From 92a9d1dd35352452e4c6c049e22001cfc9dfe0c9 Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Thu, 19 Dec 2013 17:28:12 -0600 Subject: 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 --- 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(+) (limited to 'drivers/clk') diff --git a/drivers/clk/bcm/clk-kona-setup.c b/drivers/clk/bcm/clk-kona-setup.c index 5a49deb49f2..757de19e3ea 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 bf9661c49a8..64b63614220 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 c390ca4dc67..c6285d2d2fb 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; -- cgit v1.2.3