Some clocks may have multiple downstream users that need to request a higher clock rate. Shared bus clocks provide a unique shared_bus_user clock to each user. The frequency of the bus is set to the highest enabled shared_bus_user clock, with a minimum value set by the shared bus. Drivers can use clk_enable and clk_disable to enable or disable their requirement, and clk_set_rate to set the minimum rate.
Signed-off-by: Colin Cross <[email protected]> --- arch/arm/mach-tegra/clock.h | 8 ++++ arch/arm/mach-tegra/tegra2_clocks.c | 80 +++++++++++++++++++++++++++++++++++ 2 files changed, 88 insertions(+), 0 deletions(-) diff --git a/arch/arm/mach-tegra/clock.h b/arch/arm/mach-tegra/clock.h index dd5c029..b460f17 100644 --- a/arch/arm/mach-tegra/clock.h +++ b/arch/arm/mach-tegra/clock.h @@ -85,6 +85,7 @@ struct clk { struct clk_ops *ops; unsigned long rate; unsigned long max_rate; + unsigned long min_rate; u32 flags; const char *name; @@ -98,6 +99,8 @@ struct clk { u32 reg; u32 reg_shift; + struct list_head shared_bus_list; + union { struct { unsigned int clk_num; @@ -120,6 +123,11 @@ struct clk { struct clk *main; struct clk *backup; } cpu; + struct { + struct list_head node; + bool enabled; + unsigned long rate; + } shared_bus_user; } u; spinlock_t spinlock; diff --git a/arch/arm/mach-tegra/tegra2_clocks.c b/arch/arm/mach-tegra/tegra2_clocks.c index a1c86d8..10b9f63 100644 --- a/arch/arm/mach-tegra/tegra2_clocks.c +++ b/arch/arm/mach-tegra/tegra2_clocks.c @@ -1188,6 +1188,74 @@ static struct clk_ops tegra_cdev_clk_ops = { .disable = &tegra2_cdev_clk_disable, }; +/* shared bus ops */ +/* + * Some clocks may have multiple downstream users that need to request a + * higher clock rate. Shared bus clocks provide a unique shared_bus_user + * clock to each user. The frequency of the bus is set to the highest + * enabled shared_bus_user clock, with a minimum value set by the + * shared bus. + */ +static void tegra_clk_shared_bus_update(struct clk *bus) +{ + struct clk *c; + unsigned long rate = bus->min_rate; + + list_for_each_entry(c, &bus->shared_bus_list, u.shared_bus_user.node) + if (c->u.shared_bus_user.enabled) + rate = max(c->u.shared_bus_user.rate, rate); + + if (rate != clk_get_rate(bus)) + clk_set_rate(bus, rate); +}; + +static void tegra_clk_shared_bus_init(struct clk *c) +{ + c->max_rate = c->parent->max_rate; + c->u.shared_bus_user.rate = c->parent->max_rate; + c->state = OFF; +#ifdef CONFIG_DEBUG_FS + c->set = 1; +#endif + + list_add_tail(&c->u.shared_bus_user.node, + &c->parent->shared_bus_list); +} + +static int tegra_clk_shared_bus_set_rate(struct clk *c, unsigned long rate) +{ + c->u.shared_bus_user.rate = rate; + tegra_clk_shared_bus_update(c->parent); + return 0; +} + +static long tegra_clk_shared_bus_round_rate(struct clk *c, unsigned long rate) +{ + return clk_round_rate(c->parent, rate); +} + +static int tegra_clk_shared_bus_enable(struct clk *c) +{ + c->u.shared_bus_user.enabled = true; + tegra_clk_shared_bus_update(c->parent); + return 0; +} + +static void tegra_clk_shared_bus_disable(struct clk *c) +{ + c->u.shared_bus_user.enabled = false; + tegra_clk_shared_bus_update(c->parent); +} + +static struct clk_ops tegra_clk_shared_bus_ops = { + .init = tegra_clk_shared_bus_init, + .enable = tegra_clk_shared_bus_enable, + .disable = tegra_clk_shared_bus_disable, + .set_rate = tegra_clk_shared_bus_set_rate, + .round_rate = tegra_clk_shared_bus_round_rate, +}; + + /* Clock definitions */ static struct clk tegra_clk_32k = { .name = "clk_32k", @@ -1858,6 +1926,17 @@ static struct clk_mux_sel mux_clk_32k[] = { }, \ } +#define SHARED_CLK(_name, _dev, _con, _parent) \ + { \ + .name = _name, \ + .lookup = { \ + .dev_id = _dev, \ + .con_id = _con, \ + }, \ + .ops = &tegra_clk_shared_bus_ops, \ + .parent = _parent, \ + } + struct clk tegra_list_clks[] = { PERIPH_CLK("rtc", "rtc-tegra", NULL, 4, 0, 32768, mux_clk_32k, PERIPH_NO_RESET), PERIPH_CLK("timer", "timer", NULL, 5, 0, 26000000, mux_clk_m, 0), @@ -2001,6 +2080,7 @@ struct clk *tegra_ptr_clks[] = { static void tegra2_init_one_clock(struct clk *c) { clk_init(c); + INIT_LIST_HEAD(&c->shared_bus_list); if (!c->lookup.dev_id && !c->lookup.con_id) c->lookup.con_id = c->name; c->lookup.clk = c; -- 1.7.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
