On Tue, Apr 23, 2019 at 02:58:24PM +0530, Manikanta Maddireddy wrote:
> Add support for GPIO based PERST# instead of SFIO mode controlled by AFI.
> GPIO number comes from per port PCIe device tree node.
>
> Signed-off-by: Manikanta Maddireddy <mmaddireddy@xxxxxxxxxx>
> ---
> V2: Using standard "reset-gpio" property
>
> drivers/pci/controller/pci-tegra.c | 36 +++++++++++++++++++++++++-----
> 1 file changed, 30 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/pci/controller/pci-tegra.c b/drivers/pci/controller/pci-tegra.c
> index 72d344858e25..09b3b3e847c5 100644
> --- a/drivers/pci/controller/pci-tegra.c
> +++ b/drivers/pci/controller/pci-tegra.c
> @@ -17,6 +17,7 @@
> #include <linux/debugfs.h>
> #include <linux/delay.h>
> #include <linux/export.h>
> +#include <linux/gpio.h>
> #include <linux/interrupt.h>
> #include <linux/iopoll.h>
> #include <linux/irq.h>
> @@ -26,6 +27,7 @@
> #include <linux/module.h>
> #include <linux/msi.h>
> #include <linux/of_address.h>
> +#include <linux/of_gpio.h>
> #include <linux/of_pci.h>
> #include <linux/of_platform.h>
> #include <linux/pci.h>
> @@ -400,6 +402,8 @@ struct tegra_pcie_port {
> unsigned int lanes;
>
> struct phy **phys;
> +
> + int reset_gpio;
Please store the struct gpio_desc * here.
> };
>
> struct tegra_pcie_bus {
> @@ -583,15 +587,23 @@ static void tegra_pcie_port_reset(struct tegra_pcie_port *port)
> unsigned long value;
>
> /* pulse reset signal */
> - value = afi_readl(port->pcie, ctrl);
> - value &= ~AFI_PEX_CTRL_RST;
> - afi_writel(port->pcie, value, ctrl);
> + if (gpio_is_valid(port->reset_gpio)) {
> + gpiod_set_value(gpio_to_desc(port->reset_gpio), 0);
Then there's no need for the conversion between the integer and the
descriptor.
> + } else {
> + value = afi_readl(port->pcie, ctrl);
> + value &= ~AFI_PEX_CTRL_RST;
> + afi_writel(port->pcie, value, ctrl);
> + }
>
> usleep_range(1000, 2000);
>
> - value = afi_readl(port->pcie, ctrl);
> - value |= AFI_PEX_CTRL_RST;
> - afi_writel(port->pcie, value, ctrl);
> + if (gpio_is_valid(port->reset_gpio)) {
> + gpiod_set_value(gpio_to_desc(port->reset_gpio), 1);
> + } else {
> + value = afi_readl(port->pcie, ctrl);
> + value |= AFI_PEX_CTRL_RST;
> + afi_writel(port->pcie, value, ctrl);
> + }
> }
>
> static void tegra_pcie_enable_rp_features(struct tegra_pcie_port *port)
> @@ -2299,6 +2311,18 @@ static int tegra_pcie_parse_dt(struct tegra_pcie *pcie)
> if (IS_ERR(rp->base))
> return PTR_ERR(rp->base);
>
> + rp->reset_gpio = of_get_named_gpio(port, "reset-gpio", 0);
You can use devm_gpiod_get_from_of_node() to achieve this. Also, that
function allows you to pass in flags, so you no longer need the below
extra step to configure the GPIO.
> + if (gpio_is_valid(rp->reset_gpio)) {
> + err = devm_gpio_request_one(dev, rp->reset_gpio,
> + GPIOF_OUT_INIT_LOW,
> + "pex_reset");
Perhaps we want to include the port in the label somehow?
> + if (err < 0) {
> + dev_err(dev, "failed to request reset-gpio: %d\n",
Something like the below would be more consistent with the rest of the
driver:
"failed to request reset GPIO: %d\n"
Thierry
> + err);
> + return err;
> + }
> + }
> +
> list_add_tail(&rp->list, &pcie->ports);
> }
>
> --
> 2.17.1
>
Attachment:
signature.asc
Description: PGP signature
