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Message-Id: <1392855182-21155-9-git-send-email-elder@linaro.org>
Date: Wed, 19 Feb 2014 18:12:58 -0600
From: Alex Elder <elder@...aro.org>
To: mturquette@...aro.org, bcm@...thebug.org, mporter@...aro.org,
robh+dt@...nel.org, pawel.moll@....com, mark.rutland@....com,
ijc+devicetree@...lion.org.uk, galak@...eaurora.org,
linux@....linux.org.uk
Cc: bcm-kernel-feedback-list@...adcom.com, devicetree@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH 08/12] clk: bcm281xx: add clock hysteresis support
Add support for clock gate hysteresis control. For now, if it's
defined for a clock, it's enabled.
Signed-off-by: Alex Elder <elder@...aro.org>
---
drivers/clk/bcm/clk-kona-setup.c | 30 ++++++++++++++++++++++++++++++
drivers/clk/bcm/clk-kona.c | 33 +++++++++++++++++++++++++++++++++
drivers/clk/bcm/clk-kona.h | 19 +++++++++++++++++++
3 files changed, 82 insertions(+)
diff --git a/drivers/clk/bcm/clk-kona-setup.c b/drivers/clk/bcm/clk-kona-setup.c
index 5a49deb..757de19 100644
--- a/drivers/clk/bcm/clk-kona-setup.c
+++ b/drivers/clk/bcm/clk-kona-setup.c
@@ -81,6 +81,7 @@ static bool peri_clk_data_offsets_valid(struct kona_clk *bcm_clk)
struct peri_clk_data *peri;
struct bcm_clk_policy *policy;
struct bcm_clk_gate *gate;
+ struct bcm_clk_hyst *hyst;
struct bcm_clk_div *div;
struct bcm_clk_sel *sel;
struct bcm_clk_trig *trig;
@@ -106,12 +107,25 @@ static bool peri_clk_data_offsets_valid(struct kona_clk *bcm_clk)
}
gate = &peri->gate;
+ hyst = &peri->hyst;
if (gate_exists(gate)) {
if (gate->offset > limit) {
pr_err("%s: bad gate offset for %s (%u > %u)\n",
__func__, name, gate->offset, limit);
return false;
}
+
+ if (hyst_exists(hyst)) {
+ if (hyst->offset > limit) {
+ pr_err("%s: bad hysteresis offset for %s "
+ "(%u > %u)\n", __func__,
+ name, hyst->offset, limit);
+ return false;
+ }
+ }
+ } else if (hyst_exists(hyst)) {
+ pr_err("%s: hysteresis but no gate for %s\n", __func__, name);
+ return false;
}
div = &peri->div;
@@ -261,6 +275,17 @@ static bool gate_valid(struct bcm_clk_gate *gate, const char *field_name,
return true;
}
+static bool hyst_valid(struct bcm_clk_hyst *hyst, const char *clock_name)
+{
+ if (!bit_posn_valid(hyst->en_bit, "hysteresis enable", clock_name))
+ return false;
+
+ if (!bit_posn_valid(hyst->val_bit, "hysteresis value", clock_name))
+ return false;
+
+ return true;
+}
+
/*
* A selector bitfield must be valid. Its parent_sel array must
* also be reasonable for the field.
