adapt the DIU clock initialization to the COMMON_CLK approach:
device tree based clock lookup, prepare and unprepare for clocks,
work with frequencies not dividers, call the appropriate clk_*()
routines and don't access CCM registers
the "best clock" determination now completely relies on the
platform's clock driver to pick a frequency close to what the
caller requests, and merely checks whether the desired frequency
was met (fits the tolerance of the monitor)
this approach shall succeed upon first try in the usual case,
will test a few less desirable yet acceptable frequencies in
edge cases, and will fallback to "best effort" if none of the
previously tried frequencies pass the test
provide a fallback clock lookup approach in case the OF based clock
lookup for the DIU fails, this allows for successful operation in
the presence of an outdated device tree which lacks clock specs
Cc: Anatolij Gustschin
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Gerhard Sittig
---
arch/powerpc/platforms/512x/mpc512x_shared.c | 169 ++
1 file changed, 92 insertions(+), 77 deletions(-)
diff --git a/arch/powerpc/platforms/512x/mpc512x_shared.c
b/arch/powerpc/platforms/512x/mpc512x_shared.c
index 36b5652aada2..adb95f03d4d4 100644
--- a/arch/powerpc/platforms/512x/mpc512x_shared.c
+++ b/arch/powerpc/platforms/512x/mpc512x_shared.c
@@ -12,6 +12,7 @@
* (at your option) any later version.
*/
+#include
#include
#include
#include
@@ -68,98 +69,112 @@ struct fsl_diu_shared_fb {
boolin_use;
};
-#define DIU_DIV_MASK 0x00ff
+/* receives a pixel clock spec in pico seconds, adjusts the DIU clock rate */
static void mpc512x_set_pixel_clock(unsigned int pixclock)
{
- unsigned long bestval, bestfreq, speed, busfreq;
- unsigned long minpixclock, maxpixclock, pixval;
- struct mpc512x_ccm __iomem *ccm;
struct device_node *np;
- u32 temp;
- long err;
- int i;
+ struct clk *clk_diu;
+ unsigned long epsilon, minpixclock, maxpixclock;
+ unsigned long offset, want, got, delta;
- np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121-clock");
+ /* lookup and enable the DIU clock */
+ np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121-diu");
if (!np) {
- pr_err("Can't find clock control module.\n");
+ pr_err("Could not find DIU device tree node.\n");
return;
}
-
- ccm = of_iomap(np, 0);
+ clk_diu = of_clk_get(np, 0);
+ if (IS_ERR(clk_diu)) {
+ /* backwards compat with device trees that lack clock specs */
+ clk_diu = clk_get_sys(np->name, "ipg");
+ }
of_node_put(np);
- if (!ccm) {
- pr_err("Can't map clock control module reg.\n");
+ if (IS_ERR(clk_diu)) {
+ pr_err("Could not lookup DIU clock.\n");
return;
}
-
- np = of_find_node_by_type(NULL, "cpu");
- if (np) {
- const unsigned int *prop =
- of_get_property(np, "bus-frequency", NULL);
-
- of_node_put(np);
- if (prop) {
- busfreq = *prop;
- } else {
- pr_err("Can't get bus-frequency property\n");
- return;
- }
- } else {
- pr_err("Can't find 'cpu' node.\n");
+ if (clk_prepare_enable(clk_diu)) {
+ pr_err("Could not enable DIU clock.\n");
return;
}
- /* Pixel Clock configuration */
- pr_debug("DIU: Bus Frequency = %lu\n", busfreq);
- speed = busfreq * 4; /* DIU_DIV ratio is 4 * CSB_CLK / DIU_CLK */
-
- /* Calculate the pixel clock with the smallest error */
- /* calculate the following in steps to avoid overflow */
- pr_debug("DIU pixclock in ps - %d\n", pixclock);
- temp = (10 / pixclock) * 1000;
- pixclock = temp;
- pr_debug("DIU pixclock freq - %u\n", pixclock);
-
- temp = temp / 20; /* pixclock * 0.05 */
- pr_debug("deviation = %d\n", temp);
- minpixclock = pixclock - temp;
- maxpixclock = pixclock + temp;
- pr_debug("DIU minpixclock - %lu\n", minpixclock);
- pr_debug("DIU maxpixclock - %lu\n", maxpixclock);
- pixval = speed/pixclock;
- pr_debug("DIU pixval = %lu\n", pixval);
-
- err = LONG_MAX;
- bestval = pixval;
- pr_debug("DIU bestval = %lu\n", bestval);
-
- bestfreq = 0;
- for (i = -1; i <= 1; i++) {
- temp = speed / (pixval+i);
- pr_debug("DIU test pixval i=%d, pixval=%lu, temp freq. = %u\n",
- i, pixval, temp);
- if ((temp < minpixclock) || (temp > maxpixclock))
- pr_debug("DIU exceeds monitor range (%lu to %lu)\n",
- minpixclock, maxpixclock);
- else if
