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mfd: ezx-pcap: Replace mutex_lock with spin_lock 

As mutex_lock might sleep. Function pcap_adc_irq is an interrupt handler.
The use of mutex_lock in pcap_adc_irq may cause sleep in IRQ context.
Replace mutex_lock with spin_lock to avoid this.

Signed-off-by: Fuqian Huang <huangfq.daxian@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
This commit is contained in:
Fuqian Huang 2019-08-13 18:31:33 +08:00 committed by Lee Jones
parent 5cd690a308
commit b65dc4f6b3
1 changed files with 30 additions and 23 deletions
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53
drivers/mfd/ezx-pcap.c
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@ -35,7 +35,7 @@ struct pcap_chip {
/* IO */ /* IO */
u32 buf; u32 buf;
struct mutex io_mutex; spinlock_t io_lock;
/* IRQ */ /* IRQ */
unsigned int irq_base; unsigned int irq_base;
@ -48,7 +48,7 @@ struct pcap_chip {
struct pcap_adc_request *adc_queue[PCAP_ADC_MAXQ]; struct pcap_adc_request *adc_queue[PCAP_ADC_MAXQ];
u8 adc_head; u8 adc_head;
u8 adc_tail; u8 adc_tail;
struct mutex adc_mutex; spinlock_t adc_lock;
}; };
/* IO */ /* IO */
@ -76,14 +76,15 @@ static int ezx_pcap_putget(struct pcap_chip *pcap, u32 *data)
int ezx_pcap_write(struct pcap_chip *pcap, u8 reg_num, u32 value) int ezx_pcap_write(struct pcap_chip *pcap, u8 reg_num, u32 value)
{ {
unsigned long flags;
int ret; int ret;
mutex_lock(&pcap->io_mutex); spin_lock_irqsave(&pcap->io_lock, flags);
value &= PCAP_REGISTER_VALUE_MASK; value &= PCAP_REGISTER_VALUE_MASK;
value |= PCAP_REGISTER_WRITE_OP_BIT value |= PCAP_REGISTER_WRITE_OP_BIT
| (reg_num << PCAP_REGISTER_ADDRESS_SHIFT); | (reg_num << PCAP_REGISTER_ADDRESS_SHIFT);
ret = ezx_pcap_putget(pcap, &value); ret = ezx_pcap_putget(pcap, &value);
mutex_unlock(&pcap->io_mutex); spin_unlock_irqrestore(&pcap->io_lock, flags);
return ret; return ret;
} }
@ -91,14 +92,15 @@ EXPORT_SYMBOL_GPL(ezx_pcap_write);
int ezx_pcap_read(struct pcap_chip *pcap, u8 reg_num, u32 *value) int ezx_pcap_read(struct pcap_chip *pcap, u8 reg_num, u32 *value)
{ {
unsigned long flags;
int ret; int ret;
mutex_lock(&pcap->io_mutex); spin_lock_irqsave(&pcap->io_lock, flags);
*value = PCAP_REGISTER_READ_OP_BIT *value = PCAP_REGISTER_READ_OP_BIT
| (reg_num << PCAP_REGISTER_ADDRESS_SHIFT); | (reg_num << PCAP_REGISTER_ADDRESS_SHIFT);
ret = ezx_pcap_putget(pcap, value); ret = ezx_pcap_putget(pcap, value);
mutex_unlock(&pcap->io_mutex); spin_unlock_irqrestore(&pcap->io_lock, flags);
return ret; return ret;
} }
@ -106,11 +108,12 @@ EXPORT_SYMBOL_GPL(ezx_pcap_read);
int ezx_pcap_set_bits(struct pcap_chip *pcap, u8 reg_num, u32 mask, u32 val) int ezx_pcap_set_bits(struct pcap_chip *pcap, u8 reg_num, u32 mask, u32 val)
{ {
unsigned long flags;
int ret; int ret;
u32 tmp = PCAP_REGISTER_READ_OP_BIT | u32 tmp = PCAP_REGISTER_READ_OP_BIT |
(reg_num << PCAP_REGISTER_ADDRESS_SHIFT); (reg_num << PCAP_REGISTER_ADDRESS_SHIFT);
mutex_lock(&pcap->io_mutex); spin_lock_irqsave(&pcap->io_lock, flags);
ret = ezx_pcap_putget(pcap, &tmp); ret = ezx_pcap_putget(pcap, &tmp);
