From: Sebastian Andrzej Siewior Date: Thu, 19 Dec 2013 15:28:29 +0000 (+0100) Subject: mfd: ti_am335x_tscadc: Don't read back REG_SE X-Git-Tag: v3.14-rc1~142^2~46^2~2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=7e170c6e4f7501bea900aa66b2b27a6ce5001e25;p=platform%2Fkernel%2Flinux-stable.git mfd: ti_am335x_tscadc: Don't read back REG_SE The purpose of reg_se_cache has been defeated. It should avoid the read-back of the register to avoid the latency and the fact that the bits are reset to 0 after the individual conversation took place. The reason why this is required like this to work, is that read-back of the register removes the bits of the ADC so they do not start another conversation after the register is re-written from the TSC side for the update. To avoid the not required read-back I introduce a "set once" variant which does not update the cache mask. After the conversation completes, the bit is removed from the SE register anyway and we don't plan a new conversation "any time soon". The current set function is renamed to set_cache to distinguish the two operations. This is a small preparation for a larger sync-rework. Signed-off-by: Sebastian Andrzej Siewior Acked-by: Dmitry Torokhov Acked-by: Jonathan Cameron Signed-off-by: Lee Jones --- diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c index ce8d03a..95eef8e 100644 --- a/drivers/iio/adc/ti_am335x_adc.c +++ b/drivers/iio/adc/ti_am335x_adc.c @@ -181,7 +181,7 @@ static int tiadc_buffer_postenable(struct iio_dev *indio_dev) enb |= (get_adc_step_bit(adc_dev, bit) << 1); adc_dev->buffer_en_ch_steps = enb; - am335x_tsc_se_set(adc_dev->mfd_tscadc, enb); + am335x_tsc_se_set_cache(adc_dev->mfd_tscadc, enb); tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES | IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW); @@ -332,7 +332,7 @@ static int tiadc_read_raw(struct iio_dev *indio_dev, return -EBUSY; step_en = get_adc_step_mask(adc_dev); - am335x_tsc_se_set(adc_dev->mfd_tscadc, step_en); + am335x_tsc_se_set_once(adc_dev->mfd_tscadc, step_en); /* Wait for ADC sequencer to complete sampling */ while (tiadc_readl(adc_dev, REG_ADCFSM) & SEQ_STATUS) { diff --git a/drivers/input/touchscreen/ti_am335x_tsc.c b/drivers/input/touchscreen/ti_am335x_tsc.c index 68beada..2ca5a7b 100644 --- a/drivers/input/touchscreen/ti_am335x_tsc.c +++ b/drivers/input/touchscreen/ti_am335x_tsc.c @@ -198,7 +198,7 @@ static void titsc_step_config(struct titsc *ts_dev) /* The steps1 … end and bit 0 for TS_Charge */ stepenable = (1 << (end_step + 2)) - 1; ts_dev->step_mask = stepenable; - am335x_tsc_se_set(ts_dev->mfd_tscadc, ts_dev->step_mask); + am335x_tsc_se_set_cache(ts_dev->mfd_tscadc, ts_dev->step_mask); } static void titsc_read_coordinates(struct titsc *ts_dev, @@ -322,7 +322,7 @@ static irqreturn_t titsc_irq(int irq, void *dev) if (irqclr) { titsc_writel(ts_dev, REG_IRQSTATUS, irqclr); - am335x_tsc_se_set(ts_dev->mfd_tscadc, ts_dev->step_mask); + am335x_tsc_se_set_cache(ts_dev->mfd_tscadc, ts_dev->step_mask); return IRQ_HANDLED; } return IRQ_NONE; diff --git a/drivers/mfd/ti_am335x_tscadc.c b/drivers/mfd/ti_am335x_tscadc.c index 67d0eb4..cb0c211 100644 --- a/drivers/mfd/ti_am335x_tscadc.c +++ b/drivers/mfd/ti_am335x_tscadc.c @@ -53,24 +53,32 @@ static void am335x_tsc_se_update(struct ti_tscadc_dev *tsadc) tscadc_writel(tsadc, REG_SE, tsadc->reg_se_cache); } -void am335x_tsc_se_set(struct ti_tscadc_dev *tsadc, u32 val) +void am335x_tsc_se_set_cache(struct ti_tscadc_dev *tsadc, u32 val) { unsigned long flags; spin_lock_irqsave(&tsadc->reg_lock, flags); - tsadc->reg_se_cache = tscadc_readl(tsadc, REG_SE); tsadc->reg_se_cache |= val; am335x_tsc_se_update(tsadc); spin_unlock_irqrestore(&tsadc->reg_lock, flags); } -EXPORT_SYMBOL_GPL(am335x_tsc_se_set); +EXPORT_SYMBOL_GPL(am335x_tsc_se_set_cache); + +void am335x_tsc_se_set_once(struct ti_tscadc_dev *tsadc, u32 val) +{ + unsigned long flags; + + spin_lock_irqsave(&tsadc->reg_lock, flags); + tscadc_writel(tsadc, REG_SE, tsadc->reg_se_cache | val); + spin_unlock_irqrestore(&tsadc->reg_lock, flags); +} +EXPORT_SYMBOL_GPL(am335x_tsc_se_set_once); void am335x_tsc_se_clr(struct ti_tscadc_dev *tsadc, u32 val) { unsigned long flags; spin_lock_irqsave(&tsadc->reg_lock, flags); - tsadc->reg_se_cache = tscadc_readl(tsadc, REG_SE); tsadc->reg_se_cache &= ~val; am335x_tsc_se_update(tsadc); spin_unlock_irqrestore(&tsadc->reg_lock, flags); diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h index 1fe7219..2fa9c06 100644 --- a/include/linux/mfd/ti_am335x_tscadc.h +++ b/include/linux/mfd/ti_am335x_tscadc.h @@ -176,7 +176,8 @@ static inline struct ti_tscadc_dev *ti_tscadc_dev_get(struct platform_device *p) return *tscadc_dev; } -void am335x_tsc_se_set(struct ti_tscadc_dev *tsadc, u32 val); +void am335x_tsc_se_set_cache(struct ti_tscadc_dev *tsadc, u32 val); +void am335x_tsc_se_set_once(struct ti_tscadc_dev *tsadc, u32 val); void am335x_tsc_se_clr(struct ti_tscadc_dev *tsadc, u32 val); #endif