commit 810a4e47c09033036abdd4889ad4660be6665fb9
author Allen Martin <amartin@nvidia.com> Fri May 10 16:56:55 2013 +0000
committer Tom Warren <twarren@nvidia.com> Tue May 28 12:58:42 2013 -0700
tree 4039cb357b0258f13e5a5fa3249a5aec629ade4e
parent cecd8571dc52023365dd62c9b00e8228c581caf5

Tegra: clk: always use find_best_divider() for periph clocks

When adjusting peripheral clocks always use find_best_divider()
instead of clk_get_divider() even when a secondary divider is not
available.  In the case where is requested clock is too slow to be
derived from the parent clock this allows a best effort to get close
to the requested clock.

This comes up for commands like "sf" where the user can pass a clock
speed on the command line or "sspi" where the clock is hardcoded to
1MHz, but the Tegra114 SPI controller can't go that low.

Signed-off-by: Allen Martin <amartin@nvidia.com>
Acked-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>

arch/arm/cpu/tegra-common/clock.c

diff --git a/arch/arm/cpu/tegra-common/clock.c b/arch/arm/cpu/tegra-common/clock.c
index 9156d00..268fb91 100644
--- a/arch/arm/cpu/tegra-common/clock.c
+++ b/arch/arm/cpu/tegra-common/clock.c
@@ -321,17 +321,17 @@
 	unsigned effective_rate;
 	int mux_bits, divider_bits, source;
 	int divider;
+	int xdiv = 0;
 
 	/* work out the source clock and set it */
 	source = get_periph_clock_source(periph_id, parent, &mux_bits,
 					 &divider_bits);
 
+	divider = find_best_divider(divider_bits, pll_rate[parent],
+				    rate, &xdiv);
 	if (extra_div)
-		divider = find_best_divider(divider_bits, pll_rate[parent],
-						rate, extra_div);
-	else
-		divider = clk_get_divider(divider_bits, pll_rate[parent],
-					  rate);
+		*extra_div = xdiv;
+
 	assert(divider >= 0);
 	if (adjust_periph_pll(periph_id, source, mux_bits, divider))
 		return -1U;