[PATCH 14/19] clk: at91: clk-peripheral: add support for changeable parent rate

Claudiu Beznea
2020-07-15T11:25:37Z

Some peripheral clocks on SAMA7G5 supports requesting parent to change
its rate (image related clocks: csi, csi2dc, isc). Add support
so that if registered with this option the clock rate to be
requested from parent.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
---
drivers/clk/at91/at91sam9n12.c | 2 +-
drivers/clk/at91/at91sam9x5.c | 4 +-
drivers/clk/at91/clk-peripheral.c | 109 ++++++++++++++++++++++++++++++++++++--
drivers/clk/at91/dt-compat.c | 3 +-
drivers/clk/at91/pmc.h | 3 +-
drivers/clk/at91/sam9x60.c | 2 +-
drivers/clk/at91/sama5d2.c | 5 +-
drivers/clk/at91/sama5d3.c | 3 +-
drivers/clk/at91/sama5d4.c | 4 +-
9 files changed, 119 insertions(+), 16 deletions(-)

diff --git a/drivers/clk/at91/at91sam9n12.c b/drivers/clk/at91/at91sam9n12.c
index 630dc5d87171..f4c36e6e4deb 100644
--- a/drivers/clk/at91/at91sam9n12.c
+++ b/drivers/clk/at91/at91sam9n12.c
@@ -222,7 +222,7 @@ static void __init at91sam9n12_pmc_setup(struct device_node *np)
at91sam9n12_periphck[i].n,
"masterck",
at91sam9n12_periphck[i].id,
- &range);
+ &range, INT_MIN);
if (IS_ERR(hw))
goto err_free;

diff --git a/drivers/clk/at91/at91sam9x5.c b/drivers/clk/at91/at91sam9x5.c
index 0ce3da080287..52a9d2f7ec83 100644
--- a/drivers/clk/at91/at91sam9x5.c
+++ b/drivers/clk/at91/at91sam9x5.c
@@ -257,7 +257,7 @@ static void __init at91sam9x5_pmc_setup(struct device_node *np,
at91sam9x5_periphck[i].n,
"masterck",
at91sam9x5_periphck[i].id,
- &range);
+ &range, INT_MIN);
if (IS_ERR(hw))
goto err_free;

@@ -270,7 +270,7 @@ static void __init at91sam9x5_pmc_setup(struct device_node *np,
extra_pcks[i].n,
"masterck",
extra_pcks[i].id,
- &range);
+ &range, INT_MIN);
if (IS_ERR(hw))
goto err_free;

diff --git a/drivers/clk/at91/clk-peripheral.c b/drivers/clk/at91/clk-peripheral.c
index 4c9a4147dfe5..7867eaf0447f 100644
--- a/drivers/clk/at91/clk-peripheral.c
+++ b/drivers/clk/at91/clk-peripheral.c
@@ -38,6 +38,7 @@ struct clk_sam9x5_peripheral {
u32 div;
const struct clk_pcr_layout *layout;
bool auto_div;
+ int chg_pid;
};

#define to_clk_sam9x5_peripheral(hw) \
@@ -238,6 +239,87 @@ clk_sam9x5_peripheral_recalc_rate(struct clk_hw *hw,
return parent_rate >> periph->div;
}

