On Tue, Mar 31, 2009 at 6:37 AM, Wolfgang Grandegger <w...@grandegger.com>
wrote:
> This patch makes the I2C bus speed configurable by using the I2C node
> property "clock-frequency". If the property is not defined, the old
> fixed clock settings will be used for backward comptibility.
>
> The generic I2C clock properties, especially the CPU-specific source
> clock pre-scaler are defined via the OF match table:
>
> static const struct of_device_id mpc_i2c_of_match[] = {
> {.compatible = "fsl,mpc5200b-i2c",
> .data = (void *)FSL_I2C_DEV_CLOCK_5200, },
> {.compatible = "fsl,mpc5200-i2c",
> .data = (void *)FSL_I2C_DEV_CLOCK_5200, },
> {.compatible = "fsl,mpc8313-i2c",
> .data = (void *)FSL_I2C_DEV_SEPARATE_DFSRR, },
> {.compatible = "fsl,mpc8543-i2c",
> .data = (void *)(FSL_I2C_DEV_SEPARATE_DFSRR |
> FSL_I2C_DEV_CLOCK_DIV2), },
> {.compatible = "fsl,mpc8544-i2c",
> .data = (void *)(FSL_I2C_DEV_SEPARATE_DFSRR |
> FSL_I2C_DEV_CLOCK_DIV23), },
> /* Backward compatibility */
> {.compatible = "fsl-i2c", },
> {},
> };
Instead passing in a flag (and using an ugly cast to do it) which is
then checked inside the mpc_i2c_setclock(), you should do this
instead:
struct fsl_i2c_match_data {
int static void *(setclock)(struct device_node *node, struct
mpc_i2c *i2c, u32 clock);
int flags;
/* Other stuff can go here */
};
static const struct of_device_id mpc_i2c_of_match[] = {
{.compatible = "fsl,mpc5200b-i2c",
.data = (struct fsl_i2c_match_data[]) { .setclock =
mpc_i2c_setclock_mpc5200, },
},
{.compatible = "fsl,mpc5200-i2c",
.data = (struct fsl_i2c_match_data[]) { .setclock =
mpc_i2c_setclock_mpc5200, },
},
{.compatible = "fsl,mpc8313-i2c",
.data = (struct fsl_i2c_match_data[]) { .setclock =
mpc_i2c_setclock_separate_dfsrr, },
},
{.compatible = "fsl,mpc8543-i2c",
.data = (struct fsl_i2c_match_data[]) { .setclock =
mpc_i2c_setclock_separate_dfsrr, },
.flags = FSL_I2C_DEV_CLOCK_DIV2,
},
{.compatible = "fsl,mpc8544-i2c",
.data = (struct fsl_i2c_match_data[]) { .setclock =
mpc_i2c_setclock_separate_dfsrr, },
.flags = FSL_I2C_DEV_CLOCK_DIV23,
},
/* Backward compatibility */
{.compatible = "fsl-i2c",
.data = (struct fsl_i2c_match_data[]) { .setclock =
mpc_i2c_setclock, },
},
{},
};
The table definition is more verbose this way, but I think it results
in more understandable and easier to extend code. It also adds lets
the compiler do more type checking for you.
Also, this ...
> --- linux-2.6.orig/arch/powerpc/sysdev/fsl_soc.c 2009-03-31
> 13:25:08.000000000 +0200
> +++ linux-2.6/arch/powerpc/sysdev/fsl_soc.c 2009-03-31 13:34:40.531721011
> +0200
> +int fsl_i2c_get_fdr(struct device_node *node, u32 i2c_clock, u32 i2c_flags)
> +{
> [...]
> +}
> +EXPORT_SYMBOL(fsl_i2c_get_fdr);
... and this ...
> --- linux-2.6.orig/arch/powerpc/platforms/52xx/mpc52xx_common.c 2009-03-31
> 13:25:08.000000000 +0200
> +++ linux-2.6/arch/powerpc/platforms/52xx/mpc52xx_common.c 2009-03-31
> 13:28:54.309718526 +0200
> +int fsl_i2c_get_fdr(struct device_node *node, u32 i2c_clock, u32 i2c_flags)
> +{
> [...]
> +}
> +EXPORT_SYMBOL(fsl_i2c_get_fdr);
does not work on a multiplatform kernel. Both 8xxx and 52xx support
can be selected at the same time.
g.
--
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.
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