On 5/10/22 5:51 AM, Amelie Delaunay wrote:
Hi Patrick,
Hi Sean,
On 5/9/22 16:37, Patrick DELAUNAY wrote:
Hi Sean,
On 5/8/22 20:21, Sean Anderson wrote:
On 4/26/22 8:37 AM, Patrick Delaunay wrote:
Add the counter of the PLL user n_pll_cons managed by the 2 functions
stm32_usbphyc_pll_enable / stm32_usbphyc_pll_disable.
This counter allow to remove the function stm32_usbphyc_is_init
and it is a preliminary step for ck_usbo_48m introduction.
Is it necessary to disable this clock before booting to Linux? If it isn't,
then perhaps it is simpler to just not disable the clock.
--Sean
No, it is not necessary, we only need to enable the clock for the first user.
I copy the clock behavior from kernel,
but I agree that can be simpler.
Amelie any notice about this point ?
Do you prefer that I kept the behavior - same as kernel driver - or I simplify
the U-Boot driver ?
In case the PLL has not been disabled before Kernel boot, usbphyc Kernel driver
will wait for the PLL pwerdown.
USB could also not being used in Kernel, so PLL would remain enabled, and would
waste power.
I am rather in favor of disabling the PLL.
It should be disabled if clk_ignore_unused is not in the kernel parameters,
as long as Linux is also aware of the clock.
Generally, I would like to avoid refcounting if possible. Many U-Boot
drivers do not disable their clocks (because they don't do any cleanup),
so you can end up with the clock staying on anyway.
--Sean
Regards,
Amelie
Patrick
Signed-off-by: Patrick Delaunay <patrick.delau...@foss.st.com>
---
drivers/phy/phy-stm32-usbphyc.c | 76 +++++++++++++++++++++------------
1 file changed, 48 insertions(+), 28 deletions(-)
diff --git a/drivers/phy/phy-stm32-usbphyc.c b/drivers/phy/phy-stm32-usbphyc.c
index 9c1dcfae52..16c8799eca 100644
--- a/drivers/phy/phy-stm32-usbphyc.c
+++ b/drivers/phy/phy-stm32-usbphyc.c
@@ -65,6 +65,7 @@ struct stm32_usbphyc {
bool init;
bool powered;
} phys[MAX_PHYS];
+ int n_pll_cons;
};
static void stm32_usbphyc_get_pll_params(u32 clk_rate,
@@ -124,18 +125,6 @@ static int stm32_usbphyc_pll_init(struct stm32_usbphyc
*usbphyc)
return 0;
}
-static bool stm32_usbphyc_is_init(struct stm32_usbphyc *usbphyc)
-{
- int i;
-
- for (i = 0; i < MAX_PHYS; i++) {
- if (usbphyc->phys[i].init)
- return true;
- }
-
- return false;
-}
-
static bool stm32_usbphyc_is_powered(struct stm32_usbphyc *usbphyc)
{
int i;
@@ -148,18 +137,17 @@ static bool stm32_usbphyc_is_powered(struct stm32_usbphyc
*usbphyc)
return false;
}
-static int stm32_usbphyc_phy_init(struct phy *phy)
+static int stm32_usbphyc_pll_enable(struct stm32_usbphyc *usbphyc)
{
- struct stm32_usbphyc *usbphyc = dev_get_priv(phy->dev);
- struct stm32_usbphyc_phy *usbphyc_phy = usbphyc->phys + phy->id;
bool pllen = readl(usbphyc->base + STM32_USBPHYC_PLL) & PLLEN ?
true : false;
int ret;
- dev_dbg(phy->dev, "phy ID = %lu\n", phy->id);
- /* Check if one phy port has already configured the pll */
- if (pllen && stm32_usbphyc_is_init(usbphyc))
- goto initialized;
+ /* Check if one consumer has already configured the pll */
+ if (pllen && usbphyc->n_pll_cons) {
+ usbphyc->n_pll_cons++;
+ return 0;
+ }
if (usbphyc->vdda1v1) {
ret = regulator_set_enable(usbphyc->vdda1v1, true);
@@ -190,23 +178,19 @@ static int stm32_usbphyc_phy_init(struct phy *phy)
if (!(readl(usbphyc->base + STM32_USBPHYC_PLL) & PLLEN))
return -EIO;
-initialized:
- usbphyc_phy->init = true;
+ usbphyc->n_pll_cons++;
return 0;
}
-static int stm32_usbphyc_phy_exit(struct phy *phy)
+static int stm32_usbphyc_pll_disable(struct stm32_usbphyc *usbphyc)
{
- struct stm32_usbphyc *usbphyc = dev_get_priv(phy->dev);
- struct stm32_usbphyc_phy *usbphyc_phy = usbphyc->phys + phy->id;
int ret;
- dev_dbg(phy->dev, "phy ID = %lu\n", phy->id);
- usbphyc_phy->init = false;
+ usbphyc->n_pll_cons--;
- /* Check if other phy port requires pllen */
- if (stm32_usbphyc_is_init(usbphyc))
+ /* Check if other consumer requires pllen */
+ if (usbphyc->n_pll_cons)
return 0;
clrbits_le32(usbphyc->base + STM32_USBPHYC_PLL, PLLEN);
@@ -235,6 +219,42 @@ static int stm32_usbphyc_phy_exit(struct phy *phy)
return 0;
}
+static int stm32_usbphyc_phy_init(struct phy *phy)
+{
+ struct stm32_usbphyc *usbphyc = dev_get_priv(phy->dev);
+ struct stm32_usbphyc_phy *usbphyc_phy = usbphyc->phys + phy->id;
+ int ret;
+
+ dev_dbg(phy->dev, "phy ID = %lu\n", phy->id);
+ if (usbphyc_phy->init)
+ return 0;
+
+ ret = stm32_usbphyc_pll_enable(usbphyc);
+ if (ret)
+ return log_ret(ret);
+
+ usbphyc_phy->init = true;
+
+ return 0;
+}
+
+static int stm32_usbphyc_phy_exit(struct phy *phy)
+{
+ struct stm32_usbphyc *usbphyc = dev_get_priv(phy->dev);
+ struct stm32_usbphyc_phy *usbphyc_phy = usbphyc->phys + phy->id;
+ int ret;
+
+ dev_dbg(phy->dev, "phy ID = %lu\n", phy->id);
+ if (!usbphyc_phy->init)
+ return 0;
+
+ ret = stm32_usbphyc_pll_disable(usbphyc);
+
+ usbphyc_phy->init = false;
+
+ return log_ret(ret);
+}
+
static int stm32_usbphyc_phy_power_on(struct phy *phy)
{
struct stm32_usbphyc *usbphyc = dev_get_priv(phy->dev);
