[PATCH v2 0/4] clk: at91: better support for the PCKs

[PATCH v2 0/4] clk: at91: better support for the PCKs

[Jean-Jacques Hiblot]

This serie implements a better support for the Programmable Clocks.
The first two patch are related to changing the rate of the PCKs.
The 3rd patch is a fix to handle properly the PCKRDY interrupt.
The last patch is a small optimzation/simplification of the determine_rate
algorithm for the PCK.

This has been tested on a 9261ek

Boris BREZILLON (2):
  clk: at91: replace prog clk round_rate with determine_rate
  clk: at91: propagate rate change on system clks

Jean-Jacques Hiblot (2):
  clk: at91: fix programmable clk irq handling
  clk: at91: optimization of the determine_rate callback

 drivers/clk/at91/clk-programmable.c | 202 +++++++++++-------------------------
 drivers/clk/at91/clk-system.c       |  77 ++++++++++++--
 2 files changed, 127 insertions(+), 152 deletions(-)

-- 
1.8.5.2

[PATCH v2 1/4] clk: at91: replace prog clk round_rate with determine_rate

[Jean-Jacques Hiblot]

From: Boris BREZILLON <b.brezillon@overkiz.com>

Implement the determine_rate callback to choose the best parent clk that
fulfills the requested rate.

Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com>
---
 drivers/clk/at91/clk-programmable.c | 56 ++++++++++++++++++-------------------
 1 file changed, 28 insertions(+), 28 deletions(-)

diff --git a/drivers/clk/at91/clk-programmable.c b/drivers/clk/at91/clk-programmable.c
index fd792b2..eff7016 100644
--- a/drivers/clk/at91/clk-programmable.c
+++ b/drivers/clk/at91/clk-programmable.c
@@ -102,40 +102,40 @@ static unsigned long clk_programmable_recalc_rate(struct clk_hw *hw,
 	return parent_rate >> prog->pres;
 }
 
-static long clk_programmable_round_rate(struct clk_hw *hw, unsigned long rate,
-					unsigned long *parent_rate)
+static long clk_programmable_determine_rate(struct clk_hw *hw,
+					    unsigned long rate,
+					    unsigned long *best_parent_rate,
+					    struct clk **best_parent_clk)
 {
-	unsigned long best_rate = *parent_rate;
-	unsigned long best_diff;
-	unsigned long new_diff;
-	unsigned long cur_rate;
-	int shift = shift;
-
-	if (rate > *parent_rate)
-		return *parent_rate;
-	else
-		best_diff = *parent_rate - rate;
-
-	if (!best_diff)
-		return best_rate;
+	struct clk *parent = NULL;
+	long best_rate = -EINVAL;
+	unsigned long parent_rate;
+	unsigned long tmp_rate;
+	int shift;
+	int i;
 
-	for (shift = 1; shift < PROG_PRES_MASK; shift++) {
-		cur_rate = *parent_rate >> shift;
+	for (i = 0; i < __clk_get_num_parents(hw->clk); i++) {
+		parent = clk_get_parent_by_index(hw->clk, i);
+		if (!parent)
+			continue;
 
-		if (cur_rate > rate)
-			new_diff = cur_rate - rate;
-		else
-			new_diff = rate - cur_rate;
+		parent_rate = __clk_get_rate(parent);
+		for (shift = 0; shift < PROG_PRES_MASK; shift++) {
+			tmp_rate = parent_rate >> shift;
+			if (tmp_rate <= rate)
+				break;
+		}
 
-		if (!new_diff)
-			return cur_rate;
+		if (tmp_rate > rate)
+			continue;
 
-		if (new_diff < best_diff) {
-			best_diff = new_diff;
-			best_rate = cur_rate;
+		if (best_rate < 0 || (rate - tmp_rate) < (rate - best_rate)) {
+			best_rate = tmp_rate;
+			*best_parent_rate = parent_rate;
+			*best_parent_clk = parent;
 		}
 
-		if (rate > cur_rate)
+		if (!best_rate)
 			break;
 	}
 
@@ -228,7 +228,7 @@ static const struct clk_ops programmable_ops = {
 	.prepare = clk_programmable_prepare,
 	.is_prepared = clk_programmable_is_ready,
 	.recalc_rate = clk_programmable_recalc_rate,
-	.round_rate = clk_programmable_round_rate,
+	.determine_rate = clk_programmable_determine_rate,
 	.get_parent = clk_programmable_get_parent,
 	.set_parent = clk_programmable_set_parent,
 	.set_rate = clk_programmable_set_rate,
-- 
1.8.5.2

[PATCH v2 2/4] clk: at91: propagate rate change on system clks

[Jean-Jacques Hiblot]

From: Boris BREZILLON <b.brezillon@overkiz.com>

System clks are just gates, and thus do not provide any rate operations.
Authorize clk rate change to be propagated to system clk parents.

Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com>
---
 drivers/clk/at91/clk-system.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/at91/clk-system.c b/drivers/clk/at91/clk-system.c
index 8f7c043..a98557b 100644
--- a/drivers/clk/at91/clk-system.c
+++ b/drivers/clk/at91/clk-system.c
@@ -84,7 +84,8 @@ at91_clk_register_system(struct at91_pmc *pmc, const char *name,
 	 * (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_IGNORE_UNUSED;
+	init.flags = CLK_SET_RATE_GATE | CLK_SET_RATE_PARENT |
+		     CLK_IGNORE_UNUSED;
 
 	sys->id = id;
 	sys->hw.init = &init;
-- 
1.8.5.2

[PATCH v2 3/4] clk: at91: fix programmable clk irq handling

[Jean-Jacques Hiblot]

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>
---
 drivers/clk/at91/clk-programmable.c | 108 +++++++++---------------------------
 drivers/clk/at91/clk-system.c       |  74 ++++++++++++++++++++----
 2 files changed, 89 insertions(+), 93 deletions(-)

diff --git a/drivers/clk/at91/clk-programmable.c b/drivers/clk/at91/clk-programmable.c
index eff7016..7bcc725 100644
--- a/drivers/clk/at91/clk-programmable.c
+++ b/drivers/clk/at91/clk-programmable.c
@@ -13,12 +13,9 @@
 #include <linux/clk/at91_pmc.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
-#include <linux/of_irq.h>
 #include <linux/io.h>
 #include <linux/wait.h>
 #include <linux/sched.h>
-#include <linux/interrupt.h>
-#include <linux/irq.h>
 
 #include "pmc.h"
 
@@ -38,68 +35,23 @@ struct clk_programmable_layout {
 struct clk_programmable {
 	struct clk_hw hw;
 	struct at91_pmc *pmc;
-	unsigned int irq;
-	wait_queue_head_t wait;
 	u8 id;
-	u8 css;
-	u8 pres;
-	u8 slckmck;
 	const struct clk_programmable_layout *layout;
 };
 
 #define to_clk_programmable(hw) container_of(hw, struct clk_programmable, hw)
 
-
-static irqreturn_t clk_programmable_irq_handler(int irq, void *dev_id)
-{
-	struct clk_programmable *prog = (struct clk_programmable *)dev_id;
-
-	wake_up(&prog->wait);
-
-	return IRQ_HANDLED;
-}
-
-static int clk_programmable_prepare(struct clk_hw *hw)
-{
-	u32 tmp;
-	struct clk_programmable *prog = to_clk_programmable(hw);
-	struct at91_pmc *pmc = prog->pmc;
-	const struct clk_programmable_layout *layout = prog->layout;
-	u8 id = prog->id;
-	u32 mask = PROG_STATUS_MASK(id);
-
-	tmp = prog->css | (prog->pres << layout->pres_shift);
-	if (layout->have_slck_mck && prog->slckmck)
-		tmp |= AT91_PMC_CSSMCK_MCK;
-
-	pmc_write(pmc, AT91_PMC_PCKR(id), tmp);
-
-	while (!(pmc_read(pmc, AT91_PMC_SR) & mask))
-		wait_event(prog->wait, pmc_read(pmc, AT91_PMC_SR) & mask);
-
-	return 0;
-}
-
-static int clk_programmable_is_ready(struct clk_hw *hw)
-{
-	struct clk_programmable *prog = to_clk_programmable(hw);
-	struct at91_pmc *pmc = prog->pmc;
-
-	return !!(pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_PCKR(prog->id));
-}
-
 static unsigned long clk_programmable_recalc_rate(struct clk_hw *hw,
 						  unsigned long parent_rate)
 {
-	u32 tmp;
+	u32 pres;
 	struct clk_programmable *prog = to_clk_programmable(hw);
 	struct at91_pmc *pmc = prog->pmc;
 	const struct clk_programmable_layout *layout = prog->layout;
 
