Re: [PATCH v5 6/6] mfd: tps6586x: register restart handler

Lee Jones
2023-04-20T14:04:21Z

On Tue, 18 Apr 2023, Benjamin Bara wrote:

> From: Benjamin Bara <benjamin.bara@skidata.com>
>
> There are a couple of boards which use a tps6586x as
> "ti,system-power-controller", e.g. the tegra20-tamonten.dtsi.
> For these, the only registered restart handler is the warm reboot via
> tegra's PMC. As the bootloader of the tegra20 requires the VDE, it must
> be ensured that VDE is enabled (which is the case after a cold reboot).
> For the "normal reboot", this is basically the case since 8f0c714ad9be.
> However, this workaround is not executed in case of an emergency restart.
> In case of an emergency restart, the system now simply hangs in the
> bootloader, as VDE is not enabled (because it is not used).
>
> The TPS658629-Q1 (unfortunately the only TPS6586x with public data sheet)
> provides a SOFT RST bit in the SUPPLYENE reg to request a (cold) reboot,
> which takes at least 10ms (as the data sheet states).
> This avoids the hang-up.
>
> Tested on a TPS658640.
>
> Signed-off-by: Benjamin Bara <benjamin.bara@skidata.com>
> ---
> drivers/mfd/tps6586x.c | 26 ++++++++++++++++++++++++++
> 1 file changed, 26 insertions(+)
>
> diff --git a/drivers/mfd/tps6586x.c b/drivers/mfd/tps6586x.c
> index 226e856e34e0..f7665b368071 100644
> --- a/drivers/mfd/tps6586x.c
> +++ b/drivers/mfd/tps6586x.c
> @@ -30,6 +30,7 @@
> #include <linux/mfd/tps6586x.h>
>
> #define TPS6586X_SUPPLYENE 0x14
> +#define SOFT_RST_BIT BIT(0)
> #define EXITSLREQ_BIT BIT(1)
> #define SLEEP_MODE_BIT BIT(3)
>
> @@ -475,6 +476,24 @@ static int tps6586x_power_off_handler(struct sys_off_data *data)
> return notifier_from_errno(-ETIME);
> }
>
> +static int tps6586x_restart_handler(struct sys_off_data *data)
> +{
> + int ret;
> +
> + /* tps6586x only provides a hard/cold reboot, skip others. */

TPS6586x

> + if (data->mode != REBOOT_UNDEFINED && data->mode != REBOOT_COLD &&
> + data->mode != REBOOT_HARD)
> + return NOTIFY_DONE;
> +
> + /* bring pmic into HARD REBOOT state. this takes at least 10ms. */

Same as the other patch.

> + ret = tps6586x_set_bits(data->dev, TPS6586X_SUPPLYENE, SOFT_RST_BIT);
> + if (ret)
> + return notifier_from_errno(ret);
> +
> + mdelay(20);

Why 20 here and 50 in the other patch?

> + return notifier_from_errno(-ETIME);
> +}
> +
> static void tps6586x_print_version(struct i2c_client *client, int version)
> {
> const char *name;
> @@ -575,6 +594,13 @@ static int tps6586x_i2c_probe(struct i2c_client *client)
> dev_err(&client->dev, "register power off handler failed: %d\n", ret);
> goto err_add_devs;
> }
> +
> + ret = devm_register_restart_handler(&client->dev, &tps6586x_restart_handler,
> + NULL);
> + if (ret) {
> + dev_err(&client->dev, "register restart handler failed: %d\n", ret);
> + goto err_add_devs;
> + }
> }
>
> return 0;
>
> --
> 2.34.1
>

--
Lee Jones [李琼斯]