Use of_get_named_gpio_flags to retrieve the "nshutdown" gpio connected
to the BT_EN pin of the device when retrieving platform data from device
tree.
This allows the polarity to be specified using GPIO_ACTIVE_HIGH/LOW
in device tree.
Signed-off-by: Eric Nelson <eric.nelson@xxxxxxxxxxxxxxxxxxx>
---
V2 changes comments to use "assert" and "de-assert" to refer to
the state of the nshutdown gpio instead of low/high/0/1.
drivers/misc/ti-st/st_kim.c | 34 +++++++++++++++++++++-------------
include/linux/ti_wilink_st.h | 6 +++---
2 files changed, 24 insertions(+), 16 deletions(-)
diff --git a/drivers/misc/ti-st/st_kim.c b/drivers/misc/ti-st/st_kim.c
index aaa17b0..54d5f50 100644
--- a/drivers/misc/ti-st/st_kim.c
+++ b/drivers/misc/ti-st/st_kim.c
@@ -32,6 +32,7 @@
#include <linux/sched.h>
#include <linux/sysfs.h>
#include <linux/tty.h>
+#include <linux/of_gpio.h>
#include <linux/skbuff.h>
#include <linux/ti_wilink_st.h>
@@ -481,10 +482,13 @@ long st_kim_start(void *kim_data)
if (pdata->chip_enable)
pdata->chip_enable(kim_gdata);
- /* Configure BT nShutdown to HIGH state */
- gpio_set_value(kim_gdata->nshutdown, GPIO_LOW);
+ /*
+ * De-assert nShutdown (enable bluetooth),
+ * but force a transition
+ */
+ gpio_set_value(kim_gdata->nshutdown, kim_gdata->shutdown_val);
mdelay(5); /* FIXME: a proper toggle */
- gpio_set_value(kim_gdata->nshutdown, GPIO_HIGH);
+ gpio_set_value(kim_gdata->nshutdown, !kim_gdata->shutdown_val);
mdelay(100);
/* re-initialize the completion */
reinit_completion(&kim_gdata->ldisc_installed);
@@ -527,7 +531,7 @@ long st_kim_start(void *kim_data)
* (b) upon failure to either install ldisc or download firmware.
* The function is responsible to (a) notify UIM about un-installation,
* (b) flush UART if the ldisc was installed.
- * (c) reset BT_EN - pull down nshutdown at the end.
+ * (c) reset BT_EN - assert nshutdown at the end.
* (d) invoke platform's chip disabling routine.
*/
long st_kim_stop(void *kim_data)
@@ -565,12 +569,12 @@ long st_kim_stop(void *kim_data)
err = -ETIMEDOUT;
}
- /* By default configure BT nShutdown to LOW state */
- gpio_set_value(kim_gdata->nshutdown, GPIO_LOW);
+ /* Assert nShutdown (chip disabled), but force transitions */
+ gpio_set_value(kim_gdata->nshutdown, kim_gdata->shutdown_val);
mdelay(1);
- gpio_set_value(kim_gdata->nshutdown, GPIO_HIGH);
+ gpio_set_value(kim_gdata->nshutdown, !kim_gdata->shutdown_val);
mdelay(1);
- gpio_set_value(kim_gdata->nshutdown, GPIO_LOW);
+ gpio_set_value(kim_gdata->nshutdown, kim_gdata->shutdown_val);
/* platform specific disable */
if (pdata->chip_disable)
@@ -749,6 +753,7 @@ static struct ti_st_plat_data *get_platform_data(struct device *dev)
{
struct device_node *np = dev->of_node;
const u32 *dt_property;
+ enum of_gpio_flags flags;
int len;
dt_pdata = kzalloc(sizeof(*dt_pdata), GFP_KERNEL);
@@ -759,8 +764,9 @@ static struct ti_st_plat_data *get_platform_data(struct device *dev)
dt_property = of_get_property(np, "dev_name", &len);
if (dt_property)
memcpy(&dt_pdata->dev_name, dt_property, len);
- of_property_read_u32(np, "nshutdown_gpio",
- &dt_pdata->nshutdown_gpio);
+ dt_pdata->nshutdown_gpio = of_get_named_gpio_flags
+ (np, "nshutdown_gpio", 0, &flags);
+ dt_pdata->shutdown_val = !(flags & OF_GPIO_ACTIVE_LOW);
of_property_read_u32(np, "flow_cntrl", &dt_pdata->flow_cntrl);
of_property_read_u32(np, "baud_rate", &dt_pdata->baud_rate);
@@ -808,16 +814,18 @@ static int kim_probe(struct platform_device *pdev)
/* refer to itself */
kim_gdata->core_data->kim_data = kim_gdata;
- /* Claim the chip enable nShutdown gpio from the system */
+ /* Claim the nShutdown GPIO */
kim_gdata->nshutdown = pdata->nshutdown_gpio;
+ kim_gdata->shutdown_val = pdata->shutdown_val;
err = gpio_request(kim_gdata->nshutdown, "kim");
if (unlikely(err)) {
pr_err(" gpio %d request failed ", kim_gdata->nshutdown);
return err;
}
- /* Configure nShutdown GPIO as output=0 */
- err = gpio_direction_output(kim_gdata->nshutdown, GPIO_LOW);
+ /* Configure nShutdown GPIO as output and assert */
+ err = gpio_direction_output(kim_gdata->nshutdown,
+ kim_gdata->shutdown_val);
if (unlikely(err)) {
pr_err(" unable to configure gpio %d", kim_gdata->nshutdown);
return err;
diff --git a/include/linux/ti_wilink_st.h b/include/linux/ti_wilink_st.h
index c78dcfe..7154194 100644
--- a/include/linux/ti_wilink_st.h
+++ b/include/linux/ti_wilink_st.h
@@ -212,9 +212,6 @@ void gps_chrdrv_stub_init(void);
#define MAKEWORD(a, b) ((unsigned short)(((unsigned char)(a)) \
| ((unsigned short)((unsigned char)(b))) << 8))
-#define GPIO_HIGH 1
-#define GPIO_LOW 0
-
/* the Power-On-Reset logic, requires to attempt
* to download firmware onto chip more than once
* since the self-test for chip takes a while
@@ -263,6 +260,7 @@ struct kim_data_s {
char resp_buffer[30];
const struct firmware *fw_entry;
unsigned nshutdown;
+ unsigned shutdown_val;
unsigned long rx_state;
unsigned long rx_count;
struct sk_buff *rx_skb;
@@ -418,6 +416,7 @@ struct gps_event_hdr {
* struct ti_st_plat_data - platform data shared between ST driver and
* platform specific board file which adds the ST device.
* @nshutdown_gpio: Host's GPIO line to which chip's BT_EN is connected.
+ * @shutdown_val: shutdown state (0/1) of gpio
* @dev_name: The UART/TTY name to which chip is interfaced. (eg: /dev/ttyS1)
* @flow_cntrl: Should always be 1, since UART's CTS/RTS is used for PM
* purposes.
@@ -438,6 +437,7 @@ struct gps_event_hdr {
*/
struct ti_st_plat_data {
u32 nshutdown_gpio;
+ int shutdown_val;
unsigned char dev_name[UART_DEV_NAME_LEN]; /* uart name */
u32 flow_cntrl; /* flow control flag */
u32 baud_rate;
--
1.9.1
--
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