diff options
Diffstat (limited to 'drivers/clk/at91/clk-utmi.c')
| -rw-r--r-- | drivers/clk/at91/clk-utmi.c | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/drivers/clk/at91/clk-utmi.c b/drivers/clk/at91/clk-utmi.c new file mode 100644 index 00000000000..ae3263bc147 --- /dev/null +++ b/drivers/clk/at91/clk-utmi.c @@ -0,0 +1,159 @@ +/* + * 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/interrupt.h> +#include <linux/irq.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/io.h> +#include <linux/sched.h> +#include <linux/wait.h> + +#include "pmc.h" + +#define UTMI_FIXED_MUL 40 + +struct clk_utmi { + struct clk_hw hw; + struct at91_pmc *pmc; + unsigned int irq; + wait_queue_head_t wait; +}; + +#define to_clk_utmi(hw) container_of(hw, struct clk_utmi, hw) + +static irqreturn_t clk_utmi_irq_handler(int irq, void *dev_id) +{ + struct clk_utmi *utmi = (struct clk_utmi *)dev_id; + + wake_up(&utmi->wait); + disable_irq_nosync(utmi->irq); + + return IRQ_HANDLED; +} + +static int clk_utmi_prepare(struct clk_hw *hw) +{ + struct clk_utmi *utmi = to_clk_utmi(hw); + struct at91_pmc *pmc = utmi->pmc; + u32 tmp = at91_pmc_read(AT91_CKGR_UCKR) | AT91_PMC_UPLLEN | + AT91_PMC_UPLLCOUNT | AT91_PMC_BIASEN; + + pmc_write(pmc, AT91_CKGR_UCKR, tmp); + + while (!(pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_LOCKU)) { + enable_irq(utmi->irq); + wait_event(utmi->wait, + pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_LOCKU); + } + + return 0; +} + +static int clk_utmi_is_prepared(struct clk_hw *hw) +{ + struct clk_utmi *utmi = to_clk_utmi(hw); + struct at91_pmc *pmc = utmi->pmc; + + return !!(pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_LOCKU); +} + +static void clk_utmi_unprepare(struct clk_hw *hw) +{ + struct clk_utmi *utmi = to_clk_utmi(hw); + struct at91_pmc *pmc = utmi->pmc; + u32 tmp = at91_pmc_read(AT91_CKGR_UCKR) & ~AT91_PMC_UPLLEN; + + pmc_write(pmc, AT91_CKGR_UCKR, tmp); +} + +static unsigned long clk_utmi_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + /* UTMI clk is a fixed clk multiplier */ + return parent_rate * UTMI_FIXED_MUL; +} + +static const struct clk_ops utmi_ops = { + .prepare = clk_utmi_prepare, + .unprepare = clk_utmi_unprepare, + .is_prepared = clk_utmi_is_prepared, + .recalc_rate = clk_utmi_recalc_rate, +}; + +static struct clk * __init +at91_clk_register_utmi(struct at91_pmc *pmc, unsigned int irq, + const char *name, const char *parent_name) +{ + int ret; + struct clk_utmi *utmi; + struct clk *clk = NULL; + struct clk_init_data init; + + utmi = kzalloc(sizeof(*utmi), GFP_KERNEL); + if (!utmi) + return ERR_PTR(-ENOMEM); + + init.name = name; + init.ops = &utmi_ops; + init.parent_names = parent_name ? &parent_name : NULL; + init.num_parents = parent_name ? 1 : 0; + init.flags = CLK_SET_RATE_GATE; + + utmi->hw.init = &init; + utmi->pmc = pmc; + utmi->irq = irq; + init_waitqueue_head(&utmi->wait); + irq_set_status_flags(utmi->irq, IRQ_NOAUTOEN); + ret = request_irq(utmi->irq, clk_utmi_irq_handler, + IRQF_TRIGGER_HIGH, "clk-utmi", utmi); + if (ret) + return ERR_PTR(ret); + + clk = clk_register(NULL, &utmi->hw); + if (IS_ERR(clk)) + kfree(utmi); + + return clk; +} + +static void __init +of_at91_clk_utmi_setup(struct device_node *np, struct at91_pmc *pmc) +{ + unsigned int irq; + struct clk *clk; + const char *parent_name; + const char *name = np->name; + + parent_name = of_clk_get_parent_name(np, 0); + + of_property_read_string(np, "clock-output-names", &name); + + irq = irq_of_parse_and_map(np, 0); + if (!irq) + return; + + clk = at91_clk_register_utmi(pmc, irq, name, parent_name); + if (IS_ERR(clk)) + return; + + of_clk_add_provider(np, of_clk_src_simple_get, clk); + return; +} + +void __init of_at91sam9x5_clk_utmi_setup(struct device_node *np, + struct at91_pmc *pmc) +{ + of_at91_clk_utmi_setup(np, pmc); +} |