Re: [PATCH] wilc1000: Add reset/enable GPIO support to SPI driver

From: Claudiu.Beznea
Date: Tue Dec 07 2021 - 05:11:31 EST

On 02.12.2021 05:55, David Mosberger-Tang wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>
> This patch is based on similar code from the linux4sam/linux-at91 GIT
> repository.
>
> For the SDIO driver, the RESET/ENABLE pins of WILC1000 may be
> controlled through the SDIO power sequence driver. This commit adds
> analogous support for the SPI driver. Specifically, during bus
> probing, the chip will be reset-cycled and during unloading, the chip
> will be placed into reset and disabled (both to reduce power
> consumption and to ensure the WiFi radio is off).
>
> Both RESET and ENABLE GPIOs are optional. However, if the ENABLE GPIO
> is specified, then the RESET GPIO also must be specified as otherwise
> there is no way to ensure proper timing of the ENABLE/RESET sequence.
>
> Signed-off-by: David Mosberger-Tang <davidm@xxxxxxxxxx>
> ---
> .../net/wireless/microchip,wilc1000.yaml | 11 +++
> .../net/wireless/microchip/wilc1000/Makefile | 2 +-
> drivers/net/wireless/microchip/wilc1000/hif.h | 2 +
> .../net/wireless/microchip/wilc1000/netdev.h | 10 +++
> .../net/wireless/microchip/wilc1000/power.c | 73 +++++++++++++++++++
> drivers/net/wireless/microchip/wilc1000/spi.c | 15 +++-
> .../net/wireless/microchip/wilc1000/wlan.c | 2 +-
> 7 files changed, 110 insertions(+), 5 deletions(-)
> create mode 100644 drivers/net/wireless/microchip/wilc1000/power.c
>
> diff --git a/Documentation/devicetree/bindings/net/wireless/microchip,wilc1000.yaml b/Documentation/devicetree/bindings/net/wireless/microchip,wilc1000.yaml
> index 6c35682377e6..2ce316f5e353 100644
> --- a/Documentation/devicetree/bindings/net/wireless/microchip,wilc1000.yaml
> +++ b/Documentation/devicetree/bindings/net/wireless/microchip,wilc1000.yaml
> @@ -32,6 +32,15 @@ properties:
> clock-names:
> const: rtc
>
> + enable-gpios:
> + maxItems: 1
> + description: A GPIO line connected to the ENABLE line. If this
> + is specified, then reset-gpios also must be specified.
> +
> + reset-gpios:
> + maxItems: 1
> + description: A GPIO line connected to the RESET line.
> +

Bindings should go through a different patch.

