| Message ID | 1507649178-31473-5-git-send-email-geert+renesas@glider.be (mailing list archive) |
|---|---|
| State | RFC, archived |
| Headers | show |
On Tue, Oct 10, 2017 at 05:26:17PM +0200, Geert Uytterhoeven wrote: > Backup mode is not enabled automatically, as e.g. on Renesas > Salvator-X(S) boards enabling backup mode changes the role of the ACC > switch from a power switch to a wake-up switch. Hence enabling it > prevents the board from being powered off using the ACC switch, which > may confuse the user. This sounds an awful lot like the standard power/wakeup, though the power change is a bit unexpected there. I'm also wondering if it makes sense to just only enable the wakeup mode when suspending which preserves the power off functionality while also keeping the wakeup support.
Hi Mark, On Wed, Oct 18, 2017 at 1:02 PM, Mark Brown <broonie@kernel.org> wrote: > On Tue, Oct 10, 2017 at 05:26:17PM +0200, Geert Uytterhoeven wrote: >> Backup mode is not enabled automatically, as e.g. on Renesas >> Salvator-X(S) boards enabling backup mode changes the role of the ACC >> switch from a power switch to a wake-up switch. Hence enabling it >> prevents the board from being powered off using the ACC switch, which >> may confuse the user. > > This sounds an awful lot like the standard power/wakeup, though the > power change is a bit unexpected there. I'm also wondering if it makes > sense to just only enable the wakeup mode when suspending which > preserves the power off functionality while also keeping the wakeup > support. The ACC switch is not a momentary switch (push button), but a toggle switch with two positions. Hence you cannot enable wakeup mode while suspending, as the proper system suspend/resume procedure is: 1. Enable backup mode in the PMIC, 2. Switch ACC off (no-op as backup mode has been enabled), 3. Suspend to RAM (PSCI suspend) => system suspends, 4. Switch ACC on => system wakes up. If you would combine steps 1 and 3, you can no longer do step 2 in between. Yes, it's complicated :-( Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
On Wed, Oct 18, 2017 at 01:19:08PM +0200, Geert Uytterhoeven wrote: > On Wed, Oct 18, 2017 at 1:02 PM, Mark Brown <broonie@kernel.org> wrote: > > On Tue, Oct 10, 2017 at 05:26:17PM +0200, Geert Uytterhoeven wrote: > >> Backup mode is not enabled automatically, as e.g. on Renesas > >> Salvator-X(S) boards enabling backup mode changes the role of the ACC > >> switch from a power switch to a wake-up switch. Hence enabling it > >> prevents the board from being powered off using the ACC switch, which > >> may confuse the user. > > This sounds an awful lot like the standard power/wakeup, though the > > power change is a bit unexpected there. I'm also wondering if it makes > > sense to just only enable the wakeup mode when suspending which > > preserves the power off functionality while also keeping the wakeup > > support. > The ACC switch is not a momentary switch (push button), but a toggle > switch with two positions. > Hence you cannot enable wakeup mode while suspending, as the proper > system suspend/resume procedure is: > 1. Enable backup mode in the PMIC, > 2. Switch ACC off (no-op as backup mode has been enabled), > 3. Suspend to RAM (PSCI suspend) => system suspends, > 4. Switch ACC on => system wakes up. > If you would combine steps 1 and 3, you can no longer do step 2 in between. > Yes, it's complicated :-( I'm confused, I thought this was a physical switch but that's talking about this as something software controlled (at least in step 2)?
