Many ath6k chips have a reset pin, usually labeled CHIP_PWD_L. This pin can
be pulled low by the host processor to hold the wifi chip in reset. By
holding the chip in reset, the lowest power consumption available can be
achieved.
This adds a module parameter so the ath6kl_sdio driver can control the
CHIP_PWD_L pin if the implementer so desires. This code is only available
if GPIOLIB is configured.
Signed-off-by: Steve deRosier <steve.derosier@xxxxxxxxxxxxx>
---
drivers/net/wireless/ath/ath6kl/sdio.c | 80 +++++++++++++++++++++++++++++++++-
1 file changed, 79 insertions(+), 1 deletion(-)
diff --git a/drivers/net/wireless/ath/ath6kl/sdio.c b/drivers/net/wireless/ath/ath6kl/sdio.c
index eab0ab9..7a732f3 100644
--- a/drivers/net/wireless/ath/ath6kl/sdio.c
+++ b/drivers/net/wireless/ath/ath6kl/sdio.c
@@ -67,8 +67,18 @@ struct ath6kl_sdio {
/* protects access to wr_asyncq */
spinlock_t wr_async_lock;
+
};
+#ifdef CONFIG_GPIOLIB
+#include <linux/gpio.h>
+#define NO_GPIO 0xffffffff
+
+static unsigned int reset_pwd_gpio = NO_GPIO;
+module_param(reset_pwd_gpio, uint, 0644);
+MODULE_PARM_DESC(reset_pwd_gpio, "WIFI CHIP_PWD reset pin GPIO");
+#endif
+
#define CMD53_ARG_READ 0
#define CMD53_ARG_WRITE 1
#define CMD53_ARG_BLOCK_BASIS 1
@@ -1414,20 +1424,88 @@ static struct sdio_driver ath6kl_sdio_driver = {
.drv.pm = ATH6KL_SDIO_PM_OPS,
};
+static int __init ath6kl_sdio_init_gpio(void)
+{
+ int ret = 0;
+
+#ifdef CONFIG_GPIOLIB
+ if (!gpio_is_valid(reset_pwd_gpio))
+ return 0;
+
+ /* Request the reset GPIO, and assert it to make sure we get a 100%
+ * clean boot in-case we had a floating input or other issue.
+ */
+ ret = gpio_request_one(reset_pwd_gpio,
+ GPIOF_OUT_INIT_LOW | GPIOF_EXPORT_DIR_FIXED,
+ "WIFI_RESET");
+ if (ret) {
+ ath6kl_err("Unable to get WIFI power gpio: %d\n", ret);
+ return ret;
+ }
+
+ ath6kl_dbg(ATH6KL_DBG_SUSPEND, "Setup wifi gpio #%d\n", reset_pwd_gpio);
+ usleep_range(20, 50); /* Pin must be asserted at least 5 usec */
+ gpio_set_value(reset_pwd_gpio, 1); /* De-assert the pin for operation */
+
+ /* Delay to avoid the mmc driver calling the probe on the prior notice
+ * of the chip, which we just killed. If this is missing, it results in
+ * a spurious warning:
+ * "ath6kl_sdio: probe of mmc0:0001:1 failed with error -110"
+ */
+ msleep(150); /* Time chosen experimentally, with padding */
+#endif
+
+ return ret;
+}
+
+static void __exit ath6kl_sdio_release_gpio(void)
+{
+#ifdef CONFIG_GPIOLIB
+ if (gpio_is_valid(reset_pwd_gpio)) {
+ /* Be sure we leave the chip in reset when we unload and also
+ * release the GPIO
+ */
+ gpio_set_value(reset_pwd_gpio, 0);
+ gpio_free(reset_pwd_gpio);
+ }
+#endif
+}
+
static int __init ath6kl_sdio_init(void)
{
int ret;
- ret = sdio_register_driver(&ath6kl_sdio_driver);
+ ret = ath6kl_sdio_init_gpio();
if (ret)
+ goto err_gpio;
+
+ ret = sdio_register_driver(&ath6kl_sdio_driver);
+ if (ret) {
ath6kl_err("sdio driver registration failed: %d\n", ret);
+ goto err_register;
+ }
+
+ return ret;
+
+err_register:
+ ath6kl_sdio_release_gpio();
+err_gpio:
return ret;
}
static void __exit ath6kl_sdio_exit(void)
{
sdio_unregister_driver(&ath6kl_sdio_driver);
+
+#ifdef CONFIG_GPIOLIB
+ /* Delay to avoid pulling the plug on the chip when an irq is pending
+ * and then getting a spurious message:
+ * "ath6kl: failed to get pending recv messages: -125"
+ */
+ msleep(300);
+ ath6kl_sdio_release_gpio();
+#endif
}
module_init(ath6kl_sdio_init);
--
1.9.1
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