLR BIT(24) /* Transmit Holding Register Clear */ > @@ -69,6 +70,8 @@ > #define AT91_TWI_NACK BIT(8) /* Not Acknowledged */ > #define AT91_TWI_EOSACC BIT(11) /* End Of Slave Access */ > #define AT91_TWI_LOCK BIT(23) /* TWI Lock due to Frame Errors */ > +#define AT91_TWI_SCL BIT(24) /* TWI SCL status */ > +#define AT91_TWI_SDA BIT(25) /* TWI SDA status */ > > #define AT91_TWI_INT_MASK \ > (AT91_TWI_TXCOMP | AT91_TWI_RXRDY | AT91_TWI_TXRDY | AT91_TWI_NACK \ > @@ -81,7 +84,8 @@ > #define AT91_TWI_THR 0x0034 /* Transmit Holding Register */ > > #define AT91_TWI_ACR 0x0040 /* Alternative Command Register */ > -#define AT91_TWI_ACR_DATAL(len) ((len) & 0xff) > +#define AT91_TWI_ACR_DATAL_MASK GENMASK(15, 0) > +#define AT91_TWI_ACR_DATAL(len) ((len) & AT91_TWI_ACR_DATAL_MASK) > #define AT91_TWI_ACR_DIR BIT(8) > > #define AT91_TWI_FILTR 0x0044 > @@ -118,6 +122,7 @@ struct at91_twi_pdata { > bool has_dig_filtr; > bool has_adv_dig_filtr; > bool has_ana_filtr; > + bool has_clear_cmd; > struct at_dma_slave dma_slave; > }; > >
On 30.03.2020 00:13, Ludovic Desroches - M43218 wrote: > On 2/25/2020 4:50 PM, Codrin Ciubotariu wrote: >> After a transfer timeout, some faulty I2C slave devices might hold down >> the SDA pin. We can generate a bus clear command, hoping that the slave >> might release the pins. >> If the CLEAR command is not supported, we will use gpio recovery, if >> available, to reset the bus. >> >> Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com> > > Sounds good so > Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com> > > Wolfram, you have accepted the v3 of the recovery support and requested > these changes. It has been sent as a v4, but, in fact, this patch goes > on top on v3. It could, should, have been a new patch. > > Regards > > Ludovic Hello, any updates on this patch? Do you want me to change anything? Best regards, Codrin > >> --- >> >> Changes in v4: >> - moved the HW bus clear command in a recover_bus() function, to be able >> to just call i2c_recover_bus() if a transfer fails; >> - recovery gpios are no longer taken if HW bus clear command is >> supported; >> >> Changes in v3: >> - removed unnecessary condition from info print; >> - removed unneded declarations; >> >> Changes in v2: >> - called i2c_recover_bus() after an error occurs, if SDA is down; >> - release gpios if recovery information is incomplete; >> >> drivers/i2c/busses/i2c-at91-core.c | 2 ++ >> drivers/i2c/busses/i2c-at91-master.c | 49 ++++++++++++++++++++++++---- >> drivers/i2c/busses/i2c-at91.h | 7 +++- >> 3 files changed, 50 insertions(+), 8 deletions(-) >> >> diff --git a/drivers/i2c/busses/i2c-at91-core.c b/drivers/i2c/busses/i2c-at91-core.c >> index 3da1a8acecb5..e14edd236108 100644 >> --- a/drivers/i2c/busses/i2c-at91-core.c >> +++ b/drivers/i2c/busses/i2c-at91-core.c >> @@ -131,6 +131,7 @@ static struct at91_twi_pdata sama5d2_config = { >> .has_dig_filtr = true, >> .has_adv_dig_filtr = true, >> .has_ana_filtr = true, >> + .has_clear_cmd = false, /* due to errata, CLEAR cmd is not working */ >> }; >> >> static struct at91_twi_pdata sam9x60_config = { >> @@ -142,6 +143,7 @@ static struct at91_twi_pdata sam9x60_config = { >> .has_dig_filtr = true, >> .has_adv_dig_filtr = true, >> .has_ana_filtr = true, >> + .has_clear_cmd = true, >> }; >> >> static const struct of_device_id atmel_twi_dt_ids[] = { >> diff --git a/drivers/i2c/busses/i2c-at91-master.c b/drivers/i2c/busses/i2c-at91-master.c >> index 0aba51a7df32..776e95962ab6 100644 >> --- a/drivers/i2c/busses/i2c-at91-master.c >> +++ b/drivers/i2c/busses/i2c-at91-master.c >> @@ -480,7 +480,6 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev) >> unsigned long time_left; >> bool has_unre_flag = dev->pdata->has_unre_flag; >> bool has_alt_cmd = dev->pdata->has_alt_cmd; >> - struct i2c_bus_recovery_info *rinfo = &dev->rinfo; >> >> /* >> * WARNING: the TXCOMP bit in the Status Register is NOT a clear on >> @@ -641,11 +640,12 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev) >> AT91_TWI_THRCLR | AT91_TWI_LOCKCLR); >> } >> >> - if (rinfo->get_sda && !(rinfo->get_sda(&dev->adapter))) { >> - dev_dbg(dev->dev, >> - "SDA is down; clear bus using gpio\n"); >> - i2c_recover_bus(&dev->adapter); >> - } >> + /* >> + * some faulty I2C slave devices might hold SDA down; >> + * we can send a bus clear command, hoping that the pins will be >> + * released >> + */ >> + i2c_recover_bus(&dev->adapter); >> >> return ret; >> } >> @@ -830,7 +830,7 @@ static void at91_unprepare_twi_recovery(struct i2c_adapter *adap) >> pinctrl_select_state(dev->pinctrl, dev->pinctrl_pins_default); >> } >> >> -static int at91_init_twi_recovery_info(struct platform_device *pdev, >> +static int at91_init_twi_recovery_gpio(struct platform_device *pdev, >> struct at91_twi_dev *dev) >> { >> struct i2c_bus_recovery_info *rinfo = &dev->rinfo; >> @@ -880,6 +880,41 @@ static int at91_init_twi_recovery_info(struct platform_device *pdev, >> return 0; >> } >> >> +static int at91_twi_recover_bus_cmd(struct i2c_adapter *adap) >> +{ >> + struct at91_twi_dev *dev = i2c_get_adapdata(adap); >> + >> + dev->transfer_status |= at91_twi_read(dev, AT91_TWI_SR); >> + if (!(dev->transfer_status & AT91_TWI_SDA)) { >> + dev_dbg(dev->dev, "SDA is down; sending bus clear command\n"); >> + if (dev->use_alt_cmd) { >> + unsigned int acr; >> + >> + acr = at91_twi_read(dev, AT91_TWI_ACR); >> + acr &= ~AT91_TWI_ACR_DATAL_MASK; >> + at91_twi_write(dev, AT91_TWI_ACR, acr); >> + } >> + at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_CLEAR); >> + } >> + >> + return 0; >> +} >> + >> +static int at91_init_twi_recovery_info(struct platform_device *pdev, >> + struct at91_twi_dev *dev) >> +{ >> + struct i2c_bus_recovery_info *rinfo = &dev->rinfo; >> + bool has_clear_cmd = dev->pdata->has_clear_cmd; >> + >> + if (!has_clear_cmd) >> + return at91_init_twi_recovery_gpio(pdev, dev); >> + >> + rinfo->recover_bus = at91_twi_recover_bus_cmd; >> + dev->adapter.bus_recovery_info = rinfo; >> + >> + return 0; >> +} >> + >> int at91_twi_probe_master(struct platform_device *pdev, >> u32 phy_addr, struct at91_twi_dev *dev) >> { >> diff --git a/drivers/i2c/busses/i2c-at91.h b/drivers/i2c/busses/i2c-at91.h >> index f57a6cab96b4..7e7b4955ca7f 100644 >> --- a/drivers/i2c/busses/i2c-at91.h >> +++ b/drivers/i2c/busses/i2c-at91.h >> @@ -36,6 +36,7 @@ >> #define AT91_TWI_SVDIS BIT(5) /* Slave Transfer Disable */ >> #define AT91_TWI_QUICK BIT(6) /* SMBus quick command */ >> #define AT91_TWI_SWRST BIT(7) /* Software Reset */ >> +#define AT91_TWI_CLEAR BIT(15) /* Bus clear command */ >> #define AT91_TWI_ACMEN BIT(16) /* Alternative Command Mode Enable */ >> #define AT91_TWI_ACMDIS BIT(17) /* Alternative Command Mode Disable */ >> #define AT91_TWI_THRCLR BIT(24) /* Transmit Holding Register Clear */ >> @@ -69,6 +70,8 @@ >> #define AT91_TWI_NACK BIT(8) /* Not Acknowledged */ >> #define AT91_TWI_EOSACC BIT(11) /* End Of Slave Access */ >> #define AT91_TWI_LOCK BIT(23) /* TWI Lock due to Frame Errors */ >> +#define AT91_TWI_SCL BIT(24) /* TWI SCL status */ >> +#define AT91_TWI_SDA BIT(25) /* TWI SDA status */ >> >> #define AT91_TWI_INT_MASK \ >> (AT91_TWI_TXCOMP | AT91_TWI_RXRDY | AT91_TWI_TXRDY | AT91_TWI_NACK \ >> @@ -81,7 +84,8 @@ >> #define AT91_TWI_THR 0x0034 /* Transmit Holding Register */ >> >> #define AT91_TWI_ACR 0x0040 /* Alternative Command Register */ >> -#define AT91_TWI_ACR_DATAL(len) ((len) & 0xff) >> +#define AT91_TWI_ACR_DATAL_MASK GENMASK(15, 0) >> +#define AT91_TWI_ACR_DATAL(len) ((len) & AT91_TWI_ACR_DATAL_MASK) >> #define AT91_TWI_ACR_DIR BIT(8) >> >> #define AT91_TWI_FILTR 0x0044 >> @@ -118,6 +122,7 @@ struct at91_twi_pdata { >> bool has_dig_filtr; >> bool has_adv_dig_filtr; >> bool has_ana_filtr; >> + bool has_clear_cmd; >> struct at_dma_slave dma_slave; >> }; >> >> >
On Tue, Feb 25, 2020 at 05:50:09PM +0200, Codrin Ciubotariu wrote: > After a transfer timeout, some faulty I2C slave devices might hold down > the SDA pin. We can generate a bus clear command, hoping that the slave > might release the pins. > If the CLEAR command is not supported, we will use gpio recovery, if > available, to reset the bus. > > Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com> Applied to for-next, thanks!
diff --git a/drivers/i2c/busses/i2c-at91-core.c b/drivers/i2c/busses/i2c-at91-core.c index 3da1a8acecb5..e14edd236108 100644 --- a/drivers/i2c/busses/i2c-at91-core.c +++ b/drivers/i2c/busses/i2c-at91-core.c @@ -131,6 +131,7 @@ static struct at91_twi_pdata sama5d2_config = { .has_dig_filtr = true, .has_adv_dig_filtr = true, .has_ana_filtr = true, + .has_clear_cmd = false, /* due to errata, CLEAR cmd is not working */ }; static struct at91_twi_pdata sam9x60_config = { @@ -142,6 +143,7 @@ static struct at91_twi_pdata sam9x60_config = { .has_dig_filtr = true, .has_adv_dig_filtr = true, .has_ana_filtr = true, + .has_clear_cmd = true, }; static const struct of_device_id atmel_twi_dt_ids[] = { diff --git a/drivers/i2c/busses/i2c-at91-master.c b/drivers/i2c/busses/i2c-at91-master.c index 0aba51a7df32..776e95962ab6 100644 --- a/drivers/i2c/busses/i2c-at91-master.c +++ b/drivers/i2c/busses/i2c-at91-master.c @@ -480,7 +480,6 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev) unsigned long time_left; bool has_unre_flag = dev->pdata->has_unre_flag; bool has_alt_cmd = dev->pdata->has_alt_cmd; - struct i2c_bus_recovery_info *rinfo = &dev->rinfo; /* * WARNING: the TXCOMP bit in the Status Register is NOT a clear on @@ -641,11 +640,12 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev) AT91_TWI_THRCLR | AT91_TWI_LOCKCLR); } - if (rinfo->get_sda && !(rinfo->get_sda(&dev->adapter))) { - dev_dbg(dev->dev, - "SDA is down; clear bus using gpio\n"); - i2c_recover_bus(&dev->adapter); - } + /* + * some faulty I2C slave devices might hold SDA down; + * we can send a bus clear command, hoping that the pins will be + * released + */ + i2c_recover_bus(&dev->adapter); return ret; } @@ -830,7 +830,7 @@ static void at91_unprepare_twi_recovery(struct i2c_adapter *adap) pinctrl_select_state(dev->pinctrl, dev->pinctrl_pins_default); } -static int at91_init_twi_recovery_info(struct platform_device *pdev, +static int at91_init_twi_recovery_gpio(struct platform_device *pdev, struct at91_twi_dev *dev) { struct i2c_bus_recovery_info *rinfo = &dev->rinfo; @@ -880,6 +880,41 @@ static int at91_init_twi_recovery_info(struct platform_device *pdev, return 0; } +static int at91_twi_recover_bus_cmd(struct i2c_adapter *adap) +{ + struct at91_twi_dev *dev = i2c_get_adapdata(adap); + + dev->transfer_status |= at91_twi_read(dev, AT91_TWI_SR); + if (!