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path: root/drivers/clk/at91/clk-main.c
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Diffstat (limited to 'drivers/clk/at91/clk-main.c')
-rw-r--r--drivers/clk/at91/clk-main.c187
1 files changed, 187 insertions, 0 deletions
diff --git a/drivers/clk/at91/clk-main.c b/drivers/clk/at91/clk-main.c
new file mode 100644
index 000000000000..8e9e8cc0412d
--- /dev/null
+++ b/drivers/clk/at91/clk-main.c
@@ -0,0 +1,187 @@
+/*
+ * 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/delay.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+
+#include "pmc.h"
+
+#define SLOW_CLOCK_FREQ 32768
+#define MAINF_DIV 16
+#define MAINFRDY_TIMEOUT (((MAINF_DIV + 1) * USEC_PER_SEC) / \
+ SLOW_CLOCK_FREQ)
+#define MAINF_LOOP_MIN_WAIT (USEC_PER_SEC / SLOW_CLOCK_FREQ)
+#define MAINF_LOOP_MAX_WAIT MAINFRDY_TIMEOUT
+
+struct clk_main {
+ struct clk_hw hw;
+ struct at91_pmc *pmc;
+ unsigned long rate;
+ unsigned int irq;
+ wait_queue_head_t wait;
+};
+
+#define to_clk_main(hw) container_of(hw, struct clk_main, hw)
+
+static irqreturn_t clk_main_irq_handler(int irq, void *dev_id)
+{
+ struct clk_main *clkmain = (struct clk_main *)dev_id;
+
+ wake_up(&clkmain->wait);
+ disable_irq_nosync(clkmain->irq);
+
+ return IRQ_HANDLED;
+}
+
+static int clk_main_prepare(struct clk_hw *hw)
+{
+ struct clk_main *clkmain = to_clk_main(hw);
+ struct at91_pmc *pmc = clkmain->pmc;
+ unsigned long halt_time, timeout;
+ u32 tmp;
+
+ while (!(pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_MOSCS)) {
+ enable_irq(clkmain->irq);
+ wait_event(clkmain->wait,
+ pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_MOSCS);
+ }
+
+ if (clkmain->rate)
+ return 0;
+
+ timeout = jiffies + usecs_to_jiffies(MAINFRDY_TIMEOUT);
+ do {
+ halt_time = jiffies;
+ tmp = pmc_read(pmc, AT91_CKGR_MCFR);
+ if (tmp & AT91_PMC_MAINRDY)
+ return 0;
+ usleep_range(MAINF_LOOP_MIN_WAIT, MAINF_LOOP_MAX_WAIT);
+ } while (time_before(halt_time, timeout));
+
+ return 0;
+}
+
+static int clk_main_is_prepared(struct clk_hw *hw)
+{
+ struct clk_main *clkmain = to_clk_main(hw);
+
+ return !!(pmc_read(clkmain->pmc, AT91_PMC_SR) & AT91_PMC_MOSCS);
+}
+
+static unsigned long clk_main_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ u32 tmp;
+ struct clk_main *clkmain = to_clk_main(hw);
+ struct at91_pmc *pmc = clkmain->pmc;
+
+ if (clkmain->rate)
+ return clkmain->rate;
+
+ tmp = pmc_read(pmc, AT91_CKGR_MCFR) & AT91_PMC_MAINF;
+ clkmain->rate = (tmp * parent_rate) / MAINF_DIV;
+
+ return clkmain->rate;
+}
+
+static const struct clk_ops main_ops = {
+ .prepare = clk_main_prepare,
+ .is_prepared = clk_main_is_prepared,
+ .recalc_rate = clk_main_recalc_rate,
+};
+
+static struct clk * __init
+at91_clk_register_main(struct at91_pmc *pmc,
+ unsigned int irq,
+ const char *name,
+ const char *parent_name,
+ unsigned long rate)
+{
+ int ret;
+ struct clk_main *clkmain;
+ struct clk *clk = NULL;
+ struct clk_init_data init;
+
+ if (!pmc || !irq || !name)
+ return ERR_PTR(-EINVAL);
+
+ if (!rate && !parent_name)
+ return ERR_PTR(-EINVAL);
+
+ clkmain = kzalloc(sizeof(*clkmain), GFP_KERNEL);
+ if (!clkmain)
+ return ERR_PTR(-ENOMEM);
+
+ init.name = name;
+ init.ops = &main_ops;
+ init.parent_names = parent_name ? &parent_name : NULL;
+ init.num_parents = parent_name ? 1 : 0;
+ init.flags = parent_name ? 0 : CLK_IS_ROOT;
+
+ clkmain->hw.init = &init;
+ clkmain->rate = rate;
+ clkmain->pmc = pmc;
+ clkmain->irq = irq;
+ init_waitqueue_head(&clkmain->wait);
+ irq_set_status_flags(clkmain->irq, IRQ_NOAUTOEN);
+ ret = request_irq(clkmain->irq, clk_main_irq_handler,
+ IRQF_TRIGGER_HIGH, "clk-main", clkmain);
+ if (ret)
+ return ERR_PTR(ret);
+
+ clk = clk_register(NULL, &clkmain->hw);
+ if (IS_ERR(clk)) {
+ free_irq(clkmain->irq, clkmain);
+ kfree(clkmain);
+ }
+
+ return clk;
+}
+
+
+
+static void __init
+of_at91_clk_main_setup(struct device_node *np, struct at91_pmc *pmc)
+{
+ struct clk *clk;
+ unsigned int irq;
+ const char *parent_name;
+ const char *name = np->name;
+ u32 rate = 0;
+
+ parent_name = of_clk_get_parent_name(np, 0);
+ of_property_read_string(np, "clock-output-names", &name);
+ of_property_read_u32(np, "clock-frequency", &rate);
+ irq = irq_of_parse_and_map(np, 0);
+ if (!irq)
+ return;
+
+ clk = at91_clk_register_main(pmc, irq, name, parent_name, rate);
+ if (IS_ERR(clk))
+ return;
+
+ of_clk_add_provider(np, of_clk_src_simple_get, clk);
+}
+
+void __init of_at91rm9200_clk_main_setup(struct device_node *np,
+ struct at91_pmc *pmc)
+{
+ of_at91_clk_main_setup(np, pmc);
+}