diff options
| author | Troy Kisky <troy.kisky@boundarydevices.com> | 2008-07-14 22:38:20 +0200 |
|---|---|---|
| committer | Jean Delvare <khali@mahadeva.delvare> | 2008-07-14 22:38:20 +0200 |
| commit | cc99ff70c7ad36e01db545a81a8594474964f918 (patch) | |
| tree | fb3c06bf63b6093078ca37a2c64439feedf70a47 | |
| parent | 7f101a97866e2687a455ecffeb96bcf317c8482a (diff) | |
i2c-davinci: Ensure clock between 7-12 MHz
Ensure psc value gives a clock between 7-12 MHz
Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
Signed-off-by: Kevin Hilman <khilman@mvista.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
| -rw-r--r-- | drivers/i2c/busses/i2c-davinci.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c index 7ecbfc429b19..7fdbca17d4a8 100644 --- a/drivers/i2c/busses/i2c-davinci.c +++ b/drivers/i2c/busses/i2c-davinci.c @@ -142,6 +142,7 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev) struct davinci_i2c_platform_data *pdata = dev->dev->platform_data; u16 psc; u32 clk; + u32 d; u32 clkh; u32 clkl; u32 input_clock = clk_get_rate(dev->clk); @@ -171,23 +172,29 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev) * if PSC > 1 , d = 5 */ - psc = 26; /* To get 1MHz clock */ + /* get minimum of 7 MHz clock, but max of 12 MHz */ + psc = (input_clock / 7000000) - 1; + if ((input_clock / (psc + 1)) > 12000000) + psc++; /* better to run under spec than over */ + d = (psc >= 2) ? 5 : 7 - psc; - clk = ((input_clock / (psc + 1)) / (pdata->bus_freq * 1000)) - 10; - clkh = (50 * clk) / 100; + clk = ((input_clock / (psc + 1)) / (pdata->bus_freq * 1000)) - (d << 1); + clkh = clk >> 1; clkl = clk - clkh; davinci_i2c_write_reg(dev, DAVINCI_I2C_PSC_REG, psc); davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKH_REG, clkh); davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKL_REG, clkl); - dev_dbg(dev->dev, "CLK = %d\n", clk); + dev_dbg(dev->dev, "input_clock = %d, CLK = %d\n", input_clock, clk); dev_dbg(dev->dev, "PSC = %d\n", davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG)); dev_dbg(dev->dev, "CLKL = %d\n", davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKL_REG)); dev_dbg(dev->dev, "CLKH = %d\n", davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKH_REG)); + dev_dbg(dev->dev, "bus_freq = %dkHz, bus_delay = %d\n", + pdata->bus_freq, pdata->bus_delay); /* Take the I2C module out of reset: */ w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG); |