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SubjectRe: [PATCH v6 3/3] clk: at91: pmc: Support backup for programmable clocks
On 11/12/2017 at 17:55:35 +0100, Romain Izard wrote:
> 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>
> Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

> ---
> Changes in v2:
> * register PCKs on clock startup
>
> Changes in v3:
> * improve comments on hanling 0 in pmc_register_id and pmc_register_pck
> * declare local variables earlier for checkpatch
>
> Changes in v6:
> * Use the correct author email address
>
> drivers/clk/at91/clk-programmable.c | 2 ++
> drivers/clk/at91/pmc.c | 35 +++++++++++++++++++++++++++++++++++
> drivers/clk/at91/pmc.h | 2 ++
> 3 files changed, 39 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);
> + } else {
> + pmc_register_pck(id);
> }
>
> return hw;
> diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
> index 07dc2861ad3f..1fa27f4ea538 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 +68,13 @@ static struct
> u32 pcr[PMC_MAX_IDS];
> u32 audio_pll0;
> u32 audio_pll1;
> + u32 pckr[PMC_MAX_PCKS];
> } pmc_cache;
>
> +/*
> + * As Peripheral ID 0 is invalid on AT91 chips, the identifier is stored
> + * without alteration in the table, and 0 is for unused clocks.
> + */
> void pmc_register_id(u8 id)
> {
> int i;
> @@ -82,9 +89,28 @@ void pmc_register_id(u8 id)
> }
> }
>
> +/*
> + * As Programmable Clock 0 is valid on AT91 chips, there is an offset
> + * of 1 between the stored value and the real clock ID.
> + */
> +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;
> + u8 num;
>
> regmap_read(pmcreg, AT91_PMC_SCSR, &pmc_cache.scsr);
> regmap_read(pmcreg, AT91_PMC_PCSR, &pmc_cache.pcsr0);
> @@ -103,6 +129,10 @@ static int pmc_suspend(void)
> regmap_read(pmcreg, AT91_PMC_PCR,
> &pmc_cache.pcr[registered_ids[i]]);
> }
> + for (i = 0; registered_pcks[i]; i++) {
> + num = registered_pcks[i] - 1;
> + regmap_read(pmcreg, AT91_PMC_PCKR(num), &pmc_cache.pckr[num]);
> + }
>
> return 0;
> }
> @@ -119,6 +149,7 @@ static bool pmc_ready(unsigned int mask)
> static void pmc_resume(void)
> {
> int i;
> + u8 num;
> u32 tmp;
> u32 mask = AT91_PMC_MCKRDY | AT91_PMC_LOCKA;
>
> @@ -143,6 +174,10 @@ static void pmc_resume(void)
> pmc_cache.pcr[registered_ids[i]] |
> AT91_PMC_PCR_CMD);
> }
> + for (i = 0; registered_pcks[i]; i++) {
> + 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_ */
> --
> 2.14.1
>

--
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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