diff options
Diffstat (limited to 'drivers/clk/at91/clk-system.c')
| -rw-r--r-- | drivers/clk/at91/clk-system.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/drivers/clk/at91/clk-system.c b/drivers/clk/at91/clk-system.c new file mode 100644 index 00000000000..8c96307d736 --- /dev/null +++ b/drivers/clk/at91/clk-system.c @@ -0,0 +1,189 @@ +/* + * Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + */ + +#include <linux/clk-provider.h> +#include <linux/clkdev.h> +#include <linux/clk/at91_pmc.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/io.h> +#include <linux/irq.h> +#include <linux/of_irq.h> +#include <linux/interrupt.h> +#include <linux/wait.h> +#include <linux/sched.h> + +#include "pmc.h" + +#define SYSTEM_MAX_ID 31 + +#define SYSTEM_MAX_NAME_SZ 32 + +#define to_clk_system(hw) container_of(hw, struct clk_system, hw) +struct clk_system { + struct clk_hw hw; + struct at91_pmc *pmc; + unsigned int irq; + wait_queue_head_t wait; + u8 id; +}; + +static inline int is_pck(int id) +{ + return (id >= 8) && (id <= 15); +} +static irqreturn_t clk_system_irq_handler(int irq, void *dev_id) +{ + struct clk_system *sys = (struct clk_system *)dev_id; + + wake_up(&sys->wait); + disable_irq_nosync(sys->irq); + + return IRQ_HANDLED; +} + +static int clk_system_prepare(struct clk_hw *hw) +{ + struct clk_system *sys = to_clk_system(hw); + struct at91_pmc *pmc = sys->pmc; + u32 mask = 1 << sys->id; + + pmc_write(pmc, AT91_PMC_SCER, mask); + + if (!is_pck(sys->id)) + return 0; + + while (!(pmc_read(pmc, AT91_PMC_SR) & mask)) { + if (sys->irq) { + enable_irq(sys->irq); + wait_event(sys->wait, + pmc_read(pmc, AT91_PMC_SR) & mask); + } else + cpu_relax(); + } + return 0; +} + +static void clk_system_unprepare(struct clk_hw *hw) +{ + struct clk_system *sys = to_clk_system(hw); + struct at91_pmc *pmc = sys->pmc; + + pmc_write(pmc, AT91_PMC_SCDR, 1 << sys->id); +} + +static int clk_system_is_prepared(struct clk_hw *hw) +{ + struct clk_system *sys = to_clk_system(hw); + struct at91_pmc *pmc = sys->pmc; + + if (!(pmc_read(pmc, AT91_PMC_SCSR) & (1 << sys->id))) + return 0; + + if (!is_pck(sys->id)) + return 1; + + return !!(pmc_read(pmc, AT91_PMC_SR) & (1 << sys->id)); +} + +static const struct clk_ops system_ops = { + .prepare = clk_system_prepare, + .unprepare = clk_system_unprepare, + .is_prepared = clk_system_is_prepared, +}; + +static struct clk * __init +at91_clk_register_system(struct at91_pmc *pmc, const char *name, + const char *parent_name, u8 id, int irq) +{ + struct clk_system *sys; + struct clk *clk = NULL; + struct clk_init_data init; + int ret; + + if (!parent_name || id > SYSTEM_MAX_ID) + return ERR_PTR(-EINVAL); + + sys = kzalloc(sizeof(*sys), GFP_KERNEL); + if (!sys) + return ERR_PTR(-ENOMEM); + + init.name = name; + init.ops = &system_ops; + init.parent_names = &parent_name; + init.num_parents = 1; + /* + * CLK_IGNORE_UNUSED is used to avoid ddrck switch off. + * TODO : we should implement a driver supporting at91 ddr controller + * (see drivers/memory) which would request and enable the ddrck clock. + * When this is done we will be able to remove CLK_IGNORE_UNUSED flag. + */ + init.flags = CLK_SET_RATE_PARENT | CLK_IGNORE_UNUSED; + + sys->id = id; + sys->hw.init = &init; + sys->pmc = pmc; + sys->irq = irq; + if (irq) { + init_waitqueue_head(&sys->wait); + irq_set_status_flags(sys->irq, IRQ_NOAUTOEN); + ret = request_irq(sys->irq, clk_system_irq_handler, + IRQF_TRIGGER_HIGH, name, sys); + if (ret) + return ERR_PTR(ret); + } + + clk = clk_register(NULL, &sys->hw); + if (IS_ERR(clk)) + kfree(sys); + + return clk; +} + +static void __init +of_at91_clk_sys_setup(struct device_node *np, struct at91_pmc *pmc) +{ + int num; + int irq = 0; + u32 id; + struct clk *clk; + const char *name; + struct device_node *sysclknp; + const char *parent_name; + + num = of_get_child_count(np); + if (num > (SYSTEM_MAX_ID + 1)) + return; + + for_each_child_of_node(np, sysclknp) { + if (of_property_read_u32(sysclknp, "reg", &id)) + continue; + + if (of_property_read_string(np, "clock-output-names", &name)) + name = sysclknp->name; + + if (is_pck(id)) + irq = irq_of_parse_and_map(sysclknp, 0); + + parent_name = of_clk_get_parent_name(sysclknp, 0); + + clk = at91_clk_register_system(pmc, name, parent_name, id, irq); + if (IS_ERR(clk)) + continue; + + of_clk_add_provider(sysclknp, of_clk_src_simple_get, clk); + } +} + +void __init of_at91rm9200_clk_sys_setup(struct device_node *np, + struct at91_pmc *pmc) +{ + of_at91_clk_sys_setup(np, pmc); +} |