[PATCH] power: pmic: pca9450: Add support for system reset

[Primoz Fiser]

Hi Paul,

On 4. 08. 25 19:30, Paul Geurts wrote:
>> The family of PCA9450 PMICs have the ability to perform system resets.
>> Restarting via PMIC is preferred method of restarting the system as all
>> the peripherals are brought to a know state after a power-cycle. The
>> PCA9450 features a cold restart procedure which is initiated by an I2C
>> command 0x14 to the SW_RST register.
>>
>> Support in Linux for restarting via PCA9450 PMIC has been added by
>> Linux commit 6157e62b07d9 ("regulator: pca9450: Add restart handler").
>>
>> Now add support for it also in the U-Boot via sysreset framework.
>>
>> Signed-off-by: Primoz Fiser <primoz.fiser at norik.com>
>> ---
>>  drivers/power/pmic/pca9450.c | 42 ++++++++++++++++++++++++++++++++++++
>>  include/power/pca9450.h      |  2 ++
>>  2 files changed, 44 insertions(+)
>>
>> diff --git a/drivers/power/pmic/pca9450.c b/drivers/power/pmic/pca9450.c
>> index 9d875f8bdbe8..abc39d0a1946 100644
>> --- a/drivers/power/pmic/pca9450.c
>> +++ b/drivers/power/pmic/pca9450.c
>> @@ -7,15 +7,18 @@
>>  #include <errno.h>
>>  #include <dm.h>
>>  #include <dm/device_compat.h>
>> +#include <dm/lists.h>
>>  #include <i2c.h>
>>  #include <linux/err.h>
>>  #include <log.h>
>>  #include <asm/global_data.h>
>>  #include <asm-generic/gpio.h>
>> +#include <linux/delay.h>
>>  #include <linux/printk.h>
>>  #include <power/pmic.h>
>>  #include <power/regulator.h>
>>  #include <power/pca9450.h>
>> +#include <sysreset.h>
>>  
>>  DECLARE_GLOBAL_DATA_PTR;
>>  
>> @@ -101,6 +104,14 @@ static int pca9450_probe(struct udevice *dev)
>>  		}
>>  	}
>>  
>> +	if (CONFIG_IS_ENABLED(SYSRESET)) {
>> +		ret = device_bind_driver_to_node(dev, "pca9450_sysreset",
>> +						 "pca9450_sysreset",
>> +						 dev_ofnode(dev), NULL);
>> +		if (ret)
>> +			return ret;
>> +	}
>> +
>>  	if (ofnode_read_bool(dev_ofnode(dev), "nxp,wdog_b-warm-reset"))
>>  		reset_ctrl = PCA9450_PMIC_RESET_WDOG_B_CFG_WARM;
>>  	else
>> @@ -134,3 +145,34 @@ U_BOOT_DRIVER(pmic_pca9450) = {
>>  	.ops = &pca9450_ops,
>>  	.priv_auto = sizeof(struct pca9450_priv),
>>  };
>> +
>> +#ifdef CONFIG_SYSRESET
>> +static int pca9450_sysreset_request(struct udevice *dev, enum sysreset_t type)
>> +{
>> +	u8 cmd = PCA9450_SW_RST_COLD_RST;
>> +
>> +	if (type != SYSRESET_COLD)
> 
> The PCA9450 calls it "cold reset", but it is technically SYSRESET_POWER.
> There is no option for it in the sysreset do_reset, but maybe there should be.

Yeah, the default is SYSRESET_COLD.

Additionally, there is only support for warm rst type (SYSRESET_WARM) in
do_reset for now.

I decided not to implement it to keep it as simple as possible and in
sync with your Linux support.

> 
>> +		return -EPROTONOSUPPORT;
>> +
>> +	if (pmic_write(dev->parent, PCA9450_SW_RST, &cmd, 1)) {
>> +		dev_err(dev, "reset command failed\n");
>> +	} else {
>> +		/* tRESTART is 250ms, delay 300ms just to be sure */
>> +		mdelay(300);
>> +		/* Should not get here, warn if we do */
>> +		dev_warn(dev, "didn't respond to reset command\n");
>> +	}
>> +
>> +	return -EINPROGRESS;
>> +}
>> +
>> +static struct sysreset_ops pca9450_sysreset_ops = {
>> +	.request	= pca9450_sysreset_request,
> 
> When using the PCA9450 to perform a cold reset, the CPU boot status shall
> _always_ be POR, as that is what the CPU detects. This means the boot status
> should also come from the PCA9450 when enabling CONFIG_SYSRESET option.
> 
> I think implementing pca9450_sysreset_ops.get_status() to read the
> PWRON_STAT register should do the trick, but I am not that familiar with the
> sysreset in U-Boot.

You read my mind :)

I have support for get_status() already prepared but I am waiting for
this patch to get applied first.

Your Reviewed-by tag would help here if possible?

> 
>> +};
>> +
>> +U_BOOT_DRIVER(pca9450_sysreset) = {
>> +	.name		= "pca9450_sysreset",
>> +	.id		= UCLASS_SYSRESET,
>> +	.ops		= &pca9450_sysreset_ops,
>> +};
>> +#endif /* CONFIG_SYSRESET */
>> diff --git a/include/power/pca9450.h b/include/power/pca9450.h
>> index e5ab09fb8c83..9119ef793b1f 100644
>> --- a/include/power/pca9450.h
>> +++ b/include/power/pca9450.h
>> @@ -75,4 +75,6 @@ enum {
>>  #define PCA9450_PMIC_RESET_WDOG_B_CFG_WARM		0x40
>>  #define PCA9450_PMIC_RESET_WDOG_B_CFG_COLD_LDO12	0x80
>>  
>> +#define PCA9450_SW_RST_COLD_RST		0x14
>> +
>>  #endif
>>
> 
> Thanks for porting it to U-Boot :-)

You're welcome.

Thanks for adding support in Linux.

BR,
Primoz

> 
> br,
> Paul

-- 
Primoz Fiser
phone: +386-41-390-545
email: primoz.fiser at norik.com
--
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