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authorHans de Goede <hdegoede@redhat.com>2017-08-14 23:17:24 +0300
committerWolfram Sang <wsa@the-dreams.de>2017-08-17 22:53:02 +0300
commita5a46bd008b5a87f726859c90ab25a69e6cf9473 (patch)
treeced5cd1af9e65b29ee9774cdd6b33e95b56b60e3 /drivers/i2c/busses/i2c-cht-wc.c
parent75fdc51832492d183f477442e406fc745546307c (diff)
downloadlinux-a5a46bd008b5a87f726859c90ab25a69e6cf9473.tar.xz
i2c-cht-wc: Add locking to interrupt / smbus_xfer functions
Although unlikely without locking the smbux_xfer function may miss the nack flag and further fixes in this patch-set add some more complex constructions which need protection. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'drivers/i2c/busses/i2c-cht-wc.c')
-rw-r--r--drivers/i2c/busses/i2c-cht-wc.c37
1 files changed, 24 insertions, 13 deletions
diff --git a/drivers/i2c/busses/i2c-cht-wc.c b/drivers/i2c/busses/i2c-cht-wc.c
index fe5caf70c7fe..09e0df49df6b 100644
--- a/drivers/i2c/busses/i2c-cht-wc.c
+++ b/drivers/i2c/busses/i2c-cht-wc.c
@@ -47,6 +47,7 @@ struct cht_wc_i2c_adap {
struct i2c_adapter adapter;
wait_queue_head_t wait;
struct irq_chip irqchip;
+ struct mutex adap_lock;
struct mutex irqchip_lock;
struct regmap *regmap;
struct irq_domain *irq_domain;
@@ -63,10 +64,13 @@ static irqreturn_t cht_wc_i2c_adap_thread_handler(int id, void *data)
struct cht_wc_i2c_adap *adap = data;
int ret, reg;
+ mutex_lock(&adap->adap_lock);
+
/* Read IRQs */
ret = regmap_read(adap->regmap, CHT_WC_EXTCHGRIRQ, &reg);
if (ret) {
dev_err(&adap->adapter.dev, "Error reading extchgrirq reg\n");
+ mutex_unlock(&adap->adap_lock);
return IRQ_NONE;
}
@@ -80,6 +84,16 @@ static irqreturn_t cht_wc_i2c_adap_thread_handler(int id, void *data)
if (ret)
dev_err(&adap->adapter.dev, "Error writing extchgrirq reg\n");
+ if (reg & CHT_WC_EXTCHGRIRQ_ADAP_IRQMASK) {
+ adap->nack = !!(reg & CHT_WC_EXTCHGRIRQ_NACK_IRQ);
+ adap->done = true;
+ }
+
+ mutex_unlock(&adap->adap_lock);
+
+ if (reg & CHT_WC_EXTCHGRIRQ_ADAP_IRQMASK)
+ wake_up(&adap->wait);
+
/*
* Do NOT use handle_nested_irq here, the client irq handler will
* likely want to do i2c transfers and the i2c controller uses this
@@ -96,12 +110,6 @@ static irqreturn_t cht_wc_i2c_adap_thread_handler(int id, void *data)
local_irq_enable();
}
- if (reg & CHT_WC_EXTCHGRIRQ_ADAP_IRQMASK) {
- adap->nack = !!(reg & CHT_WC_EXTCHGRIRQ_NACK_IRQ);
- adap->done = true;
- wake_up(&adap->wait);
- }
-
return IRQ_HANDLED;
}
@@ -119,8 +127,10 @@ static int cht_wc_i2c_adap_smbus_xfer(struct i2c_adapter *_adap, u16 addr,
struct cht_wc_i2c_adap *adap = i2c_get_adapdata(_adap);
int ret, reg;
+ mutex_lock(&adap->adap_lock);
adap->nack = false;
adap->done = false;
+ mutex_unlock(&adap->adap_lock);
ret = regmap_write(adap->regmap, CHT_WC_I2C_CLIENT_ADDR, addr);
if (ret)
@@ -146,18 +156,18 @@ static int cht_wc_i2c_adap_smbus_xfer(struct i2c_adapter *_adap, u16 addr,
ret = wait_event_timeout(adap->wait, adap->done, 3 * HZ);
if (ret == 0)
return -ETIMEDOUT;
- if (adap->nack)
- return -EIO;
- if (read_write == I2C_SMBUS_READ) {
+ ret = 0;
+ mutex_lock(&adap->adap_lock);
+ if (adap->nack)
+ ret = -EIO;
+ else if (read_write == I2C_SMBUS_READ) {
ret = regmap_read(adap->regmap, CHT_WC_I2C_RDDATA, &reg);
- if (ret)
- return ret;
-
data->byte = reg;
}
+ mutex_unlock(&adap->adap_lock);
- return 0;
+ return ret;
}
static const struct i2c_algorithm cht_wc_i2c_adap_algo = {
@@ -241,6 +251,7 @@ static int cht_wc_i2c_adap_i2c_probe(struct platform_device *pdev)
return -ENOMEM;
init_waitqueue_head(&adap->wait);
+ mutex_init(&adap->adap_lock);
mutex_init(&adap->irqchip_lock);
adap->irqchip = cht_wc_i2c_irq_chip;
adap->regmap = pmic->regmap;