270 lines
6.5 KiB
C
270 lines
6.5 KiB
C
/*
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* Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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*/
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#include <linux/clk-provider.h>
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#include <linux/clkdev.h>
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#include <linux/clk/at91_pmc.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#include <linux/of_irq.h>
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#include <linux/io.h>
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#include <linux/wait.h>
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#include <linux/sched.h>
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#include <linux/interrupt.h>
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#include <linux/irq.h>
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#include "pmc.h"
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#define MASTER_SOURCE_MAX 4
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#define MASTER_PRES_MASK 0x7
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#define MASTER_PRES_MAX MASTER_PRES_MASK
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#define MASTER_DIV_SHIFT 8
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#define MASTER_DIV_MASK 0x3
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struct clk_master_characteristics {
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struct clk_range output;
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u32 divisors[4];
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u8 have_div3_pres;
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};
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struct clk_master_layout {
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u32 mask;
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u8 pres_shift;
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};
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#define to_clk_master(hw) container_of(hw, struct clk_master, hw)
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struct clk_master {
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struct clk_hw hw;
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struct at91_pmc *pmc;
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unsigned int irq;
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wait_queue_head_t wait;
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const struct clk_master_layout *layout;
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const struct clk_master_characteristics *characteristics;
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};
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static irqreturn_t clk_master_irq_handler(int irq, void *dev_id)
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{
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struct clk_master *master = (struct clk_master *)dev_id;
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wake_up(&master->wait);
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disable_irq_nosync(master->irq);
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return IRQ_HANDLED;
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}
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static int clk_master_prepare(struct clk_hw *hw)
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{
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struct clk_master *master = to_clk_master(hw);
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struct at91_pmc *pmc = master->pmc;
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while (!(pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_MCKRDY)) {
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enable_irq(master->irq);
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wait_event(master->wait,
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pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_MCKRDY);
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}
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return 0;
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}
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static int clk_master_is_prepared(struct clk_hw *hw)
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{
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struct clk_master *master = to_clk_master(hw);
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return !!(pmc_read(master->pmc, AT91_PMC_SR) & AT91_PMC_MCKRDY);
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}
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static unsigned long clk_master_recalc_rate(struct clk_hw *hw,
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unsigned long parent_rate)
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{
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u8 pres;
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u8 div;
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unsigned long rate = parent_rate;
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struct clk_master *master = to_clk_master(hw);
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struct at91_pmc *pmc = master->pmc;
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const struct clk_master_layout *layout = master->layout;
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const struct clk_master_characteristics *characteristics =
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master->characteristics;
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u32 tmp;
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pmc_lock(pmc);
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tmp = pmc_read(pmc, AT91_PMC_MCKR) & layout->mask;
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pmc_unlock(pmc);
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pres = (tmp >> layout->pres_shift) & MASTER_PRES_MASK;
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div = (tmp >> MASTER_DIV_SHIFT) & MASTER_DIV_MASK;
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if (characteristics->have_div3_pres && pres == MASTER_PRES_MAX)
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rate /= 3;
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else
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rate >>= pres;
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rate /= characteristics->divisors[div];
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if (rate < characteristics->output.min)
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pr_warn("master clk is underclocked");
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else if (rate > characteristics->output.max)
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pr_warn("master clk is overclocked");
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return rate;
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}
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static u8 clk_master_get_parent(struct clk_hw *hw)
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{
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struct clk_master *master = to_clk_master(hw);
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struct at91_pmc *pmc = master->pmc;
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return pmc_read(pmc, AT91_PMC_MCKR) & AT91_PMC_CSS;
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}
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static const struct clk_ops master_ops = {
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.prepare = clk_master_prepare,
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.is_prepared = clk_master_is_prepared,
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.recalc_rate = clk_master_recalc_rate,
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.get_parent = clk_master_get_parent,
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};
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static struct clk * __init
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at91_clk_register_master(struct at91_pmc *pmc, unsigned int irq,
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const char *name, int num_parents,
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const char **parent_names,
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const struct clk_master_layout *layout,
