From: Peter Ujfalusi <peter.ujfalusi@ti.com>
To: Mugunthan V N <mugunthanvnm@ti.com>, <linux-iio@vger.kernel.org>
Cc: Tony Lindgren <tony@atomide.com>,
Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Russell King <linux@armlinux.org.uk>,
Jonathan Cameron <jic23@kernel.org>,
Hartmut Knaack <knaack.h@gmx.de>,
Lars-Peter Clausen <lars@metafoo.de>,
Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
Lee Jones <lee.jones@linaro.org>, Vignesh R <vigneshr@ti.com>,
"Andrew F . Davis" <afd@ti.com>, <linux-omap@vger.kernel.org>,
<devicetree@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>, Sekhar Nori <nsekhar@ti.com>
Subject: Re: [PATCH 2/4] drivers: iio: ti_am335x_adc: add dma support
Date: Thu, 22 Sep 2016 10:20:33 +0300 [thread overview]
Message-ID: <94b46406-577e-9cec-8e79-1134581932c5@ti.com> (raw)
In-Reply-To: <20160921161134.6951-3-mugunthanvnm@ti.com>
On 09/21/16 19:11, Mugunthan V N wrote:
> This patch adds the required pieces to ti_am335x_adc driver for
> DMA support
>
> Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
> ---
> drivers/iio/adc/ti_am335x_adc.c | 160 ++++++++++++++++++++++++++++++++++-
> include/linux/mfd/ti_am335x_tscadc.h | 7 ++
> 2 files changed, 164 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
> index c3cfacca..89d0b07 100644
> --- a/drivers/iio/adc/ti_am335x_adc.c
> +++ b/drivers/iio/adc/ti_am335x_adc.c
> @@ -30,10 +30,32 @@
> #include <linux/iio/buffer.h>
> #include <linux/iio/kfifo_buf.h>
>
> +#include <linux/dmaengine.h>
> +#include <linux/dma-mapping.h>
> +
> +#define DMA_BUFFER_SIZE SZ_2K
> +
> +struct tiadc_dma {
> + /* Filter function */
> + dma_filter_fn fn;
> + /* Parameter to the filter function */
> + void *param;
> + struct dma_slave_config conf;
> + struct dma_chan *chan;
> + dma_addr_t addr;
> + dma_cookie_t cookie;
> + u8 *buf;
> + bool valid_buf_seg;
> + int buf_offset;
> + u8 fifo_thresh;
> +};
> +
> struct tiadc_device {
> struct ti_tscadc_dev *mfd_tscadc;
> + struct tiadc_dma dma;
> struct mutex fifo1_lock; /* to protect fifo access */
> int channels;
> + int total_ch_enabled;
> u8 channel_line[8];
> u8 channel_step[8];
> int buffer_en_ch_steps;
> @@ -184,6 +206,7 @@ static irqreturn_t tiadc_worker_h(int irq, void *private)
> u16 *data = adc_dev->data;
>
> fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
> +
> for (k = 0; k < fifo1count; k = k + i) {
> for (i = 0; i < (indio_dev->scan_bytes)/2; i++) {
> read = tiadc_readl(adc_dev, REG_FIFO1);
> @@ -198,6 +221,68 @@ static irqreturn_t tiadc_worker_h(int irq, void *private)
> return IRQ_HANDLED;
> }
>
> +static void tiadc_dma_rx_complete(void *param)
> +{
> + struct iio_dev *indio_dev = param;
> + struct tiadc_device *adc_dev = iio_priv(indio_dev);
> + struct tiadc_dma *dma = &adc_dev->dma;
> + u8 *data;
> + int i;
> +
> + data = dma->valid_buf_seg ? dma->buf + dma->buf_offset : dma->buf;
bool valid_buf_seg ? The buffer segment is valid or not valid? Which buffer
segment is valid when valid_buf_seg is true?
I know what this is doing, but it is logically not correct.
Instead you could have:
int current_period; /* The period the DMA is working on */
When you start the DMA:
dma->current_period = 0; /* We start to fill period 0 */
In here:
u8 *data = dma->buf + (dma->current_period * dma_period_size);
> + dma->valid_buf_seg = !dma->valid_buf_seg;
/* Currently we have only two periods, so we can just */
dma->current_period = !dma->current_period;
/* or */
dma->current_period = 1 - dma->current_period; /* swap the buffer ID */
I think this would make it better to follow and if later you figure that you
want three or more periods instead of the two, it is going to be easier to add
that.
> +
> + for (i = 0; i < dma->buf_offset; i += indio_dev->scan_bytes) {
> + iio_push_to_buffers(indio_dev, data);
> + data += indio_dev->scan_bytes;
> + }
> +}
> +
> +static int tiadc_start_dma(struct iio_dev *indio_dev)
> +{
> + struct tiadc_device *adc_dev = iio_priv(indio_dev);
> + struct tiadc_dma *dma = &adc_dev->dma;
> + struct dma_async_tx_descriptor *desc;
> +
> + dma->valid_buf_seg = false;
> + dma->fifo_thresh = FIFO1_THRESHOLD;
FIFO1_THRESHOLD is defined as 19 in the global header file, so
if you have 2 channels enabled the trigger comes when the FIFO have 10
samples/ch, in case of all 8 channels enabled you will round it down the
trigger comes when you have 2 samples/ch.
Would not be better to try to use high threshold for the FIFO to reduce the
number of DMA requests needed runtime?
It is OK as it is at the moment, but I think it would make sense to try to
maximize the FIFO usage.
> + /*
> + * Make the fifo thresh as the multiple of total number of
> + * channels enabled, so make sure that that cyclic DMA period
> + * length is also a multiple of total number of channels
> + * enabled. This ensures that no invalid data is reported
> + * to the stack via iio_push_to_buffers().