-	tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id));
-	prog->pres = (tmp >> layout->pres_shift) & PROG_PRES_MASK;
-
-	return parent_rate >> prog->pres;
+	pres = (pmc_read(pmc, AT91_PMC_PCKR(prog->id)) >> layout->pres_shift) &
+	       PROG_PRES_MASK;
+	return parent_rate >> pres;
 }
 
 static long clk_programmable_determine_rate(struct clk_hw *hw,
@@ -146,17 +98,22 @@ static int clk_programmable_set_parent(struct clk_hw *hw, u8 index)
 {
 	struct clk_programmable *prog = to_clk_programmable(hw);
 	const struct clk_programmable_layout *layout = prog->layout;
+	struct at91_pmc *pmc = prog->pmc;
+	u32 tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id)) & ~layout->css_mask;
+
+	if (layout->have_slck_mck)
+		tmp &= AT91_PMC_CSSMCK_MCK;
+
 	if (index > layout->css_mask) {
 		if (index > PROG_MAX_RM9200_CSS && layout->have_slck_mck) {
-			prog->css = 0;
-			prog->slckmck = 1;
+			tmp |= AT91_PMC_CSSMCK_MCK;
 			return 0;
 		} else {
 			return -EINVAL;
 		}
 	}
 
-	prog->css = index;
+	pmc_write(pmc, AT91_PMC_PCKR(prog->id), tmp | index);
 	return 0;
 }
 
@@ -169,13 +126,9 @@ static u8 clk_programmable_get_parent(struct clk_hw *hw)
 	const struct clk_programmable_layout *layout = prog->layout;
 
 	tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id));
-	prog->css = tmp & layout->css_mask;
-	ret = prog->css;
-	if (layout->have_slck_mck) {
-		prog->slckmck = !!(tmp & AT91_PMC_CSSMCK_MCK);
-		if (prog->slckmck && !ret)
-			ret = PROG_MAX_RM9200_CSS + 1;
-	}
+	ret = tmp & layout->css_mask;
+	if (layout->have_slck_mck && (tmp & AT91_PMC_CSSMCK_MCK) && !ret)
+		ret = PROG_MAX_RM9200_CSS + 1;
 
 	return ret;
 }
@@ -184,11 +137,15 @@ static int clk_programmable_set_rate(struct clk_hw *hw, unsigned long rate,
 				     unsigned long parent_rate)
 {
 	struct clk_programmable *prog = to_clk_programmable(hw);
+	struct at91_pmc *pmc = prog->pmc;
+	const struct clk_programmable_layout *layout = prog->layout;
 	unsigned long best_rate = parent_rate;
 	unsigned long best_diff;
 	unsigned long new_diff;
 	unsigned long cur_rate;
 	int shift = 0;
+	u32 tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id)) &
+		  ~(PROG_PRES_MASK << layout->pres_shift);
 
 	if (rate > parent_rate)
 		return parent_rate;
@@ -196,7 +153,7 @@ static int clk_programmable_set_rate(struct clk_hw *hw, unsigned long rate,
 		best_diff = parent_rate - rate;
 
 	if (!best_diff) {
-		prog->pres = shift;
+		pmc_write(pmc, AT91_PMC_PCKR(prog->id), tmp | shift);
 		return 0;
 	}
 
@@ -220,13 +177,13 @@ static int clk_programmable_set_rate(struct clk_hw *hw, unsigned long rate,
 			break;
 	}
 
-	prog->pres = shift;
+	pmc_write(pmc, AT91_PMC_PCKR(prog->id),
+		  tmp | (shift << layout->pres_shift));
+
 	return 0;
 }
 
 static const struct clk_ops programmable_ops = {
-	.prepare = clk_programmable_prepare,
-	.is_prepared = clk_programmable_is_ready,
 	.recalc_rate = clk_programmable_recalc_rate,
 	.determine_rate = clk_programmable_determine_rate,
 	.get_parent = clk_programmable_get_parent,
@@ -235,16 +192,14 @@ static const struct clk_ops programmable_ops = {
 };
 
