[v2] clk: zynqmp: fix compile testing without ZYNQMP_FIRMWARE

Commit Message

Michal Simek June 21, 2021, 1:13 p.m. UTC

From: Arnd Bergmann <[e-mail]>

When the firmware code is disabled, the incomplete error handling
in the clk driver causes compile-time warnings:

drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
drivers/clk/zynqmp/pll.c:147:29: error: 'fbdiv' is used uninitialized [-Werror=uninitialized]
  147 |         rate =  parent_rate * fbdiv;
      |                 ~~~~~~~~~~~~^~~~~~~
In function 'zynqmp_pll_get_mode',
    inlined from 'zynqmp_pll_recalc_rate' at drivers/clk/zynqmp/pll.c:148:6:
drivers/clk/zynqmp/pll.c:61:27: error: 'ret_payload' is used uninitialized [-Werror=uninitialized]
   61 |         return ret_payload[1];
      |                ~~~~~~~~~~~^~~
drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
drivers/clk/zynqmp/pll.c:53:13: note: 'ret_payload' declared here
   53 |         u32 ret_payload[PAYLOAD_ARG_CNT];
      |             ^~~~~~~~~~~
drivers/clk/zynqmp/clk-mux-zynqmp.c: In function 'zynqmp_clk_mux_get_parent':
drivers/clk/zynqmp/clk-mux-zynqmp.c:57:16: error: 'val' is used uninitialized [-Werror=uninitialized]
   57 |         return val;
      |                ^~~

As it was apparently intentional to support this for compile testing
purposes, change the code to have just enough error handling for the
compiler to not notice the remaining bugs.

Fixes: 21f237534661 ("clk: zynqmp: Drop dependency on ARCH_ZYNQMP")
Signed-off-by: Arnd Bergmann <[e-mail]>
Signed-off-by: Michal Simek <[e-mail]>
---

Changes in v2:
Based on discussion here
Link: https://lore.kernel.org/r/[e-mail]
I have updated error return value which I got from clock core based on
error cases.

zynqmp_clk_mux_get_parent() should return num_parents() as error defined in
clk_core_get_parent_by_index() where num_parents is incorrect index.

Extend zynqmp_pll_get_mode() with PLL_MODE_ERROR to handle error case.

zynqmp_pll_recalc_rate() returns 0 because __clk_core_init() consider 0 as
default rate. But maybe -1ul which was used by Arnd is also good option.

---
 drivers/clk/zynqmp/clk-mux-zynqmp.c | 10 ++++++++--
 drivers/clk/zynqmp/pll.c            | 15 ++++++++++-----
 2 files changed, 18 insertions(+), 7 deletions(-)

Comments

Arnd Bergmann June 21, 2021, 1:51 p.m. UTC | #1

On Mon, Jun 21, 2021 at 3:14 PM Michal Simek <[e-mail]> wrote:
>
> From: Arnd Bergmann <[e-mail]>
>
> When the firmware code is disabled, the incomplete error handling
> in the clk driver causes compile-time warnings:
>
> drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
> drivers/clk/zynqmp/pll.c:147:29: error: 'fbdiv' is used uninitialized [-Werror=uninitialized]
>   147 |         rate =  parent_rate * fbdiv;
>       |                 ~~~~~~~~~~~~^~~~~~~
> In function 'zynqmp_pll_get_mode',
>     inlined from 'zynqmp_pll_recalc_rate' at drivers/clk/zynqmp/pll.c:148:6:
> drivers/clk/zynqmp/pll.c:61:27: error: 'ret_payload' is used uninitialized [-Werror=uninitialized]
>    61 |         return ret_payload[1];
>       |                ~~~~~~~~~~~^~~
> drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
> drivers/clk/zynqmp/pll.c:53:13: note: 'ret_payload' declared here
>    53 |         u32 ret_payload[PAYLOAD_ARG_CNT];
>       |             ^~~~~~~~~~~
> drivers/clk/zynqmp/clk-mux-zynqmp.c: In function 'zynqmp_clk_mux_get_parent':
> drivers/clk/zynqmp/clk-mux-zynqmp.c:57:16: error: 'val' is used uninitialized [-Werror=uninitialized]
>    57 |         return val;
>       |                ^~~
>
> As it was apparently intentional to support this for compile testing
> purposes, change the code to have just enough error handling for the
> compiler to not notice the remaining bugs.
>
> Fixes: 21f237534661 ("clk: zynqmp: Drop dependency on ARCH_ZYNQMP")
> Signed-off-by: Arnd Bergmann <[e-mail]>
> Signed-off-by: Michal Simek <[e-mail]>
> ---
>
> Changes in v2:
> Based on discussion here
> Link: https://lore.kernel.org/r/[e-mail]
> I have updated error return value which I got from clock core based on
> error cases.
>
> zynqmp_clk_mux_get_parent() should return num_parents() as error defined in
> clk_core_get_parent_by_index() where num_parents is incorrect index.
>
> Extend zynqmp_pll_get_mode() with PLL_MODE_ERROR to handle error case.
>
> zynqmp_pll_recalc_rate() returns 0 because __clk_core_init() consider 0 as
> default rate. But maybe -1ul which was used by Arnd is also good option.

