[PATCH v1 0/3] Polling support for s3c64xx spi controller

[PATCH v1 0/3] Polling support for s3c64xx spi controller

[Girish K S]

This patch series adds support for the polling mode only. Also 2nd patch
in the series adds support for dedicated cs pin. After Thomas's patch for
using default gpio is merged(commit id: 00ab539), one of the patch in this
series is dropped and new series is generated.

Girish K S (3):
  spi: s3c64xx: added support for polling mode
  spi: s3c64xx: Added provision for dedicated cs pin
  spi: s3c64xx: Added support for exynos5440 spi

 drivers/spi/spi-s3c64xx.c |  197 ++++++++++++++++++++++++++++++++-------------
 1 files changed, 140 insertions(+), 57 deletions(-)

-- 
1.7.5.4

[PATCH v1 1/3] spi: s3c64xx: added support for polling mode

[Girish K S]

From: Girish K S <girishks2000@gmail.com>

The 64xx spi driver supports partial polling mode.
Only the last chunk of the transfer length is transferred
or recieved in polling mode.

Some SoC's that adopt this controller might not have have dma
interface. This patch adds support for complete polling mode
and gives flexibity for the user to select poll/dma mode.

Signed-off-by: Girish K S <ks.giri@samsung.com>
---
changes in v1:
		Addressed the performance issue reported by Mark Brown
caused due to this patch. The wait_for_timeout function is modified to
address this issue in dma mode.

 drivers/spi/spi-s3c64xx.c |  153 ++++++++++++++++++++++++++++++--------------
 1 files changed, 104 insertions(+), 49 deletions(-)

diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
index 5000586..0a80692 100644
--- a/drivers/spi/spi-s3c64xx.c
+++ b/drivers/spi/spi-s3c64xx.c
@@ -39,6 +39,7 @@
 #endif
 
 #define MAX_SPI_PORTS		3
+#define S3C64XX_SPI_QUIRK_POLL		(1 << 0)
 
 /* Registers and bit-fields */
 
@@ -130,6 +131,7 @@
 #define S3C64XX_SPI_TRAILCNT		S3C64XX_SPI_MAX_TRAILCNT
 
 #define msecs_to_loops(t) (loops_per_jiffy / 1000 * HZ * t)
+#define is_polling(x)	(x->port_conf->quirks & S3C64XX_SPI_QUIRK_POLL)
 
 #define RXBUSY    (1<<2)
 #define TXBUSY    (1<<3)
@@ -158,6 +160,7 @@ struct s3c64xx_spi_port_config {
 	int	fifo_lvl_mask[MAX_SPI_PORTS];
 	int	rx_lvl_offset;
 	int	tx_st_done;
+	int	quirks;
 	bool	high_speed;
 	bool	clk_from_cmu;
 };
@@ -344,8 +347,12 @@ static int s3c64xx_spi_prepare_transfer(struct spi_master *spi)
 {
 	struct s3c64xx_spi_driver_data *sdd = spi_master_get_devdata(spi);
 
-	/* Acquire DMA channels */
-	while (!acquire_dma(sdd))
+	/*
+	 * If DMA resource was not available during
+	 * probe, no need to continue with dma requests
+	 * else Acquire DMA channels
+	 */
+	while (!is_polling(sdd) && !acquire_dma(sdd))
 		usleep_range(10000, 11000);
 
 	pm_runtime_get_sync(&sdd->pdev->dev);
@@ -358,9 +365,12 @@ static int s3c64xx_spi_unprepare_transfer(struct spi_master *spi)
 	struct s3c64xx_spi_driver_data *sdd = spi_master_get_devdata(spi);
 