 static struct clk * __init
-at91_clk_register_programmable(struct at91_pmc *pmc, unsigned int irq,
+at91_clk_register_programmable(struct at91_pmc *pmc,
 			       const char *name, const char **parent_names,
 			       u8 num_parents, u8 id,
 			       const struct clk_programmable_layout *layout)
 {
-	int ret;
 	struct clk_programmable *prog;
 	struct clk *clk = NULL;
 	struct clk_init_data init;
-	char irq_name[11];
 
 	if (id > PROG_ID_MAX)
 		return ERR_PTR(-EINVAL);
@@ -263,14 +218,6 @@ at91_clk_register_programmable(struct at91_pmc *pmc, unsigned int irq,
 	prog->layout = layout;
 	prog->hw.init = &init;
 	prog->pmc = pmc;
-	prog->irq = irq;
-	init_waitqueue_head(&prog->wait);
-	irq_set_status_flags(prog->irq, IRQ_NOAUTOEN);
-	snprintf(irq_name, sizeof(irq_name), "clk-prog%d", id);
-	ret = request_irq(prog->irq, clk_programmable_irq_handler,
-			  IRQF_TRIGGER_HIGH, irq_name, prog);
-	if (ret)
-		return ERR_PTR(ret);
 
 	clk = clk_register(NULL, &prog->hw);
 	if (IS_ERR(clk))
@@ -304,7 +251,6 @@ of_at91_clk_prog_setup(struct device_node *np, struct at91_pmc *pmc,
 	int num;
 	u32 id;
 	int i;
-	unsigned int irq;
 	struct clk *clk;
 	int num_parents;
 	const char *parent_names[PROG_SOURCE_MAX];
@@ -332,11 +278,7 @@ of_at91_clk_prog_setup(struct device_node *np, struct at91_pmc *pmc,
 		if (of_property_read_string(np, "clock-output-names", &name))
 			name = progclknp->name;
 
-		irq = irq_of_parse_and_map(progclknp, 0);
-		if (!irq)
-			continue;
-
-		clk = at91_clk_register_programmable(pmc, irq, name,
+		clk = at91_clk_register_programmable(pmc, name,
 						     parent_names, num_parents,
 						     id, layout);
 		if (IS_ERR(clk))
diff --git a/drivers/clk/at91/clk-system.c b/drivers/clk/at91/clk-system.c
index a98557b..82c5f44 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);
@@ -90,6 +131,15 @@ 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))
@@ -102,6 +152,7 @@ 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;
@@ -119,9 +170,12 @@ 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;
 
-- 
1.8.5.2

[PATCH v2 4/4] clk: at91: optimization of the determine_rate callback

[Jean-Jacques Hiblot]

Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com>
Signed-off-by: Jean-Jacques Hiblot <jjhiblot@traphandler.com>
---
 drivers/clk/at91/clk-programmable.c | 38 ++++++++-----------------------------
 1 file changed, 8 insertions(+), 30 deletions(-)

diff --git a/drivers/clk/at91/clk-programmable.c b/drivers/clk/at91/clk-programmable.c
index 7bcc725..62e2509 100644
--- a/drivers/clk/at91/clk-programmable.c
+++ b/drivers/clk/at91/clk-programmable.c
@@ -139,43 +139,21 @@ static int clk_programmable_set_rate(struct clk_hw *hw, unsigned long rate,
 	struct clk_programmable *prog = to_clk_programmable(hw);
 	struct at91_pmc *pmc = prog->pmc;
 	const struct clk_programmable_layout *layout = prog->layout;
-	unsigned long best_rate = parent_rate;
-	unsigned long best_diff;
-	unsigned long new_diff;
-	unsigned long cur_rate;
+	unsigned long div = parent_rate / rate;
 	int shift = 0;
 	u32 tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id)) &
 		  ~(PROG_PRES_MASK << layout->pres_shift);
 
-	if (rate > parent_rate)
-		return parent_rate;
-	else
-		best_diff = parent_rate - rate;
+	if (!div)
+		return -EINVAL;
 
-	if (!best_diff) {
-		pmc_write(pmc, AT91_PMC_PCKR(prog->id), tmp | shift);
-		return 0;
-	}
-
-	for (shift = 1; shift < PROG_PRES_MASK; shift++) {
-		cur_rate = parent_rate >> shift;
-
-		if (cur_rate > rate)
-			new_diff = cur_rate - rate;
-		else
-			new_diff = rate - cur_rate;
-
-		if (!new_diff)
-			break;
+	shift = fls(div) - 1;
 
