[v2,3/9] clk: at91: pmc: Support backup for programmable clocks

Message ID 20170915140411.31716-4-romain.izard.pro@gmail.com
State New
Headers show
Series
  • Various patches for SAMA5D2 backup mode
Related show

Commit Message

Romain Izard Sept. 15, 2017, 2:04 p.m.
From: Romain Izard <romain.izard@mobile-devices.fr>

When an AT91 programmable clock is declared in the device tree, register
it into the Power Management Controller driver. On entering suspend mode,
the driver saves and restores the Programmable Clock registers to support
the backup mode for these clocks.

Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>
---
Changes in v2:
* register PCKs on clock startup

 drivers/clk/at91/clk-programmable.c |  2 ++
 drivers/clk/at91/pmc.c              | 27 +++++++++++++++++++++++++++
 drivers/clk/at91/pmc.h              |  2 ++
 3 files changed, 31 insertions(+)

Comments

Nicolas Ferre Sept. 22, 2017, 10:31 a.m. | #1
On 15/09/2017 at 16:04, Romain Izard wrote:
> From: Romain Izard <romain.izard@mobile-devices.fr>
> 
> When an AT91 programmable clock is declared in the device tree, register
> it into the Power Management Controller driver. On entering suspend mode,
> the driver saves and restores the Programmable Clock registers to support
> the backup mode for these clocks.
> 
> Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>

Romain,

Some nitpicking and one comment. But on the overall patch, here is my:
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>

See below:

> ---
> Changes in v2:
> * register PCKs on clock startup
> 
>  drivers/clk/at91/clk-programmable.c |  2 ++
>  drivers/clk/at91/pmc.c              | 27 +++++++++++++++++++++++++++
>  drivers/clk/at91/pmc.h              |  2 ++
>  3 files changed, 31 insertions(+)
> 
> diff --git a/drivers/clk/at91/clk-programmable.c b/drivers/clk/at91/clk-programmable.c
> index 85a449cf61e3..0e6aab1252fc 100644
> --- a/drivers/clk/at91/clk-programmable.c
> +++ b/drivers/clk/at91/clk-programmable.c
> @@ -204,6 +204,8 @@ at91_clk_register_programmable(struct regmap *regmap,
>  	if (ret) {
>  		kfree(prog);
>  		hw = ERR_PTR(ret);

Nit: "else" not needed.

> +	} else {
> +		pmc_register_pck(id);
>  	}
>  
>  	return hw;
> diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
> index 07dc2861ad3f..3910b7537152 100644
> --- a/drivers/clk/at91/pmc.c
> +++ b/drivers/clk/at91/pmc.c
> @@ -22,6 +22,7 @@
>  #include "pmc.h"
>  
>  #define PMC_MAX_IDS 128
> +#define PMC_MAX_PCKS 8
>  
>  int of_at91_get_clk_range(struct device_node *np, const char *propname,
>  			  struct clk_range *range)
> @@ -50,6 +51,7 @@ EXPORT_SYMBOL_GPL(of_at91_get_clk_range);
>  static struct regmap *pmcreg;
>  
>  static u8 registered_ids[PMC_MAX_IDS];
> +static u8 registered_pcks[PMC_MAX_PCKS];
>  
>  static struct
>  {
> @@ -66,8 +68,10 @@ static struct
>  	u32 pcr[PMC_MAX_IDS];
>  	u32 audio_pll0;
>  	u32 audio_pll1;
> +	u32 pckr[PMC_MAX_PCKS];
>  } pmc_cache;
>  
> +/* Clock ID 0 is invalid */

(read: so we can use the 0 value as an indicator that this place in the
table hasn't been filled, so unused)

>  void pmc_register_id(u8 id)
>  {
>  	int i;
> @@ -82,6 +86,21 @@ void pmc_register_id(u8 id)
>  	}
>  }
>  
> +/* Programmable Clock 0 is valid */

I understand the rationale behind these ^^ two comments, but I would
like that it's more explicit. Saying that you will store the pck id as
(id + 1) and that you would have to invert this operation while using
the stored id.
Maybe add a comment about this transformation to the struct definition
as well...