 	/* Free DMA channels */
-	sdd->ops->release((enum dma_ch)sdd->rx_dma.ch, &s3c64xx_spi_dma_client);
-	sdd->ops->release((enum dma_ch)sdd->tx_dma.ch, &s3c64xx_spi_dma_client);
-
+	if (!is_polling(sdd)) {
+		sdd->ops->release((enum dma_ch)sdd->rx_dma.ch,
+					&s3c64xx_spi_dma_client);
+		sdd->ops->release((enum dma_ch)sdd->tx_dma.ch,
+					&s3c64xx_spi_dma_client);
+	}
 	pm_runtime_put(&sdd->pdev->dev);
 
 	return 0;
@@ -464,8 +474,10 @@ static int s3c64xx_spi_unprepare_transfer(struct spi_master *spi)
 	struct s3c64xx_spi_driver_data *sdd = spi_master_get_devdata(spi);
 
 	/* Free DMA channels */
-	dma_release_channel(sdd->rx_dma.ch);
-	dma_release_channel(sdd->tx_dma.ch);
+	if (!is_polling(sdd)) {
+		dma_release_channel(sdd->rx_dma.ch);
+		dma_release_channel(sdd->tx_dma.ch);
+	}
 
 	pm_runtime_put(&sdd->pdev->dev);
 	return 0;
@@ -566,6 +578,30 @@ static inline void enable_cs(struct s3c64xx_spi_driver_data *sdd,
 
 	cs = spi->controller_data;
 	gpio_set_value(cs->line, spi->mode & SPI_CS_HIGH ? 1 : 0);
+
+	/* Start the signals */
+	writel(0, sdd->regs + S3C64XX_SPI_SLAVE_SEL);
+}
+
+static u32 wait_for_timeout(struct s3c64xx_spi_driver_data *sdd,
+					int timeout_ms)
+{
+	void __iomem *regs = sdd->regs;
+	unsigned long val = 1;
+	u32 status;
+
+	/* max fifo depth available */
+	u32 max_fifo = (FIFO_LVL_MASK(sdd) >> 1) + 1;
+
+	if (timeout_ms)
+		val = msecs_to_loops(timeout_ms);
+
+	do {
+		status = readl(regs + S3C64XX_SPI_STATUS);
+	} while (RX_FIFO_LVL(status, sdd) < max_fifo && --val);
+
+	/* return the actual received data length */
+	return RX_FIFO_LVL(status, sdd);
 }
 
 static int wait_for_xfer(struct s3c64xx_spi_driver_data *sdd,
@@ -590,20 +626,19 @@ static int wait_for_xfer(struct s3c64xx_spi_driver_data *sdd,
 		} while (RX_FIFO_LVL(status, sdd) < xfer->len && --val);
 	}
 
-	if (!val)
-		return -EIO;
-
 	if (dma_mode) {
 		u32 status;
 
 		/*
+		 * If the previous xfer was completed within timeout, then
+		 * proceed further else return -EIO.
 		 * DmaTx returns after simply writing data in the FIFO,
 		 * w/o waiting for real transmission on the bus to finish.
 		 * DmaRx returns only after Dma read data from FIFO which
 		 * needs bus transmission to finish, so we don't worry if
 		 * Xfer involved Rx(with or without Tx).
 		 */
-		if (xfer->rx_buf == NULL) {
+		if (val && !xfer->rx_buf) {
 			val = msecs_to_loops(10);
 			status = readl(regs + S3C64XX_SPI_STATUS);
 			while ((TX_FIFO_LVL(status, sdd)
@@ -613,30 +648,53 @@ static int wait_for_xfer(struct s3c64xx_spi_driver_data *sdd,
 				status = readl(regs + S3C64XX_SPI_STATUS);
 			}
 
-			if (!val)
-				return -EIO;
 		}
+
+		/* If timed out while checking rx/tx status return error */
+		if (!val)
+			return -EIO;
 	} else {
+		int loops;
+		u32 cpy_len;
+		u8 *buf;
+
 		/* If it was only Tx */
-		if (xfer->rx_buf == NULL) {
+		if (!xfer->rx_buf) {
 			sdd->state &= ~TXBUSY;
 			return 0;
 		}
 
