[PATCH 05/13] power: reset: ltc2952: reduce dependency on global variables

From: Frans Klaver
Date: Wed Oct 22 2014 - 10:34:55 EST


Documentation/CodingStyle ch.4 mentions in a side node that global
variables should only be used if you really need them. Reduce the use of
the global instance of ltc2952_poweroff so we may eventually remove it
entirely.

While at it, rename ltc2952_poweroff_data to ltc2952_poweroff, just to
save that little bit of typing.

Signed-off-by: Frans Klaver <frans.klaver@xxxxxxxxx>
---
drivers/power/reset/ltc2952-poweroff.c | 75 +++++++++++++++++++---------------
1 file changed, 41 insertions(+), 34 deletions(-)

diff --git a/drivers/power/reset/ltc2952-poweroff.c b/drivers/power/reset/ltc2952-poweroff.c
index 1e96b5b..9d493b5 100644
--- a/drivers/power/reset/ltc2952-poweroff.c
+++ b/drivers/power/reset/ltc2952-poweroff.c
@@ -63,7 +63,7 @@
#include <linux/gpio/consumer.h>
#include <linux/reboot.h>

-struct ltc2952_poweroff_data {
+struct ltc2952_poweroff {
struct hrtimer timer_trigger;
struct hrtimer timer_wde;

@@ -77,8 +77,14 @@ struct ltc2952_poweroff_data {
struct gpio_desc *gpio_kill;
};

+#define to_ltc2952(p, m) container_of(p, struct ltc2952_poweroff, m)
+
+/*
+ * This global variable is only needed for pm_power_off. We should
+ * remove it entirely once we don't need the global state anymore.
+ */
+static struct ltc2952_poweroff *ltc2952_data;
static int ltc2952_poweroff_panic;
-static struct ltc2952_poweroff_data *ltc2952_data;

/**
* ltc2952_poweroff_timer_wde - Timer callback
@@ -94,29 +100,29 @@ static enum hrtimer_restart ltc2952_poweroff_timer_wde(struct hrtimer *timer)
ktime_t now;
int state;
unsigned long overruns;
+ struct ltc2952_poweroff *data = to_ltc2952(timer, timer_wde);

if (ltc2952_poweroff_panic)
return HRTIMER_NORESTART;

- state = gpiod_get_value(ltc2952_data->gpio_watchdog);
- gpiod_set_value(ltc2952_data->gpio_watchdog, !state);
+ state = gpiod_get_value(data->gpio_watchdog);
+ gpiod_set_value(data->gpio_watchdog, !state);

now = hrtimer_cb_get_time(timer);
- overruns = hrtimer_forward(timer, now, ltc2952_data->wde_interval);
+ overruns = hrtimer_forward(timer, now, data->wde_interval);

return HRTIMER_RESTART;
}

-static enum hrtimer_restart ltc2952_poweroff_timer_trigger(
- struct hrtimer *timer)
+static enum hrtimer_restart
+ltc2952_poweroff_timer_trigger(struct hrtimer *timer)
{
- int ret;
-
- ret = hrtimer_start(&ltc2952_data->timer_wde,
- ltc2952_data->wde_interval, HRTIMER_MODE_REL);
+ struct ltc2952_poweroff *data = to_ltc2952(timer, timer_trigger);
+ int ret = hrtimer_start(&data->timer_wde,
+ data->wde_interval, HRTIMER_MODE_REL);

if (ret) {
- dev_err(ltc2952_data->dev, "unable to start the timer\n");
+ dev_err(data->dev, "unable to start the timer\n");
/*
* The device will not toggle the watchdog reset,
* thus shut down is only safe if the PowerPath controller
@@ -127,7 +133,7 @@ static enum hrtimer_restart ltc2952_poweroff_timer_trigger(
*/
}

- dev_info(ltc2952_data->dev, "executing shutdown\n");
+ dev_info(data->dev, "executing shutdown\n");

orderly_poweroff(true);

@@ -146,7 +152,7 @@ static enum hrtimer_restart ltc2952_poweroff_timer_trigger(
static irqreturn_t ltc2952_poweroff_handler(int irq, void *dev_id)
{
int ret;
- struct ltc2952_poweroff_data *data = dev_id;
+ struct ltc2952_poweroff *data = dev_id;

if (ltc2952_poweroff_panic)
goto irq_ok;
@@ -187,7 +193,7 @@ static int ltc2952_poweroff_resume(struct platform_device *pdev)
return -ENOSYS;
}