> + */
> + dma->fifo_thresh -= (dma->fifo_thresh + 1) % adc_dev->total_ch_enabled;
> + dma->buf_offset = DMA_BUFFER_SIZE / 2;
> + /* Make sure that period length is multiple of fifo thresh level */
> + dma->buf_offset -= dma->buf_offset % ((dma->fifo_thresh + 1) *
> + sizeof(u16));
> +
> + dma->conf.src_maxburst = dma->fifo_thresh + 1;
> + dmaengine_slave_config(dma->chan, &dma->conf);
> +
> + desc = dmaengine_prep_dma_cyclic(dma->chan, dma->addr,
> + dma->buf_offset * 2,
> + dma->buf_offset, DMA_DEV_TO_MEM,
I find the buf_offset name and it's use really confusing. It should be called
period_size, really.
> + DMA_PREP_INTERRUPT);
> + if (!desc)
> + return -EBUSY;
> +
> + desc->callback = tiadc_dma_rx_complete;
> + desc->callback_param = indio_dev;
> +
> + dma->cookie = dmaengine_submit(desc);
> +
> + dma_async_issue_pending(dma->chan);
> +
> + tiadc_writel(adc_dev, REG_FIFO1THR, dma->fifo_thresh);
> + tiadc_writel(adc_dev, REG_DMA1REQ, dma->fifo_thresh);
> + tiadc_writel(adc_dev, REG_DMAENABLE_SET, DMA_FIFO1);
> +
> + return 0;
> +}
> +
> static int tiadc_buffer_preenable(struct iio_dev *indio_dev)
> {
> struct tiadc_device *adc_dev = iio_priv(indio_dev);
> @@ -218,20 +303,30 @@ static int tiadc_buffer_preenable(struct iio_dev *indio_dev)
> static int tiadc_buffer_postenable(struct iio_dev *indio_dev)
> {
> struct tiadc_device *adc_dev = iio_priv(indio_dev);
> + struct tiadc_dma *dma = &adc_dev->dma;
> unsigned int enb = 0;
> u8 bit;
> + u32 irq_enable;
>
> tiadc_step_config(indio_dev);
> - for_each_set_bit(bit, indio_dev->active_scan_mask, adc_dev->channels)
> + for_each_set_bit(bit, indio_dev->active_scan_mask, adc_dev->channels) {
> enb |= (get_adc_step_bit(adc_dev, bit) << 1);
> + adc_dev->total_ch_enabled++;
> + }
> adc_dev->buffer_en_ch_steps = enb;
>
> + if (dma->chan)
> + tiadc_start_dma(indio_dev);
> +
> am335x_tsc_se_set_cache(adc_dev->mfd_tscadc, enb);
>
> tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES
> | IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW);
> - tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES
> - | IRQENB_FIFO1OVRRUN);
> +
> + irq_enable = IRQENB_FIFO1OVRRUN;
> + if (!dma->chan)
> + irq_enable |= IRQENB_FIFO1THRES;
> + tiadc_writel(adc_dev, REG_IRQENABLE, irq_enable);
>
> return 0;
> }
> @@ -239,12 +334,18 @@ static int tiadc_buffer_postenable(struct iio_dev *indio_dev)
> static int tiadc_buffer_predisable(struct iio_dev *indio_dev)
> {
> struct tiadc_device *adc_dev = iio_priv(indio_dev);
> + struct tiadc_dma *dma = &adc_dev->dma;
> int fifo1count, i, read;
>
> tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES |
> IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW));
> am335x_tsc_se_clr(adc_dev->mfd_tscadc, adc_dev->buffer_en_ch_steps);
> adc_dev->buffer_en_ch_steps = 0;
> + adc_dev->total_ch_enabled = 0;
> + if (dma->chan) {
> + tiadc_writel(adc_dev, REG_DMAENABLE_CLEAR, 0x2);
> + dmaengine_terminate_async(dma->chan);
> + }
>
> /* Flush FIFO of leftover data in the time it takes to disable adc */
> fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
> @@ -430,6 +531,50 @@ static const struct iio_info tiadc_info = {
> .driver_module = THIS_MODULE,
> };
>
> +static bool the_no_dma_filter_fn(struct dma_chan *chan, void *param)
> +{
> + return false;
> +}
> +
> +static int tiadc_request_dma(struct platform_device *pdev,
> + struct tiadc_device *adc_dev)
> +{
> + struct tiadc_dma *dma = &adc_dev->dma;
> + dma_cap_mask_t mask;
> +
> + dma->fn = the_no_dma_filter_fn;
> +
> + /* Default slave configuration parameters */
> + dma->conf.direction = DMA_DEV_TO_MEM;
> + dma->conf.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
> + dma->conf.src_addr = adc_dev->mfd_tscadc->tscadc_phys_base + REG_FIFO1;
> +
> + dma_cap_zero(mask);
> + dma_cap_set(DMA_CYCLIC, mask);
> +
> + /* Get a channel for RX */
> + dma->chan = dma_request_slave_channel_compat(mask,
> + dma->fn, dma->param,
> + adc_dev->mfd_tscadc->dev,
> + "fifo1");
dma_request_chan()
> + if (!dma->chan)
> + return -ENODEV;
> +
> + /* RX buffer */
> + dma->buf = dma_alloc_coherent(dma->chan->device->dev, DMA_BUFFER_SIZE,
> + &dma->addr, GFP_KERNEL);
> + if (!dma->buf)
> + goto err;
> +
> + dev_dbg_ratelimited(adc_dev->mfd_tscadc->dev, "got dma channel\n");
> +
> + return 0;
> +err:
> + dma_release_channel(dma->chan);
> +
> + return -ENOMEM;
> +}
> +
> static int tiadc_parse_dt(struct platform_device *pdev,
> struct tiadc_device *adc_dev)
> {
> @@ -512,8 +657,14 @@ static int tiadc_probe(struct platform_device *pdev)
>
> platform_set_drvdata(pdev, indio_dev);
>
> + err = tiadc_request_dma(pdev, adc_dev);
> + if (err && err != -ENODEV)
> + goto err_dma;
> +
> return 0;
>
> +err_dma:
> + iio_device_unregister(indio_dev);
> err_buffer_unregister:
> tiadc_iio_buffered_hardware_remove(indio_dev);
