On 25/05/07 09:34 -0700, David Brownell wrote:
> On Friday 25 May 2007, Domen Puncer wrote:
>
> > For clk.h, it does seem quite some code, compared what's there currently.
>
> You're using it wrong then ...
I meant this + the clock.c part.
>
>
> > --- work-powerpc.git.orig/drivers/spi/mpc52xx_psc_spi.c
> > +++ work-powerpc.git/drivers/spi/mpc52xx_psc_spi.c
> > @@ -18,6 +18,7 @@
> >
> > #if defined(CONFIG_PPC_MERGE)
> > #include <asm/of_platform.h>
> > +#include <linux/clk.h>
> > #else
> > #include <linux/platform_device.h>
> > #endif
> > @@ -106,13 +107,52 @@ static void mpc52xx_psc_spi_activate_cs(
> > /* Set clock frequency and bits per word
> > * Because psc->ccr is defined as 16bit register instead of 32bit
> > * just set the lower byte of BitClkDiv
> > + * Because BitClkDiv is 8-bit on mpc5200. Lets stay compatible.
> > */
> > +#if defined(CONFIG_PPC_MERGE)
> > ccr = in_be16(&psc->ccr);
> > ccr &= 0xFF00;
> > + {
> > + u8 bitclkdiv = 2; /* minimum bitclkdiv */
> > + int speed = cs->speed_hz ? cs->speed_hz : 1000000;
> > + char clk_name[10];
> > + struct clk *clk; // TODO into mps, clk_get, clk_put
> > + int mclk;
> > + int system;
> > + /*
> > + * pscclk = mclk/(bitclkdiv+1)) bitclkdiv is 8-bit, >= 2
> > + * mclk = fsys/(mclkdiv+1) mclkdiv is 9-bit, >= 1
> > + * as mclkdiv has higher precision, we want is as big as
> > possible
> > + * => we get < 0.002*clock error
> > + */
> > +
> > + snprintf(clk_name, 10, "psc%i_mclk", spi->master->bus_num);
> > +
> > + clk = clk_get(&spi->dev, clk_name);
>
> Don't expect spi->dev to have a clock. Instead, the host controller
> has a clock, which would be looked up the probe() routine, then released
> in remove(): clock = clk_get(dev, "clockname"), with the clock framework
> using "dev" to identify which clock it returns. (That is, the function
> clock for all SPI controllers would have the same name ... not for
> example "spi1_fclk", "spi2_fclk", etc. but instead "spi_fclk".)
Aha, so that's what struct dev* is for. :-)
Now I see two options:
- create something like at91_clock_associate(), and call it from
_probe (of_devices are created automatically from device tree,
so we can't call it the way at91_clock_associate is).
- in clk_get() call dev_get_drvdata(dev), cast it to spi_master *,
_hope_ it really is that, use bus_id.
Sure there must be a third, right one?
Domen
>
>
> > + if (!clk)
> > + dev_err(&spi->dev, "couldn't get %s clock\n", clk_name);
> > +
> > + system = clk_get_rate(clk_get_parent(clk)); // TODO,
> > checking, refcounting
> > + mclk = speed * (bitclkdiv+1);
> > + if (system/mclk > 512) { /* bigger than mclkdiv */
> > + bitclkdiv = system/512/speed;
> > + mclk = speed * (bitclkdiv+1);
> > + }
> > +
> > + if (clk_set_rate(clk, mclk))
> > + dev_err(&spi->dev, "couldn't set %s's rate\n",
> > clk_name);
> > +
> > + dev_info(&spi->dev, "clock: wanted: %i, got: %li\n", speed,
> > + clk_round_rate(clk, mclk) / (bitclkdiv+1));
> > +
> > + ccr |= bitclkdiv;
> > + }
> > +#else
> > if (cs->speed_hz)
> > ccr |= (MCLK / cs->speed_hz - 1) & 0xFF;
> > else /* by default SPI Clk 1MHz */
> > ccr |= (MCLK / 1000000 - 1) & 0xFF;
> > +#endif
> > out_be16(&psc->ccr, ccr);
> > mps->bits_per_word = cs->bits_per_word;
> >
> \
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