mfd: rk808: Check pm_power_off pointer

The function pointer pm_power_off may point to function from other
module (PSCI for example). If rk808 is removed, pm_power_off is
overwritten to NULL and the system cannot be powered off.

This patch checks if pm_power_off points to a module function.

Signed-off-by: Stefan Mavrodiev <stefan@olimex.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

diff --git a/drivers/mfd/rk808.c b/drivers/mfd/rk808.c
index 6ee1c461a3bba555617562dd4841ebf7547bc76b..e234720fee02346ac9d032a16fdb0669ec16663c 100644 (file)
--- a/drivers/mfd/rk808.c
+++ b/drivers/mfd/rk808.c
@@ -562,7 +562,6 @@ static int rk808_probe(struct i2c_client *client,
        struct rk808 *rk808;
        const struct rk808_reg_data *pre_init_reg;
        const struct mfd_cell *cells;
-       void (*pm_pwroff_fn)(void) = NULL;
        int nr_pre_init_regs;
        int nr_cells;
        int pm_off = 0, msb, lsb;
@@ -609,7 +608,7 @@ static int rk808_probe(struct i2c_client *client,
                nr_pre_init_regs = ARRAY_SIZE(rk805_pre_init_reg);
                cells = rk805s;
                nr_cells = ARRAY_SIZE(rk805s);
-               pm_pwroff_fn = rk805_device_shutdown;
+               rk808->pm_pwroff_fn = rk805_device_shutdown;
                break;
        case RK808_ID:
                rk808->regmap_cfg = &rk808_regmap_config;
@@ -618,7 +617,7 @@ static int rk808_probe(struct i2c_client *client,
                nr_pre_init_regs = ARRAY_SIZE(rk808_pre_init_reg);
                cells = rk808s;
                nr_cells = ARRAY_SIZE(rk808s);
-               pm_pwroff_fn = rk808_device_shutdown;
+               rk808->pm_pwroff_fn = rk808_device_shutdown;
                break;
        case RK818_ID:
                rk808->regmap_cfg = &rk818_regmap_config;
@@ -627,7 +626,7 @@ static int rk808_probe(struct i2c_client *client,
                nr_pre_init_regs = ARRAY_SIZE(rk818_pre_init_reg);
                cells = rk818s;
                nr_cells = ARRAY_SIZE(rk818s);
-               pm_pwroff_fn = rk818_device_shutdown;
+               rk808->pm_pwroff_fn = rk818_device_shutdown;
                break;
        case RK809_ID:
        case RK817_ID:
@@ -692,7 +691,7 @@ static int rk808_probe(struct i2c_client *client,
                                "rockchip,system-power-controller");
        if (pm_off && !pm_power_off) {
                rk808_i2c_client = client;
-               pm_power_off = pm_pwroff_fn;
+               pm_power_off = rk808->pm_pwroff_fn;
        }
 
        return 0;
@@ -707,7 +706,13 @@ static int rk808_remove(struct i2c_client *client)
        struct rk808 *rk808 = i2c_get_clientdata(client);
 
        regmap_del_irq_chip(client->irq, rk808->irq_data);
-       pm_power_off = NULL;
+
+       /**
+        * pm_power_off may points to a function from another module.
+        * Check if the pointer is set by us and only then overwrite it.
+        */
+       if (rk808->pm_pwroff_fn && pm_power_off == rk808->pm_pwroff_fn)
+               pm_power_off = NULL;
 
        return 0;
 }

diff --git a/include/linux/mfd/rk808.h b/include/linux/mfd/rk808.h
index 2a9cd01691b2f9c0020bbb6a2da6628a3aa94ec4..2863163756362275cfd02452fae62bbdc48836d1 100644 (file)
--- a/include/linux/mfd/rk808.h
+++ b/include/linux/mfd/rk808.h
@@ -628,5 +628,6 @@ struct rk808 {
        long                            variant;
        const struct regmap_config      *regmap_cfg;
        const struct regmap_irq_chip    *regmap_irq_chip;
+       void                            (*pm_pwroff_fn)(void);
 };
 #endif /* __LINUX_REGULATOR_RK808_H */