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
Signed-off-by: Boris BREZILLON <[email protected]>
Signed-off-by: Jean-Jacques Hiblot <[email protected]>
---
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
From: Boris BREZILLON <[email protected]>
Implement the determine_rate callback to choose the best parent clk that
fulfills the requested rate.
Signed-off-by: Boris BREZILLON <[email protected]>
---
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
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 <[email protected]>
Signed-off-by: Jean-Jacques Hiblot <[email protected]>
---
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
From: Boris BREZILLON <[email protected]>
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 <[email protected]>
---
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
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 <[email protected]>
> Signed-off-by: Jean-Jacques Hiblot <[email protected]>
> ---
> 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));
Signed-off-by: Boris BREZILLON <[email protected]>
Signed-off-by: Jean-Jacques Hiblot <[email protected]>
---
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
Quoting Jean-Jacques Hiblot (2014-02-05 00:37:36)
> From: Boris BREZILLON <[email protected]>
>
> 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 <[email protected]>
> ---
> 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
>
Hi Mike,
On 27/02/2014 01:42, Mike Turquette wrote:
> Quoting Jean-Jacques Hiblot (2014-02-05 00:37:36)
>> From: Boris BREZILLON <[email protected]>
>>
>> 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 <[email protected]>
>> ---
>> 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
>>