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const struct clk_master_characteristics *characteristics)
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{
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int ret;
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struct clk_master *master;
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struct clk *clk = NULL;
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struct clk_init_data init;
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if (!pmc || !irq || !name || !num_parents || !parent_names)
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return ERR_PTR(-EINVAL);
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master = kzalloc(sizeof(*master), GFP_KERNEL);
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if (!master)
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return ERR_PTR(-ENOMEM);
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init.name = name;
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init.ops = &master_ops;
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init.parent_names = parent_names;
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init.num_parents = num_parents;
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init.flags = 0;
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master->hw.init = &init;
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master->layout = layout;
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master->characteristics = characteristics;
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master->pmc = pmc;
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master->irq = irq;
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init_waitqueue_head(&master->wait);
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irq_set_status_flags(master->irq, IRQ_NOAUTOEN);
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ret = request_irq(master->irq, clk_master_irq_handler,
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IRQF_TRIGGER_HIGH, "clk-master", master);
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if (ret) {
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kfree(master);
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return ERR_PTR(ret);
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}
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clk = clk_register(NULL, &master->hw);
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if (IS_ERR(clk)) {
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free_irq(master->irq, master);
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kfree(master);
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}
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return clk;
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}
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static const struct clk_master_layout at91rm9200_master_layout = {
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.mask = 0x31F,
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.pres_shift = 2,
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};
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static const struct clk_master_layout at91sam9x5_master_layout = {
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.mask = 0x373,
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.pres_shift = 4,
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};
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static struct clk_master_characteristics * __init
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of_at91_clk_master_get_characteristics(struct device_node *np)
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{
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struct clk_master_characteristics *characteristics;
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characteristics = kzalloc(sizeof(*characteristics), GFP_KERNEL);
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if (!characteristics)
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return NULL;
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if (of_at91_get_clk_range(np, "atmel,clk-output-range", &characteristics->output))
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goto out_free_characteristics;
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of_property_read_u32_array(np, "atmel,clk-divisors",
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characteristics->divisors, 4);
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characteristics->have_div3_pres =
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of_property_read_bool(np, "atmel,master-clk-have-div3-pres");
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return characteristics;
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out_free_characteristics:
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kfree(characteristics);
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return NULL;
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}
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static void __init
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of_at91_clk_master_setup(struct device_node *np, struct at91_pmc *pmc,
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const struct clk_master_layout *layout)
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{
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struct clk *clk;
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int num_parents;
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unsigned int irq;
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const char *parent_names[MASTER_SOURCE_MAX];
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const char *name = np->name;
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struct clk_master_characteristics *characteristics;
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num_parents = of_clk_get_parent_count(np);
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if (num_parents <= 0 || num_parents > MASTER_SOURCE_MAX)
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return;
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of_clk_parent_fill(np, parent_names, num_parents);
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of_property_read_string(np, "clock-output-names", &name);
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characteristics = of_at91_clk_master_get_characteristics(np);
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if (!characteristics)
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return;
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irq = irq_of_parse_and_map(np, 0);
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if (!irq)
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goto out_free_characteristics;
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clk = at91_clk_register_master(pmc, irq, name, num_parents,
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parent_names, layout,
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characteristics);
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if (IS_ERR(clk))
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goto out_free_characteristics;
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of_clk_add_provider(np, of_clk_src_simple_get, clk);
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return;
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out_free_characteristics:
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kfree(characteristics);
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}
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void __init of_at91rm9200_clk_master_setup(struct device_node *np,
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struct at91_pmc *pmc)
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{
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of_at91_clk_master_setup(np, pmc, &at91rm9200_master_layout);
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}
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void __init of_at91sam9x5_clk_master_setup(struct device_node *np,
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struct at91_pmc *pmc)
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{
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of_at91_clk_master_setup(np, pmc, &at91sam9x5_master_layout);
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}
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