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[PATCH 0/3] i.MX7 PCI support

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  [PATCH 0/3] i.MX7 PCI support Andrey Smirnov <andrew.smirnov@gmail.com> - 2017-01-19 17:50 +0100
    Re: [PATCH 2/3] PCI: imx6: Allow probe deferal by reset GPIO Lucas Stach <l.stach@pengutronix.de> - 2017-01-19 17:50 +0100
    [PATCH 2/3] PCI: imx6: Allow probe deferal by reset GPIO Andrey Smirnov <andrew.smirnov@gmail.com> - 2017-01-19 17:50 +0100

#1562900 — [PATCH 0/3] i.MX7 PCI support

Hello, everyone:

This is a small patchset intended to add PCI-subsystem bits necessary
for enabling PCI support on i.MX7. This patchset is not
self-sufficient and depends on three other patchsets:

  - Changes to anatop regulator driver
  - Chagnes to i.MX device tree code pertaining to anatop regulator
  - Changes to i.MX device tree pertaining to PCIe controller

I submitted first two in [1] and [2], and, unless adwised otherwise,
am planning on submitting the last one once [1], [2] and this patchset
are accepted.

This patch was tested against i210 card on i.MX7 Sabre board
(connected via mini-PCIe to PCIe adapter) with general functionality
and bandwidth tests.

Note that this patchset have known "blemish" where Gen1 cards (at
least) report this message:

 imx6q-pcie 33800000.pcie: Speed change timeout
 imx6q-pcie 33800000.pcie: Failed to bring link up!

due to hardware not clearing PORT_LOGIC_SPEED_CHANGE bit after speed
change is requested, but since this does not seem to affect the
functioning of the link I am hoping this is not a deal breaker.

I posted a question on NXP community web-site [3] hoping to get some
additional info to help resolve the matter and if anyone has any
suggestions I'd love to hear them.

Thanks,
Andrey Smirnov

[1] https://www.spinics.net/lists/arm-kernel/msg553215.html
[2] https://www.spinics.net/lists/kernel/msg2418471.html
[3] https://community.nxp.com/message/867943

Andrey Smirnov (3):
  PCI: imx6: Fix a typo in error message
  PCI: imx6: Allow probe deferal by reset GPIO
  PCI: imx6: Add code to support i.MX7D

 .../devicetree/bindings/pci/fsl,imx6q-pcie.txt     |   6 +-
 drivers/pci/host/pci-imx6.c                        | 197 ++++++++++++++++++---
 include/linux/mfd/syscon/imx7-gpc.h                |  18 ++
 include/linux/mfd/syscon/imx7-iomuxc-gpr.h         |   4 +
 include/linux/mfd/syscon/imx7-src.h                |  18 ++
 5 files changed, 214 insertions(+), 29 deletions(-)
 create mode 100644 include/linux/mfd/syscon/imx7-gpc.h
 create mode 100644 include/linux/mfd/syscon/imx7-src.h

-- 
2.9.3

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#1562909 — Re: [PATCH 2/3] PCI: imx6: Allow probe deferal by reset GPIO

Am Donnerstag, den 19.01.2017, 08:36 -0800 schrieb Andrey Smirnov:
> Some designs implement reset GPIO via a GPIO expander connected to a
> peripheral bus. One such example would be i.MX7 Sabre board where said
> GPIO is provided by SPI shift register connected to a bitbanged SPI
> bus. In order to support such designs allow reset GPIO request to defer
> probing of the driver.
> 
> Cc: yurovsky@gmail.com
> Cc: Richard Zhu <hongxing.zhu@nxp.com>
> Cc: Lucas Stach <l.stach@pengutronix.de>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: Fabio Estevam <festevam@gmail.com>
> Cc: Shawn Guo <shawnguo@kernel.org>
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
> ---
>  drivers/pci/host/pci-imx6.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c
> index 50a1291..574f026 100644
> --- a/drivers/pci/host/pci-imx6.c
> +++ b/drivers/pci/host/pci-imx6.c
> @@ -653,6 +653,9 @@ static int __init imx6_pcie_probe(struct platform_device *pdev)
>  			dev_err(dev, "unable to get reset gpio\n");
>  			return ret;
>  		}
> +	} else if (imx6_pcie->reset_gpio == -EPROBE_DEFER) {
> +		dev_info(dev, "probe is defered by reset GPIO\n");

No, please no messages for probe deferrals, as those might happen quite
often until the required driver is there and then just spams the logs.
Otherwise looks good.

> +		return imx6_pcie->reset_gpio;
>  	}
>  
>  	/* Fetch clocks */
> @@ -746,11 +749,12 @@ static struct platform_driver imx6_pcie_driver = {
>  		.name	= "imx6q-pcie",
>  		.of_match_table = imx6_pcie_of_match,
>  	},
> +	.probe    = imx6_pcie_probe,
>  	.shutdown = imx6_pcie_shutdown,
>  };
>  
>  static int __init imx6_pcie_init(void)
>  {
> -	return platform_driver_probe(&imx6_pcie_driver, imx6_pcie_probe);
> +	return platform_driver_register(&imx6_pcie_driver);
>  }
>  device_initcall(imx6_pcie_init);

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#1562912 — [PATCH 2/3] PCI: imx6: Allow probe deferal by reset GPIO

Some designs implement reset GPIO via a GPIO expander connected to a
peripheral bus. One such example would be i.MX7 Sabre board where said
GPIO is provided by SPI shift register connected to a bitbanged SPI
bus. In order to support such designs allow reset GPIO request to defer
probing of the driver.

Cc: yurovsky@gmail.com
Cc: Richard Zhu <hongxing.zhu@nxp.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
---
 drivers/pci/host/pci-imx6.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c
index 50a1291..574f026 100644
--- a/drivers/pci/host/pci-imx6.c
+++ b/drivers/pci/host/pci-imx6.c
@@ -653,6 +653,9 @@ static int __init imx6_pcie_probe(struct platform_device *pdev)
 			dev_err(dev, "unable to get reset gpio\n");
 			return ret;
 		}
+	} else if (imx6_pcie->reset_gpio == -EPROBE_DEFER) {
+		dev_info(dev, "probe is defered by reset GPIO\n");
+		return imx6_pcie->reset_gpio;
 	}
 
 	/* Fetch clocks */
@@ -746,11 +749,12 @@ static struct platform_driver imx6_pcie_driver = {
 		.name	= "imx6q-pcie",
 		.of_match_table = imx6_pcie_of_match,
 	},
+	.probe    = imx6_pcie_probe,
 	.shutdown = imx6_pcie_shutdown,
 };
 
 static int __init imx6_pcie_init(void)
 {
-	return platform_driver_probe(&imx6_pcie_driver, imx6_pcie_probe);
+	return platform_driver_register(&imx6_pcie_driver);
 }
 device_initcall(imx6_pcie_init);
-- 
2.9.3

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