Re: [PATCH 18/44] mfd: twl4030-power: Register with kernel poweroff handler

Lee Jones
2014-10-07T07:52:38Z

On Mon, 06 Oct 2014, Guenter Roeck wrote:

> Register with kernel poweroff handler instead of setting pm_power_off
> directly. Register with a low priority value of 64 to reflect that
> the original code only sets pm_power_off if it was not already set.
>
> Make twl4030_power_off static as it is only called from the twl4030-power
> driver.
>
> Cc: Samuel Ortiz <sameo@linux.intel.com>
> Cc: Lee Jones <lee.jones@linaro.org>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
> drivers/mfd/twl4030-power.c | 25 +++++++++++++++++++++----
> include/linux/i2c/twl.h | 1 -
> 2 files changed, 21 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/mfd/twl4030-power.c b/drivers/mfd/twl4030-power.c
> index 4d3ff37..bd6b830 100644
> --- a/drivers/mfd/twl4030-power.c
> +++ b/drivers/mfd/twl4030-power.c
> @@ -25,9 +25,10 @@
> */
>
> #include <linux/module.h>
> -#include <linux/pm.h>
> +#include <linux/notifier.h>
> #include <linux/i2c/twl.h>
> #include <linux/platform_device.h>
> +#include <linux/pm.h>
> #include <linux/of.h>
> #include <linux/of_device.h>
>
> @@ -611,7 +612,8 @@ twl4030_power_configure_resources(const struct twl4030_power_data *pdata)
> * After a successful execution, TWL shuts down the power to the SoC
> * and all peripherals connected to it.
> */
> -void twl4030_power_off(void)
> +static int twl4030_power_off(struct notifier_block *this, unsigned long unused1,
> + void *unused2)
> {
> int err;
>
> @@ -619,8 +621,15 @@ void twl4030_power_off(void)
> TWL4030_PM_MASTER_P1_SW_EVENTS);
> if (err)
> pr_err("TWL4030 Unable to power off\n");
> +
> + return NOTIFY_DONE;
> }
>
> +static struct notifier_block twl4030_poweroff_nb = {
> + .notifier_call = twl4030_power_off,
> + .priority = 64,

64 out of what? How is this calculated? Wouldn't it be better to
define these?

> +};
> +
> static bool twl4030_power_use_poweroff(const struct twl4030_power_data *pdata,
> struct device_node *node)
> {
> @@ -836,7 +845,7 @@ static int twl4030_power_probe(struct platform_device *pdev)
> }
>
> /* Board has to be wired properly to use this feature */
> - if (twl4030_power_use_poweroff(pdata, node) && !pm_power_off) {
> + if (twl4030_power_use_poweroff(pdata, node)) {
> /* Default for SEQ_OFFSYNC is set, lets ensure this */
> err = twl_i2c_read_u8(TWL_MODULE_PM_MASTER, &val,
> TWL4030_PM_MASTER_CFG_P123_TRANSITION);
> @@ -853,7 +862,13 @@ static int twl4030_power_probe(struct platform_device *pdev)
> }
> }
>
> - pm_power_off = twl4030_power_off;
> + err = register_poweroff_handler(&twl4030_poweroff_nb);
> + if (err) {
> + dev_err(&pdev->dev,
> + "Failed to register poweroff handler\n");

If this is not fatal, you should issue a dev_warn() instead.

> + /* Not a fatal error */
> + err = 0;

How about using your own variable for this? Then you don't have to
worry about resetting it.

> + }
> }
>
> relock:
> @@ -869,6 +884,8 @@ relock:
>
> static int twl4030_power_remove(struct platform_device *pdev)
> {
> + unregister_poweroff_handler(&twl4030_poweroff_nb);

Perhaps a naive question, but is there any way you can do this using
devres (devm_* managed resources)?

> return 0;
> }
>
> diff --git a/include/linux/i2c/twl.h b/include/linux/i2c/twl.h
> index 8cfb50f..f8544f1 100644
> --- a/include/linux/i2c/twl.h
> +++ b/include/linux/i2c/twl.h
> @@ -680,7 +680,6 @@ struct twl4030_power_data {
> };
>
> extern int twl4030_remove_script(u8 flags);
> -extern void twl4030_power_off(void);
>
> struct twl4030_codec_data {
> unsigned int digimic_delay; /* in ms */

--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org â”‚ Open source software for ARM SoCs
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