> err_free_channels:
> @@ -525,8 +676,11 @@ static int tiadc_remove(struct platform_device *pdev)
> {
> struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> struct tiadc_device *adc_dev = iio_priv(indio_dev);
> + struct tiadc_dma *dma = &adc_dev->dma;
> u32 step_en;
>
> + if (dma->chan)
> + dma_release_channel(dma->chan);
> iio_device_unregister(indio_dev);
> tiadc_iio_buffered_hardware_remove(indio_dev);
> tiadc_channels_remove(indio_dev);
> diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
> index e45a208..fb9dc99 100644
> --- a/include/linux/mfd/ti_am335x_tscadc.h
> +++ b/include/linux/mfd/ti_am335x_tscadc.h
> @@ -23,6 +23,8 @@
> #define REG_IRQENABLE 0x02C
> #define REG_IRQCLR 0x030
> #define REG_IRQWAKEUP 0x034
> +#define REG_DMAENABLE_SET 0x038
> +#define REG_DMAENABLE_CLEAR 0x038
> #define REG_CTRL 0x040
> #define REG_ADCFSM 0x044
> #define REG_CLKDIV 0x04C
> @@ -36,6 +38,7 @@
> #define REG_FIFO0THR 0xE8
> #define REG_FIFO1CNT 0xF0
> #define REG_FIFO1THR 0xF4
> +#define REG_DMA1REQ 0xF8
> #define REG_FIFO0 0x100
> #define REG_FIFO1 0x200
>
> @@ -126,6 +129,10 @@
> #define FIFOREAD_DATA_MASK (0xfff << 0)
> #define FIFOREAD_CHNLID_MASK (0xf << 16)
>
> +/* DMA ENABLE/CLEAR Register */
> +#define DMA_FIFO0 BIT(0)
> +#define DMA_FIFO1 BIT(1)
> +
> /* Sequencer Status */
> #define SEQ_STATUS BIT(5)
> #define CHARGE_STEP 0x11
>
--
Péter
WARNING: multiple messages have this Message-ID (diff)
From: Peter Ujfalusi <peter.ujfalusi-l0cyMroinI0@public.gmane.org>
To: Mugunthan V N <mugunthanvnm-l0cyMroinI0@public.gmane.org>,
linux-iio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: Tony Lindgren <tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org>,
Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>,
Russell King <linux-I+IVW8TIWO2tmTQ+vhA3Yw@public.gmane.org>,
Jonathan Cameron <jic23-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Hartmut Knaack <knaack.h-Mmb7MZpHnFY@public.gmane.org>,
Lars-Peter Clausen <lars-Qo5EllUWu/uELgA04lAiVw@public.gmane.org>,
Peter Meerwald-Stadler
<pmeerw-jW+XmwGofnusTnJN9+BGXg@public.gmane.org>,
Lee Jones <lee.jones-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
Vignesh R <vigneshr-l0cyMroinI0@public.gmane.org>,
"Andrew F . Davis" <afd-l0cyMroinI0@public.gmane.org>,
linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Sekhar Nori <nsekhar-l0cyMroinI0@public.gmane.org>
Subject: Re: [PATCH 2/4] drivers: iio: ti_am335x_adc: add dma support
Date: Thu, 22 Sep 2016 10:20:33 +0300 [thread overview]
Message-ID: <94b46406-577e-9cec-8e79-1134581932c5@ti.com> (raw)
In-Reply-To: <20160921161134.6951-3-mugunthanvnm-l0cyMroinI0@public.gmane.org>
On 09/21/16 19:11, Mugunthan V N wrote:
> This patch adds the required pieces to ti_am335x_adc driver for
> DMA support
>
> Signed-off-by: Mugunthan V N <mugunthanvnm-l0cyMroinI0@public.gmane.org>
> ---
> drivers/iio/adc/ti_am335x_adc.c | 160 ++++++++++++++++++++++++++++++++++-
> include/linux/mfd/ti_am335x_tscadc.h | 7 ++
> 2 files changed, 164 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
> index c3cfacca..89d0b07 100644
> --- a/drivers/iio/adc/ti_am335x_adc.c
> +++ b/drivers/iio/adc/ti_am335x_adc.c
> @@ -30,10 +30,32 @@
> #include <linux/iio/buffer.h>
> #include <linux/iio/kfifo_buf.h>
>
> +#include <linux/dmaengine.h>
> +#include <linux/dma-mapping.h>
> +
> +#define DMA_BUFFER_SIZE SZ_2K
> +
> +struct tiadc_dma {
> + /* Filter function */
> + dma_filter_fn fn;
> + /* Parameter to the filter function */
> + void *param;
> + struct dma_slave_config conf;
> + struct dma_chan *chan;
> + dma_addr_t addr;
> + dma_cookie_t cookie;
> + u8 *buf;
> + bool valid_buf_seg;
> + int buf_offset;
> + u8 fifo_thresh;
> +};
> +
> struct tiadc_device {
> struct ti_tscadc_dev *mfd_tscadc;
> + struct tiadc_dma dma;
> struct mutex fifo1_lock; /* to protect fifo access */
> int channels;
> + int total_ch_enabled;
> u8 channel_line[8];
> u8 channel_step[8];
> int buffer_en_ch_steps;
> @@ -184,6 +206,7 @@ static irqreturn_t tiadc_worker_h(int irq, void *private)
> u16 *data = adc_dev->data;
>
> fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
> +
> for (k = 0; k < fifo1count; k = k + i) {
> for (i = 0; i < (indio_dev->scan_bytes)/2; i++) {
> read = tiadc_readl(adc_dev, REG_FIFO1);
> @@ -198,6 +221,68 @@ static irqreturn_t tiadc_worker_h(int irq, void *private)
> return IRQ_HANDLED;
> }
>
> +static void tiadc_dma_rx_complete(void *param)
> +{
> + struct iio_dev *indio_dev = param;
> + struct tiadc_device *adc_dev = iio_priv(indio_dev);
> + struct tiadc_dma *dma = &adc_dev->dma;
> + u8 *data;
> + int i;
> +
> + data = dma->valid_buf_seg ? dma->buf + dma->buf_offset : dma->buf;
bool valid_buf_seg ? The buffer segment is valid or not valid? Which buffer
segment is valid when valid_buf_seg is true?