+static void clk_sam9x5_peripheral_best_diff(struct clk_rate_request *req,
+ struct clk_hw *parent,
+ unsigned long parent_rate,
+ u32 shift, long *best_diff,
+ long *best_rate)
+{
+ unsigned long tmp_rate = parent_rate >> shift;
+ unsigned long tmp_diff = abs(req->rate - tmp_rate);
+
+ if (*best_diff < 0 || *best_diff >= tmp_diff) {
+ *best_rate = tmp_rate;
+ *best_diff = tmp_diff;
+ req->best_parent_rate = parent_rate;
+ req->best_parent_hw = parent;
+ }
+}
+
+static int clk_sam9x5_peripheral_determine_rate(struct clk_hw *hw,
+ struct clk_rate_request *req)
+{
+ struct clk_sam9x5_peripheral *periph = to_clk_sam9x5_peripheral(hw);
+ struct clk_hw *parent = clk_hw_get_parent(hw);
+ struct clk_rate_request req_parent = *req;
+ unsigned long parent_rate = clk_hw_get_rate(parent);
+ unsigned long tmp_rate;
+ long best_rate = LONG_MIN;
+ long best_diff = LONG_MIN;
+ u32 shift;
+
+ if (periph->id < PERIPHERAL_ID_MIN || !periph->range.max)
+ return parent_rate;
+
+ /* Fist step: check the available dividers. */
+ for (shift = 0; shift <= PERIPHERAL_MAX_SHIFT; shift++) {
+ tmp_rate = parent_rate >> shift;
+
+ if (periph->range.max && tmp_rate > periph->range.max)
+ continue;
+
+ clk_sam9x5_peripheral_best_diff(req, parent, parent_rate,
+ shift, &best_diff, &best_rate);
+
+ if (!best_diff || best_rate <= req->rate)
+ break;
+ }
+
+ if (periph->chg_pid < 0)
+ goto end;
+
+ /* Step two: try to request rate from parent. */
+ parent = clk_hw_get_parent_by_index(hw, periph->chg_pid);
+ if (!parent)
+ goto end;
+
+ for (shift = 0; shift <= PERIPHERAL_MAX_SHIFT; shift++) {
+ req_parent.rate = req->rate << shift;
+
+ if (__clk_determine_rate(parent, &req_parent))
+ continue;
+
+ clk_sam9x5_peripheral_best_diff(req, parent, req_parent.rate,
+ shift, &best_diff, &best_rate);
+
+ if (!best_diff)
+ break;
+ }
+end:
+ if (best_rate < 0 ||
+ (periph->range.max && best_rate > periph->range.max))
+ return -EINVAL;
+
+ pr_debug("PCK: %s, best_rate = %ld, parent clk: %s @ %ld\n",
+ __func__, best_rate,
+ __clk_get_name((req->best_parent_hw)->clk),
+ req->best_parent_rate);
+
+ req->rate = best_rate;
+
+ return 0;
+}
+
static long clk_sam9x5_peripheral_round_rate(struct clk_hw *hw,
unsigned long rate,
unsigned long *parent_rate)
@@ -320,11 +402,21 @@ static const struct clk_ops sam9x5_peripheral_ops = {
.set_rate = clk_sam9x5_peripheral_set_rate,
};

+static const struct clk_ops sam9x5_peripheral_chg_ops = {
+ .enable = clk_sam9x5_peripheral_enable,
+ .disable = clk_sam9x5_peripheral_disable,
+ .is_enabled = clk_sam9x5_peripheral_is_enabled,
+ .recalc_rate = clk_sam9x5_peripheral_recalc_rate,
+ .determine_rate = clk_sam9x5_peripheral_determine_rate,
+ .set_rate = clk_sam9x5_peripheral_set_rate,
+};
+
struct clk_hw * __init
at91_clk_register_sam9x5_peripheral(struct regmap *regmap, spinlock_t *lock,
const struct clk_pcr_layout *layout,
const char *name, const char *parent_name,
- u32 id, const struct clk_range *range)
+ u32 id, const struct clk_range *range,
+ int chg_pid)
{
struct clk_sam9x5_peripheral *periph;
struct clk_init_data init;
@@ -339,10 +431,16 @@ at91_clk_register_sam9x5_peripheral(struct regmap *regmap, spinlock_t *lock,
return ERR_PTR(-ENOMEM);

init.name = name;
- init.ops = &sam9x5_peripheral_ops;
- init.parent_names = (parent_name ? &parent_name : NULL);
- init.num_parents = (parent_name ? 1 : 0);
- init.flags = 0;
+ init.parent_names = &parent_name;
+ init.num_parents = 1;
+ if (chg_pid < 0) {
+ init.flags = 0;
+ init.ops = &sam9x5_peripheral_ops;
+ } else {
+ init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE |
+ CLK_SET_RATE_PARENT;
+ init.ops = &sam9x5_peripheral_chg_ops;
+ }

periph->id = id;
periph->hw.init = &init;
@@ -353,6 +451,7 @@ at91_clk_register_sam9x5_peripheral(struct regmap *regmap, spinlock_t *lock,
periph->auto_div = true;
periph->layout = layout;
periph->range = *range;
+ periph->chg_pid = chg_pid;

