[PATCH v2] davinci: I2C: Adding bus frequency as module parameter

[PATCH v2] davinci: I2C: Adding bus frequency as module parameter

[vishwa]

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 <vishwanath.k-l0cyMroinI0@public.gmane.org>
---
Since v1:
a. added MODULE_PARAM_DESC.
b. Moved module parameter definitions to the beginning of the file.
c. 'pdata->bus_freq' is being set in i2c_davinci_init() function.

 drivers/i2c/busses/i2c-davinci.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index 2222c87..8fbfaa2 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -98,6 +98,10 @@
 #define DAVINCI_I2C_IMR_NACK	BIT(1)
 #define DAVINCI_I2C_IMR_AL	BIT(0)
 
+static int i2c_davinci_busfreq;
+module_param(i2c_davinci_busfreq, int, 0);
+MODULE_PARM_DESC(i2c_davinci_busfreq, "bus frequency");
+
 struct davinci_i2c_dev {
 	struct device           *dev;
 	void __iomem		*base;
@@ -243,6 +247,9 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev)
 	/* put I2C into reset */
 	davinci_i2c_reset_ctrl(dev, 0);
 
+	if (i2c_davinci_busfreq != 0)
+		pdata->bus_freq = i2c_davinci_busfreq;
+
 	/* compute clock dividers */
 	i2c_davinci_calc_clk_dividers(dev);
 
-- 
1.5.6

Re: [PATCH v2] davinci: I2C: Adding bus frequency as module parameter

[Kevin Hilman]

vishwa <vishwanath.k-l0cyMroinI0@public.gmane.org> writes:

> 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 <vishwanath.k-l0cyMroinI0@public.gmane.org>
> ---
> Since v1:
> a. added MODULE_PARAM_DESC.
> b. Moved module parameter definitions to the beginning of the file.
> c. 'pdata->bus_freq' is being set in i2c_davinci_init() function.
>
>  drivers/i2c/busses/i2c-davinci.c |    7 +++++++
>  1 files changed, 7 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
> index 2222c87..8fbfaa2 100644
> --- a/drivers/i2c/busses/i2c-davinci.c
> +++ b/drivers/i2c/busses/i2c-davinci.c
> @@ -98,6 +98,10 @@
>  #define DAVINCI_I2C_IMR_NACK	BIT(1)
>  #define DAVINCI_I2C_IMR_AL	BIT(0)
>  
> +static int i2c_davinci_busfreq;
> +module_param(i2c_davinci_busfreq, int, 0);
> +MODULE_PARM_DESC(i2c_davinci_busfreq, "bus frequency");
> +
>  struct davinci_i2c_dev {
>  	struct device           *dev;
>  	void __iomem		*base;
> @@ -243,6 +247,9 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev)
>  	/* put I2C into reset */
>  	davinci_i2c_reset_ctrl(dev, 0);
>  
> +	if (i2c_davinci_busfreq != 0)
> +		pdata->bus_freq = i2c_davinci_busfreq;

I don't really like using a module parameter to modify the contents of
struct platform_data, especially when this comes from a board file.

Intead this should look something like

	if (!i2c_davinci_busfreq)
		i2c_davinci_bus_freq = pdata->bus_freq;

and the code should use i2c_davinci_busfreq instead of pdata->bus_freq.

Kevin