I know what this is doing, but it is logically not correct.
Instead you could have:
int current_period; /* The period the DMA is working on */
When you start the DMA:
dma->current_period = 0; /* We start to fill period 0 */
In here:
u8 *data = dma->buf + (dma->current_period * dma_period_size);
> + dma->valid_buf_seg = !dma->valid_buf_seg;
/* Currently we have only two periods, so we can just */
dma->current_period = !dma->current_period;
/* or */
dma->current_period = 1 - dma->current_period; /* swap the buffer ID */
I think this would make it better to follow and if later you figure that you
want three or more periods instead of the two, it is going to be easier to add
that.
> +
> + for (i = 0; i < dma->buf_offset; i += indio_dev->scan_bytes) {
> + iio_push_to_buffers(indio_dev, data);
> + data += indio_dev->scan_bytes;
> + }
> +}
> +
> +static int tiadc_start_dma(struct iio_dev *indio_dev)
> +{
> + struct tiadc_device *adc_dev = iio_priv(indio_dev);
> + struct tiadc_dma *dma = &adc_dev->dma;
> + struct dma_async_tx_descriptor *desc;
> +
> + dma->valid_buf_seg = false;
> + dma->fifo_thresh = FIFO1_THRESHOLD;
FIFO1_THRESHOLD is defined as 19 in the global header file, so
if you have 2 channels enabled the trigger comes when the FIFO have 10
samples/ch, in case of all 8 channels enabled you will round it down the
trigger comes when you have 2 samples/ch.
Would not be better to try to use high threshold for the FIFO to reduce the
number of DMA requests needed runtime?
It is OK as it is at the moment, but I think it would make sense to try to
maximize the FIFO usage.
> + /*
> + * Make the fifo thresh as the multiple of total number of
> + * channels enabled, so make sure that that cyclic DMA period
> + * length is also a multiple of total number of channels
> + * enabled. This ensures that no invalid data is reported
> + * to the stack via iio_push_to_buffers().
> + */
> + dma->fifo_thresh -= (dma->fifo_thresh + 1) % adc_dev->total_ch_enabled;
> + dma->buf_offset = DMA_BUFFER_SIZE / 2;
> + /* Make sure that period length is multiple of fifo thresh level */
> + dma->buf_offset -= dma->buf_offset % ((dma->fifo_thresh + 1) *
> + sizeof(u16));
> +
> + dma->conf.src_maxburst = dma->fifo_thresh + 1;
> + dmaengine_slave_config(dma->chan, &dma->conf);
> +
> + desc = dmaengine_prep_dma_cyclic(dma->chan, dma->addr,
> + dma->buf_offset * 2,
> + dma->buf_offset, DMA_DEV_TO_MEM,
I find the buf_offset name and it's use really confusing. It should be called
period_size, really.
> + DMA_PREP_INTERRUPT);
> + if (!desc)
> + return -EBUSY;
> +
> + desc->callback = tiadc_dma_rx_complete;
> + desc->callback_param = indio_dev;
> +
> + dma->cookie = dmaengine_submit(desc);
> +
> + dma_async_issue_pending(dma->chan);
> +
> + tiadc_writel(adc_dev, REG_FIFO1THR, dma->fifo_thresh);
> + tiadc_writel(adc_dev, REG_DMA1REQ, dma->fifo_thresh);
> + tiadc_writel(adc_dev, REG_DMAENABLE_SET, DMA_FIFO1);
> +
> + return 0;
> +}
> +
> static int tiadc_buffer_preenable(struct iio_dev *indio_dev)
> {
> struct tiadc_device *adc_dev = iio_priv(indio_dev);
> @@ -218,20 +303,30 @@ static int tiadc_buffer_preenable(struct iio_dev *indio_dev)
> static int tiadc_buffer_postenable(struct iio_dev *indio_dev)
> {
> struct tiadc_device *adc_dev = iio_priv(indio_dev);
> + struct tiadc_dma *dma = &adc_dev->dma;
> unsigned int enb = 0;
> u8 bit;
> + u32 irq_enable;
>
> tiadc_step_config(indio_dev);
> - for_each_set_bit(bit, indio_dev->active_scan_mask, adc_dev->channels)
> + for_each_set_bit(bit, indio_dev->active_scan_mask, adc_dev->channels) {
> enb |= (get_adc_step_bit(adc_dev, bit) << 1);
> + adc_dev->total_ch_enabled++;
> + }
> adc_dev->buffer_en_ch_steps = enb;
>
> + if (dma->chan)
> + tiadc_start_dma(indio_dev);
> +
> am335x_tsc_se_set_cache(adc_dev->mfd_tscadc, enb);
>
> tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES
> | IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW);
> - tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES
> - | IRQENB_FIFO1OVRRUN);
> +
> + irq_enable = IRQENB_FIFO1OVRRUN;
> + if (!dma->chan)
> + irq_enable |= IRQENB_FIFO1THRES;
> + tiadc_writel(adc_dev, REG_IRQENABLE, irq_enable);
>
> return 0;
> }
> @@ -239,12 +334,18 @@ static int tiadc_buffer_postenable(struct iio_dev *indio_dev)
> static int tiadc_buffer_predisable(struct iio_dev *indio_dev)
> {