Looks good to me. You changed more than I did now, so it might be better
to change my authorship to Co-developed-by, probably not worth respinning
for that.

       Arnd

Michal Simek June 21, 2021, 1:54 p.m. UTC | #2

On 6/21/21 3:51 PM, Arnd Bergmann wrote:
> On Mon, Jun 21, 2021 at 3:14 PM Michal Simek <[e-mail]> wrote:
>>
>> From: Arnd Bergmann <[e-mail]>
>>
>> When the firmware code is disabled, the incomplete error handling
>> in the clk driver causes compile-time warnings:
>>
>> drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
>> drivers/clk/zynqmp/pll.c:147:29: error: 'fbdiv' is used uninitialized [-Werror=uninitialized]
>>   147 |         rate =  parent_rate * fbdiv;
>>       |                 ~~~~~~~~~~~~^~~~~~~
>> In function 'zynqmp_pll_get_mode',
>>     inlined from 'zynqmp_pll_recalc_rate' at drivers/clk/zynqmp/pll.c:148:6:
>> drivers/clk/zynqmp/pll.c:61:27: error: 'ret_payload' is used uninitialized [-Werror=uninitialized]
>>    61 |         return ret_payload[1];
>>       |                ~~~~~~~~~~~^~~
>> drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
>> drivers/clk/zynqmp/pll.c:53:13: note: 'ret_payload' declared here
>>    53 |         u32 ret_payload[PAYLOAD_ARG_CNT];
>>       |             ^~~~~~~~~~~
>> drivers/clk/zynqmp/clk-mux-zynqmp.c: In function 'zynqmp_clk_mux_get_parent':
>> drivers/clk/zynqmp/clk-mux-zynqmp.c:57:16: error: 'val' is used uninitialized [-Werror=uninitialized]
>>    57 |         return val;
>>       |                ^~~
>>
>> As it was apparently intentional to support this for compile testing
>> purposes, change the code to have just enough error handling for the
>> compiler to not notice the remaining bugs.
>>
>> Fixes: 21f237534661 ("clk: zynqmp: Drop dependency on ARCH_ZYNQMP")
>> Signed-off-by: Arnd Bergmann <[e-mail]>
>> Signed-off-by: Michal Simek <[e-mail]>
>> ---
>>
>> Changes in v2:
>> Based on discussion here
>> Link: https://lore.kernel.org/r/[e-mail]
>> I have updated error return value which I got from clock core based on
>> error cases.
>>
>> zynqmp_clk_mux_get_parent() should return num_parents() as error defined in
>> clk_core_get_parent_by_index() where num_parents is incorrect index.
>>
>> Extend zynqmp_pll_get_mode() with PLL_MODE_ERROR to handle error case.
>>
>> zynqmp_pll_recalc_rate() returns 0 because __clk_core_init() consider 0 as
>> default rate. But maybe -1ul which was used by Arnd is also good option.
> 
> Looks good to me. You changed more than I did now, so it might be better
> to change my authorship to Co-developed-by, probably not worth respinning
> for that.

Let's see what Stephen said about these changes.

