On Wed, Sep 12, 2012 at 08:39:51PM -0700, Guenter Roeck wrote: > From: Thomas Kavanagh <[email protected]> > > As implemented, the code always selects turbo mode for PCA9665, no matter > which > clock frequency is configured. This is because it compares clock boundaries > against constants reflecting (boundary / 100), but uses the actual clock > frequency > to compare against. To fix the problem, use a variable reflecting (clock / > 100), > not the actual clock frequency, when comparing against (boundary / 100).
Good point, however... > > Cc: Wolfram Sang <[email protected]> > Signed-off-by: Thomas Kavanagh <[email protected]> > Signed-off-by: Guenter Roeck <[email protected]> > --- > drivers/i2c/algos/i2c-algo-pca.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/i2c/algos/i2c-algo-pca.c > b/drivers/i2c/algos/i2c-algo-pca.c > index 07ccbef..572251b 100644 > --- a/drivers/i2c/algos/i2c-algo-pca.c > +++ b/drivers/i2c/algos/i2c-algo-pca.c > @@ -477,17 +477,17 @@ static int pca_init(struct i2c_adapter *adap) > /* To avoid integer overflow, use clock/100 for calculations */ > clock = pca_clock(pca_data) / 100; > > - if (pca_data->i2c_clock > 10000) { > + if (clock > 10000) { ... we should make the code more readable if we are at it. I'd suggest to drop the "/ 100" from above and move it below this if-block. This will allow for much more readable comparisons, e.g. "clock > 1000000" etc which is really the clock in Hz. > mode = I2C_PCA_MODE_TURBO; > min_tlow = 14; > min_thi = 5; > raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */ > - } else if (pca_data->i2c_clock > 4000) { > + } else if (clock > 4000) { > mode = I2C_PCA_MODE_FASTP; > min_tlow = 17; > min_thi = 9; > raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */ > - } else if (pca_data->i2c_clock > 1000) { > + } else if (clock > 1000) { > mode = I2C_PCA_MODE_FAST; > min_tlow = 44; > min_thi = 20; > -- > 1.7.9.7 > -- Pengutronix e.K. | Wolfram Sang | Industrial Linux Solutions | http://www.pengutronix.de/ |
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