-		if (new_diff < best_diff) {
-			best_diff = new_diff;
-			best_rate = cur_rate;
-		}
+	if (div != (1<<shift))
+		return -EINVAL;
 
-		if (rate > cur_rate)
-			break;
-	}
+	if (shift >= PROG_PRES_MASK)
+		return -EINVAL;
 
 	pmc_write(pmc, AT91_PMC_PCKR(prog->id),
 		  tmp | (shift << layout->pres_shift));
-- 
1.8.5.2

Re: [PATCH v2 4/4] clk: at91: optimization of the determine_rate callback

[Boris BREZILLON]

Hi JJ,

I guess you're commit message is wrong: you're optimizing set_rate not 
determine_rate.

Best Regards,

Boris

On 05/02/2014 09:37, Jean-Jacques Hiblot wrote:
> Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com>
> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@traphandler.com>
> ---
>   drivers/clk/at91/clk-programmable.c | 38 ++++++++-----------------------------
>   1 file changed, 8 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/clk/at91/clk-programmable.c b/drivers/clk/at91/clk-programmable.c
> index 7bcc725..62e2509 100644
> --- a/drivers/clk/at91/clk-programmable.c
> +++ b/drivers/clk/at91/clk-programmable.c
> @@ -139,43 +139,21 @@ static int clk_programmable_set_rate(struct clk_hw *hw, unsigned long rate,
>   	struct clk_programmable *prog = to_clk_programmable(hw);
>   	struct at91_pmc *pmc = prog->pmc;
>   	const struct clk_programmable_layout *layout = prog->layout;
> -	unsigned long best_rate = parent_rate;
> -	unsigned long best_diff;
> -	unsigned long new_diff;
> -	unsigned long cur_rate;
> +	unsigned long div = parent_rate / rate;
>   	int shift = 0;
>   	u32 tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id)) &
>   		  ~(PROG_PRES_MASK << layout->pres_shift);
>   
> -	if (rate > parent_rate)
> -		return parent_rate;
> -	else
> -		best_diff = parent_rate - rate;
> +	if (!div)
> +		return -EINVAL;
>   
> -	if (!best_diff) {
> -		pmc_write(pmc, AT91_PMC_PCKR(prog->id), tmp | shift);
> -		return 0;
> -	}
> -
> -	for (shift = 1; shift < PROG_PRES_MASK; shift++) {
> -		cur_rate = parent_rate >> shift;
> -
> -		if (cur_rate > rate)
> -			new_diff = cur_rate - rate;
> -		else
> -			new_diff = rate - cur_rate;
> -
> -		if (!new_diff)
> -			break;
> +	shift = fls(div) - 1;
>   
> -		if (new_diff < best_diff) {
> -			best_diff = new_diff;
> -			best_rate = cur_rate;
> -		}
> +	if (div != (1<<shift))
> +		return -EINVAL;
>   
> -		if (rate > cur_rate)
> -			break;
> -	}
> +	if (shift >= PROG_PRES_MASK)
> +		return -EINVAL;
>   
>   	pmc_write(pmc, AT91_PMC_PCKR(prog->id),
>   		  tmp | (shift << layout->pres_shift));

[PATCH v2] clk: at91: optimization of the set_rate callback

[Jean-Jacques Hiblot]

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

Hi,
this fixes the commit's log as indicated by Boris.
cheers,
Jean-jacques

 drivers/clk/at91/clk-programmable.c | 38 ++++++++-----------------------------
 1 file changed, 8 insertions(+), 30 deletions(-)

diff --git a/drivers/clk/at91/clk-programmable.c b/drivers/clk/at91/clk-programmable.c
index 7bcc725..62e2509 100644
--- a/drivers/clk/at91/clk-programmable.c
+++ b/drivers/clk/at91/clk-programmable.c
@@ -139,43 +139,21 @@ static int clk_programmable_set_rate(struct clk_hw *hw, unsigned long rate,
 	struct clk_programmable *prog = to_clk_programmable(hw);
 	struct at91_pmc *pmc = prog->pmc;
 	const struct clk_programmable_layout *layout = prog->layout;
-	unsigned long best_rate = parent_rate;
-	unsigned long best_diff;
-	unsigned long new_diff;
-	unsigned long cur_rate;
+	unsigned long div = parent_rate / rate;
 	int shift = 0;
 	u32 tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id)) &
 		  ~(PROG_PRES_MASK << layout->pres_shift);
 
