| Message ID | 1430516629-32692-1-git-send-email-linux_wi@tinag.ch |
|---|---|
| State | Not Applicable |
| Headers | show |
On Sat, May 2, 2015 at 3:13 AM, Silvan Wicki <linux_wi@tinag.ch> wrote: > Prevents that cdiv can be an uneven number as per datasheet cdiv is > always rounded down to an even number. > > Datasheet at page 34 on > http://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf > > Signed-off-by: Silvan Wicki <linux_wi@tinag.ch> > --- Reviewed-by: Rajeev Kumar <rajeevkumar.linux@gmail.com> > drivers/i2c/busses/i2c-bcm2708.c | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-bcm2708.c b/drivers/i2c/busses/i2c-bcm2708.c > index 81e9374..dd7094a 100644 > --- a/drivers/i2c/busses/i2c-bcm2708.c > +++ b/drivers/i2c/busses/i2c-bcm2708.c > @@ -67,6 +67,9 @@ > #define BSC_S_DONE 0x00000002 > #define BSC_S_TA 0x00000001 > > +#define BSC_CDIV_MAX 0xFFFE > +#define BSC_CDIV_BITMASK 0xEFFF > + > #define I2C_TIMEOUT_MS 150 > #define I2C_WAIT_LOOP_COUNT 40 > > @@ -441,9 +444,15 @@ static int bcm2708_i2c_probe(struct platform_device *pdev) > > bus_hz = clk_get_rate(bi->clk); > cdiv = bus_hz / baudrate; > - if (cdiv > 0xffff) { > - cdiv = 0xffff; > + /* as per datasheet cdiv is always rounded down to an even number */ > + if (cdiv > BSC_CDIV_MAX) { > + cdiv = BSC_CDIV_MAX; > baudrate = bus_hz / cdiv; > + } else { > + if ((cdiv & BSC_CDIV_BITMASK) != cdiv) { > + cdiv &= BSC_CDIV_BITMASK; > + baudrate = bus_hz / cdiv; > + } > } > bi->cdiv = cdiv; > > -- > 2.1.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-i2c" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, May 04, 2015 at 10:20:42AM +0530, rajeev kumar wrote: > On Sat, May 2, 2015 at 3:13 AM, Silvan Wicki <linux_wi@tinag.ch> wrote: > > Prevents that cdiv can be an uneven number as per datasheet cdiv is > > always rounded down to an even number. > > > > Datasheet at page 34 on > > http://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf > > > > Signed-off-by: Silvan Wicki <linux_wi@tinag.ch> > > --- > Reviewed-by: Rajeev Kumar <rajeevkumar.linux@gmail.com> > > > drivers/i2c/busses/i2c-bcm2708.c | 13 +++++++++++-- > > 1 file changed, 11 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/i2c/busses/i2c-bcm2708.c b/drivers/i2c/busses/i2c-bcm2708.c > > index 81e9374..dd7094a 100644 > > --- a/drivers/i2c/busses/i2c-bcm2708.c > > +++ b/drivers/i2c/busses/i2c-bcm2708.c > > @@ -67,6 +67,9 @@ > > #define BSC_S_DONE 0x00000002 > > #define BSC_S_TA 0x00000001 > > > > +#define BSC_CDIV_MAX 0xFFFE > > +#define BSC_CDIV_BITMASK 0xEFFF BSC_CDIV_BITMASK needs to be 0xFFFE; please don't change > > + > > #define I2C_TIMEOUT_MS 150 > > #define I2C_WAIT_LOOP_COUNT 40 > > > > @@ -441,9 +444,15 @@ static int bcm2708_i2c_probe(struct platform_device *pdev) > > > > bus_hz = clk_get_rate(bi->clk); > > cdiv = bus_hz / baudrate; > > - if (cdiv > 0xffff) { > > - cdiv = 0xffff; > > + /* as per datasheet cdiv is always rounded down to an even number */ > > + if (cdiv > BSC_CDIV_MAX) { > > + cdiv = BSC_CDIV_MAX; > > baudrate = bus_hz / cdiv; > > + } else { > > + if ((cdiv & BSC_CDIV_BITMASK) != cdiv) { > > + cdiv &= BSC_CDIV_BITMASK; > > + baudrate = bus_hz / cdiv; > > + } > > } > > bi->cdiv = cdiv; > > > > -- > > 2.1.4 > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-i2c" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, May 01, 2015 at 11:43:49PM +0200, Silvan Wicki wrote: > Prevents that cdiv can be an uneven number as per datasheet cdiv is > always rounded down to an even number. > > Datasheet at page 34 on > http://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf > > Signed-off-by: Silvan Wicki <linux_wi@tinag.ch> > --- > drivers/i2c/busses/i2c-bcm2708.c | 13 +++++++++++-- Which kernel are you using? We don't have such a driver in upstream.
diff --git a/drivers/i2c/busses/i2c-bcm2708.c b/drivers/i2c/busses/i2c-bcm2708.c index 81e9374..dd7094a 100644 --- a/drivers/i2c/busses/i2c-bcm2708.c +++ b/drivers/i2c/busses/i2c-bcm2708.c @@ -67,6 +67,9 @@ #define BSC_S_DONE 0x00000002 #define BSC_S_TA 0x00000001 +#define BSC_CDIV_MAX 0xFFFE +#define BSC_CDIV_BITMASK 0xFFFE + #define I2C_TIMEOUT_MS 150 #define I2C_WAIT_LOOP_COUNT 40 @@ -441,9 +444,15 @@ static int bcm2708_i2c_probe(struct platform_device *pdev) bus_hz = clk_get_rate(bi->clk); cdiv = bus_hz / baudrate; - if (cdiv > 0xffff) { - cdiv = 0xffff; + /* as per datasheet cdiv is always rounded down to an even number */ + if (cdiv > BSC_CDIV_MAX) { + cdiv = BSC_CDIV_MAX; baudrate = bus_hz / cdiv; + } else { + if ((cdiv & BSC_CDIV_BITMASK) != cdiv) { + cdiv &= BSC_CDIV_BITMASK; + baudrate = bus_hz / cdiv; + } } bi->cdiv = cdiv;
Prevents that cdiv can be an uneven number as per datasheet cdiv is always rounded down to an even number. Datasheet at page 34 on http://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf Signed-off-by: Silvan Wicki <linux_wi@tinag.ch> --- drivers/i2c/busses/i2c-bcm2708.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)