[PATCH v2] powerpc: i2c-mpc: make I2C bus speed configurable

[Grant Likely]

On Wed, Apr 1, 2009 at 7:44 AM, Grant Likely <grant.likely at secretlab.ca> wrote:
> On Wed, Apr 1, 2009 at 7:13 AM, Wolfgang Grandegger <wg at 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 compatibility.
>
> I mostly like this patch.  However, as I mentioned in my other reply,
> I'm going to NAK it because the divisor tables are not common code and
> do not belong in common code files.
>
> Other than that, I like this version of the patch and I think it is
> almost finished.  More comments below.

Oh, and you should look in MAINTAINERS and cc this patch to Ben Dooks
and the linux-i2c at vger.kernel.org mailing list.

g.

>
>> -static void mpc_i2c_setclock(struct mpc_i2c *i2c)
>> -{
>> -       /* Set clock and filters */
>> -       if (i2c->flags & FSL_I2C_DEV_SEPARATE_DFSRR) {
>> -               writeb(0x31, i2c->base + MPC_I2C_FDR);
>> -               writeb(0x10, i2c->base + MPC_I2C_DFSRR);
>> -       } else if (i2c->flags & FSL_I2C_DEV_CLOCK_5200)
>> -               writeb(0x3f, i2c->base + MPC_I2C_FDR);
>> -       else
>> -               writel(0x1031, i2c->base + MPC_I2C_FDR);
>> +static void mpc_i2c_setclock_52xx(struct device_node *node,
>> +                                 struct mpc_i2c *i2c,
>> +                                 u32 clock, u32 prescaler)
>> +{
>> +       int fdr = mpc52xx_i2c_get_fdr(node, clock, prescaler);
>> +
>> +       if (fdr < 0)
>> +               fdr = 0x3f; /* backward compatibility */
>> +       writeb(fdr & 0xff, i2c->base + MPC_I2C_FDR);
>> +       dev_info(i2c->dev, "clock %d Hz (fdr=%d)\n", clock, fdr);
>> +}
>> +
>> +static void mpc_i2c_setclock_8xxx(struct device_node *node,
>> +                                 struct mpc_i2c *i2c,
>> +                                 u32 clock, u32 prescaler)
>> +{
>> +       int fdr = fsl_i2c_get_fdr(node, clock, prescaler);
>> +
>> +       if (fdr < 0)
>> +               fdr = 0x1031; /* backward compatibility */
>> +       writeb(fdr & 0xff, i2c->base + MPC_I2C_FDR);
>> +       writeb((fdr >> 8) & 0xff, i2c->base + MPC_I2C_DFSRR);
>> +       dev_info(i2c->dev, "clock %d Hz (dfsrr=%d fdr=%d)\n",
>> +                clock, fdr >> 8, fdr & 0xff);
>>  }
>
> Very neat and tidy indeed.  I like this.
>
>> Index: linux-2.6/arch/powerpc/sysdev/fsl_soc.c
>> ===================================================================
>> --- linux-2.6.orig/arch/powerpc/sysdev/fsl_soc.c        2009-03-31 21:27:52.000000000 +0200
>> +++ linux-2.6/arch/powerpc/sysdev/fsl_soc.c     2009-04-01 12:09:18.796719327 +0200
>> @@ -39,7 +39,7 @@
>>  #include <sysdev/fsl_soc.h>
>>  #include <mm/mmu_decl.h>
>>  #include <asm/cpm2.h>
>> -
>> +#define DEBUG
>  ^^^^^^^^^^^^^^^^^^^^^^^  oops?
>
> g.
>
> --
> Grant Likely, B.Sc., P.Eng.
> Secret Lab Technologies Ltd.
>



-- 
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.