diff mbox series

[v5,1/2] wilc1000: Add reset/enable GPIO support to SPI driver

Message ID 20211215030501.3779911-2-davidm@egauge.net
State Superseded
Headers show
Series wilc1000: Add reset/enable GPIO support to SPI driver | expand

Commit Message

David Mosberger-Tang Dec. 15, 2021, 3:05 a.m. UTC
For the SDIO driver, the RESET/ENABLE pins of WILC1000 are controlled
through the SDIO power sequence driver.  This commit adds analogous
support for the SPI driver.  Specifically, during initialization, the
chip will be ENABLEd and taken out of RESET and during
deinitialization, the chip will be placed back 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 should normally also be specified as
otherwise there is no way to ensure proper timing of the ENABLE/RESET
sequence.

Signed-off-by: David Mosberger-Tang <davidm@egauge.net>
---
 drivers/net/wireless/microchip/wilc1000/spi.c | 58 ++++++++++++++++++-
 .../net/wireless/microchip/wilc1000/wlan.c    |  2 +-
 2 files changed, 56 insertions(+), 4 deletions(-)

Comments

David Mosberger-Tang Dec. 16, 2021, 3:26 p.m. UTC | #1
On Thu, 2021-12-16 at 10:10 +0200, Kalle Valo wrote:
> David Mosberger-Tang <davidm@egauge.net> writes:
> 
> > > > +       } else {
> > > > +               gpiod_set_value(gpios->reset, 1);       /* assert RESET */
> > > > +               gpiod_set_value(gpios->enable, 0);      /* deassert ENABLE */
> > > 
> > > I don't usually see comments near the code line in kernel. Maybe move them
> > > before the actual code line or remove them at all as the code is impler enough?
> > 
> > You're kidding, right?
> 
> I agree with Claudiu, the comments are not really providing more
> information from what can be seen from the code. And the style of having
> the comment in the same line is not commonly used in upstream.

The code is obvious if you think of 1 as "assert" and 0 as "deassert".  It looks
utterly wrong if you think of 1 as outputting 3.3V and 0 as outputting 0V.

But if you insist, I'll remove the comments.

  --david
Kalle Valo Dec. 20, 2021, 8:46 a.m. UTC | #2
David Mosberger-Tang <davidm@egauge.net> writes:

> On Thu, 2021-12-16 at 10:10 +0200, Kalle Valo wrote:
>> David Mosberger-Tang <davidm@egauge.net> writes:
>> 
>> > > > +       } else {
>> > > > +               gpiod_set_value(gpios->reset, 1);       /* assert RESET */
>> > > > +               gpiod_set_value(gpios->enable, 0);      /* deassert ENABLE */
>> > > 
>> > > I don't usually see comments near the code line in kernel. Maybe move them
>> > > before the actual code line or remove them at all as the code is impler enough?
>> > 
>> > You're kidding, right?
>> 
>> I agree with Claudiu, the comments are not really providing more
>> information from what can be seen from the code. And the style of having
>> the comment in the same line is not commonly used in upstream.
>
> The code is obvious if you think of 1 as "assert" and 0 as "deassert".  It looks
> utterly wrong if you think of 1 as outputting 3.3V and 0 as outputting 0V.

Yeah, I guess for people who are more hardware orientated that looks
wrong :)

> But if you insist, I'll remove the comments.

I don't insist removing the comments, but please move them to their own
line so that the style is consistent.
diff mbox series

Patch

diff --git a/drivers/net/wireless/microchip/wilc1000/spi.c b/drivers/net/wireless/microchip/wilc1000/spi.c
index 6e7fd18c14e7..0b4425e56bfa 100644
--- a/drivers/net/wireless/microchip/wilc1000/spi.c
+++ b/drivers/net/wireless/microchip/wilc1000/spi.c
@@ -8,6 +8,7 @@ 
 #include <linux/spi/spi.h>
 #include <linux/crc7.h>
 #include <linux/crc-itu-t.h>
+#include <linux/gpio/consumer.h>
 
 #include "netdev.h"
 #include "cfg80211.h"
@@ -43,6 +44,10 @@  struct wilc_spi {
 	bool probing_crc;	/* true if we're probing chip's CRC config */
 	bool crc7_enabled;	/* true if crc7 is currently enabled */
 	bool crc16_enabled;	/* true if crc16 is currently enabled */
+	struct wilc_gpios {
+		struct gpio_desc *enable;	/* ENABLE GPIO or NULL */
+		struct gpio_desc *reset;	/* RESET GPIO or NULL */
+	} gpios;
 };
 
 static const struct wilc_hif_func wilc_hif_spi;
@@ -152,6 +157,46 @@  struct wilc_spi_special_cmd_rsp {
 	u8 status;
 } __packed;
 
+static int wilc_parse_gpios(struct wilc *wilc)
+{
+	struct spi_device *spi = to_spi_device(wilc->dev);
+	struct wilc_spi *spi_priv = wilc->bus_data;
+	struct wilc_gpios *gpios = &spi_priv->gpios;
+
+	/* get ENABLE pin and deassert it (if it is defined): */
+	gpios->enable = devm_gpiod_get_optional(&spi->dev,
+						"enable", GPIOD_OUT_LOW);
+	/* get RESET pin and assert it (if it is defined): */
+	if (gpios->enable) {
+		/* if enable pin exists, reset must exist as well */
+		gpios->reset = devm_gpiod_get(&spi->dev,
+					      "reset", GPIOD_OUT_HIGH);
+		if (IS_ERR(gpios->reset)) {
+			dev_err(&spi->dev, "missing reset gpio.\n");
+			return PTR_ERR(gpios->reset);
+		}
+	} else {
+		gpios->reset = devm_gpiod_get_optional(&spi->dev,
+						       "reset", GPIOD_OUT_HIGH);
+	}
+	return 0;
+}
+
+static void wilc_wlan_power(struct wilc *wilc, bool on)
+{
+	struct wilc_spi *spi_priv = wilc->bus_data;
+	struct wilc_gpios *gpios = &spi_priv->gpios;
+
+	if (on) {
+		gpiod_set_value(gpios->enable, 1);	/* assert ENABLE */
+		mdelay(5);
+		gpiod_set_value(gpios->reset, 0);	/* deassert RESET */
+	} else {
+		gpiod_set_value(gpios->reset, 1);	/* assert RESET */
+		gpiod_set_value(gpios->enable, 0);	/* deassert ENABLE */
+	}
+}
+
 static int wilc_bus_probe(struct spi_device *spi)
 {
 	int ret;
@@ -171,6 +216,10 @@  static int wilc_bus_probe(struct spi_device *spi)
 	wilc->bus_data = spi_priv;
 	wilc->dev_irq_num = spi->irq;
 
+	ret = wilc_parse_gpios(wilc);
+	if (ret < 0)
+		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);
@@ -984,9 +1033,10 @@  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;
 }
 
@@ -1007,6 +1057,8 @@  static int wilc_spi_init(struct wilc *wilc, bool resume)
 		dev_err(&spi->dev, "Fail cmd read chip id...\n");
 	}
 
+	wilc_wlan_power(wilc, true);
+
 	/*
 	 * configure protocol
 	 */
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,