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authorPhil Elwell <phil@raspberrypi.org>2017-06-01 15:14:16 +0100
committerStephen Boyd <sboyd@codeaurora.org>2017-06-02 15:42:19 -0700
commit8c0de581c4f590450a9e9850e8049f9313bb1e62 (patch)
tree92e6dfad93e399713aec8cf9ff9a27366b285a4d /drivers/clk/bcm
parente45098d703fbb9a7b02eae581aadb684b31e0eec (diff)
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clk: bcm2835: Limit PCM clock to OSC and PLLD_PER
Restrict clock sources for the PCM peripheral to the oscillator and PLLD_PER because other source may have varying rates or be switched off. Prevent other sources from being selected by replacing their names in the list of potential parents with dummy entries (entry index is significant). Signed-off-by: Phil Elwell <phil@raspberrypi.org> Reviewed-by: Eric Anholt <eric@anholt.net> Acked-by: Stefan Wahren <stefan.wahren@i2se.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Diffstat (limited to 'drivers/clk/bcm')
-rw-r--r--drivers/clk/bcm/clk-bcm2835.c27
1 files changed, 26 insertions, 1 deletions
diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c
index 7a35df6b45bd..8ee0f0b28ea3 100644
--- a/drivers/clk/bcm/clk-bcm2835.c
+++ b/drivers/clk/bcm/clk-bcm2835.c
@@ -1518,6 +1518,31 @@ static const char *const bcm2835_clock_per_parents[] = {
.parents = bcm2835_clock_per_parents, \
__VA_ARGS__)
+/*
+ * Restrict clock sources for the PCM peripheral to the oscillator and
+ * PLLD_PER because other source may have varying rates or be switched
+ * off.
+ *
+ * Prevent other sources from being selected by replacing their names in
+ * the list of potential parents with dummy entries (entry index is
+ * significant).
+ */
+static const char *const bcm2835_pcm_per_parents[] = {
+ "-",
+ "xosc",
+ "-",
+ "-",
+ "-",
+ "-",
+ "plld_per",
+ "-",
+};
+
+#define REGISTER_PCM_CLK(...) REGISTER_CLK( \
+ .num_mux_parents = ARRAY_SIZE(bcm2835_pcm_per_parents), \
+ .parents = bcm2835_pcm_per_parents, \
+ __VA_ARGS__)
+
/* main vpu parent mux */
static const char *const bcm2835_clock_vpu_parents[] = {
"gnd",
@@ -1995,7 +2020,7 @@ static const struct bcm2835_clk_desc clk_desc_array[] = {
.int_bits = 4,
.frac_bits = 8,
.tcnt_mux = 22),
- [BCM2835_CLOCK_PCM] = REGISTER_PER_CLK(
+ [BCM2835_CLOCK_PCM] = REGISTER_PCM_CLK(
.name = "pcm",
.ctl_reg = CM_PCMCTL,
.div_reg = CM_PCMDIV,