if (ret) if (ret)
goto out_unlock; goto out_unlock;
@ -121,7 +124,7 @@ int ezx_pcap_set_bits(struct pcap_chip *pcap, u8 reg_num, u32 mask, u32 val)
ret = ezx_pcap_putget(pcap, &tmp); ret = ezx_pcap_putget(pcap, &tmp);
out_unlock: out_unlock:
mutex_unlock(&pcap->io_mutex); spin_unlock_irqrestore(&pcap->io_lock, flags);
return ret; return ret;
} }
@ -212,14 +215,15 @@ static void pcap_irq_handler(struct irq_desc *desc)
/* ADC */ /* ADC */
void pcap_set_ts_bits(struct pcap_chip *pcap, u32 bits) void pcap_set_ts_bits(struct pcap_chip *pcap, u32 bits)
{ {
unsigned long flags;
u32 tmp; u32 tmp;
mutex_lock(&pcap->adc_mutex); spin_lock_irqsave(&pcap->adc_lock, flags);
ezx_pcap_read(pcap, PCAP_REG_ADC, &tmp); ezx_pcap_read(pcap, PCAP_REG_ADC, &tmp);
tmp &= ~(PCAP_ADC_TS_M_MASK | PCAP_ADC_TS_REF_LOWPWR); tmp &= ~(PCAP_ADC_TS_M_MASK | PCAP_ADC_TS_REF_LOWPWR);
tmp |= bits & (PCAP_ADC_TS_M_MASK | PCAP_ADC_TS_REF_LOWPWR); tmp |= bits & (PCAP_ADC_TS_M_MASK | PCAP_ADC_TS_REF_LOWPWR);
ezx_pcap_write(pcap, PCAP_REG_ADC, tmp); ezx_pcap_write(pcap, PCAP_REG_ADC, tmp);
mutex_unlock(&pcap->adc_mutex); spin_unlock_irqrestore(&pcap->adc_lock, flags);
} }
EXPORT_SYMBOL_GPL(pcap_set_ts_bits); EXPORT_SYMBOL_GPL(pcap_set_ts_bits);
@ -234,15 +238,16 @@ static void pcap_disable_adc(struct pcap_chip *pcap)
static void pcap_adc_trigger(struct pcap_chip *pcap) static void pcap_adc_trigger(struct pcap_chip *pcap)
{ {
unsigned long flags;
u32 tmp; u32 tmp;
u8 head; u8 head;
mutex_lock(&pcap->adc_mutex); spin_lock_irqsave(&pcap->adc_lock, flags);
head = pcap->adc_head; head = pcap->adc_head;
if (!pcap->adc_queue[head]) { if (!pcap->adc_queue[head]) {
/* queue is empty, save power */ /* queue is empty, save power */
pcap_disable_adc(pcap); pcap_disable_adc(pcap);
mutex_unlock(&pcap->adc_mutex); spin_unlock_irqrestore(&pcap->adc_lock, flags);
return; return;
} }
/* start conversion on requested bank, save TS_M bits */ /* start conversion on requested bank, save TS_M bits */
@ -254,7 +259,7 @@ static void pcap_adc_trigger(struct pcap_chip *pcap)
tmp |= PCAP_ADC_AD_SEL1; tmp |= PCAP_ADC_AD_SEL1;
ezx_pcap_write(pcap, PCAP_REG_ADC, tmp); ezx_pcap_write(pcap, PCAP_REG_ADC, tmp);
mutex_unlock(&pcap->adc_mutex); spin_unlock_irqrestore(&pcap->adc_lock, flags);
ezx_pcap_write(pcap, PCAP_REG_ADR, PCAP_ADR_ASC); ezx_pcap_write(pcap, PCAP_REG_ADR, PCAP_ADR_ASC);
} }
@ -265,11 +270,11 @@ static irqreturn_t pcap_adc_irq(int irq, void *_pcap)
u16 res[2]; u16 res[2];
u32 tmp; u32 tmp;
mutex_lock(&pcap->adc_mutex); spin_lock(&pcap->adc_lock);
req = pcap->adc_queue[pcap->adc_head]; req = pcap->adc_queue[pcap->adc_head];
if (WARN(!req, "adc irq without pending request\n")) { if (WARN(!req, "adc irq without pending request\n")) {
mutex_unlock(&pcap->adc_mutex); spin_unlock(&pcap->adc_lock);
return IRQ_HANDLED; return IRQ_HANDLED;
} }
@ -285,7 +290,7 @@ static irqreturn_t pcap_adc_irq(int irq, void *_pcap)
pcap->adc_queue[pcap->adc_head] = NULL; pcap->adc_queue[pcap->adc_head] = NULL;
