diff mbox series

[v2,1/2] phy: qcom: pcie: Determine has_nocsr_reset dynamically

Message ID 20250211094231.1813558-2-quic_wenbyao@quicinc.com
State Superseded
Headers show
Series phy: qcom: qmp-pcie: Add PCIe PHY no_csr reset support | expand

Commit Message

Wenbin Yao Feb. 11, 2025, 9:42 a.m. UTC 
From: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>

Decide the in-driver logic based on whether the nocsr reset is present
and defer checking the appropriateness of that to dt-bindings to save
on boilerplate.

Reset controller APIs are fine consuming a nullptr, so no additional
checks are necessary there.

Signed-off-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Wenbin Yao <quic_wenbyao@quicinc.com>
Reviewed-by: Abel Vesa <abel.vesa@linaro.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---
 drivers/phy/qualcomm/phy-qcom-qmp-pcie.c | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

Comments

Konrad Dybcio Feb. 12, 2025, 12:31 p.m. UTC | #1 
On 11.02.2025 10:53 AM, Philipp Zabel wrote:
> On Di, 2025-02-11 at 17:42 +0800, Wenbin Yao wrote:
>> From: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
>>
>> Decide the in-driver logic based on whether the nocsr reset is present
>> and defer checking the appropriateness of that to dt-bindings to save
>> on boilerplate.
>>
>> Reset controller APIs are fine consuming a nullptr, so no additional
>> checks are necessary there.
>>
>> Signed-off-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
>> Signed-off-by: Wenbin Yao <quic_wenbyao@quicinc.com>
>> Reviewed-by: Abel Vesa <abel.vesa@linaro.org>
>> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
>> ---

[...]

>>  static void qmp_pcie_init_port_b(struct qmp_pcie *qmp, const struct qmp_phy_cfg_tbls *tbls)
>> @@ -4203,11 +4196,14 @@ static int qmp_pcie_reset_init(struct qmp_pcie *qmp)
>>  	if (ret)
>>  		return dev_err_probe(dev, ret, "failed to get resets\n");
>>  
>> -	if (cfg->has_nocsr_reset) {
>> -		qmp->nocsr_reset = devm_reset_control_get_exclusive(dev, "phy_nocsr");
>> -		if (IS_ERR(qmp->nocsr_reset))
>> +	qmp->nocsr_reset = devm_reset_control_get_exclusive(dev, "phy_nocsr");
>> +	if (IS_ERR(qmp->nocsr_reset)) {
>> +		if (PTR_ERR(qmp->nocsr_reset) == -ENOENT ||
>> +		    PTR_ERR(qmp->nocsr_reset) == -EINVAL)
> 
> Why is -EINVAL ignored here?

If the NOCSR (partial) reset is missing, we can still assert the "full" reset
and program the hardware from the ground up. It's also needed for backwards
dt compat as not all platforms described it when originally added.

> Without this you could just use
> devm_reset_control_get_optional_exclusive(), which already turns -
> ENOENT into NULL. That seems to me the correct thing to do, as from
> driver point-of-view, this reset control is optional.

Good point, I forgot _optional_ was a thing in the reset framework

Konrad
Wenbin Yao Feb. 13, 2025, 8:09 a.m. UTC | #2 
On 2/12/2025 8:31 PM, Konrad Dybcio wrote:
> On 11.02.2025 10:53 AM, Philipp Zabel wrote:
>> On Di, 2025-02-11 at 17:42 +0800, Wenbin Yao wrote:
>>> From: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
>>>
>>> Decide the in-driver logic based on whether the nocsr reset is present
>>> and defer checking the appropriateness of that to dt-bindings to save
>>> on boilerplate.
>>>
>>> Reset controller APIs are fine consuming a nullptr, so no additional
>>> checks are necessary there.
>>>
>>> Signed-off-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
>>> Signed-off-by: Wenbin Yao <quic_wenbyao@quicinc.com>
>>> Reviewed-by: Abel Vesa <abel.vesa@linaro.org>
>>> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
>>> ---
> [...]
>
>>>   static void qmp_pcie_init_port_b(struct qmp_pcie *qmp, const struct qmp_phy_cfg_tbls *tbls)
>>> @@ -4203,11 +4196,14 @@ static int qmp_pcie_reset_init(struct qmp_pcie *qmp)
>>>   	if (ret)
>>>   		return dev_err_probe(dev, ret, "failed to get resets\n");
>>>   
>>> -	if (cfg->has_nocsr_reset) {
>>> -		qmp->nocsr_reset = devm_reset_control_get_exclusive(dev, "phy_nocsr");
>>> -		if (IS_ERR(qmp->nocsr_reset))
>>> +	qmp->nocsr_reset = devm_reset_control_get_exclusive(dev, "phy_nocsr");
>>> +	if (IS_ERR(qmp->nocsr_reset)) {
>>> +		if (PTR_ERR(qmp->nocsr_reset) == -ENOENT ||
>>> +		    PTR_ERR(qmp->nocsr_reset) == -EINVAL)
>> Why is -EINVAL ignored here?
> If the NOCSR (partial) reset is missing, we can still assert the "full" reset
> and program the hardware from the ground up. It's also needed for backwards
> dt compat as not all platforms described it when originally added.