-		switch (sdd->cur_bpw) {
-		case 32:
-			ioread32_rep(regs + S3C64XX_SPI_RX_DATA,
-				xfer->rx_buf, xfer->len / 4);
-			break;
-		case 16:
-			ioread16_rep(regs + S3C64XX_SPI_RX_DATA,
-				xfer->rx_buf, xfer->len / 2);
-			break;
-		default:
-			ioread8_rep(regs + S3C64XX_SPI_RX_DATA,
-				xfer->rx_buf, xfer->len);
-			break;
-		}
+		/*
+		 * If the receive length is bigger than the controller fifo
+		 * size, calculate the loops and read the fifo as many times.
+		 * loops = length / max fifo size (calculated by using the
+		 * fifo mask).
+		 * For any size less than the fifo size the below code is
+		 * executed atleast once.
+		 */
+		loops = xfer->len / ((FIFO_LVL_MASK(sdd) >> 1) + 1);
+		buf = xfer->rx_buf;
+		do {
+			/* wait for data to be received in the fifo */
+			cpy_len = wait_for_timeout(sdd, (loops ? ms : 0));
+
+			switch (sdd->cur_bpw) {
+			case 32:
+				ioread32_rep(regs + S3C64XX_SPI_RX_DATA,
+					buf, cpy_len / 4);
+				break;
+			case 16:
+				ioread16_rep(regs + S3C64XX_SPI_RX_DATA,
+					buf, cpy_len / 2);
+				break;
+			default:
+				ioread8_rep(regs + S3C64XX_SPI_RX_DATA,
+					buf, cpy_len);
+				break;
+			}
+
+			buf = buf + cpy_len;
+		} while (loops--);
 		sdd->state &= ~RXBUSY;
 	}
 
@@ -652,6 +710,9 @@ static inline void disable_cs(struct s3c64xx_spi_driver_data *sdd,
 		sdd->tgl_spi = NULL;
 
 	gpio_set_value(cs->line, spi->mode & SPI_CS_HIGH ? 0 : 1);
+
+	/* Quiese the signals */
+	writel(S3C64XX_SPI_SLAVE_SIG_INACT, sdd->regs + S3C64XX_SPI_SLAVE_SEL);
 }
 
 static void s3c64xx_spi_config(struct s3c64xx_spi_driver_data *sdd)
@@ -733,7 +794,7 @@ static int s3c64xx_spi_map_mssg(struct s3c64xx_spi_driver_data *sdd,
 	struct device *dev = &sdd->pdev->dev;
 	struct spi_transfer *xfer;
 
-	if (msg->is_dma_mapped)
+	if (is_polling(sdd) || msg->is_dma_mapped)
 		return 0;
 
 	/* First mark all xfer unmapped */
@@ -782,7 +843,7 @@ static void s3c64xx_spi_unmap_mssg(struct s3c64xx_spi_driver_data *sdd,
 	struct device *dev = &sdd->pdev->dev;
 	struct spi_transfer *xfer;
 
-	if (msg->is_dma_mapped)
+	if (is_polling(sdd) || msg->is_dma_mapped)
 		return;
 
 	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
@@ -861,8 +922,9 @@ static int s3c64xx_spi_transfer_one_message(struct spi_master *master,
 
 		/* Polling method for xfers not bigger than FIFO capacity */
 		use_dma = 0;
-		if (sdd->rx_dma.ch && sdd->tx_dma.ch &&
-		    (xfer->len > ((FIFO_LVL_MASK(sdd) >> 1) + 1)))
+		if (!is_polling(sdd) &&
+			(sdd->rx_dma.ch && sdd->tx_dma.ch &&
+			(xfer->len > ((FIFO_LVL_MASK(sdd) >> 1) + 1))))
 			use_dma = 1;
 
 		spin_lock_irqsave(&sdd->lock, flags);
@@ -876,17 +938,10 @@ static int s3c64xx_spi_transfer_one_message(struct spi_master *master,
 		/* Slave Select */
 		enable_cs(sdd, spi);
 
