Re: [Xen-devel] [PATCH 23/44] power/reset: qnap-poweroff: Register with kernel poweroff handler

[Andrew Lunn <andrew@xxxxxxx>]

On Mon, Oct 06, 2014 at 10:28:25PM -0700, Guenter Roeck wrote:
> Register with kernel poweroff handler instead of setting pm_power_off
> directly. Register with default priority value of 128 to reflect that
> the original code generates an error if another poweroff handler has
> already been registered when the driver is loaded.
> 
> Cc: Sebastian Reichel <sre@xxxxxxxxxx>
> Cc: Dmitry Eremin-Solenikov <dbaryshkov@xxxxxxxxx>
> Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
> Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>

Acked-by: Andrew Lunn <andrew@xxxxxxx>

Thanks
        Andrew

> ---
>  drivers/power/reset/qnap-poweroff.c | 28 ++++++++++++++--------------
>  1 file changed, 14 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/power/reset/qnap-poweroff.c 
> b/drivers/power/reset/qnap-poweroff.c
> index a75db7f..c474980 100644
> --- a/drivers/power/reset/qnap-poweroff.c
> +++ b/drivers/power/reset/qnap-poweroff.c
> @@ -16,7 +16,9 @@
>  
>  #include <linux/kernel.h>
>  #include <linux/module.h>
> +#include <linux/notifier.h>
>  #include <linux/platform_device.h>
> +#include <linux/pm.h>
>  #include <linux/serial_reg.h>
>  #include <linux/kallsyms.h>
>  #include <linux/of.h>
> @@ -55,7 +57,8 @@ static void __iomem *base;
>  static unsigned long tclk;
>  static const struct power_off_cfg *cfg;
>  
> -static void qnap_power_off(void)
> +static int qnap_power_off(struct notifier_block *this, unsigned long unused1,
> +                       void *unused2)
>  {
>       const unsigned divisor = ((tclk + (8 * cfg->baud)) / (16 * cfg->baud));
>  
> @@ -72,14 +75,20 @@ static void qnap_power_off(void)
>  
>       /* send the power-off command to PIC */
>       writel(cfg->cmd, UART1_REG(TX));
> +
> +     return NOTIFY_DONE;
>  }
>  
> +static struct notifier_block qnap_poweroff_nb = {
> +     .notifier_call = qnap_power_off,
> +     .priority = 128,
> +};
> +
>  static int qnap_power_off_probe(struct platform_device *pdev)
>  {
>       struct device_node *np = pdev->dev.of_node;
>       struct resource *res;
>       struct clk *clk;
> -     char symname[KSYM_NAME_LEN];
>  
>       const struct of_device_id *match =
>               of_match_node(qnap_power_off_of_match_table, np);
> @@ -106,22 +115,13 @@ static int qnap_power_off_probe(struct platform_device 
> *pdev)
>  
>       tclk = clk_get_rate(clk);
>  
> -     /* Check that nothing else has already setup a handler */
> -     if (pm_power_off) {
> -             lookup_symbol_name((ulong)pm_power_off, symname);
> -             dev_err(&pdev->dev,
> -                     "pm_power_off already claimed %p %s",
> -                     pm_power_off, symname);
> -             return -EBUSY;
> -     }
> -     pm_power_off = qnap_power_off;
> -
> -     return 0;
> +     return register_poweroff_handler(&qnap_poweroff_nb);
>  }
>  
>  static int qnap_power_off_remove(struct platform_device *pdev)
>  {
> -     pm_power_off = NULL;
> +     unregister_poweroff_handler(&qnap_poweroff_nb);
> +
>       return 0;
>  }
>  
> -- 
> 1.9.1
> 
> 
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