> struct tiadc_device *adc_dev = iio_priv(indio_dev);
> + struct tiadc_dma *dma = &adc_dev->dma;
> int fifo1count, i, read;
>
> tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES |
> IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW));
> am335x_tsc_se_clr(adc_dev->mfd_tscadc, adc_dev->buffer_en_ch_steps);
> adc_dev->buffer_en_ch_steps = 0;
> + adc_dev->total_ch_enabled = 0;
> + if (dma->chan) {
> + tiadc_writel(adc_dev, REG_DMAENABLE_CLEAR, 0x2);
> + dmaengine_terminate_async(dma->chan);
> + }
>
> /* Flush FIFO of leftover data in the time it takes to disable adc */
> fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
> @@ -430,6 +531,50 @@ static const struct iio_info tiadc_info = {
> .driver_module = THIS_MODULE,
> };
>
> +static bool the_no_dma_filter_fn(struct dma_chan *chan, void *param)
> +{
> + return false;
> +}
> +
> +static int tiadc_request_dma(struct platform_device *pdev,
> + struct tiadc_device *adc_dev)
> +{
> + struct tiadc_dma *dma = &adc_dev->dma;
> + dma_cap_mask_t mask;
> +
> + dma->fn = the_no_dma_filter_fn;
> +
> + /* Default slave configuration parameters */
> + dma->conf.direction = DMA_DEV_TO_MEM;
> + dma->conf.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
> + dma->conf.src_addr = adc_dev->mfd_tscadc->tscadc_phys_base + REG_FIFO1;
> +
> + dma_cap_zero(mask);
> + dma_cap_set(DMA_CYCLIC, mask);
> +
> + /* Get a channel for RX */
> + dma->chan = dma_request_slave_channel_compat(mask,
> + dma->fn, dma->param,
> + adc_dev->mfd_tscadc->dev,
> + "fifo1");
dma_request_chan()
> + if (!dma->chan)
> + return -ENODEV;
> +
> + /* RX buffer */
> + dma->buf = dma_alloc_coherent(dma->chan->device->dev, DMA_BUFFER_SIZE,
> + &dma->addr, GFP_KERNEL);
> + if (!dma->buf)
> + goto err;
> +
> + dev_dbg_ratelimited(adc_dev->mfd_tscadc->dev, "got dma channel\n");
> +
> + return 0;
> +err:
> + dma_release_channel(dma->chan);
> +
> + return -ENOMEM;
> +}
> +
> static int tiadc_parse_dt(struct platform_device *pdev,
> struct tiadc_device *adc_dev)
> {
> @@ -512,8 +657,14 @@ static int tiadc_probe(struct platform_device *pdev)
>
> platform_set_drvdata(pdev, indio_dev);
>
> + err = tiadc_request_dma(pdev, adc_dev);
> + if (err && err != -ENODEV)
> + goto err_dma;
> +
> return 0;
>
> +err_dma:
> + iio_device_unregister(indio_dev);
> err_buffer_unregister:
> tiadc_iio_buffered_hardware_remove(indio_dev);
> err_free_channels:
> @@ -525,8 +676,11 @@ static int tiadc_remove(struct platform_device *pdev)
> {
> struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> struct tiadc_device *adc_dev = iio_priv(indio_dev);
> + struct tiadc_dma *dma = &adc_dev->dma;
> u32 step_en;
>
> + if (dma->chan)
> + dma_release_channel(dma->chan);
> iio_device_unregister(indio_dev);
> tiadc_iio_buffered_hardware_remove(indio_dev);
> tiadc_channels_remove(indio_dev);
> diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
> index e45a208..fb9dc99 100644
> --- a/include/linux/mfd/ti_am335x_tscadc.h
> +++ b/include/linux/mfd/ti_am335x_tscadc.h
> @@ -23,6 +23,8 @@
> #define REG_IRQENABLE 0x02C
> #define REG_IRQCLR 0x030
> #define REG_IRQWAKEUP 0x034
> +#define REG_DMAENABLE_SET 0x038
> +#define REG_DMAENABLE_CLEAR 0x038
> #define REG_CTRL 0x040
> #define REG_ADCFSM 0x044
> #define REG_CLKDIV 0x04C
> @@ -36,6 +38,7 @@
> #define REG_FIFO0THR 0xE8
> #define REG_FIFO1CNT 0xF0
> #define REG_FIFO1THR 0xF4
> +#define REG_DMA1REQ 0xF8
> #define REG_FIFO0 0x100
> #define REG_FIFO1 0x200
>
> @@ -126,6 +129,10 @@
> #define FIFOREAD_DATA_MASK (0xfff << 0)
> #define FIFOREAD_CHNLID_MASK (0xf << 16)
>
> +/* DMA ENABLE/CLEAR Register */
> +#define DMA_FIFO0 BIT(0)
> +#define DMA_FIFO1 BIT(1)
> +
> /* Sequencer Status */
> #define SEQ_STATUS BIT(5)
> #define CHARGE_STEP 0x11
>
--
Péter
WARNING: multiple messages have this Message-ID (diff)
From: peter.ujfalusi@ti.com (Peter Ujfalusi)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/4] drivers: iio: ti_am335x_adc: add dma support
Date: Thu, 22 Sep 2016 10:20:33 +0300 [thread overview]
Message-ID: <94b46406-577e-9cec-8e79-1134581932c5@ti.com> (raw)
In-Reply-To: <20160921161134.6951-3-mugunthanvnm@ti.com>
On 09/21/16 19:11, Mugunthan V N wrote:
> This patch adds the required pieces to ti_am335x_adc driver for
> DMA support
>
> Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
> ---
> drivers/iio/adc/ti_am335x_adc.c | 160 ++++++++++++++++++++++++++++++++++-
