clk: at91: fix programmable clk irq handling

The PCKRDY bit is not set until the system clock is enabled.
This patch moves the management of the ready status in the system clock
driver.

Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com>
Signed-off-by: Jean-Jacques Hiblot <jjhiblot@traphandler.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

1 files changed, 64 insertions, 10 deletions

diff --git a/drivers/clk/at91/clk-system.c b/drivers/clk/at91/clk-system.c
index 48c89fe0cfe8..8c96307d7363 100644
--- a/drivers/clk/at91/clk-system.c
+++ b/drivers/clk/at91/clk-system.c
@@ -14,6 +14,11 @@
 #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"
 
@@ -25,19 +30,48 @@
 struct clk_system {
 	struct clk_hw hw;
 	struct at91_pmc *pmc;
+	unsigned int irq;
+	wait_queue_head_t wait;
 	u8 id;
 };
 
-static int clk_system_enable(struct clk_hw *hw)
+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, 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_disable(struct clk_hw *hw)
+static void clk_system_unprepare(struct clk_hw *hw)
 {
 	struct clk_system *sys = to_clk_system(hw);
 	struct at91_pmc *pmc = sys->pmc;
@@ -45,27 +79,34 @@ static void clk_system_disable(struct clk_hw *hw)
 	pmc_write(pmc, AT91_PMC_SCDR, 1 << sys->id);
 }
 
-static int clk_system_is_enabled(struct clk_hw *hw)
+static int clk_system_is_prepared(struct clk_hw *hw)
 {
 	struct clk_system *sys = to_clk_system(hw);
 	struct at91_pmc *pmc = sys->pmc;
 
-	return !!(pmc_read(pmc, AT91_PMC_SCSR) & (1 << sys->id));
+	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 = {
-	.enable = clk_system_enable,
-	.disable = clk_system_disable,
-	.is_enabled = clk_system_is_enabled,
+	.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)
+			 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);
@@ -89,6 +130,15 @@ at91_clk_register_system(struct at91_pmc *pmc, const char *name,
 	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))
@@ -101,6 +151,7 @@ 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;
@@ -118,9 +169,12 @@ of_at91_clk_sys_setup(struct device_node *np, struct at91_pmc *pmc)
 		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);
+		clk = at91_clk_register_system(pmc, name, parent_name, id, irq);
 		if (IS_ERR(clk))
 			continue;