Hi Vishwanath,
On Thu, Jul 22, 2010 at 14:25:45, Kamalapur, Vishwanath wrote:
> From: vishwa <[email protected]>
>
> With current implementation, when I2C is used as a module,
> for slave devices which operate at different frequencies,
> the bus frequency needs to be modified in the board
> configuration file and kernel needs to be re-built.
>
> This patch addresses this issue by adding bus frequency as
> module parameter.
>
> Signed-off-by: vishwa <[email protected]>
> ---
> drivers/i2c/busses/i2c-davinci.c | 11 +++++++++++
> 1 files changed, 11 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-davinci.c
> b/drivers/i2c/busses/i2c-davinci.c
> index 2222c87..ba0817c 100644
> --- a/drivers/i2c/busses/i2c-davinci.c
> +++ b/drivers/i2c/busses/i2c-davinci.c
> @@ -98,6 +98,13 @@
> #define DAVINCI_I2C_IMR_NACK BIT(1)
> #define DAVINCI_I2C_IMR_AL BIT(0)
>
> +/*
> + * Following are the default values for the module parameters
> + * If user didn't specify the bus frequency, driver will
> + * take the bus freq from board configuration.
> + */
No need of this comment, I think.
> +static int i2c_davinci_busfreq;
> +
> struct davinci_i2c_dev {
> struct device *dev;
> void __iomem *base;
> @@ -217,6 +224,9 @@ static void i2c_davinci_calc_clk_dividers(struct
> davinci_i2c_dev *dev)
> psc++; /* better to run under spec than over */
> d = (psc >= 2) ? 5 : 7 - psc;
>
> + if (i2c_davinci_busfreq != 0)
> + pdata->bus_freq = i2c_davinci_busfreq;
> +
This is rather done in davinci_i2c_init() right after the pdata is sanitized.
> clk = ((input_clock / (psc + 1)) / (pdata->bus_freq * 1000)) - (d << 1);
> clkh = clk >> 1;
> clkl = clk - clkh;
> @@ -818,6 +828,7 @@ static void __exit davinci_i2c_exit_driver(void)
> platform_driver_unregister(&davinci_i2c_driver);
> }
> module_exit(davinci_i2c_exit_driver);
> +module_param(i2c_davinci_busfreq, int, 0);
Module parameters are usually defined at the beginning
of the file. Please add a MODULE_PARM_DESC() as well.
You can check drivers/mmc/host/davinci_mmc.c for an example.
Once done, please submit to I2C subsystem list and CC the I2C
maintainers and this list.
Thanks,
Sekhar
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