> include/linux/mfd/ti_am335x_tscadc.h | 7 ++
> 2 files changed, 164 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
> index c3cfacca..89d0b07 100644
> --- a/drivers/iio/adc/ti_am335x_adc.c
> +++ b/drivers/iio/adc/ti_am335x_adc.c
> @@ -30,10 +30,32 @@
> #include <linux/iio/buffer.h>
> #include <linux/iio/kfifo_buf.h>
>
> +#include <linux/dmaengine.h>
> +#include <linux/dma-mapping.h>
> +
> +#define DMA_BUFFER_SIZE SZ_2K
> +
> +struct tiadc_dma {
> + /* Filter function */
> + dma_filter_fn fn;
> + /* Parameter to the filter function */
> + void *param;
> + struct dma_slave_config conf;
> + struct dma_chan *chan;
> + dma_addr_t addr;
> + dma_cookie_t cookie;
> + u8 *buf;
> + bool valid_buf_seg;
> + int buf_offset;
> + u8 fifo_thresh;
> +};
> +
> struct tiadc_device {
> struct ti_tscadc_dev *mfd_tscadc;
> + struct tiadc_dma dma;
> struct mutex fifo1_lock; /* to protect fifo access */
> int channels;
> + int total_ch_enabled;
> u8 channel_line[8];
> u8 channel_step[8];
> int buffer_en_ch_steps;
> @@ -184,6 +206,7 @@ static irqreturn_t tiadc_worker_h(int irq, void *private)
> u16 *data = adc_dev->data;
>
> fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
> +
> for (k = 0; k < fifo1count; k = k + i) {
> for (i = 0; i < (indio_dev->scan_bytes)/2; i++) {
> read = tiadc_readl(adc_dev, REG_FIFO1);
> @@ -198,6 +221,68 @@ static irqreturn_t tiadc_worker_h(int irq, void *private)
> return IRQ_HANDLED;
> }
>
> +static void tiadc_dma_rx_complete(void *param)
> +{
> + struct iio_dev *indio_dev = param;
> + struct tiadc_device *adc_dev = iio_priv(indio_dev);
> + struct tiadc_dma *dma = &adc_dev->dma;
> + u8 *data;
> + int i;
> +
> + data = dma->valid_buf_seg ? dma->buf + dma->buf_offset : dma->buf;
bool valid_buf_seg ? The buffer segment is valid or not valid? Which buffer
segment is valid when valid_buf_seg is true?
I know what this is doing, but it is logically not correct.
Instead you could have:
int current_period; /* The period the DMA is working on */
When you start the DMA:
dma->current_period = 0; /* We start to fill period 0 */
In here:
u8 *data = dma->buf + (dma->current_period * dma_period_size);
> + dma->valid_buf_seg = !dma->valid_buf_seg;
/* Currently we have only two periods, so we can just */
dma->current_period = !dma->current_period;
/* or */
dma->current_period = 1 - dma->current_period; /* swap the buffer ID */
I think this would make it better to follow and if later you figure that you
want three or more periods instead of the two, it is going to be easier to add
that.
> +
> + for (i = 0; i < dma->buf_offset; i += indio_dev->scan_bytes) {
> + iio_push_to_buffers(indio_dev, data);
> + data += indio_dev->scan_bytes;
> + }
> +}
> +
> +static int tiadc_start_dma(struct iio_dev *indio_dev)
> +{
> + struct tiadc_device *adc_dev = iio_priv(indio_dev);
> + struct tiadc_dma *dma = &adc_dev->dma;
> + struct dma_async_tx_descriptor *desc;
> +
> + dma->valid_buf_seg = false;
> + dma->fifo_thresh = FIFO1_THRESHOLD;
FIFO1_THRESHOLD is defined as 19 in the global header file, so
if you have 2 channels enabled the trigger comes when the FIFO have 10
samples/ch, in case of all 8 channels enabled you will round it down the
trigger comes when you have 2 samples/ch.
Would not be better to try to use high threshold for the FIFO to reduce the
number of DMA requests needed runtime?
It is OK as it is at the moment, but I think it would make sense to try to
maximize the FIFO usage.
> + /*
> + * Make the fifo thresh as the multiple of total number of
> + * channels enabled, so make sure that that cyclic DMA period
> + * length is also a multiple of total number of channels
> + * enabled. This ensures that no invalid data is reported
> + * to the stack via iio_push_to_buffers().
> + */
> + dma->fifo_thresh -= (dma->fifo_thresh + 1) % adc_dev->total_ch_enabled;
> + dma->buf_offset = DMA_BUFFER_SIZE / 2;
> + /* Make sure that period length is multiple of fifo thresh level */
> + dma->buf_offset -= dma->buf_offset % ((dma->fifo_thresh + 1) *
> + sizeof(u16));
> +
> + dma->conf.src_maxburst = dma->fifo_thresh + 1;
> + dmaengine_slave_config(dma->chan, &dma->conf);
> +
> + desc = dmaengine_prep_dma_cyclic(dma->chan, dma->addr,
> + dma->buf_offset * 2,
> + dma->buf_offset, DMA_DEV_TO_MEM,
I find the buf_offset name and it's use really confusing. It should be called
period_size, really.