Thanks,
Michal

Quanyang Wang June 22, 2021, 7:12 a.m. UTC | #3

Hi Michal & Arnd,

On 6/21/21 9:13 PM, Michal Simek wrote:
> From: Arnd Bergmann <[e-mail]>
> 
> When the firmware code is disabled, the incomplete error handling
> in the clk driver causes compile-time warnings:
> 
> drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
> drivers/clk/zynqmp/pll.c:147:29: error: 'fbdiv' is used uninitialized [-Werror=uninitialized]
>    147 |         rate =  parent_rate * fbdiv;
>        |                 ~~~~~~~~~~~~^~~~~~~
> In function 'zynqmp_pll_get_mode',
>      inlined from 'zynqmp_pll_recalc_rate' at drivers/clk/zynqmp/pll.c:148:6:
> drivers/clk/zynqmp/pll.c:61:27: error: 'ret_payload' is used uninitialized [-Werror=uninitialized]
>     61 |         return ret_payload[1];
>        |                ~~~~~~~~~~~^~~
> drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
> drivers/clk/zynqmp/pll.c:53:13: note: 'ret_payload' declared here
>     53 |         u32 ret_payload[PAYLOAD_ARG_CNT];
>        |             ^~~~~~~~~~~
> drivers/clk/zynqmp/clk-mux-zynqmp.c: In function 'zynqmp_clk_mux_get_parent':
> drivers/clk/zynqmp/clk-mux-zynqmp.c:57:16: error: 'val' is used uninitialized [-Werror=uninitialized]
>     57 |         return val;
>        |                ^~~
> 
> As it was apparently intentional to support this for compile testing
> purposes, change the code to have just enough error handling for the
> compiler to not notice the remaining bugs.
> 
> Fixes: 21f237534661 ("clk: zynqmp: Drop dependency on ARCH_ZYNQMP")
> Signed-off-by: Arnd Bergmann <[e-mail]>
> Signed-off-by: Michal Simek <[e-mail]>
> ---
> 
> Changes in v2:
> Based on discussion here
> Link: https://lore.kernel.org/r/[e-mail]
> I have updated error return value which I got from clock core based on
> error cases.
> 
> zynqmp_clk_mux_get_parent() should return num_parents() as error defined in
> clk_core_get_parent_by_index() where num_parents is incorrect index.
> 
> Extend zynqmp_pll_get_mode() with PLL_MODE_ERROR to handle error case.
> 
> zynqmp_pll_recalc_rate() returns 0 because __clk_core_init() consider 0 as
> default rate. But maybe -1ul which was used by Arnd is also good option.
> 
> ---
>   drivers/clk/zynqmp/clk-mux-zynqmp.c | 10 ++++++++--
>   drivers/clk/zynqmp/pll.c            | 15 ++++++++++-----
>   2 files changed, 18 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/clk/zynqmp/clk-mux-zynqmp.c b/drivers/clk/zynqmp/clk-mux-zynqmp.c
> index 06194149be83..d576c900dee0 100644
> --- a/drivers/clk/zynqmp/clk-mux-zynqmp.c
> +++ b/drivers/clk/zynqmp/clk-mux-zynqmp.c
> @@ -38,7 +38,7 @@ struct zynqmp_clk_mux {
>    * zynqmp_clk_mux_get_parent() - Get parent of clock
>    * @hw:		handle between common and hardware-specific interfaces
>    *
> - * Return: Parent index
> + * Return: Parent index on success or number of parents in case of error
>    */
>   static u8 zynqmp_clk_mux_get_parent(struct clk_hw *hw)
>   {
> @@ -50,9 +50,15 @@ static u8 zynqmp_clk_mux_get_parent(struct clk_hw *hw)
>   
>   	ret = zynqmp_pm_clock_getparent(clk_id, &val);
>   
> -	if (ret)
> +	if (ret) {
>   		pr_warn_once("%s() getparent failed for clock: %s, ret = %d\n",
>   			     __func__, clk_name, ret);
> +		/*
> +		 * clk_core_get_parent_by_index() takes num_parents as incorrect
> +		 * index which is exactly what I want to return here
> +		 */
> +		return clk_hw_get_num_parents(hw);
> +	}
>   
>   	return val;
>   }
> diff --git a/drivers/clk/zynqmp/pll.c b/drivers/clk/zynqmp/pll.c
> index abe6afbf3407..3fe4d21227d0 100644
> --- a/drivers/clk/zynqmp/pll.c
> +++ b/drivers/clk/zynqmp/pll.c
> @@ -31,8 +31,9 @@ struct zynqmp_pll {
>   #define PS_PLL_VCO_MAX 3000000000UL
>   
>   enum pll_mode {
> -	PLL_MODE_INT,
> -	PLL_MODE_FRAC,
> +	PLL_MODE_INT = 0,
> +	PLL_MODE_FRAC = 1,
> +	PLL_MODE_ERROR = 2,
>   };
>   
>   #define FRAC_OFFSET 0x8
> @@ -54,9 +55,11 @@ static inline enum pll_mode zynqmp_pll_get_mode(struct clk_hw *hw)
>   	int ret;
>   
>   	ret = zynqmp_pm_get_pll_frac_mode(clk_id, ret_payload);
> -	if (ret)
> +	if (ret) {
>   		pr_warn_once("%s() PLL get frac mode failed for %s, ret = %d\n",
>   			     __func__, clk_name, ret);
> +		return PLL_MODE_ERROR;
> +	}
>   
>   	return ret_payload[1];
>   }
> @@ -126,7 +129,7 @@ static long zynqmp_pll_round_rate(struct clk_hw *hw, unsigned long rate,
>    * @hw:			Handle between common and hardware-specific interfaces
>    * @parent_rate:	Clock frequency of parent clock
>    *
> - * Return: Current clock frequency
> + * Return: Current clock frequency or 0 in case of error
>    */
>   static unsigned long zynqmp_pll_recalc_rate(struct clk_hw *hw,
>   					    unsigned long parent_rate)
> @@ -140,9 +143,11 @@ static unsigned long zynqmp_pll_recalc_rate(struct clk_hw *hw,
>   	int ret;
>   
>   	ret = zynqmp_pm_clock_getdivider(clk_id, &fbdiv);
> -	if (ret)
> +	if (ret) {
>   		pr_warn_once("%s() get divider failed for %s, ret = %d\n",
>   			     __func__, clk_name, ret);
> +		return 0ul;
> +	}
>   
Since zynqmp_pll_get_mode may return err now, maybe here should add a 
condition check for PLL_MODE_ERR:
	if (zynqmp_pll_get_mode(hw) == PLL_MODE_ERR)
		return 0ul;