-		/* Start the signals */
-		writel(0, sdd->regs + S3C64XX_SPI_SLAVE_SEL);
-
 		spin_unlock_irqrestore(&sdd->lock, flags);
 
 		status = wait_for_xfer(sdd, xfer, use_dma);
 
-		/* Quiese the signals */
-		writel(S3C64XX_SPI_SLAVE_SIG_INACT,
-		       sdd->regs + S3C64XX_SPI_SLAVE_SEL);
-
 		if (status) {
 			dev_err(&spi->dev, "I/O Error: rx-%d tx-%d res:rx-%c tx-%c len-%d\n",
 				xfer->rx_buf ? 1 : 0, xfer->tx_buf ? 1 : 0,
@@ -1287,19 +1342,19 @@ static int s3c64xx_spi_probe(struct platform_device *pdev)
 	if (!sdd->pdev->dev.of_node) {
 		res = platform_get_resource(pdev, IORESOURCE_DMA,  0);
 		if (!res) {
-			dev_err(&pdev->dev, "Unable to get SPI tx dma "
-					"resource\n");
-			return -ENXIO;
-		}
-		sdd->tx_dma.dmach = res->start;
+			dev_warn(&pdev->dev, "Unable to get SPI tx dma "
+					"resource. Switching to poll mode\n");
+			sdd->port_conf->quirks = S3C64XX_SPI_QUIRK_POLL;
+		} else
+			sdd->tx_dma.dmach = res->start;
 
 		res = platform_get_resource(pdev, IORESOURCE_DMA,  1);
 		if (!res) {
-			dev_err(&pdev->dev, "Unable to get SPI rx dma "
-					"resource\n");
-			return -ENXIO;
-		}
-		sdd->rx_dma.dmach = res->start;
+			dev_warn(&pdev->dev, "Unable to get SPI rx dma "
+					"resource. Switching to poll mode\n");
+			sdd->port_conf->quirks = S3C64XX_SPI_QUIRK_POLL;
+		} else
+			sdd->rx_dma.dmach = res->start;
 	}
 
 	sdd->tx_dma.direction = DMA_MEM_TO_DEV;
-- 
1.7.5.4

[PATCH v1 2/3] spi: s3c64xx: Added provision for dedicated cs pin

[Girish K S]

From: Girish K S <girishks2000@gmail.com>

The existing driver supports gpio based /cs signal.
For controller's that have one device per controller,
the slave device's /cs signal might be internally controlled
by the chip select bit of slave select register. They are not
externally asserted/deasserted using gpio pin.

This patch adds support for controllers with dedicated /cs pin.
if "cs-gpio" property doesnt exist in a spi dts node, the controller
would treat the /cs pin as dedicated.

Signed-off-by: Girish K S <ks.giri@samsung.com>
---
changes in v1:
		Added the missing data structure that caused the
compilation error

 drivers/spi/spi-s3c64xx.c |   34 ++++++++++++++++++++++++++--------
 1 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
index 0a80692..eaf9e1c 100644
--- a/drivers/spi/spi-s3c64xx.c
+++ b/drivers/spi/spi-s3c64xx.c
@@ -208,6 +208,7 @@ struct s3c64xx_spi_driver_data {
 	struct s3c64xx_spi_port_config	*port_conf;
 	unsigned int			port_id;
 	unsigned long			gpios[4];
+	bool				cs_gpio;
 };
 
 static void flush_fifo(struct s3c64xx_spi_driver_data *sdd)
@@ -570,14 +571,16 @@ static inline void enable_cs(struct s3c64xx_spi_driver_data *sdd,
 		if (sdd->tgl_spi != spi) { /* if last mssg on diff device */
 			/* Deselect the last toggled device */
 			cs = sdd->tgl_spi->controller_data;
-			gpio_set_value(cs->line,
-				spi->mode & SPI_CS_HIGH ? 0 : 1);
+			if (sdd->cs_gpio)
+				gpio_set_value(cs->line,
+					spi->mode & SPI_CS_HIGH ? 0 : 1);
 		}
 		sdd->tgl_spi = NULL;
 	}
 
 	cs = spi->controller_data;
-	gpio_set_value(cs->line, spi->mode & SPI_CS_HIGH ? 1 : 0);
+	if (sdd->cs_gpio)
+		gpio_set_value(cs->line, spi->mode & SPI_CS_HIGH ? 1 : 0);
 