hw = &periph->hw;
ret = clk_hw_register(NULL, &periph->hw);
diff --git a/drivers/clk/at91/dt-compat.c b/drivers/clk/at91/dt-compat.c
index cc95d42f4d53..1b90c4f7b1d1 100644
--- a/drivers/clk/at91/dt-compat.c
+++ b/drivers/clk/at91/dt-compat.c
@@ -463,7 +463,8 @@ of_at91_clk_periph_setup(struct device_node *np, u8 type)
&dt_pcr_layout,
name,
parent_name,
- id, &range);
+ id, &range,
+ INT_MIN);
}

if (IS_ERR(hw))
diff --git a/drivers/clk/at91/pmc.h b/drivers/clk/at91/pmc.h
index 29d150feaa46..34c9506e6275 100644
--- a/drivers/clk/at91/pmc.h
+++ b/drivers/clk/at91/pmc.h
@@ -168,7 +168,8 @@ struct clk_hw * __init
at91_clk_register_sam9x5_peripheral(struct regmap *regmap, spinlock_t *lock,
const struct clk_pcr_layout *layout,
const char *name, const char *parent_name,
- u32 id, const struct clk_range *range);
+ u32 id, const struct clk_range *range,
+ int chg_pid);

struct clk_hw * __init
at91_clk_register_pll(struct regmap *regmap, const char *name,
diff --git a/drivers/clk/at91/sam9x60.c b/drivers/clk/at91/sam9x60.c
index 3ad16d74577e..25b57c6105cd 100644
--- a/drivers/clk/at91/sam9x60.c
+++ b/drivers/clk/at91/sam9x60.c
@@ -277,7 +277,7 @@ static void __init sam9x60_pmc_setup(struct device_node *np)
sam9x60_periphck[i].n,
"masterck",
sam9x60_periphck[i].id,
- &range);
+ &range, INT_MIN);
if (IS_ERR(hw))
goto err_free;

diff --git a/drivers/clk/at91/sama5d2.c b/drivers/clk/at91/sama5d2.c
index 6a685d00f16d..c7765b664940 100644
--- a/drivers/clk/at91/sama5d2.c
+++ b/drivers/clk/at91/sama5d2.c
@@ -291,7 +291,7 @@ static void __init sama5d2_pmc_setup(struct device_node *np)
sama5d2_periphck[i].n,
"masterck",
sama5d2_periphck[i].id,
- &range);
+ &range, INT_MIN);
if (IS_ERR(hw))
goto err_free;

@@ -304,7 +304,8 @@ static void __init sama5d2_pmc_setup(struct device_node *np)
sama5d2_periph32ck[i].n,
"h32mxck",
sama5d2_periph32ck[i].id,
- &sama5d2_periph32ck[i].r);
+ &sama5d2_periph32ck[i].r,
+ INT_MIN);
if (IS_ERR(hw))
goto err_free;

diff --git a/drivers/clk/at91/sama5d3.c b/drivers/clk/at91/sama5d3.c
index 5e4e44dd4c37..1597124609e5 100644
--- a/drivers/clk/at91/sama5d3.c
+++ b/drivers/clk/at91/sama5d3.c
@@ -223,7 +223,8 @@ static void __init sama5d3_pmc_setup(struct device_node *np)
sama5d3_periphck[i].n,
"masterck",
sama5d3_periphck[i].id,
- &sama5d3_periphck[i].r);
+ &sama5d3_periphck[i].r,
+ INT_MIN);
if (IS_ERR(hw))
goto err_free;

diff --git a/drivers/clk/at91/sama5d4.c b/drivers/clk/at91/sama5d4.c
index 662ff5fa6e98..fa121897d95d 100644
--- a/drivers/clk/at91/sama5d4.c
+++ b/drivers/clk/at91/sama5d4.c
@@ -246,7 +246,7 @@ static void __init sama5d4_pmc_setup(struct device_node *np)
sama5d4_periphck[i].n,
"masterck",
sama5d4_periphck[i].id,
- &range);
+ &range, INT_MIN);
if (IS_ERR(hw))
goto err_free;

@@ -259,7 +259,7 @@ static void __init sama5d4_pmc_setup(struct device_node *np)
sama5d4_periph32ck[i].n,
"h32mxck",
sama5d4_periph32ck[i].id,
- &range);
+ &range, INT_MIN);
if (IS_ERR(hw))
goto err_free;

--
2.7.4