Thanks,
Quanyang
>   	rate =  parent_rate * fbdiv;
>   	if (zynqmp_pll_get_mode(hw) == PLL_MODE_FRAC) {
>

Michal Simek June 22, 2021, 10:15 a.m. UTC | #4

Hi,

On 6/22/21 9:12 AM, quanyang.wang wrote:
> Hi Michal & Arnd,
> 
> On 6/21/21 9:13 PM, Michal Simek wrote:
>> From: Arnd Bergmann <[e-mail]>
>>
>> When the firmware code is disabled, the incomplete error handling
>> in the clk driver causes compile-time warnings:
>>
>> drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
>> drivers/clk/zynqmp/pll.c:147:29: error: 'fbdiv' is used uninitialized
>> [-Werror=uninitialized]
>>    147 |         rate =  parent_rate * fbdiv;
>>        |                 ~~~~~~~~~~~~^~~~~~~
>> In function 'zynqmp_pll_get_mode',
>>      inlined from 'zynqmp_pll_recalc_rate' at
>> drivers/clk/zynqmp/pll.c:148:6:
>> drivers/clk/zynqmp/pll.c:61:27: error: 'ret_payload' is used
>> uninitialized [-Werror=uninitialized]
>>     61 |         return ret_payload[1];
>>        |                ~~~~~~~~~~~^~~
>> drivers/clk/zynqmp/pll.c: In function 'zynqmp_pll_recalc_rate':
>> drivers/clk/zynqmp/pll.c:53:13: note: 'ret_payload' declared here
>>     53 |         u32 ret_payload[PAYLOAD_ARG_CNT];
>>        |             ^~~~~~~~~~~
>> drivers/clk/zynqmp/clk-mux-zynqmp.c: In function
>> 'zynqmp_clk_mux_get_parent':
>> drivers/clk/zynqmp/clk-mux-zynqmp.c:57:16: error: 'val' is used
>> uninitialized [-Werror=uninitialized]
>>     57 |         return val;
>>        |                ^~~
>>
>> As it was apparently intentional to support this for compile testing
>> purposes, change the code to have just enough error handling for the
>> compiler to not notice the remaining bugs.
>>
>> Fixes: 21f237534661 ("clk: zynqmp: Drop dependency on ARCH_ZYNQMP")
>> Signed-off-by: Arnd Bergmann <[e-mail]>
>> Signed-off-by: Michal Simek <[e-mail]>
>> ---
>>
>> Changes in v2:
>> Based on discussion here
>> Link: https://lore.kernel.org/r/[e-mail]
>> I have updated error return value which I got from clock core based on
>> error cases.
>>
>> zynqmp_clk_mux_get_parent() should return num_parents() as error
>> defined in
>> clk_core_get_parent_by_index() where num_parents is incorrect index.
>>
>> Extend zynqmp_pll_get_mode() with PLL_MODE_ERROR to handle error case.
>>
>> zynqmp_pll_recalc_rate() returns 0 because __clk_core_init() consider
>> 0 as
>> default rate. But maybe -1ul which was used by Arnd is also good option.
>>
>> ---
>>   drivers/clk/zynqmp/clk-mux-zynqmp.c | 10 ++++++++--
>>   drivers/clk/zynqmp/pll.c            | 15 ++++++++++-----
>>   2 files changed, 18 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/clk/zynqmp/clk-mux-zynqmp.c
>> b/drivers/clk/zynqmp/clk-mux-zynqmp.c
>> index 06194149be83..d576c900dee0 100644
>> --- a/drivers/clk/zynqmp/clk-mux-zynqmp.c
>> +++ b/drivers/clk/zynqmp/clk-mux-zynqmp.c