 	/* Start the signals */
 	writel(0, sdd->regs + S3C64XX_SPI_SLAVE_SEL);
@@ -709,7 +712,8 @@ static inline void disable_cs(struct s3c64xx_spi_driver_data *sdd,
 	if (sdd->tgl_spi == spi)
 		sdd->tgl_spi = NULL;
 
-	gpio_set_value(cs->line, spi->mode & SPI_CS_HIGH ? 0 : 1);
+	if (sdd->cs_gpio)
+		gpio_set_value(cs->line, spi->mode & SPI_CS_HIGH ? 0 : 1);
 
 	/* Quiese the signals */
 	writel(S3C64XX_SPI_SLAVE_SIG_INACT, sdd->regs + S3C64XX_SPI_SLAVE_SEL);
@@ -997,8 +1001,10 @@ static struct s3c64xx_spi_csinfo *s3c64xx_get_slave_ctrldata(
 {
 	struct s3c64xx_spi_csinfo *cs;
 	struct device_node *slave_np, *data_np = NULL;
+	struct s3c64xx_spi_driver_data *sdd;
 	u32 fb_delay = 0;
 
+	sdd = spi_master_get_devdata(spi->master);
 	slave_np = spi->dev.of_node;
 	if (!slave_np) {
 		dev_err(&spi->dev, "device node not found\n");
@@ -1018,7 +1024,10 @@ static struct s3c64xx_spi_csinfo *s3c64xx_get_slave_ctrldata(
 		return ERR_PTR(-ENOMEM);
 	}
 
-	cs->line = of_get_named_gpio(data_np, "cs-gpio", 0);
+	/* The CS line is asserted/deasserted by the gpio pin */
+	if (sdd->cs_gpio)
+		cs->line = of_get_named_gpio(data_np, "cs-gpio", 0);
+
 	if (!gpio_is_valid(cs->line)) {
 		dev_err(&spi->dev, "chip select gpio is not specified or invalid\n");
 		kfree(cs);
@@ -1058,7 +1067,8 @@ static int s3c64xx_spi_setup(struct spi_device *spi)
 		return -ENODEV;
 	}
 
-	if (!spi_get_ctldata(spi)) {
+	/* Request gpio only if cs line is asserted by gpio pins */
+	if (sdd->cs_gpio) {
 		err = gpio_request_one(cs->line, GPIOF_OUT_INIT_HIGH,
 				       dev_name(&spi->dev));
 		if (err) {
@@ -1067,9 +1077,11 @@ static int s3c64xx_spi_setup(struct spi_device *spi)
 				cs->line, err);
 			goto err_gpio_req;
 		}
-		spi_set_ctldata(spi, cs);
 	}
 
+	if (!spi_get_ctldata(spi))
+		spi_set_ctldata(spi, cs);
+
 	sci = sdd->cntrlr_info;
 
 	spin_lock_irqsave(&sdd->lock, flags);
@@ -1147,8 +1159,10 @@ err_gpio_req:
 static void s3c64xx_spi_cleanup(struct spi_device *spi)
 {
 	struct s3c64xx_spi_csinfo *cs = spi_get_ctldata(spi);
+	struct s3c64xx_spi_driver_data *sdd;
 
-	if (cs) {
+	sdd = spi_master_get_devdata(spi->master);
+	if (cs && sdd->cs_gpio) {
 		gpio_free(cs->line);
 		if (spi->dev.of_node)
 			kfree(cs);
@@ -1325,7 +1339,11 @@ static int s3c64xx_spi_probe(struct platform_device *pdev)
 	sdd->cntrlr_info = sci;
 	sdd->pdev = pdev;
 	sdd->sfr_start = mem_res->start;
+	sdd->cs_gpio = false;
 	if (pdev->dev.of_node) {
+		if (of_find_property(pdev->dev.of_node, "cs-gpio", NULL))
+			sdd->cs_gpio = true;
+
 		ret = of_alias_get_id(pdev->dev.of_node, "spi");
 		if (ret < 0) {
 			dev_err(&pdev->dev, "failed to get alias id, errno %d\n",
-- 
1.7.5.4