-static void ltc2952_poweroff_default(struct ltc2952_poweroff_data *data)
+static void ltc2952_poweroff_default(struct ltc2952_poweroff *data)
{
data->wde_interval = ktime_set(0, 300L*1E6L);
data->trigger_delay = ktime_set(2, 500L*1E6L);
@@ -202,36 +208,34 @@ static void ltc2952_poweroff_default(struct ltc2952_poweroff_data *data)
static int ltc2952_poweroff_init(struct platform_device *pdev)
{
int ret, virq;
- struct ltc2952_poweroff_data *data;
+ struct ltc2952_poweroff *data = platform_get_drvdata(pdev);

- data = ltc2952_data;
- ltc2952_poweroff_default(ltc2952_data);
+ ltc2952_poweroff_default(data);

- ltc2952_data->gpio_watchdog = devm_gpiod_get(&pdev->dev, "watchdog",
- GPIOD_OUT_LOW);
- if (IS_ERR(ltc2952_data->gpio_watchdog)) {
- ret = PTR_ERR(ltc2952_data->gpio_watchdog);
+ data->gpio_watchdog = devm_gpiod_get(&pdev->dev, "watchdog",
+ GPIOD_OUT_LOW);
+ if (IS_ERR(data->gpio_watchdog)) {
+ ret = PTR_ERR(data->gpio_watchdog);
dev_err(&pdev->dev, "unable to claim gpio \"watchdog\"\n");
return ret;
}

- ltc2952_data->gpio_kill = devm_gpiod_get(&pdev->dev, "kill",
- GPIOD_OUT_LOW);
- if (IS_ERR(ltc2952_data->gpio_kill)) {
- ret = PTR_ERR(ltc2952_data->gpio_kill);
+ data->gpio_kill = devm_gpiod_get(&pdev->dev, "kill", GPIOD_OUT_LOW);
+ if (IS_ERR(data->gpio_kill)) {
+ ret = PTR_ERR(data->gpio_kill);
dev_err(&pdev->dev, "unable to claim gpio \"kill\"\n");
return ret;
}

- ltc2952_data->gpio_trigger = devm_gpiod_get(&pdev->dev, "trigger",
- GPIOD_IN);
+ data->gpio_trigger = devm_gpiod_get(&pdev->dev, "trigger",
+ GPIOD_IN);
if (IS_ERR(ltc2952_data->gpio_trigger)) {
ret = PTR_ERR(ltc2952_data->gpio_trigger);
dev_err(&pdev->dev, "unable to claim gpio \"trigger\"\n");
return ret;
}

- virq = gpiod_to_irq(ltc2952_data->gpio_trigger);
+ virq = gpiod_to_irq(data->gpio_trigger);
if (virq < 0) {
dev_err(&pdev->dev, "cannot map GPIO as interrupt");
return ret;
@@ -241,7 +245,7 @@ static int ltc2952_poweroff_init(struct platform_device *pdev)
ltc2952_poweroff_handler,
(IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING),
"ltc2952-poweroff",
- ltc2952_data);
+ data);

if (ret) {
dev_err(&pdev->dev, "cannot configure an interrupt handler\n");
@@ -254,23 +258,26 @@ static int ltc2952_poweroff_init(struct platform_device *pdev)
static int ltc2952_poweroff_probe(struct platform_device *pdev)
{
int ret;
+ struct ltc2952_poweroff *data;

if (pm_power_off) {
dev_err(&pdev->dev, "pm_power_off already registered");
return -EBUSY;
}

- ltc2952_data = devm_kzalloc(&pdev->dev, sizeof(*ltc2952_data),
- GFP_KERNEL);
- if (!ltc2952_data)
+ data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+ if (!data)
return -ENOMEM;

- ltc2952_data->dev = &pdev->dev;
+ data->dev = &pdev->dev;
+ platform_set_drvdata(pdev, data);

ret = ltc2952_poweroff_init(pdev);
if (ret)
return ret;

+ /* TODO: remove ltc2952_data */
+ ltc2952_data = data;
pm_power_off = &ltc2952_poweroff_kill;

dev_info(&pdev->dev, "probe successful\n");
--
2.1.0

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