From: Andrew Murray <andrew.murray@arm.com>
To: Remi Pommarel <repk@triplefau.lt>
Cc: Yue Wang <yue.wang@Amlogic.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Bjorn Helgaas <bhelgaas@google.com>,
Kevin Hilman <khilman@baylibre.com>,
linux-pci@vger.kernel.org, linux-amlogic@lists.infradead.org
Subject: Re: [PATCH] PCI: amlogic: Fix reset assertion via gpio descriptor
Date: Mon, 2 Sep 2019 11:55:36 +0100 [thread overview]
Message-ID: <20190902105536.GG9720@e119886-lin.cambridge.arm.com> (raw)
In-Reply-To: <20190901133915.12899-1-repk@triplefau.lt>
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@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@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
>
next prev parent reply other threads:[~2019-09-02 10:55 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-01 13:39 [PATCH] PCI: amlogic: Fix reset assertion via gpio descriptor Remi Pommarel
2019-09-01 21:46 ` Martin Blumenstingl
2019-09-02 8:11 ` Neil Armstrong
2019-09-02 10:55 ` Andrew Murray [this message]
2019-09-02 14:43 ` Remi Pommarel
2019-09-02 22:34 ` Martin Blumenstingl
2019-10-15 14:02 ` Lorenzo Pieralisi
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