[PATCH v1 3/3] spi: s3c64xx: Added support for exynos5440 spi

[Girish K S]

From: Girish K S <girishks2000@gmail.com>

This patch adds support for the exynos5440 spi controller.
The integration of the spi IP in exynos5440 is different from
other SoC's. The I/O pins are no more configured via gpio, they
have dedicated pins.

Signed-off-by: Girish K S <ks.giri@samsung.com>
---
 drivers/spi/spi-s3c64xx.c |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
index eaf9e1c..bd43888 100644
--- a/drivers/spi/spi-s3c64xx.c
+++ b/drivers/spi/spi-s3c64xx.c
@@ -1608,6 +1608,15 @@ static struct s3c64xx_spi_port_config exynos4_spi_port_config = {
 	.clk_from_cmu	= true,
 };
 
+static struct s3c64xx_spi_port_config exynos5440_spi_port_config = {
+	.fifo_lvl_mask	= { 0x1ff },
+	.rx_lvl_offset	= 15,
+	.tx_st_done	= 25,
+	.high_speed	= true,
+	.clk_from_cmu	= true,
+	.quirks		= S3C64XX_SPI_QUIRK_POLL,
+};
+
 static struct platform_device_id s3c64xx_spi_driver_ids[] = {
 	{
 		.name		= "s3c2443-spi",
@@ -1636,6 +1645,9 @@ static const struct of_device_id s3c64xx_spi_dt_match[] = {
 	{ .compatible = "samsung,exynos4210-spi",
 			.data = (void *)&exynos4_spi_port_config,
 	},
+	{ .compatible = "samsung,exynos5440-spi",
+			.data = (void *)&exynos5440_spi_port_config,
+	},
 	{ },
 };
 MODULE_DEVICE_TABLE(of, s3c64xx_spi_dt_match);
-- 
1.7.5.4

Re: [PATCH v1 0/3] Polling support for s3c64xx spi controller

[Girish KS]

Hello Mark,

Can you please check the performance with this patch set

On Mon, May 20, 2013 at 12:21 PM, Girish K S <girishks2000@gmail.com> wrote:
> This patch series adds support for the polling mode only. Also 2nd patch
> in the series adds support for dedicated cs pin. After Thomas's patch for
> using default gpio is merged(commit id: 00ab539), one of the patch in this
> series is dropped and new series is generated.
>
> Girish K S (3):
>   spi: s3c64xx: added support for polling mode
>   spi: s3c64xx: Added provision for dedicated cs pin
>   spi: s3c64xx: Added support for exynos5440 spi
>
>  drivers/spi/spi-s3c64xx.c |  197 ++++++++++++++++++++++++++++++++-------------
>  1 files changed, 140 insertions(+), 57 deletions(-)
>
> --
> 1.7.5.4
>

Re: [PATCH v1 0/3] Polling support for s3c64xx spi controller

[Girish KS]

Hello Mark,

pls let me know if there is any issue with this series



On Mon, May 20, 2013 at 12:21 PM, Girish K S <girishks2000@gmail.com> wrote:
> This patch series adds support for the polling mode only. Also 2nd patch
> in the series adds support for dedicated cs pin. After Thomas's patch for
> using default gpio is merged(commit id: 00ab539), one of the patch in this
> series is dropped and new series is generated.
>
> Girish K S (3):
>   spi: s3c64xx: added support for polling mode
>   spi: s3c64xx: Added provision for dedicated cs pin
>   spi: s3c64xx: Added support for exynos5440 spi
>
>  drivers/spi/spi-s3c64xx.c |  197 ++++++++++++++++++++++++++++++++-------------
>  1 files changed, 140 insertions(+), 57 deletions(-)
>
> --
> 1.7.5.4
>

Re: [PATCH v1 1/3] spi: s3c64xx: added support for polling mode

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 432 bytes --]

On Mon, May 20, 2013 at 12:21:32PM +0530, Girish K S wrote:
> From: Girish K S <girishks2000@gmail.com>

> The 64xx spi driver supports partial polling mode.
> Only the last chunk of the transfer length is transferred
> or recieved in polling mode.

