From mboxrd@z Thu Jan 1 00:00:00 1970 From: Troy Kisky Subject: [PATCH 2/5] I2C: DaVinci: clock between 7-12 Mhz Date: Thu, 20 Mar 2008 20:06:07 -0700 Message-ID: <1206068770-15458-3-git-send-email-troy.kisky@boundarydevices.com> References: <1206068770-15458-1-git-send-email-troy.kisky@boundarydevices.com> <1206068770-15458-2-git-send-email-troy.kisky@boundarydevices.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1206068770-15458-2-git-send-email-troy.kisky-Q5RJGjKts06CY9SHAMCTRUEOCMrvLtNR@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: i2c-bounces-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org Errors-To: i2c-bounces-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org To: i2c-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org Cc: Kevin Hilman List-Id: linux-i2c@vger.kernel.org Ensure psc value gives a clock between 7-12 Mhz Signed-off-by: Troy Kisky Signed-off-by: Kevin Hilman --- drivers/i2c/busses/i2c-davinci.c | 19 ++++++++++++------- 1 files changed, 12 insertions(+), 7 deletions(-) diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c index fde2634..82d4b7f 100755 --- 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 7mHz clock, but max of 12mHz */ + psc = (input_clock/7000000)-1; + if ((input_clock/(psc+1)) > 12000000) + psc++; + 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); @@ -338,12 +345,10 @@ i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) for (i = 0; i < num; i++) { ret = i2c_davinci_xfer_msg(adap, &msgs[i], (i == (num - 1))); + dev_dbg(dev->dev, "%s ret: %d\n", __func__, ret); if (ret < 0) return ret; } - - dev_dbg(dev->dev, "%s:%d ret: %d\n", __FUNCTION__, __LINE__, ret); - return num; } -- 1.5.4 _______________________________________________ i2c mailing list i2c-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org http://lists.lm-sensors.org/mailman/listinfo/i2c