-	if (rate > parent_rate)
-		return parent_rate;
-	else
-		best_diff = parent_rate - rate;
+	if (!div)
+		return -EINVAL;
 
-	if (!best_diff) {
-		pmc_write(pmc, AT91_PMC_PCKR(prog->id), tmp | shift);
-		return 0;
-	}
-
-	for (shift = 1; shift < PROG_PRES_MASK; shift++) {
-		cur_rate = parent_rate >> shift;
-
-		if (cur_rate > rate)
-			new_diff = cur_rate - rate;
-		else
-			new_diff = rate - cur_rate;
-
-		if (!new_diff)
-			break;
+	shift = fls(div) - 1;
 
-		if (new_diff < best_diff) {
-			best_diff = new_diff;
-			best_rate = cur_rate;
-		}
+	if (div != (1<<shift))
+		return -EINVAL;
 
-		if (rate > cur_rate)
-			break;
-	}
+	if (shift >= PROG_PRES_MASK)
+		return -EINVAL;
 
 	pmc_write(pmc, AT91_PMC_PCKR(prog->id),
 		  tmp | (shift << layout->pres_shift));
-- 
1.8.5.3

Re: [PATCH v2 2/4] clk: at91: propagate rate change on system clks

[Mike Turquette]

Quoting Jean-Jacques Hiblot (2014-02-05 00:37:36)
> From: Boris BREZILLON <b.brezillon@overkiz.com>
> 
> System clks are just gates, and thus do not provide any rate operations.
> Authorize clk rate change to be propagated to system clk parents.
> 
> Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com>
> ---
>  drivers/clk/at91/clk-system.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/clk/at91/clk-system.c b/drivers/clk/at91/clk-system.c
> index 8f7c043..a98557b 100644
> --- a/drivers/clk/at91/clk-system.c
> +++ b/drivers/clk/at91/clk-system.c
> @@ -84,7 +84,8 @@ at91_clk_register_system(struct at91_pmc *pmc, const char *name,
>          * (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_IGNORE_UNUSED;
> +       init.flags = CLK_SET_RATE_GATE | CLK_SET_RATE_PARENT |

Just wanted to do a quick sanity check here. Do you really need
CLK_SET_RATE_GATE? Otherwise these patches look fine.

Regards,
Mike

> +                    CLK_IGNORE_UNUSED;
>  
>         sys->id = id;
>         sys->hw.init = &init;
> -- 
> 1.8.5.2
> 

Re: [PATCH v2 2/4] clk: at91: propagate rate change on system clks

[Boris BREZILLON]

Hi Mike,

On 27/02/2014 01:42, Mike Turquette wrote:
> Quoting Jean-Jacques Hiblot (2014-02-05 00:37:36)
>> From: Boris BREZILLON <b.brezillon@overkiz.com>
>>
>> System clks are just gates, and thus do not provide any rate operations.
>> Authorize clk rate change to be propagated to system clk parents.
>>
>> Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com>
>> ---
>>   drivers/clk/at91/clk-system.c | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/clk/at91/clk-system.c b/drivers/clk/at91/clk-system.c
>> index 8f7c043..a98557b 100644
>> --- a/drivers/clk/at91/clk-system.c
>> +++ b/drivers/clk/at91/clk-system.c
>> @@ -84,7 +84,8 @@ at91_clk_register_system(struct at91_pmc *pmc, const char *name,
>>           * (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_IGNORE_UNUSED;
>> +       init.flags = CLK_SET_RATE_GATE | CLK_SET_RATE_PARENT |
> Just wanted to do a quick sanity check here. Do you really need
> CLK_SET_RATE_GATE?

After taking a closer look, I'd say I don't need this flag, because it's
already set on programmable clks, am I right ?

Do you want me to send a new version removing this flag ?

> Otherwise these patches look fine.
>
> Regards,
> Mike
>
>> +                    CLK_IGNORE_UNUSED;
>>   
>>          sys->id = id;
>>          sys->hw.init = &init;
>> -- 
>> 1.8.5.2
>>