> +void pmc_register_pck(u8 pck)
> +{
> +	int i;
> +
> +	for (i = 0; i < PMC_MAX_PCKS; i++) {
> +		if (registered_pcks[i] == 0) {
> +			registered_pcks[i] = pck + 1;
> +			break;
> +		}
> +		if (registered_pcks[i] == (pck + 1))
> +			break;
> +	}
> +}
> +
>  static int pmc_suspend(void)
>  {
>  	int i;
> @@ -103,6 +122,10 @@ static int pmc_suspend(void)
>  		regmap_read(pmcreg, AT91_PMC_PCR,
>  			    &pmc_cache.pcr[registered_ids[i]]);
>  	}
> +	for (i = 0; registered_pcks[i]; i++) {
> +		u8 num = registered_pcks[i] - 1;

Nit: declaration are better made at the beginning of the function. This
lead to a checkpatch warning:
"WARNING: Missing a blank line after declarations"

> +		regmap_read(pmcreg, AT91_PMC_PCKR(num), &pmc_cache.pckr[num]);
> +	}
>  
>  	return 0;
>  }
> @@ -143,6 +166,10 @@ static void pmc_resume(void)
>  			     pmc_cache.pcr[registered_ids[i]] |
>  			     AT91_PMC_PCR_CMD);
>  	}
> +	for (i = 0; registered_pcks[i]; i++) {
> +		u8 num = registered_pcks[i] - 1;

Ditto

> +		regmap_write(pmcreg, AT91_PMC_PCKR(num), pmc_cache.pckr[num]);
> +	}
>  
>  	if (pmc_cache.uckr & AT91_PMC_UPLLEN)
>  		mask |= AT91_PMC_LOCKU;
> diff --git a/drivers/clk/at91/pmc.h b/drivers/clk/at91/pmc.h
> index 858e8ef7e8db..d22b1fa9ecdc 100644
> --- a/drivers/clk/at91/pmc.h
> +++ b/drivers/clk/at91/pmc.h
> @@ -31,8 +31,10 @@ int of_at91_get_clk_range(struct device_node *np, const char *propname,
>  
>  #ifdef CONFIG_PM
>  void pmc_register_id(u8 id);
> +void pmc_register_pck(u8 pck);
>  #else
>  static inline void pmc_register_id(u8 id) {}
> +static inline void pmc_register_pck(u8 pck) {}
>  #endif
>  
>  #endif /* __PMC_H_ */
>
Romain Izard Sept. 25, 2017, 8:25 a.m. | #2
2017-09-22 12:31 GMT+02:00 Nicolas Ferre <nicolas.ferre@microchip.com>:
> On 15/09/2017 at 16:04, Romain Izard wrote:
>> From: Romain Izard <romain.izard@mobile-devices.fr>
>>
>> When an AT91 programmable clock is declared in the device tree, register
>> it into the Power Management Controller driver. On entering suspend mode,
>> the driver saves and restores the Programmable Clock registers to support
>> the backup mode for these clocks.
>>
>> Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>
>
> Romain,
>
> Some nitpicking and one comment. But on the overall patch, here is my:
> Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
>
> See below:
>
>> ---
>> Changes in v2:
>> * register PCKs on clock startup
>>
>>  drivers/clk/at91/clk-programmable.c |  2 ++
>>  drivers/clk/at91/pmc.c              | 27 +++++++++++++++++++++++++++
>>  drivers/clk/at91/pmc.h              |  2 ++
>>  3 files changed, 31 insertions(+)
>>
>> diff --git a/drivers/clk/at91/clk-programmable.c b/drivers/clk/at91/clk-programmable.c
>> index 85a449cf61e3..0e6aab1252fc 100644
>> --- a/drivers/clk/at91/clk-programmable.c
>> +++ b/drivers/clk/at91/clk-programmable.c
>> @@ -204,6 +204,8 @@ at91_clk_register_programmable(struct regmap *regmap,
>>       if (ret) {
>>               kfree(prog);
>>               hw = ERR_PTR(ret);
>
> Nit: "else" not needed.
>
This is a shared idiom in all the atmel clock drivers, so I prefer to keep
it this way.