@@ -378,6 +403,7 @@ peri_clk_data_valid(struct kona_clk *bcm_clk)
struct peri_clk_data *peri;
struct bcm_clk_policy *policy;
struct bcm_clk_gate *gate;
+ struct bcm_clk_hyst *hyst;
struct bcm_clk_sel *sel;
struct bcm_clk_div *div;
struct bcm_clk_div *pre_div;
@@ -405,6 +431,10 @@ peri_clk_data_valid(struct kona_clk *bcm_clk)
if (gate_exists(gate) && !gate_valid(gate, "gate", name))
return false;
+ hyst = &peri->hyst;
+ if (hyst_exists(hyst) && !hyst_valid(hyst, name))
+ return false;
+
sel = &peri->sel;
if (selector_exists(sel)) {
if (!sel_valid(sel, "selector", name))
diff --git a/drivers/clk/bcm/clk-kona.c b/drivers/clk/bcm/clk-kona.c
index bf9661c..64b6361 100644
--- a/drivers/clk/bcm/clk-kona.c
+++ b/drivers/clk/bcm/clk-kona.c
@@ -527,6 +527,35 @@ static int clk_gate(struct ccu_data *ccu, const char *name,
return -EIO;
}
+/* Hysteresis operations */
+
+/*
+ * If a clock gate requires a turn-off delay it will have
+ * "hysteresis" register bits defined. The first, if set, enables
+ * the delay; and if enabled, the second bit determines whether the
+ * delay is "low" or "high" (1 means high). For now, if it's
+ * defined for a clock, we set it.
+ */
+static bool hyst_init(struct ccu_data *ccu, struct bcm_clk_hyst *hyst)
+{
+ u32 offset;
+ u32 reg_val;
+ u32 mask;
+
+ if (!hyst_exists(hyst))
+ return true;
+
+ offset = hyst->offset;
+ mask = (u32)1 << hyst->en_bit;
+ mask |= (u32)1 << hyst->val_bit;
+
+ reg_val = __ccu_read(ccu, offset);
+ reg_val |= mask;
+ __ccu_write(ccu, offset, reg_val);
+
+ return true;
+}
+
/* Trigger operations */
/*
@@ -1129,6 +1158,10 @@ static bool __peri_clk_init(struct kona_clk *bcm_clk)
pr_err("%s: error initializing gate for %s\n", __func__, name);
return false;
}
+ if (!hyst_init(ccu, &peri->hyst)) {
+ pr_err("%s: error initializing hyst for %s\n", __func__, name);
+ return false;
+ }
if (!div_init(ccu, &peri->gate, &peri->div, &peri->trig)) {
pr_err("%s: error initializing divider for %s\n", __func__,
name);
diff --git a/drivers/clk/bcm/clk-kona.h b/drivers/clk/bcm/clk-kona.h
index c390ca4..c6285d2 100644
--- a/drivers/clk/bcm/clk-kona.h
+++ b/drivers/clk/bcm/clk-kona.h
@@ -60,6 +60,8 @@
#define gate_flip_enabled(gate) FLAG_FLIP(gate, GATE, ENABLED)
+#define hyst_exists(hyst) ((hyst)->offset != 0)
+
#define divider_exists(div) FLAG_TEST(div, DIV, EXISTS)
#define divider_is_fixed(div) FLAG_TEST(div, DIV, FIXED)
#define divider_has_fraction(div) (!divider_is_fixed(div) && \
@@ -205,6 +207,22 @@ struct bcm_clk_gate {
.flags = FLAG(GATE, HW)|FLAG(GATE, EXISTS), \
}
+/* Gate hysteresis for clocks */
+struct bcm_clk_hyst {
+ u32 offset; /* hyst register offset (normally CLKGATE) */
+ u32 en_bit; /* bit used to enable hysteresis */
+ u32 val_bit; /* if enabled: 0 = low delay; 1 = high delay */
+};
+
+/* Hysteresis initialization macro */
+
+#define HYST(_offset, _en_bit, _val_bit) \
+ { \
+ .offset = (_offset), \
+ .en_bit = (_en_bit), \
+ .val_bit = (_val_bit), \
+ }
+
/*
* Each clock can have zero, one, or two dividers which change the
* output rate of the clock. Each divider can be either fixed or
@@ -372,6 +390,7 @@ struct bcm_clk_trig {
struct peri_clk_data {
struct bcm_clk_policy policy;
struct bcm_clk_gate gate;
+ struct bcm_clk_hyst hyst;
struct bcm_clk_trig pre_trig;
struct bcm_clk_div pre_div;
struct bcm_clk_trig trig;
--
1.7.9.5
--
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