Hi Mark, On Wed, Oct 18, 2017 at 1:24 PM, Mark Brown <broonie@kernel.org> wrote: > On Wed, Oct 18, 2017 at 01:19:08PM +0200, Geert Uytterhoeven wrote: >> On Wed, Oct 18, 2017 at 1:02 PM, Mark Brown <broonie@kernel.org> wrote: >> > On Tue, Oct 10, 2017 at 05:26:17PM +0200, Geert Uytterhoeven wrote: >> >> Backup mode is not enabled automatically, as e.g. on Renesas >> >> Salvator-X(S) boards enabling backup mode changes the role of the ACC >> >> switch from a power switch to a wake-up switch. Hence enabling it >> >> prevents the board from being powered off using the ACC switch, which >> >> may confuse the user. > >> > This sounds an awful lot like the standard power/wakeup, though the >> > power change is a bit unexpected there. I'm also wondering if it makes >> > sense to just only enable the wakeup mode when suspending which >> > preserves the power off functionality while also keeping the wakeup >> > support. > >> The ACC switch is not a momentary switch (push button), but a toggle >> switch with two positions. >> Hence you cannot enable wakeup mode while suspending, as the proper >> system suspend/resume procedure is: >> 1. Enable backup mode in the PMIC, >> 2. Switch ACC off (no-op as backup mode has been enabled), >> 3. Suspend to RAM (PSCI suspend) => system suspends, >> 4. Switch ACC on => system wakes up. >> If you would combine steps 1 and 3, you can no longer do step 2 in between. > >> Yes, it's complicated :-( > > I'm confused, I thought this was a physical switch but that's talking > about this as something software controlled (at least in step 2)? The ACC switch is a physical switch. Steps 1 and 3 are performed by software running on the board's SoC. Steps 2 and 4 are performed by the external user (human or remote board farm control hookup). Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
On Wed, Oct 18, 2017 at 01:28:30PM +0200, Geert Uytterhoeven wrote: > On Wed, Oct 18, 2017 at 1:24 PM, Mark Brown <broonie@kernel.org> wrote: > >> Hence you cannot enable wakeup mode while suspending, as the proper > >> system suspend/resume procedure is: > >> 1. Enable backup mode in the PMIC, > >> 2. Switch ACC off (no-op as backup mode has been enabled), > >> 3. Suspend to RAM (PSCI suspend) => system suspends, > >> 4. Switch ACC on => system wakes up. > >> If you would combine steps 1 and 3, you can no longer do step 2 in between. > >> Yes, it's complicated :-( > > I'm confused, I thought this was a physical switch but that's talking > > about this as something software controlled (at least in step 2)? > The ACC switch is a physical switch. > Steps 1 and 3 are performed by software running on the board's SoC. > Steps 2 and 4 are performed by the external user (human or remote board > farm control hookup). That's horrible. There's still the question about potentially using the existing wakeup file to manage if the device is a wakeup source but otherwise I guess the only other thing that'd make sense would be just having a property in the DT.
diff --git a/drivers/regulator/bd9571mwv-regulator.c b/drivers/regulator/bd9571mwv-regulator.c index c67a83d53c4cb76b..c7ff67938c3eb48a 100644 --- a/drivers/regulator/bd9571mwv-regulator.c +++ b/drivers/regulator/bd9571mwv-regulator.c @@ -24,6 +24,14 @@ #include <linux/mfd/bd9571mwv.h> +struct bd9571mwv_reg { + struct bd9571mwv *bd; + + /* DDR Backup Power */ + u8 bkup_mode_cnt_keepon; /* from "rohm,ddr-backup-power" */ + u8 bkup_mode_cnt_shadow; +}; + enum bd9571mwv_regulators { VD09, VD18, VD25, VD33, DVFS }; #define BD9571MWV_REG(_name, _of, _id, _ops, _vr, _vm, _nv, _min, _step, _lmin)\ @@ -131,14 +139,99 @@ static struct regulator_desc regulators[] = { 0x80, 600000, 10000, 0x3c), }; +static int bd9571mwv_bkup_mode_set(struct bd9571mwv_reg *bdreg, u8 mode) +{ + int ret; + + ret = regmap_write(bdreg->bd->regmap, BD9571MWV_BKUP_MODE_CNT, mode); + if (ret) { + dev_err(bdreg->bd->dev, + "Failed to configure backup mode 0x%x (ret=%i)\n", + mode, ret); + return ret; + } + + bdreg->bkup_mode_cnt_shadow = mode; + return 0; +} + +static ssize_t backup_mode_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct bd9571mwv_reg *bdreg = dev_get_drvdata(dev); + int enabled = bdreg->bkup_mode_cnt_shadow & + BD9571MWV_BKUP_MODE_CNT_KEEPON_MASK; + + return sprintf(buf, "%s\n", enabled ? "on" : "off"); +} + +static ssize_t backup_mode_store(struct device *dev, + struct device_attribute *attr, + const char *buf, + size_t count) +{ + struct bd9571mwv_reg *bdreg = dev_get_drvdata(dev); + bool enable; + ssize_t ret; + u8 mode; + + if (!count) + return 0; + + ret = kstrtobool(buf, &enable); + if (ret) + return ret; + + mode = bdreg->bkup_mode_cnt_shadow & + ~BD9571MWV_BKUP_MODE_CNT_KEEPON_MASK; + if (enable) + mode |= bdreg->bkup_mode_cnt_keepon; + + if (mode == bdreg->bkup_mode_cnt_shadow) + return count; + + ret = bd9571mwv_bkup_mode_set(bdreg, mode); + if (ret) + return ret; + + return count; +} + +DEVICE_ATTR_RW(backup_mode); + +#ifdef CONFIG_PM_SLEEP +static int bd9571mwv_resume(struct device *dev) +{ + struct bd9571mwv_reg *bdreg = dev_get_drvdata(dev); + + return bd9571mwv_bkup_mode_set(bdreg, bdreg->bkup_mode_cnt_shadow); +} + +static const struct dev_pm_ops bd9571mwv_pm = { + SET_SYSTEM_SLEEP_PM_OPS(NULL, bd9571mwv_resume) +}; + +#define DEV_PM_OPS &bd9571mwv_pm +#else +#define DEV_PM_OPS NULL +#endif /* CONFIG_PM_SLEEP */ + static int bd9571mwv_regulator_probe(struct platform_device *pdev) { struct bd9571mwv *bd = dev_get_drvdata(pdev->dev.parent); struct regulator_config config = { }; + struct bd9571mwv_reg *bdreg; struct regulator_dev *rdev; - int i; + unsigned int val; + int i, ret; + + bdreg = devm_kzalloc(&pdev->dev, sizeof(*bdreg), GFP_KERNEL); + if (!bdreg) + return -ENOMEM; + + bdreg->bd = bd; - platform_set_drvdata(pdev, bd); + platform_set_drvdata(pdev, bdreg); config.dev = &pdev->dev; config.dev->of_node = bd->dev->of_node; @@ -155,6 +248,28 @@ static int bd9571mwv_regulator_probe(struct platform_device *pdev) } } + val = 0; + of_property_read_u32(bd->dev->of_node, "rohm,ddr-backup-power", &val); + if (val & ~BD9571MWV_BKUP_MODE_CNT_KEEPON_MASK) { + dev_err(bd->dev, "invalid %s mode %u\n", + "rohm,ddr-backup-power", val); + return -EINVAL; + } + bdreg->bkup_mode_cnt_keepon = val; + + ret = regmap_read(bd->regmap, BD9571MWV_BKUP_MODE_CNT, &val); + if (ret) { + dev_err(bd->dev, "Failed to read backup mode (ret=%i)\n", ret); + return ret; + } + bdreg->bkup_mode_cnt_shadow = val; + + return device_create_file(&pdev->dev, &dev_attr_backup_mode); +} + +static int bd9571mwv_regulator_remove(struct platform_device *pdev) +{ + device_remove_file(&pdev->dev, &dev_attr_backup_mode); return 0; } @@ -167,8 +282,10 @@ MODULE_DEVICE_TABLE(platform, bd9571mwv_regulator_id_table); static struct platform_driver bd9571mwv_regulator_driver = { .driver = { .name = "bd9571mwv-regulator", + .pm = DEV_PM_OPS, }, .probe = bd9571mwv_regulator_probe, + .remove = bd9571mwv_regulator_remove, .id_table = bd9571mwv_regulator_id_table, }; module_platform_driver(bd9571mwv_regulator_driver);
The BD9571MWV PMIC supports backup mode, which keeps one or more DDR rails powered while the main SoC is powered down. Which DDR rails are to be kept powered is board-specific, and controlled using the optional "rohm,ddr-backup-power" DT property. In the absence of this property, backup mode is not available. Backup mode is not enabled automatically, as e.g. on Renesas Salvator-X(S) boards enabling backup mode changes the role of the ACC switch from a power switch to a wake-up switch. Hence enabling it prevents the board from being powered off using the ACC switch, which may confuse the user. Backup mode can be enabled or disabled by the user using the "backup_mode" sysfs file, e.g. echo on > /sys/devices/platform/soc/e60b0000.i2c/i2c-7/7-0030/bd9571mwv-regulator.3.auto/backup_mode If enabled by the boot loader, initial backup mode state is retained. As state is lost by PSCI system suspend, it is restored during system resume. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> --- What's the right place to document regulator sysfs files? --- drivers/regulator/bd9571mwv-regulator.c | 121 +++++++++++++++++++++++++++++++- 1 file changed, 119 insertions(+), 2 deletions(-)