Merge Linus master into drm-next

The merge is clean, but the arm build fails afterwards,
due to API changes in the regulator tree.

I've included the patch into the merge to fix the build.

Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 253 insertions, 138 deletions

diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c
index 419a782ab6d5..f63864a893c5 100644
--- a/drivers/spi/spi-bcm2835.c
+++ b/drivers/spi/spi-bcm2835.c
@@ -3,6 +3,7 @@
  *
  * Copyright (C) 2012 Chris Boot
  * Copyright (C) 2013 Stephen Warren
+ * Copyright (C) 2015 Martin Sperl
  *
  * This driver is inspired by:
  * spi-ath79.c, Copyright (C) 2009-2011 Gabor Juhos <juhosg@openwrt.org>
@@ -29,6 +30,7 @@
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_irq.h>
+#include <linux/of_gpio.h>
 #include <linux/of_device.h>
 #include <linux/spi/spi.h>
 
@@ -66,8 +68,10 @@
 #define BCM2835_SPI_CS_CS_10		0x00000002
 #define BCM2835_SPI_CS_CS_01		0x00000001
 
-#define BCM2835_SPI_TIMEOUT_MS	30000
-#define BCM2835_SPI_MODE_BITS	(SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_NO_CS)
+#define BCM2835_SPI_POLLING_LIMIT_US	30
+#define BCM2835_SPI_TIMEOUT_MS		30000
+#define BCM2835_SPI_MODE_BITS	(SPI_CPOL | SPI_CPHA | SPI_CS_HIGH \
+				| SPI_NO_CS | SPI_3WIRE)
 
 #define DRV_NAME	"spi-bcm2835"
 
@@ -75,10 +79,10 @@ struct bcm2835_spi {
 	void __iomem *regs;
 	struct clk *clk;
 	int irq;
-	struct completion done;
 	const u8 *tx_buf;
 	u8 *rx_buf;
-	int len;
+	int tx_len;
+	int rx_len;
 };
 
 static inline u32 bcm2835_rd(struct bcm2835_spi *bs, unsigned reg)
@@ -91,205 +95,315 @@ static inline void bcm2835_wr(struct bcm2835_spi *bs, unsigned reg, u32 val)
 	writel(val, bs->regs + reg);
 }
 
-static inline void bcm2835_rd_fifo(struct bcm2835_spi *bs, int len)
+static inline void bcm2835_rd_fifo(struct bcm2835_spi *bs)
 {
 	u8 byte;
 
-	while (len--) {
+	while ((bs->rx_len) &&
+	       (bcm2835_rd(bs, BCM2835_SPI_CS) & BCM2835_SPI_CS_RXD)) {
 		byte = bcm2835_rd(bs, BCM2835_SPI_FIFO);
 		if (bs->rx_buf)
 			*bs->rx_buf++ = byte;
+		bs->rx_len--;
 	}
 }
 
-static inline void bcm2835_wr_fifo(struct bcm2835_spi *bs, int len)
+static inline void bcm2835_wr_fifo(struct bcm2835_spi *bs)
 {
 	u8 byte;
 
-	if (len > bs->len)
-		len = bs->len;
-
-	while (len--) {
+	while ((bs->tx_len) &&
+	       (bcm2835_rd(bs, BCM2835_SPI_CS) & BCM2835_SPI_CS_TXD)) {
 		byte = bs->tx_buf ? *bs->tx_buf++ : 0;
 		bcm2835_wr(bs, BCM2835_SPI_FIFO, byte);
-		bs->len--;
+		bs->tx_len--;
 	}
 }
 
+static void bcm2835_spi_reset_hw(struct spi_master *master)
+{
+	struct bcm2835_spi *bs = spi_master_get_devdata(master);
+	u32 cs = bcm2835_rd(bs, BCM2835_SPI_CS);
+
+	/* Disable SPI interrupts and transfer */
+	cs &= ~(BCM2835_SPI_CS_INTR |
+		BCM2835_SPI_CS_INTD |
+		BCM2835_SPI_CS_TA);
+	/* and reset RX/TX FIFOS */
+	cs |= BCM2835_SPI_CS_CLEAR_RX | BCM2835_SPI_CS_CLEAR_TX;
+
+	/* and reset the SPI_HW */
+	bcm2835_wr(bs, BCM2835_SPI_CS, cs);
+}
+
 static irqreturn_t bcm2835_spi_interrupt(int irq, void *dev_id)
 {
 	struct spi_master *master = dev_id;
 	struct bcm2835_spi *bs = spi_master_get_devdata(master);
-	u32 cs = bcm2835_rd(bs, BCM2835_SPI_CS);
 