>> +     } else {
>> +             pmc_register_pck(id);
>>       }
>>
>>       return hw;
>> diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
>> index 07dc2861ad3f..3910b7537152 100644
>> --- a/drivers/clk/at91/pmc.c
>> +++ b/drivers/clk/at91/pmc.c
>> @@ -22,6 +22,7 @@
>>  #include "pmc.h"
>>
>>  #define PMC_MAX_IDS 128
>> +#define PMC_MAX_PCKS 8
>>
>>  int of_at91_get_clk_range(struct device_node *np, const char *propname,
>>                         struct clk_range *range)
>> @@ -50,6 +51,7 @@ EXPORT_SYMBOL_GPL(of_at91_get_clk_range);
>>  static struct regmap *pmcreg;
>>
>>  static u8 registered_ids[PMC_MAX_IDS];
>> +static u8 registered_pcks[PMC_MAX_PCKS];
>>
>>  static struct
>>  {
>> @@ -66,8 +68,10 @@ static struct
>>       u32 pcr[PMC_MAX_IDS];
>>       u32 audio_pll0;
>>       u32 audio_pll1;
>> +     u32 pckr[PMC_MAX_PCKS];
>>  } pmc_cache;
>>
>> +/* Clock ID 0 is invalid */
>
> (read: so we can use the 0 value as an indicator that this place in the
> table hasn't been filled, so unused)
>
>>  void pmc_register_id(u8 id)
>>  {
>>       int i;
>> @@ -82,6 +86,21 @@ void pmc_register_id(u8 id)
>>       }
>>  }
>>
>> +/* Programmable Clock 0 is valid */
>
> I understand the rationale behind these ^^ two comments, but I would
> like that it's more explicit. Saying that you will store the pck id as
> (id + 1) and that you would have to invert this operation while using
> the stored id.
> Maybe add a comment about this transformation to the struct definition
> as well...
>

I will improve the comments for the next revision.

>
>> +void pmc_register_pck(u8 pck)
>> +{
>> +     int i;
>> +
>> +     for (i = 0; i < PMC_MAX_PCKS; i++) {
>> +             if (registered_pcks[i] == 0) {
>> +                     registered_pcks[i] = pck + 1;
>> +                     break;
>> +             }
>> +             if (registered_pcks[i] == (pck + 1))
>> +                     break;
>> +     }
>> +}
>> +
>>  static int pmc_suspend(void)
>>  {
>>       int i;
>> @@ -103,6 +122,10 @@ static int pmc_suspend(void)
>>               regmap_read(pmcreg, AT91_PMC_PCR,
>>                           &pmc_cache.pcr[registered_ids[i]]);
>>       }
>> +     for (i = 0; registered_pcks[i]; i++) {
>> +             u8 num = registered_pcks[i] - 1;
>
> Nit: declaration are better made at the beginning of the function. This
> lead to a checkpatch warning:
> "WARNING: Missing a blank line after declarations"
>

I'll fix this as well.

>> +             regmap_read(pmcreg, AT91_PMC_PCKR(num), &pmc_cache.pckr[num]);
>> +     }
>>
>>       return 0;
>>  }
>> @@ -143,6 +166,10 @@ static void pmc_resume(void)
>>                            pmc_cache.pcr[registered_ids[i]] |
>>                            AT91_PMC_PCR_CMD);
>>       }
>> +     for (i = 0; registered_pcks[i]; i++) {
>> +             u8 num = registered_pcks[i] - 1;
>
> Ditto
>
>> +             regmap_write(pmcreg, AT91_PMC_PCKR(num), pmc_cache.pckr[num]);
>> +     }
>>
>>       if (pmc_cache.uckr & AT91_PMC_UPLLEN)
>>               mask |= AT91_PMC_LOCKU;
>> diff --git a/drivers/clk/at91/pmc.h b/drivers/clk/at91/pmc.h
>> index 858e8ef7e8db..d22b1fa9ecdc 100644
>> --- a/drivers/clk/at91/pmc.h
>> +++ b/drivers/clk/at91/pmc.h
>> @@ -31,8 +31,10 @@ int of_at91_get_clk_range(struct device_node *np, const char *propname,
>>
>>  #ifdef CONFIG_PM
>>  void pmc_register_id(u8 id);
>> +void pmc_register_pck(u8 pck);
>>  #else
>>  static inline void pmc_register_id(u8 id) {}
>> +static inline void pmc_register_pck(u8 pck) {}
>>  #endif
>>
>>  #endif /* __PMC_H_ */
>>