Applied, though I will send a followup since:

> +static u32 wait_for_timeout(struct s3c64xx_spi_driver_data *sdd,
> +					int timeout_ms)

...this function name is way too generic.

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Re: [PATCH v1 2/3] spi: s3c64xx: Added provision for dedicated cs pin

[Mark Brown]

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On Mon, May 20, 2013 at 12:21:33PM +0530, Girish K S wrote:
> From: Girish K S <girishks2000@gmail.com>
> 
> The existing driver supports gpio based /cs signal.
> For controller's that have one device per controller,
> the slave device's /cs signal might be internally controlled
> by the chip select bit of slave select register. They are not
> externally asserted/deasserted using gpio pin.
> 
> This patch adds support for controllers with dedicated /cs pin.
> if "cs-gpio" property doesnt exist in a spi dts node, the controller
> would treat the /cs pin as dedicated.

This breaks SPI operation on my s3c64xx based system since...

>  	if (pdev->dev.of_node) {
> +		if (of_find_property(pdev->dev.of_node, "cs-gpio", NULL))
> +			sdd->cs_gpio = true;
> +
>  		ret = of_alias_get_id(pdev->dev.of_node, "spi");
>  		if (ret < 0) {
>  			dev_err(&pdev->dev, "failed to get alias id, errno %d\n",

sdd->cs_gpio is only set to true by this code so if you're using a board
file then the GPIO will be ignored.

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Re: [PATCH v1 2/3] spi: s3c64xx: Added provision for dedicated cs pin

[Girish KS]

On Wed, Jun 19, 2013 at 11:53 PM, Mark Brown <broonie@kernel.org> wrote:
> On Mon, May 20, 2013 at 12:21:33PM +0530, Girish K S wrote:
>> From: Girish K S <girishks2000@gmail.com>
>>
>> The existing driver supports gpio based /cs signal.
>> For controller's that have one device per controller,
>> the slave device's /cs signal might be internally controlled
>> by the chip select bit of slave select register. They are not
>> externally asserted/deasserted using gpio pin.
>>
>> This patch adds support for controllers with dedicated /cs pin.
>> if "cs-gpio" property doesnt exist in a spi dts node, the controller
>> would treat the /cs pin as dedicated.
>
> This breaks SPI operation on my s3c64xx based system since...
>
>>       if (pdev->dev.of_node) {
>> +             if (of_find_property(pdev->dev.of_node, "cs-gpio", NULL))
>> +                     sdd->cs_gpio = true;
>> +
>>               ret = of_alias_get_id(pdev->dev.of_node, "spi");
>>               if (ret < 0) {
>>                       dev_err(&pdev->dev, "failed to get alias id, errno %d\n",
>
> sdd->cs_gpio is only set to true by this code so if you're using a board
> file then the GPIO will be ignored.

Reversing the default assignment for "sdd->cs_gpio" and the following
"if condition" shall handle both dt and non-dt case. Will do it and
resubmit only this patch in the series.

Re: [PATCH v1 2/3] spi: s3c64xx: Added provision for dedicated cs pin

[Mark Brown]

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On Thu, Jun 20, 2013 at 02:52:07PM +0530, Girish KS wrote:

> Reversing the default assignment for "sdd->cs_gpio" and the following
> "if condition" shall handle both dt and non-dt case. Will do it and
> resubmit only this patch in the series.

You'll need to resend patch 3 as well, I stopped due to this one not
working.

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