>> @@ -38,7 +38,7 @@ struct zynqmp_clk_mux {
>>    * zynqmp_clk_mux_get_parent() - Get parent of clock
>>    * @hw:        handle between common and hardware-specific interfaces
>>    *
>> - * Return: Parent index
>> + * Return: Parent index on success or number of parents in case of error
>>    */
>>   static u8 zynqmp_clk_mux_get_parent(struct clk_hw *hw)
>>   {
>> @@ -50,9 +50,15 @@ static u8 zynqmp_clk_mux_get_parent(struct clk_hw *hw)
>>         ret = zynqmp_pm_clock_getparent(clk_id, &val);
>>   -    if (ret)
>> +    if (ret) {
>>           pr_warn_once("%s() getparent failed for clock: %s, ret = %d\n",
>>                    __func__, clk_name, ret);
>> +        /*
>> +         * clk_core_get_parent_by_index() takes num_parents as incorrect
>> +         * index which is exactly what I want to return here
>> +         */
>> +        return clk_hw_get_num_parents(hw);
>> +    }
>>         return val;
>>   }
>> diff --git a/drivers/clk/zynqmp/pll.c b/drivers/clk/zynqmp/pll.c
>> index abe6afbf3407..3fe4d21227d0 100644
>> --- a/drivers/clk/zynqmp/pll.c
>> +++ b/drivers/clk/zynqmp/pll.c
>> @@ -31,8 +31,9 @@ struct zynqmp_pll {
>>   #define PS_PLL_VCO_MAX 3000000000UL
>>     enum pll_mode {
>> -    PLL_MODE_INT,
>> -    PLL_MODE_FRAC,
>> +    PLL_MODE_INT = 0,
>> +    PLL_MODE_FRAC = 1,
>> +    PLL_MODE_ERROR = 2,
>>   };
>>     #define FRAC_OFFSET 0x8
>> @@ -54,9 +55,11 @@ static inline enum pll_mode
>> zynqmp_pll_get_mode(struct clk_hw *hw)
>>       int ret;
>>         ret = zynqmp_pm_get_pll_frac_mode(clk_id, ret_payload);
>> -    if (ret)
>> +    if (ret) {
>>           pr_warn_once("%s() PLL get frac mode failed for %s, ret =
>> %d\n",
>>                    __func__, clk_name, ret);
>> +        return PLL_MODE_ERROR;
>> +    }
>>         return ret_payload[1];
>>   }
>> @@ -126,7 +129,7 @@ static long zynqmp_pll_round_rate(struct clk_hw
>> *hw, unsigned long rate,
>>    * @hw:            Handle between common and hardware-specific
>> interfaces
>>    * @parent_rate:    Clock frequency of parent clock
>>    *
>> - * Return: Current clock frequency
>> + * Return: Current clock frequency or 0 in case of error
>>    */
>>   static unsigned long zynqmp_pll_recalc_rate(struct clk_hw *hw,
>>                           unsigned long parent_rate)
>> @@ -140,9 +143,11 @@ static unsigned long
>> zynqmp_pll_recalc_rate(struct clk_hw *hw,
>>       int ret;
>>         ret = zynqmp_pm_clock_getdivider(clk_id, &fbdiv);
>> -    if (ret)
>> +    if (ret) {
>>           pr_warn_once("%s() get divider failed for %s, ret = %d\n",
>>                    __func__, clk_name, ret);
>> +        return 0ul;
>> +    }
>>   
> Since zynqmp_pll_get_mode may return err now, maybe here should add a
> condition check for PLL_MODE_ERR:
>     if (zynqmp_pll_get_mode(hw) == PLL_MODE_ERR)
>         return 0ul;