pcap->adc_head = (pcap->adc_head + 1) & (PCAP_ADC_MAXQ - 1); pcap->adc_head = (pcap->adc_head + 1) & (PCAP_ADC_MAXQ - 1);
mutex_unlock(&pcap->adc_mutex); spin_unlock(&pcap->adc_lock);
/* pass the results and release memory */ /* pass the results and release memory */
req->callback(req->data, res); req->callback(req->data, res);
@ -301,6 +306,7 @@ int pcap_adc_async(struct pcap_chip *pcap, u8 bank, u32 flags, u8 ch[],
void *callback, void *data) void *callback, void *data)
{ {
struct pcap_adc_request *req; struct pcap_adc_request *req;
unsigned long irq_flags;
/* This will be freed after we have a result */ /* This will be freed after we have a result */
req = kmalloc(sizeof(struct pcap_adc_request), GFP_KERNEL); req = kmalloc(sizeof(struct pcap_adc_request), GFP_KERNEL);
@ -314,15 +320,15 @@ int pcap_adc_async(struct pcap_chip *pcap, u8 bank, u32 flags, u8 ch[],
req->callback = callback; req->callback = callback;
req->data = data; req->data = data;
mutex_lock(&pcap->adc_mutex); spin_lock_irqsave(&pcap->adc_lock, irq_flags);
if (pcap->adc_queue[pcap->adc_tail]) { if (pcap->adc_queue[pcap->adc_tail]) {
mutex_unlock(&pcap->adc_mutex); spin_unlock_irqrestore(&pcap->adc_lock, irq_flags);
kfree(req); kfree(req);
return -EBUSY; return -EBUSY;
} }
pcap->adc_queue[pcap->adc_tail] = req; pcap->adc_queue[pcap->adc_tail] = req;
pcap->adc_tail = (pcap->adc_tail + 1) & (PCAP_ADC_MAXQ - 1); pcap->adc_tail = (pcap->adc_tail + 1) & (PCAP_ADC_MAXQ - 1);
mutex_unlock(&pcap->adc_mutex); spin_unlock_irqrestore(&pcap->adc_lock, irq_flags);
/* start conversion */ /* start conversion */
pcap_adc_trigger(pcap); pcap_adc_trigger(pcap);
@ -389,16 +395,17 @@ static int pcap_add_subdev(struct pcap_chip *pcap,
static int ezx_pcap_remove(struct spi_device *spi) static int ezx_pcap_remove(struct spi_device *spi)
{ {
struct pcap_chip *pcap = spi_get_drvdata(spi); struct pcap_chip *pcap = spi_get_drvdata(spi);
unsigned long flags;
int i; int i;
/* remove all registered subdevs */ /* remove all registered subdevs */
device_for_each_child(&spi->dev, NULL, pcap_remove_subdev); device_for_each_child(&spi->dev, NULL, pcap_remove_subdev);
/* cleanup ADC */ /* cleanup ADC */
mutex_lock(&pcap->adc_mutex); spin_lock_irqsave(&pcap->adc_lock, flags);
for (i = 0; i < PCAP_ADC_MAXQ; i++) for (i = 0; i < PCAP_ADC_MAXQ; i++)
kfree(pcap->adc_queue[i]); kfree(pcap->adc_queue[i]);
mutex_unlock(&pcap->adc_mutex); spin_unlock_irqrestore(&pcap->adc_lock, flags);
/* cleanup irqchip */ /* cleanup irqchip */
for (i = pcap->irq_base; i < (pcap->irq_base + PCAP_NIRQS); i++) for (i = pcap->irq_base; i < (pcap->irq_base + PCAP_NIRQS); i++)
@ -426,8 +433,8 @@ static int ezx_pcap_probe(struct spi_device *spi)
goto ret; goto ret;
} }
mutex_init(&pcap->io_mutex); spin_lock_init(&pcap->io_lock);
mutex_init(&pcap->adc_mutex); spin_lock_init(&pcap->adc_lock);
INIT_WORK(&pcap->isr_work, pcap_isr_work); INIT_WORK(&pcap->isr_work, pcap_isr_work);
INIT_WORK(&pcap->msr_work, pcap_msr_work); INIT_WORK(&pcap->msr_work, pcap_msr_work);
spi_set_drvdata(spi, pcap); spi_set_drvdata(spi, pcap);