Patch

diff --git a/drivers/clk/at91/clk-programmable.c b/drivers/clk/at91/clk-programmable.c
index 85a449cf61e3..0e6aab1252fc 100644
--- a/drivers/clk/at91/clk-programmable.c
+++ b/drivers/clk/at91/clk-programmable.c
@@ -204,6 +204,8 @@  at91_clk_register_programmable(struct regmap *regmap,
 	if (ret) {
 		kfree(prog);
 		hw = ERR_PTR(ret);
+	} else {
+		pmc_register_pck(id);
 	}
 
 	return hw;
diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
index 07dc2861ad3f..3910b7537152 100644
--- a/drivers/clk/at91/pmc.c
+++ b/drivers/clk/at91/pmc.c
@@ -22,6 +22,7 @@ 
 #include "pmc.h"
 
 #define PMC_MAX_IDS 128
+#define PMC_MAX_PCKS 8
 
 int of_at91_get_clk_range(struct device_node *np, const char *propname,
 			  struct clk_range *range)
@@ -50,6 +51,7 @@  EXPORT_SYMBOL_GPL(of_at91_get_clk_range);
 static struct regmap *pmcreg;
 
 static u8 registered_ids[PMC_MAX_IDS];
+static u8 registered_pcks[PMC_MAX_PCKS];
 
 static struct
 {
@@ -66,8 +68,10 @@  static struct
 	u32 pcr[PMC_MAX_IDS];
 	u32 audio_pll0;
 	u32 audio_pll1;
+	u32 pckr[PMC_MAX_PCKS];
 } pmc_cache;
 
+/* Clock ID 0 is invalid */
 void pmc_register_id(u8 id)
 {
 	int i;
@@ -82,6 +86,21 @@  void pmc_register_id(u8 id)
 	}
 }
 
+/* Programmable Clock 0 is valid */
+void pmc_register_pck(u8 pck)
+{
+	int i;
+
+	for (i = 0; i < PMC_MAX_PCKS; i++) {
+		if (registered_pcks[i] == 0) {
+			registered_pcks[i] = pck + 1;
+			break;
+		}
+		if (registered_pcks[i] == (pck + 1))
+			break;
+	}
+}
+
 static int pmc_suspend(void)
 {
 	int i;
@@ -103,6 +122,10 @@  static int pmc_suspend(void)
 		regmap_read(pmcreg, AT91_PMC_PCR,
 			    &pmc_cache.pcr[registered_ids[i]]);
 	}
+	for (i = 0; registered_pcks[i]; i++) {
+		u8 num = registered_pcks[i] - 1;
+		regmap_read(pmcreg, AT91_PMC_PCKR(num), &pmc_cache.pckr[num]);
+	}
 
 	return 0;
 }
@@ -143,6 +166,10 @@  static void pmc_resume(void)
 			     pmc_cache.pcr[registered_ids[i]] |
 			     AT91_PMC_PCR_CMD);
 	}
+	for (i = 0; registered_pcks[i]; i++) {
+		u8 num = registered_pcks[i] - 1;
+		regmap_write(pmcreg, AT91_PMC_PCKR(num), pmc_cache.pckr[num]);
+	}
 
 	if (pmc_cache.uckr & AT91_PMC_UPLLEN)
 		mask |= AT91_PMC_LOCKU;
diff --git a/drivers/clk/at91/pmc.h b/drivers/clk/at91/pmc.h
index 858e8ef7e8db..d22b1fa9ecdc 100644
--- a/drivers/clk/at91/pmc.h
+++ b/drivers/clk/at91/pmc.h
@@ -31,8 +31,10 @@  int of_at91_get_clk_range(struct device_node *np, const char *propname,
 
 #ifdef CONFIG_PM
 void pmc_register_id(u8 id);
+void pmc_register_pck(u8 pck);
 #else
 static inline void pmc_register_id(u8 id) {}
+static inline void pmc_register_pck(u8 pck) {}
 #endif
 
 #endif /* __PMC_H_ */