> + DMA_PREP_INTERRUPT);
> + if (!desc)
> + return -EBUSY;
> +
> + desc->callback = tiadc_dma_rx_complete;
> + desc->callback_param = indio_dev;
> +
> + dma->cookie = dmaengine_submit(desc);
> +
> + dma_async_issue_pending(dma->chan);
> +
> + tiadc_writel(adc_dev, REG_FIFO1THR, dma->fifo_thresh);
> + tiadc_writel(adc_dev, REG_DMA1REQ, dma->fifo_thresh);
> + tiadc_writel(adc_dev, REG_DMAENABLE_SET, DMA_FIFO1);
> +
> + return 0;
> +}
> +
> static int tiadc_buffer_preenable(struct iio_dev *indio_dev)
> {
> struct tiadc_device *adc_dev = iio_priv(indio_dev);
> @@ -218,20 +303,30 @@ static int tiadc_buffer_preenable(struct iio_dev *indio_dev)
> static int tiadc_buffer_postenable(struct iio_dev *indio_dev)
> {
> struct tiadc_device *adc_dev = iio_priv(indio_dev);
> + struct tiadc_dma *dma = &adc_dev->dma;
> unsigned int enb = 0;
> u8 bit;
> + u32 irq_enable;
>
> tiadc_step_config(indio_dev);
> - for_each_set_bit(bit, indio_dev->active_scan_mask, adc_dev->channels)
> + for_each_set_bit(bit, indio_dev->active_scan_mask, adc_dev->channels) {
> enb |= (get_adc_step_bit(adc_dev, bit) << 1);
> + adc_dev->total_ch_enabled++;
> + }
> adc_dev->buffer_en_ch_steps = enb;
>
> + if (dma->chan)
> + tiadc_start_dma(indio_dev);
> +
> am335x_tsc_se_set_cache(adc_dev->mfd_tscadc, enb);
>
> tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES
> | IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW);
> - tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES
> - | IRQENB_FIFO1OVRRUN);
> +
> + irq_enable = IRQENB_FIFO1OVRRUN;
> + if (!dma->chan)
> + irq_enable |= IRQENB_FIFO1THRES;
> + tiadc_writel(adc_dev, REG_IRQENABLE, irq_enable);
>
> return 0;
> }
> @@ -239,12 +334,18 @@ static int tiadc_buffer_postenable(struct iio_dev *indio_dev)
> static int tiadc_buffer_predisable(struct iio_dev *indio_dev)
> {
> struct tiadc_device *adc_dev = iio_priv(indio_dev);
> + struct tiadc_dma *dma = &adc_dev->dma;
> int fifo1count, i, read;
>
> tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES |
> IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW));
> am335x_tsc_se_clr(adc_dev->mfd_tscadc, adc_dev->buffer_en_ch_steps);
> adc_dev->buffer_en_ch_steps = 0;
> + adc_dev->total_ch_enabled = 0;
> + if (dma->chan) {
> + tiadc_writel(adc_dev, REG_DMAENABLE_CLEAR, 0x2);
> + dmaengine_terminate_async(dma->chan);
> + }
>
> /* Flush FIFO of leftover data in the time it takes to disable adc */
> fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
> @@ -430,6 +531,50 @@ static const struct iio_info tiadc_info = {
> .driver_module = THIS_MODULE,
> };
>
> +static bool the_no_dma_filter_fn(struct dma_chan *chan, void *param)
> +{
> + return false;
> +}
> +
> +static int tiadc_request_dma(struct platform_device *pdev,
> + struct tiadc_device *adc_dev)
> +{
> + struct tiadc_dma *dma = &adc_dev->dma;
> + dma_cap_mask_t mask;
> +
> + dma->fn = the_no_dma_filter_fn;
> +
> + /* Default slave configuration parameters */
> + dma->conf.direction = DMA_DEV_TO_MEM;
> + dma->conf.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
> + dma->conf.src_addr = adc_dev->mfd_tscadc->tscadc_phys_base + REG_FIFO1;
> +
> + dma_cap_zero(mask);
> + dma_cap_set(DMA_CYCLIC, mask);
> +
> + /* Get a channel for RX */
> + dma->chan = dma_request_slave_channel_compat(mask,
> + dma->fn, dma->param,
> + adc_dev->mfd_tscadc->dev,
> + "fifo1");
dma_request_chan()
> + if (!dma->chan)
> + return -ENODEV;
> +
> + /* RX buffer */
> + dma->buf = dma_alloc_coherent(dma->chan->device->dev, DMA_BUFFER_SIZE,
> + &dma->addr, GFP_KERNEL);
> + if (!dma->buf)
> + goto err;
> +
> + dev_dbg_ratelimited(adc_dev->mfd_tscadc->dev, "got dma channel\n");
> +
> + return 0;
> +err:
> + dma_release_channel(dma->chan);
> +
> + return -ENOMEM;
> +}
> +
> static int tiadc_parse_dt(struct platform_device *pdev,
> struct tiadc_device *adc_dev)
> {
> @@ -512,8 +657,14 @@ static int tiadc_probe(struct platform_device *pdev)
>
> platform_set_drvdata(pdev, indio_dev);
>
> + err = tiadc_request_dma(pdev, adc_dev);
> + if (err && err != -ENODEV)
> + goto err_dma;
> +
> return 0;
>
> +err_dma:
> + iio_device_unregister(indio_dev);
> err_buffer_unregister:
> tiadc_iio_buffered_hardware_remove(indio_dev);
> err_free_channels:
> @@ -525,8 +676,11 @@ static int tiadc_remove(struct platform_device *pdev)
> {
> struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> struct tiadc_device *adc_dev = iio_priv(indio_dev);
