[PATCH] PCI: amlogic: Fix reset assertion via gpio descriptor

Andrew Murray andrew.murray at arm.com
Mon Sep 2 03:55:36 PDT 2019


On Sun, Sep 01, 2019 at 03:39:15PM +0200, Remi Pommarel wrote:
> Normally asserting reset signal on gpio would be achieved with:
> 	gpiod_set_value_cansleep(reset_gpio, 1);
> 
> Meson PCI driver set reset value to '0' instead of '1' as it takes into
> account the PERST# signal polarity. The polarity should be taken care
> in the device tree instead.
> 
> This fixes the reset assertion meaning and moves out the polarity
> configuration in DT (please note that there is no DT currently using
> this driver).

The device tree bindings for this give an example configuration:

        pcie: pcie at f9800000 {
                        compatible = "amlogic,axg-pcie", "snps,dw-pcie";
                        reg = <0x0 0xf9800000 0x0 0x400000
                                        0x0 0xff646000 0x0 0x2000
                                        0x0 0xff644000 0x0 0x2000
                                        0x0 0xf9f00000 0x0 0x100000>;
                        reg-names = "elbi", "cfg", "phy", "config";
                        reset-gpios = <&gpio GPIOX_19 GPIO_ACTIVE_HIGH>;

Is the 'reset-gpios' line still consistent with this change, or does
this need to be updated as well?

Thanks,

Andrew Murray

> 
> Signed-off-by: Remi Pommarel <repk at triplefau.lt>
> ---
>  drivers/pci/controller/dwc/pci-meson.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pci-meson.c b/drivers/pci/controller/dwc/pci-meson.c
> index e35e9eaa50ee..541f37a6f6a5 100644
> --- a/drivers/pci/controller/dwc/pci-meson.c
> +++ b/drivers/pci/controller/dwc/pci-meson.c
> @@ -287,9 +287,9 @@ static inline void meson_cfg_writel(struct meson_pcie *mp, u32 val, u32 reg)
>  
>  static void meson_pcie_assert_reset(struct meson_pcie *mp)
>  {
> -	gpiod_set_value_cansleep(mp->reset_gpio, 0);
> -	udelay(500);
>  	gpiod_set_value_cansleep(mp->reset_gpio, 1);
> +	udelay(500);
> +	gpiod_set_value_cansleep(mp->reset_gpio, 0);
>  }
>  
>  static void meson_pcie_init_dw(struct meson_pcie *mp)
> -- 
> 2.20.1
> 



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