Agree. I have sent v3 with this there. Please review.

Thanks,
Michal

Patch

diff --git a/drivers/clk/zynqmp/clk-mux-zynqmp.c b/drivers/clk/zynqmp/clk-mux-zynqmp.c
index 06194149be83..d576c900dee0 100644
--- a/drivers/clk/zynqmp/clk-mux-zynqmp.c
+++ b/drivers/clk/zynqmp/clk-mux-zynqmp.c
@@ -38,7 +38,7 @@  struct zynqmp_clk_mux {
  * zynqmp_clk_mux_get_parent() - Get parent of clock
  * @hw:		handle between common and hardware-specific interfaces
  *
- * Return: Parent index
+ * Return: Parent index on success or number of parents in case of error
  */
 static u8 zynqmp_clk_mux_get_parent(struct clk_hw *hw)
 {
@@ -50,9 +50,15 @@  static u8 zynqmp_clk_mux_get_parent(struct clk_hw *hw)
 
 	ret = zynqmp_pm_clock_getparent(clk_id, &val);
 
-	if (ret)
+	if (ret) {
 		pr_warn_once("%s() getparent failed for clock: %s, ret = %d\n",
 			     __func__, clk_name, ret);
+		/*
+		 * clk_core_get_parent_by_index() takes num_parents as incorrect
+		 * index which is exactly what I want to return here
+		 */
+		return clk_hw_get_num_parents(hw);
+	}
 
 	return val;
 }
diff --git a/drivers/clk/zynqmp/pll.c b/drivers/clk/zynqmp/pll.c
index abe6afbf3407..3fe4d21227d0 100644
--- a/drivers/clk/zynqmp/pll.c
+++ b/drivers/clk/zynqmp/pll.c
@@ -31,8 +31,9 @@  struct zynqmp_pll {
 #define PS_PLL_VCO_MAX 3000000000UL
 
 enum pll_mode {
-	PLL_MODE_INT,
-	PLL_MODE_FRAC,
+	PLL_MODE_INT = 0,
+	PLL_MODE_FRAC = 1,
+	PLL_MODE_ERROR = 2,
 };
 
 #define FRAC_OFFSET 0x8
@@ -54,9 +55,11 @@  static inline enum pll_mode zynqmp_pll_get_mode(struct clk_hw *hw)
 	int ret;
 
 	ret = zynqmp_pm_get_pll_frac_mode(clk_id, ret_payload);
-	if (ret)
+	if (ret) {
 		pr_warn_once("%s() PLL get frac mode failed for %s, ret = %d\n",
 			     __func__, clk_name, ret);
+		return PLL_MODE_ERROR;
+	}
 
 	return ret_payload[1];
 }
@@ -126,7 +129,7 @@  static long zynqmp_pll_round_rate(struct clk_hw *hw, unsigned long rate,
  * @hw:			Handle between common and hardware-specific interfaces
  * @parent_rate:	Clock frequency of parent clock
  *
- * Return: Current clock frequency
+ * Return: Current clock frequency or 0 in case of error
  */
 static unsigned long zynqmp_pll_recalc_rate(struct clk_hw *hw,
 					    unsigned long parent_rate)
@@ -140,9 +143,11 @@  static unsigned long zynqmp_pll_recalc_rate(struct clk_hw *hw,
 	int ret;
 
 	ret = zynqmp_pm_clock_getdivider(clk_id, &fbdiv);
-	if (ret)
+	if (ret) {
 		pr_warn_once("%s() get divider failed for %s, ret = %d\n",
 			     __func__, clk_name, ret);
+		return 0ul;
+	}
 
 	rate =  parent_rate * fbdiv;
 	if (zynqmp_pll_get_mode(hw) == PLL_MODE_FRAC) {