> required:
> - compatible
> - interrupts
> @@ -51,6 +60,8 @@ examples:
> interrupts = <27 0>;
> clocks = <&pck1>;
> clock-names = "rtc";
> + enable-gpios = <&pioA 5 0>;
> + reset-gpios = <&pioA 6 0>;
> };
> };
>
> diff --git a/drivers/net/wireless/microchip/wilc1000/Makefile b/drivers/net/wireless/microchip/wilc1000/Makefile
> index c3c9e34c1eaa..baf9f021a1d6 100644
> --- a/drivers/net/wireless/microchip/wilc1000/Makefile
> +++ b/drivers/net/wireless/microchip/wilc1000/Makefile
> @@ -2,7 +2,7 @@
> obj-$(CONFIG_WILC1000) += wilc1000.o
>
> wilc1000-objs := cfg80211.o netdev.o mon.o \
> - hif.o wlan_cfg.o wlan.o
> + hif.o wlan_cfg.o wlan.o power.o
>
> obj-$(CONFIG_WILC1000_SDIO) += wilc1000-sdio.o
> wilc1000-sdio-objs += sdio.o
> diff --git a/drivers/net/wireless/microchip/wilc1000/hif.h b/drivers/net/wireless/microchip/wilc1000/hif.h
> index cccd54ed0518..a57095d8088e 100644
> --- a/drivers/net/wireless/microchip/wilc1000/hif.h
> +++ b/drivers/net/wireless/microchip/wilc1000/hif.h
> @@ -213,4 +213,6 @@ void wilc_network_info_received(struct wilc *wilc, u8 *buffer, u32 length);
> void wilc_gnrl_async_info_received(struct wilc *wilc, u8 *buffer, u32 length);
> void *wilc_parse_join_bss_param(struct cfg80211_bss *bss,
> struct cfg80211_crypto_settings *crypto);
> +int wilc_of_parse_power_pins(struct wilc *wilc);
> +void wilc_wlan_power(struct wilc *wilc, bool on);
> #endif
> diff --git a/drivers/net/wireless/microchip/wilc1000/netdev.h b/drivers/net/wireless/microchip/wilc1000/netdev.h
> index b9a88b3e322f..b95a247322a6 100644
> --- a/drivers/net/wireless/microchip/wilc1000/netdev.h
> +++ b/drivers/net/wireless/microchip/wilc1000/netdev.h
> @@ -197,6 +197,15 @@ struct wilc_vif {
> struct cfg80211_bss *bss;
> };
>
> +struct wilc_power_gpios {
> + int reset;
> + int chip_en;
> +};
> +
> +struct wilc_power {
> + struct wilc_power_gpios gpios;
> +};
> +
> struct wilc_tx_queue_status {
> u8 buffer[AC_BUFFER_SIZE];
> u16 end_index;
> @@ -265,6 +274,7 @@ struct wilc {
> bool suspend_event;
>
> struct workqueue_struct *hif_workqueue;
> + struct wilc_power power;

For SDIO power should be controlled though MMC pwrseq driver. Thus I would
keep this code for SPI only and move this member to struct wilc_spi.

> struct wilc_cfg cfg;
> void *bus_data;
> struct net_device *monitor_dev;
> diff --git a/drivers/net/wireless/microchip/wilc1000/power.c b/drivers/net/wireless/microchip/wilc1000/power.c
> new file mode 100644
> index 000000000000..d26a39b7698d
> --- /dev/null
> +++ b/drivers/net/wireless/microchip/wilc1000/power.c
> @@ -0,0 +1,73 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2012 - 2018 Microchip Technology Inc., and its subsidiaries.
> + * All rights reserved.

This is not in the GIT repo. It should have been:
"Copyright (c) 2021 Microchip Technology Inc. and its subsidiaries"
^
current year

> + */
> +#include <linux/delay.h>
> +#include <linux/gpio.h>
> +#include <linux/of.h>
> +#include <linux/of_gpio.h>
> +#include <linux/version.h>
> +
> +#include "netdev.h"
> +
> +/**
> + * wilc_of_parse_power_pins() - parse power sequence pins
> + *
> + * @wilc: wilc data structure
> + *
> + * Returns: 0 on success, negative error number on failures.
> + */
> +int wilc_of_parse_power_pins(struct wilc *wilc)
> +{
> + struct device_node *of = wilc->dev->of_node;
> + struct wilc_power *power = &wilc->power;
> + int ret;
> +
> + power->gpios.reset = of_get_named_gpio_flags(of, "reset-gpios", 0,
> + NULL);
> + power->gpios.chip_en = of_get_named_gpio_flags(of, "chip_en-gpios", 0,
> + NULL);

Consider using gpio descriptors and devm_gpiod_get().

> + if (!gpio_is_valid(power->gpios.reset))
> + return 0; /* assume SDIO power sequence driver is used */

In case of SDIO we should rely on mmc pwrseq all the time. It keeps things
cleaner. I would keep the code in this file only for SPI.

