From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sebastian Andrzej Siewior Subject: [PATCH 3/5] mfd: ti_am335x_tscadc: Don't read back REG_SE Date: Thu, 19 Dec 2013 16:28:29 +0100 Message-ID: <1387466911-3732-4-git-send-email-bigeasy@linutronix.de> References: <1387466911-3732-1-git-send-email-bigeasy@linutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <1387466911-3732-1-git-send-email-bigeasy@linutronix.de> Sender: linux-kernel-owner@vger.kernel.org To: Lee Jones , Samuel Ortiz Cc: Jonathan Cameron , Dmitry Torokhov , Zubair Lutfullah , Felipe Balbi , linux-iio@vger.kernel.org, linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, Sebastian Andrzej Siewior List-Id: linux-input@vger.kernel.org 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 wh= ich 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. Acked-by: Lee Jones Signed-off-by: Sebastian Andrzej Siewior --- drivers/iio/adc/ti_am335x_adc.c | 4 ++-- drivers/input/touchscreen/ti_am335x_tsc.c | 4 ++-- drivers/mfd/ti_am335x_tscadc.c | 16 ++++++++++++---- include/linux/mfd/ti_am335x_tscadc.h | 3 ++- 4 files changed, 18 insertions(+), 9 deletions(-) diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335= x_adc.c index e948454..b5197a0 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 |=3D (get_adc_step_bit(adc_dev, bit) << 1); adc_dev->buffer_en_ch_steps =3D enb; =20 - am335x_tsc_se_set(adc_dev->mfd_tscadc, enb); + am335x_tsc_se_set_cache(adc_dev->mfd_tscadc, enb); =20 tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES | IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW); @@ -335,7 +335,7 @@ static int tiadc_read_raw(struct iio_dev *indio_dev= , return -EBUSY; =20 step_en =3D 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); =20 /* 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 =E2=80=A6 end and bit 0 for TS_Charge */ stepenable =3D (1 << (end_step + 2)) - 1; ts_dev->step_mask =3D 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); } =20 static void titsc_read_coordinates(struct titsc *ts_dev, @@ -322,7 +322,7 @@ static irqreturn_t titsc_irq(int irq, void *dev) =20 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_tsc= adc.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_d= ev *tsadc) tscadc_writel(tsadc, REG_SE, tsadc->reg_se_cache); } =20 -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; =20 spin_lock_irqsave(&tsadc->reg_lock, flags); - tsadc->reg_se_cache =3D tscadc_readl(tsadc, REG_SE); tsadc->reg_se_cache |=3D 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); =20 void am335x_tsc_se_clr(struct ti_tscadc_dev *tsadc, u32 val) { unsigned long flags; =20 spin_lock_irqsave(&tsadc->reg_lock, flags); - tsadc->reg_se_cache =3D tscadc_readl(tsadc, REG_SE); tsadc->reg_se_cache &=3D ~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/t= i_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_g= et(struct platform_device *p) return *tscadc_dev; } =20 -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); =20 #endif --=20 1.8.5.1