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Date: Thu, 23 Sep 2021 15:16:40 +0200 From: Alexandre Ghiti <alexandre.ghiti@...onical.com> To: Ben Dooks <ben.dooks@...ethink.co.uk> Cc: Support Opensource <support.opensource@...semi.com>, Lee Jones <lee.jones@...aro.org>, linux-riscv <linux-riscv@...ts.infradead.org>, "linux-kernel@...r.kernel.org List" <linux-kernel@...r.kernel.org> Subject: Re: [PATCH] drivers: mfd: da9063: Add restart notifier implementation On Tue, Sep 21, 2021 at 1:33 PM Alexandre Ghiti <alexandre.ghiti@...onical.com> wrote: > > On Tue, Sep 21, 2021 at 12:25 PM Ben Dooks <ben.dooks@...ethink.co.uk> wrote: > > > > On 21/09/2021 06:33, Alexandre Ghiti wrote: > > > The SiFive Unmatched board uses the da9063 PMIC for reset: add a restart > > > notifier that will execute a small i2c sequence allowing to reset the > > > board. > > > > > > The original implementation comes from Marcus Comstedt and Anders Montonen > > > (https://forums.sifive.com/t/reboot-command/4721/28). > > > > > > Signed-off-by: Alexandre Ghiti <alexandre.ghiti@...onical.com> > > > > I've got a couple of comments here, mainly is this the right place > > and has anyone other than you tested. I tried something similar on > > my Unmatched and it just turned the board off. > > Someone else in the thread I mention in the commit log tried it, but > more feedback are welcome :) > > For the Unmatched, this solution will be temporary, the best place > being openSBI which lacks i2c support for now. > But I think this can be used by other boards using this PMIC. > > > > > > --- > > > drivers/mfd/da9063-core.c | 25 +++++++++++++++++++++++++ > > > include/linux/mfd/da9063/core.h | 3 +++ > > > 2 files changed, 28 insertions(+) > > > > > > diff --git a/drivers/mfd/da9063-core.c b/drivers/mfd/da9063-core.c > > > index df407c3afce3..c87b8d611f20 100644 > > > --- a/drivers/mfd/da9063-core.c > > > +++ b/drivers/mfd/da9063-core.c > > > @@ -20,6 +20,7 @@ > > > #include <linux/mutex.h> > > > #include <linux/mfd/core.h> > > > #include <linux/regmap.h> > > > +#include <linux/reboot.h> > > > > > > #include <linux/mfd/da9063/core.h> > > > #include <linux/mfd/da9063/registers.h> > > > @@ -158,6 +159,18 @@ static int da9063_clear_fault_log(struct da9063 *da9063) > > > return ret; > > > } > > > > > > +static int da9063_restart_notify(struct notifier_block *this, > > > + unsigned long mode, void *cmd) > > > +{ > > > + struct da9063 *da9063 = container_of(this, struct da9063, restart_handler); > > > + > > > + regmap_write(da9063->regmap, DA9063_REG_PAGE_CON, 0x00); > > > + regmap_write(da9063->regmap, DA9063_REG_CONTROL_F, 0x04); > > > + regmap_write(da9063->regmap, DA9063_REG_CONTROL_A, 0x68); > > > + > > > + return NOTIFY_DONE; > > > +} > > > + > > > > Firstly, do you also need to force the AUTOBOOT (bit 3, CONTROL_C) > > to ensure the PMIC does restart. > > I tried this too and actually, it seems that the value is read from > OTP at reboot and as it is not set here, it has no effect. > > > > > > int da9063_device_init(struct da9063 *da9063, unsigned int irq) > > > { > > > int ret; > > > @@ -197,6 +210,18 @@ int da9063_device_init(struct da9063 *da9063, unsigned int irq) > > > } > > > } > > > > > > + da9063->restart_handler.notifier_call = da9063_restart_notify; > > > + da9063->restart_handler.priority = 128; > > > + ret = register_restart_handler(&da9063->restart_handler); > > > + if (ret) { > > > + dev_err(da9063->dev, "Failed to register restart handler\n"); > > > + return ret; > > > + } > > > + > > > + devm_add_action(da9063->dev, > > > + (void (*)(void *))unregister_restart_handler, > > > + &da9063->restart_handler); > > > > there's devm_register_reboot_notifier() > > Thanks for that! Actually restart_notifier and reboot_notifier are not the same, see https://elixir.bootlin.com/linux/latest/source/kernel/reboot.c#L72. What we need here is restart_handler. Thanks anyway :) Alex > > > > > > > > + > > > return ret; > > > } > > > > > > diff --git a/include/linux/mfd/da9063/core.h b/include/linux/mfd/da9063/core.h > > > index fa7a43f02f27..1b20c498e340 100644 > > > --- a/include/linux/mfd/da9063/core.h > > > +++ b/include/linux/mfd/da9063/core.h > > > @@ -85,6 +85,9 @@ struct da9063 { > > > int chip_irq; > > > unsigned int irq_base; > > > struct regmap_irq_chip_data *regmap_irq; > > > + > > > + /* Restart */ > > > + struct notifier_block restart_handler; > > > }; > > > > > > int da9063_device_init(struct da9063 *da9063, unsigned int irq); > > > > Note, the watchdog driver for the DA9063 also has a restart method > > although it also does not set the AUTOBOOT bit either. > > > > The best thing is to enable the watchdog driver, the SiFive release > > does not have either the core DA9063 or the watchdog driver for it > > enabled. > > It seems that for the restart implemented here to work, the AUTOBOOT > bit needs to be set in the OTP, which seems not to be the case with > the chip on this board: it's been discussed here > https://www.dialog-semiconductor.com/products/pmics?post_id=10052#tab-support_tab_content > (see the accepted answer). > > Thanks, > > Alex > > > > > -- > > Ben Dooks http://www.codethink.co.uk/ > > Senior Engineer Codethink - Providing Genius > > > > https://www.codethink.co.uk/privacy.html
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