From b65dc4f6b339ff57321fd95f2f7b6197a3c24ba4 Mon Sep 17 00:00:00 2001 From: Fuqian Huang Date: Tue, 13 Aug 2019 18:31:33 +0800 Subject: [PATCH] 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 Signed-off-by: Lee Jones --- drivers/mfd/ezx-pcap.c | 53 ++++++++++++++++++++++++------------------ 1 file changed, 30 insertions(+), 23 deletions(-) diff --git a/drivers/mfd/ezx-pcap.c b/drivers/mfd/ezx-pcap.c index f505e3e1274b..70fa18b04ad2 100644 --- a/drivers/mfd/ezx-pcap.c +++ b/drivers/mfd/ezx-pcap.c @@ -35,7 +35,7 @@ struct pcap_chip { /* IO */ u32 buf; - struct mutex io_mutex; + spinlock_t io_lock; /* IRQ */ unsigned int irq_base; @@ -48,7 +48,7 @@ struct pcap_chip { struct pcap_adc_request *adc_queue[PCAP_ADC_MAXQ]; u8 adc_head; u8 adc_tail; - struct mutex adc_mutex; + spinlock_t adc_lock; }; /* 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) { + unsigned long flags; int ret; - mutex_lock(&pcap->io_mutex); + spin_lock_irqsave(&pcap->io_lock, flags); value &= PCAP_REGISTER_VALUE_MASK; value |= PCAP_REGISTER_WRITE_OP_BIT | (reg_num << PCAP_REGISTER_ADDRESS_SHIFT); ret = ezx_pcap_putget(pcap, &value); - mutex_unlock(&pcap->io_mutex); + spin_unlock_irqrestore(&pcap->io_lock, flags); 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) { + unsigned long flags; int ret; - mutex_lock(&pcap->io_mutex); + spin_lock_irqsave(&pcap->io_lock, flags); *value = PCAP_REGISTER_READ_OP_BIT | (reg_num << PCAP_REGISTER_ADDRESS_SHIFT); ret = ezx_pcap_putget(pcap, value); - mutex_unlock(&pcap->io_mutex); + spin_unlock_irqrestore(&pcap->io_lock, flags); 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) { + unsigned long flags; int ret; u32 tmp = PCAP_REGISTER_READ_OP_BIT | (reg_num << PCAP_REGISTER_ADDRESS_SHIFT); - mutex_lock(&pcap->io_mutex); + spin_lock_irqsave(&pcap->io_lock, flags); ret = ezx_pcap_putget(pcap, &tmp); if (ret) 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); out_unlock: - mutex_unlock(&pcap->io_mutex); + spin_unlock_irqrestore(&pcap->io_lock, flags); return ret; } @@ -212,14 +215,15 @@ static void pcap_irq_handler(struct irq_desc *desc) /* ADC */ void pcap_set_ts_bits(struct pcap_chip *pcap, u32 bits) { + unsigned long flags; u32 tmp; - mutex_lock(&pcap->adc_mutex); + spin_lock_irqsave(&pcap->adc_lock, flags); ezx_pcap_read(pcap, PCAP_REG_ADC, &tmp); tmp &= ~(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); - mutex_unlock(&pcap->adc_mutex); + spin_unlock_irqrestore(&pcap->adc_lock, flags); } 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) { + unsigned long flags; u32 tmp; u8 head; - mutex_lock(&pcap->adc_mutex); + spin_lock_irqsave(&pcap->adc_lock, flags); head = pcap->adc_head; if (!pcap->adc_queue[head]) { /* queue is empty, save power */ pcap_disable_adc(pcap); - mutex_unlock(&pcap->adc_mutex); + spin_unlock_irqrestore(&pcap->adc_lock, flags); return; } /* 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; 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); } @@ -265,11 +270,11 @@ static irqreturn_t pcap_adc_irq(int irq, void *_pcap) u16 res[2]; u32 tmp; - mutex_lock(&pcap->adc_mutex); + spin_lock(&pcap->adc_lock); req = pcap->adc_queue[pcap->adc_head]; if (WARN(!req, "adc irq without pending request\n")) { - mutex_unlock(&pcap->adc_mutex); + spin_unlock(&pcap->adc_lock); 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_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 */ 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) { struct pcap_adc_request *req; + unsigned long irq_flags; /* This will be freed after we have a result */ 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->data = data; - mutex_lock(&pcap->adc_mutex); + spin_lock_irqsave(&pcap->adc_lock, irq_flags); if (pcap->adc_queue[pcap->adc_tail]) { - mutex_unlock(&pcap->adc_mutex); + spin_unlock_irqrestore(&pcap->adc_lock, irq_flags); kfree(req); return -EBUSY; } pcap->adc_queue[pcap->adc_tail] = req; 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 */ 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) { struct pcap_chip *pcap = spi_get_drvdata(spi); + unsigned long flags; int i; /* remove all registered subdevs */ device_for_each_child(&spi->dev, NULL, pcap_remove_subdev); /* cleanup ADC */ - mutex_lock(&pcap->adc_mutex); + spin_lock_irqsave(&pcap->adc_lock, flags); for (i = 0; i < PCAP_ADC_MAXQ; i++) kfree(pcap->adc_queue[i]); - mutex_unlock(&pcap->adc_mutex); + spin_unlock_irqrestore(&pcap->adc_lock, flags); /* cleanup irqchip */ 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; } - mutex_init(&pcap->io_mutex); - mutex_init(&pcap->adc_mutex); + spin_lock_init(&pcap->io_lock); + spin_lock_init(&pcap->adc_lock); INIT_WORK(&pcap->isr_work, pcap_isr_work); INIT_WORK(&pcap->msr_work, pcap_msr_work); spi_set_drvdata(spi, pcap);