> +
> + if (gpio_is_valid(power->gpios.chip_en)) {
> + ret = devm_gpio_request(wilc->dev, power->gpios.chip_en,
> + "CHIP_EN");
> + if (ret)
> + return ret;
> + }
> + return devm_gpio_request(wilc->dev, power->gpios.reset, "RESET");
> +}
> +EXPORT_SYMBOL_GPL(wilc_of_parse_power_pins);
> +
> +/**
> + * wilc_wlan_power() - handle power on/off commands
> + *
> + * @wilc: wilc data structure
> + * @on: requested power status
> + *
> + * Returns: none
> + */
> +void wilc_wlan_power(struct wilc *wilc, bool on)
> +{
> + if (!gpio_is_valid(wilc->power.gpios.reset)) {
> + /* In case SDIO power sequence driver is used to power this
> + * device then the powering sequence is handled by the bus
> + * via pm_runtime_* functions. */

I see this function is called anyway only in SPI context, so, don't think
this handling for SDIO is necessary. Maybe these is something I miss with
regards to it. Ajay, please correct me if I'm wrong.

> + return;
> + }
> +
> + if (on) {
> + if (gpio_is_valid(wilc->power.gpios.chip_en)) {
> + gpio_direction_output(wilc->power.gpios.chip_en, 1);
> + mdelay(5);
> + }
> + gpio_direction_output(wilc->power.gpios.reset, 1);
> + } else {
> + gpio_direction_output(wilc->power.gpios.reset, 0);
> + if (gpio_is_valid(wilc->power.gpios.chip_en))
> + gpio_direction_output(wilc->power.gpios.chip_en, 0);
> + }
> +}
> +EXPORT_SYMBOL_GPL(wilc_wlan_power);
> diff --git a/drivers/net/wireless/microchip/wilc1000/spi.c b/drivers/net/wireless/microchip/wilc1000/spi.c
> index 640850f989dd..884ad7f954d4 100644
> --- a/drivers/net/wireless/microchip/wilc1000/spi.c
> +++ b/drivers/net/wireless/microchip/wilc1000/spi.c
> @@ -171,6 +171,10 @@ static int wilc_bus_probe(struct spi_device *spi)
> wilc->bus_data = spi_priv;
> wilc->dev_irq_num = spi->irq;
>
> + ret = wilc_of_parse_power_pins(wilc);
> + if (ret)
> + goto netdev_cleanup;
> +
> wilc->rtc_clk = devm_clk_get_optional(&spi->dev, "rtc");
> if (IS_ERR(wilc->rtc_clk)) {
> ret = PTR_ERR(wilc->rtc_clk);
> @@ -178,6 +182,10 @@ static int wilc_bus_probe(struct spi_device *spi)
> }
> clk_prepare_enable(wilc->rtc_clk);
>
> + /* ensure WILC1000 is reset and enabled: */
> + wilc_wlan_power(wilc, false);
> + wilc_wlan_power(wilc, true);
> +
> return 0;
>
> netdev_cleanup:
> @@ -977,9 +985,10 @@ static int wilc_spi_reset(struct wilc *wilc)
>
> static int wilc_spi_deinit(struct wilc *wilc)
> {
> - /*
> - * TODO:
> - */
> + struct wilc_spi *spi_priv = wilc->bus_data;
> +
> + spi_priv->isinit = false;
> + wilc_wlan_power(wilc, false);
> return 0;
> }
>
> diff --git a/drivers/net/wireless/microchip/wilc1000/wlan.c b/drivers/net/wireless/microchip/wilc1000/wlan.c
> index 82566544419a..f1e4ac3a2ad5 100644
> --- a/drivers/net/wireless/microchip/wilc1000/wlan.c
> +++ b/drivers/net/wireless/microchip/wilc1000/wlan.c
> @@ -1253,7 +1253,7 @@ void wilc_wlan_cleanup(struct net_device *dev)
> wilc->rx_buffer = NULL;
> kfree(wilc->tx_buffer);
> wilc->tx_buffer = NULL;
> - wilc->hif_func->hif_deinit(NULL);
> + wilc->hif_func->hif_deinit(wilc);
> }
>
> static int wilc_wlan_cfg_commit(struct wilc_vif *vif, int type,
> --
> 2.25.1
>