On Sat, Apr 23, 2011 at 01:31:35PM -0400, Michael Williamson wrote:
> The davinci-i2c bus driver currently supports being probed with a NULL
> platform_data structure by using a default configuration when none is
> provided. However, the i2c_davinci_calc_clk_dividers does not
> check the provided platform_data for NULL prior to using it, so
> the support is incomplete.
>
> Rather than have each runtime call check for NULL and avoid future
> problems, copy a pointer to the default data to the device structure
> during the probe. This should be OK, as the information in this
> structure is not modified by the driver.
>
> Tested on a MityDSP-L138 module (OMAP-L138 based SOM).
>
> Signed-off-by: Micahel Williamson <michael.williamson@xxxxxxxxxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-davinci.c | 12 +++++-------
> 1 files changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
> index 5795c83..1db8fc9 100644
> --- a/drivers/i2c/busses/i2c-davinci.c
> +++ b/drivers/i2c/busses/i2c-davinci.c
> @@ -163,8 +163,7 @@ static void i2c_recover_bus(struct davinci_i2c_dev *dev)
> flag |= DAVINCI_I2C_MDR_NACK;
> /* write the data into mode register */
> davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
> - if (pdata)
> - generic_i2c_clock_pulse(pdata->scl_pin);
> + generic_i2c_clock_pulse(pdata->scl_pin);
This looks like a change in the behaviour of the code, since if there was
no pdata supplied we now can try generic_i2c_clock_pulse() with what is
probably gpio pin 0.
> /* Send STOP */
> flag = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
> flag |= DAVINCI_I2C_MDR_STP;
> @@ -235,10 +234,11 @@ static void i2c_davinci_calc_clk_dividers(struct davinci_i2c_dev *dev)
> */
> static int i2c_davinci_init(struct davinci_i2c_dev *dev)
> {
> - struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
> + struct davinci_i2c_platform_data *pdata;
>
> - if (!pdata)
> - pdata = &davinci_i2c_platform_data_default;
> + if (!dev->dev->platform_data)
> + dev->dev->platform_data = &davinci_i2c_platform_data_default;
> + pdata = dev->dev->platform_data;
Hmm, not going to work well if the driver is a module, as you'll unload
the module, leave the default pointer in and then re-load later at a
possibly different address with the old pointer in.
> /* put I2C into reset */
> davinci_i2c_reset_ctrl(dev, 0);
> @@ -313,8 +313,6 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
> u16 w;
> int r;
>
> - if (!pdata)
> - pdata = &davinci_i2c_platform_data_default;
> /* Introduce a delay, required for some boards (e.g Davinci EVM) */
> if (pdata->bus_delay)
> udelay(pdata->bus_delay);
> --
> 1.7.0.4
>
> --
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--
Ben Dooks, ben@xxxxxxxxx, http://www.fluff.org/ben/
Large Hadron Colada: A large Pina Colada that makes the universe disappear.
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