(dev->transfer_status & AT91_TWI_SDA)) { + dev_dbg(dev->dev, "SDA is down; sending bus clear command\n"); + if (dev->use_alt_cmd) { + unsigned int acr; + + acr = at91_twi_read(dev, AT91_TWI_ACR); + acr &= ~AT91_TWI_ACR_DATAL_MASK; + at91_twi_write(dev, AT91_TWI_ACR, acr); + } + at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_CLEAR); + } + + return 0; +} + +static int at91_init_twi_recovery_info(struct platform_device *pdev, + struct at91_twi_dev *dev) +{ + struct i2c_bus_recovery_info *rinfo = &dev->rinfo; + bool has_clear_cmd = dev->pdata->has_clear_cmd; + + if (!has_clear_cmd) + return at91_init_twi_recovery_gpio(pdev, dev); + + rinfo->recover_bus = at91_twi_recover_bus_cmd; + dev->adapter.bus_recovery_info = rinfo; + + return 0; +} + int at91_twi_probe_master(struct platform_device *pdev, u32 phy_addr, struct at91_twi_dev *dev) { diff --git a/drivers/i2c/busses/i2c-at91.h b/drivers/i2c/busses/i2c-at91.h index f57a6cab96b4..7e7b4955ca7f 100644 --- a/drivers/i2c/busses/i2c-at91.h +++ b/drivers/i2c/busses/i2c-at91.h @@ -36,6 +36,7 @@ #define AT91_TWI_SVDIS BIT(5) /* Slave Transfer Disable */ #define AT91_TWI_QUICK BIT(6) /* SMBus quick command */ #define AT91_TWI_SWRST BIT(7) /* Software Reset */ +#define AT91_TWI_CLEAR BIT(15) /* Bus clear command */ #define AT91_TWI_ACMEN BIT(16) /* Alternative Command Mode Enable */ #define AT91_TWI_ACMDIS BIT(17) /* Alternative Command Mode Disable */ #define AT91_TWI_THRCLR BIT(24) /* Transmit Holding Register Clear */ @@ -69,6 +70,8 @@ #define AT91_TWI_NACK BIT(8) /* Not Acknowledged */ #define AT91_TWI_EOSACC BIT(11) /* End Of Slave Access */ #define AT91_TWI_LOCK BIT(23) /* TWI Lock due to Frame Errors */ +#define AT91_TWI_SCL BIT(24) /* TWI SCL status */ +#define AT91_TWI_SDA BIT(25) /* TWI SDA status */ #define AT91_TWI_INT_MASK \ (AT91_TWI_TXCOMP | AT91_TWI_RXRDY | AT91_TWI_TXRDY | AT91_TWI_NACK \ @@ -81,7 +84,8 @@ #define AT91_TWI_THR 0x0034 /* Transmit Holding Register */ #define AT91_TWI_ACR 0x0040 /* Alternative Command Register */ -#define AT91_TWI_ACR_DATAL(len) ((len) & 0xff) +#define AT91_TWI_ACR_DATAL_MASK GENMASK(15, 0) +#define AT91_TWI_ACR_DATAL(len) ((len) & AT91_TWI_ACR_DATAL_MASK) #define AT91_TWI_ACR_DIR BIT(8) #define AT91_TWI_FILTR 0x0044 @@ -118,6 +122,7 @@ struct at91_twi_pdata { bool has_dig_filtr; bool has_adv_dig_filtr; bool has_ana_filtr; + bool has_clear_cmd; struct at_dma_slave dma_slave; };
After a transfer timeout, some faulty I2C slave devices might hold down the SDA pin. We can generate a bus clear command, hoping that the slave might release the pins. If the CLEAR command is not supported, we will use gpio recovery, if available, to reset the bus. Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com> --- Changes in v4: - moved the HW bus clear command in a recover_bus() function, to be able to just call i2c_recover_bus() if a transfer fails; - recovery gpios are no longer taken if HW bus clear command is supported; Changes in v3: - removed unnecessary condition from info print; - removed unneded declarations; Changes in v2: - called i2c_recover_bus() after an error occurs, if SDA is down; - release gpios if recovery information is incomplete; drivers/i2c/busses/i2c-at91-core.c | 2 ++ drivers/i2c/busses/i2c-at91-master.c | 49 ++++++++++++++++++++++++---- drivers/i2c/busses/i2c-at91.h | 7 +++- 3 files changed, 50 insertions(+), 8 deletions(-)