> + struct tiadc_dma *dma = &adc_dev->dma;
> u32 step_en;
>
> + if (dma->chan)
> + dma_release_channel(dma->chan);
> iio_device_unregister(indio_dev);
> tiadc_iio_buffered_hardware_remove(indio_dev);
> tiadc_channels_remove(indio_dev);
> diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
> index e45a208..fb9dc99 100644
> --- a/include/linux/mfd/ti_am335x_tscadc.h
> +++ b/include/linux/mfd/ti_am335x_tscadc.h
> @@ -23,6 +23,8 @@
> #define REG_IRQENABLE 0x02C
> #define REG_IRQCLR 0x030
> #define REG_IRQWAKEUP 0x034
> +#define REG_DMAENABLE_SET 0x038
> +#define REG_DMAENABLE_CLEAR 0x038
> #define REG_CTRL 0x040
> #define REG_ADCFSM 0x044
> #define REG_CLKDIV 0x04C
> @@ -36,6 +38,7 @@
> #define REG_FIFO0THR 0xE8
> #define REG_FIFO1CNT 0xF0
> #define REG_FIFO1THR 0xF4
> +#define REG_DMA1REQ 0xF8
> #define REG_FIFO0 0x100
> #define REG_FIFO1 0x200
>
> @@ -126,6 +129,10 @@
> #define FIFOREAD_DATA_MASK (0xfff << 0)
> #define FIFOREAD_CHNLID_MASK (0xf << 16)
>
> +/* DMA ENABLE/CLEAR Register */
> +#define DMA_FIFO0 BIT(0)
> +#define DMA_FIFO1 BIT(1)
> +
> /* Sequencer Status */
> #define SEQ_STATUS BIT(5)
> #define CHARGE_STEP 0x11
>
--
P?ter
next prev parent reply other threads:[~2016-09-22 7:23 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-21 16:11 [PATCH 0/4] Add DMA support for ti_am335x_adc driver Mugunthan V N
2016-09-21 16:11 ` Mugunthan V N
2016-09-21 16:11 ` Mugunthan V N
2016-09-21 16:11 ` [PATCH 1/4] mfd: ti_am335x_tscadc: store physical address Mugunthan V N
2016-09-21 16:11 ` Mugunthan V N
2016-09-21 16:11 ` Mugunthan V N
2016-09-27 19:40 ` Lee Jones
2016-09-27 19:40 ` Lee Jones
2016-09-27 19:40 ` Lee Jones
2016-09-30 8:43 ` Mugunthan V N
2016-09-30 8:43 ` Mugunthan V N
2016-09-30 8:43 ` Mugunthan V N
2016-10-26 12:17 ` Lee Jones
2016-10-26 12:17 ` Lee Jones
2016-10-26 12:17 ` Lee Jones
2016-10-30 17:05 ` Jonathan Cameron
2016-10-30 17:05 ` Jonathan Cameron
2016-10-31 8:16 ` Lee Jones
2016-10-31 8:16 ` Lee Jones
2016-10-31 8:16 ` Lee Jones
2016-11-05 17:45 ` Jonathan Cameron
2016-11-05 17:45 ` Jonathan Cameron
2016-11-05 17:45 ` Jonathan Cameron
2016-09-21 16:11 ` [PATCH 2/4] drivers: iio: ti_am335x_adc: add dma support Mugunthan V N
2016-09-21 16:11 ` Mugunthan V N
2016-09-21 16:11 ` Mugunthan V N
[not found] ` <20160921161134.6951-3-mugunthanvnm-l0cyMroinI0@public.gmane.org>
2016-09-21 17:44 ` Peter Meerwald-Stadler
2016-09-21 17:44 ` Peter Meerwald-Stadler
[not found] ` <alpine.DEB.2.02.1609211936540.12662-jW+XmwGofnusTnJN9+BGXg@public.gmane.org>
2016-09-22 10:37 ` Mugunthan V N
2016-09-22 10:37 ` Mugunthan V N
2016-09-22 6:18 ` Vignesh R
2016-09-22 6:18 ` Vignesh R
2016-09-22 6:18 ` Vignesh R
2016-09-22 10:45 ` Mugunthan V N
2016-09-22 10:45 ` Mugunthan V N
2016-09-22 10:45 ` Mugunthan V N
2016-09-22 11:16 ` Peter Ujfalusi
2016-09-22 11:16 ` Peter Ujfalusi
2016-09-22 11:16 ` Peter Ujfalusi
2016-09-22 7:20 ` Peter Ujfalusi [this message]
2016-09-22 7:20 ` Peter Ujfalusi
2016-09-22 7:20 ` Peter Ujfalusi
2016-09-22 10:56 ` Mugunthan V N
2016-09-22 10:56 ` Mugunthan V N
2016-09-22 10:56 ` Mugunthan V N
2016-09-21 16:11 ` [PATCH 3/4] ARM: dts: am33xx: add DMA properties for tscadc Mugunthan V N
2016-09-21 16:11 ` Mugunthan V N
2016-09-21 16:11 ` Mugunthan V N
2016-09-21 16:11 ` [PATCH 4/4] ARM: dts: am4372: " Mugunthan V N
2016-09-21 16:11 ` Mugunthan V N
2016-09-21 16:11 ` Mugunthan V N
2016-09-25 9:41 ` [PATCH 0/4] Add DMA support for ti_am335x_adc driver Jonathan Cameron
2016-09-25 9:41 ` Jonathan Cameron
2016-09-25 9:41 ` Jonathan Cameron
2016-09-29 13:01 ` Mugunthan V N
2016-09-29 13:01 ` Mugunthan V N
2016-09-29 13:01 ` Mugunthan V N
2016-09-30 3:37 ` John Syne
2016-09-30 3:37 ` John Syne
2016-09-30 3:37 ` John Syne
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=94b46406-577e-9cec-8e79-1134581932c5@ti.com \
--to=peter.ujfalusi@ti.com \
--cc=afd@ti.com \
--cc=devicetree@vger.kernel.org \
--cc=jic23@kernel.org \
--cc=knaack.h@gmx.de \
--cc=lars@metafoo.de \
--cc=lee.jones@linaro.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-iio@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-omap@vger.kernel.org \
--cc=linux@armlinux.org.uk \
--cc=mark.rutland@arm.com \
--cc=mugunthanvnm@ti.com \
--cc=nsekhar@ti.com \
--cc=pmeerw@pmeerw.net \
--cc=robh+dt@kernel.org \
--cc=tony@atomide.com \
--cc=vigneshr@ti.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.