Seems like we really can't ignore -EINVAL. If no_csr reset is missing in
dts, it will return -ENOENT, which is turned into NULL by
devm_reset_control_get_optional_exclusive. -EINVAL indicates something
wrong in args we passed to the function and the reset property that need to
be fixed.

>
>> Without this you could just use
>> devm_reset_control_get_optional_exclusive(), which already turns -
>> ENOENT into NULL. That seems to me the correct thing to do, as from
>> driver point-of-view, this reset control is optional.
> Good point, I forgot _optional_ was a thing in the reset framework
>
> Konrad

Will use devm_reset_control_get_optional_exclusive function in patch v3.
diff mbox series

Patch

diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
index 873f2f9844c6..ac42e4b01065 100644
--- a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
+++ b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
@@ -2793,8 +2793,6 @@  struct qmp_phy_cfg {
 
 	bool skip_start_delay;
 
-	bool has_nocsr_reset;
-
 	/* QMP PHY pipe clock interface rate */
 	unsigned long pipe_clock_rate;
 
@@ -3685,7 +3683,6 @@  static const struct qmp_phy_cfg sm8550_qmp_gen4x2_pciephy_cfg = {
 
 	.pwrdn_ctrl		= SW_PWRDN | REFCLK_DRV_DSBL,
 	.phy_status		= PHYSTATUS_4_20,
-	.has_nocsr_reset	= true,
 
 	/* 20MHz PHY AUX Clock */
 	.aux_clock_rate		= 20000000,
@@ -3718,7 +3715,6 @@  static const struct qmp_phy_cfg sm8650_qmp_gen4x2_pciephy_cfg = {
 
 	.pwrdn_ctrl		= SW_PWRDN | REFCLK_DRV_DSBL,
 	.phy_status		= PHYSTATUS_4_20,
-	.has_nocsr_reset	= true,
 
 	/* 20MHz PHY AUX Clock */
 	.aux_clock_rate		= 20000000,
@@ -3836,7 +3832,6 @@  static const struct qmp_phy_cfg x1e80100_qmp_gen4x2_pciephy_cfg = {
 
 	.pwrdn_ctrl		= SW_PWRDN | REFCLK_DRV_DSBL,
 	.phy_status		= PHYSTATUS_4_20,
-	.has_nocsr_reset	= true,
 };
 
 static const struct qmp_phy_cfg x1e80100_qmp_gen4x4_pciephy_cfg = {
@@ -3870,7 +3865,6 @@  static const struct qmp_phy_cfg x1e80100_qmp_gen4x4_pciephy_cfg = {
 
 	.pwrdn_ctrl		= SW_PWRDN | REFCLK_DRV_DSBL,
 	.phy_status		= PHYSTATUS_4_20,
-	.has_nocsr_reset	= true,
 };
 
 static const struct qmp_phy_cfg x1e80100_qmp_gen4x8_pciephy_cfg = {
@@ -3902,7 +3896,6 @@  static const struct qmp_phy_cfg x1e80100_qmp_gen4x8_pciephy_cfg = {
 
 	.pwrdn_ctrl		= SW_PWRDN | REFCLK_DRV_DSBL,
 	.phy_status		= PHYSTATUS_4_20,
-	.has_nocsr_reset	= true,
 };
 
 static void qmp_pcie_init_port_b(struct qmp_pcie *qmp, const struct qmp_phy_cfg_tbls *tbls)
@@ -4203,11 +4196,14 @@  static int qmp_pcie_reset_init(struct qmp_pcie *qmp)
 	if (ret)
 		return dev_err_probe(dev, ret, "failed to get resets\n");
 
-	if (cfg->has_nocsr_reset) {
-		qmp->nocsr_reset = devm_reset_control_get_exclusive(dev, "phy_nocsr");
-		if (IS_ERR(qmp->nocsr_reset))
+	qmp->nocsr_reset = devm_reset_control_get_exclusive(dev, "phy_nocsr");
+	if (IS_ERR(qmp->nocsr_reset)) {
+		if (PTR_ERR(qmp->nocsr_reset) == -ENOENT ||
+		    PTR_ERR(qmp->nocsr_reset) == -EINVAL)
+			qmp->nocsr_reset = NULL;
+		else
 			return dev_err_probe(dev, PTR_ERR(qmp->nocsr_reset),
-						"failed to get no-csr reset\n");
+					     "failed to get no-csr reset\n");
 	}
 
 	return 0;