-	/*
-	 * RXR - RX needs Reading. This means 12 (or more) bytes have been
-	 * transmitted and hence 12 (or more) bytes have been received.
-	 *
-	 * The FIFO is 16-bytes deep. We check for this interrupt to keep the
-	 * FIFO full; we have a 4-byte-time buffer for IRQ latency. We check
-	 * this before DONE (TX empty) just in case we delayed processing this
-	 * interrupt for some reason.
-	 *
-	 * We only check for this case if we have more bytes to TX; at the end
-	 * of the transfer, we ignore this pipelining optimization, and let
-	 * bcm2835_spi_finish_transfer() drain the RX FIFO.
+	/* Read as many bytes as possible from FIFO */
+	bcm2835_rd_fifo(bs);
+	/* Write as many bytes as possible to FIFO */
+	bcm2835_wr_fifo(bs);
+
+	/* based on flags decide if we can finish the transfer */
+	if (bcm2835_rd(bs, BCM2835_SPI_CS) & BCM2835_SPI_CS_DONE) {
+		/* Transfer complete - reset SPI HW */
+		bcm2835_spi_reset_hw(master);
+		/* wake up the framework */
+		complete(&master->xfer_completion);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int bcm2835_spi_transfer_one_poll(struct spi_master *master,
+					 struct spi_device *spi,
+					 struct spi_transfer *tfr,
+					 u32 cs,
+					 unsigned long xfer_time_us)
+{
+	struct bcm2835_spi *bs = spi_master_get_devdata(master);
+	unsigned long timeout = jiffies +
+		max(4 * xfer_time_us * HZ / 1000000, 2uL);
+
+	/* enable HW block without interrupts */
+	bcm2835_wr(bs, BCM2835_SPI_CS, cs | BCM2835_SPI_CS_TA);
+
+	/* set timeout to 4x the expected time, or 2 jiffies */
+	/* loop until finished the transfer */
+	while (bs->rx_len) {
+		/* read from fifo as much as possible */
+		bcm2835_rd_fifo(bs);
+		/* fill in tx fifo as much as possible */
+		bcm2835_wr_fifo(bs);
+		/* if we still expect some data after the read,
+		 * check for a possible timeout
+		 */
+		if (bs->rx_len && time_after(jiffies, timeout)) {
+			/* Transfer complete - reset SPI HW */
+			bcm2835_spi_reset_hw(master);
+			/* and return timeout */
+			return -ETIMEDOUT;
+		}
+	}
+
+	/* Transfer complete - reset SPI HW */
+	bcm2835_spi_reset_hw(master);
+	/* and return without waiting for completion */
+	return 0;
+}
+
+static int bcm2835_spi_transfer_one_irq(struct spi_master *master,
+					struct spi_device *spi,
+					struct spi_transfer *tfr,
+					u32 cs)
+{
+	struct bcm2835_spi *bs = spi_master_get_devdata(master);
+
+	/* fill in fifo if we have gpio-cs
+	 * note that there have been rare events where the native-CS
+	 * flapped for <1us which may change the behaviour
+	 * with gpio-cs this does not happen, so it is implemented
+	 * only for this case
 	 */
-	if (bs->len && (cs & BCM2835_SPI_CS_RXR)) {
-		/* Read 12 bytes of data */
-		bcm2835_rd_fifo(bs, 12);
-
-		/* Write up to 12 bytes */
-		bcm2835_wr_fifo(bs, 12);
-
-		/*
-		 * We must have written something to the TX FIFO due to the
-		 * bs->len check above, so cannot be DONE. Hence, return
-		 * early. Note that DONE could also be set if we serviced an
-		 * RXR interrupt really late.
+	if (gpio_is_valid(spi->cs_gpio)) {
+		/* enable HW block, but without interrupts enabled
+		 * this would triggern an immediate interrupt
 		 */
-		return IRQ_HANDLED;
+		bcm2835_wr(bs, BCM2835_SPI_CS,
+			   cs | BCM2835_SPI_CS_TA);
+		/* fill in tx fifo as much as possible */
+		bcm2835_wr_fifo(bs);
 	}
 
 	/*
-	 * DONE - TX empty. This occurs when we first enable the transfer
-	 * since we do not pre-fill the TX FIFO. At any other time, given that
-	 * we refill the TX FIFO above based on RXR, and hence ignore DONE if
-	 * RXR is set, DONE really does mean end-of-transfer.
+	 * Enable the HW block. This will immediately trigger a DONE (TX
+	 * empty) interrupt, upon which we will fill the TX FIFO with the
+	 * first TX bytes. Pre-filling the TX FIFO here to avoid the
+	 * interrupt doesn't work:-(
 	 */
-	if (cs & BCM2835_SPI_CS_DONE) {
-		if (bs->len) { /* First interrupt in a transfer */
-			bcm2835_wr_fifo(bs, 16);
-		} else { /* Transfer complete */
-			/* Disable SPI interrupts */
-			cs &= ~(BCM2835_SPI_CS_INTR | BCM2835_SPI_CS_INTD);
-			bcm2835_wr(bs, BCM2835_SPI_CS, cs);
-
-			/*
-			 * Wake up bcm2835_spi_transfer_one(), which will call
-			 * bcm2835_spi_finish_transfer(), to drain the RX FIFO.
-			 */
-			complete(&bs->done);
-		}
-
-		return IRQ_HANDLED;
-	}
+	cs |= BCM2835_SPI_CS_INTR | BCM2835_SPI_CS_INTD | BCM2835_SPI_CS_TA;
+	bcm2835_wr(bs, BCM2835_SPI_CS, cs);
 
-	return IRQ_NONE;
+	/* signal that we need to wait for completion */
+	return 1;
 }
 
-static int bcm2835_spi_start_transfer(struct spi_device *spi,
-		struct spi_transfer *tfr)
+static int bcm2835_spi_transfer_one(struct spi_master *master,
+				    struct spi_device *spi,
+				    struct spi_transfer *tfr)
 {
-	struct bcm2835_spi *bs = spi_master_get_devdata(spi->master);
+	struct bcm2835_spi *bs = spi_master_get_devdata(master);
 	unsigned long spi_hz, clk_hz, cdiv;
-	u32 cs = BCM2835_SPI_CS_INTR | BCM2835_SPI_CS_INTD | BCM2835_SPI_CS_TA;
+	unsigned long spi_used_hz, xfer_time_us;
+	u32 cs = bcm2835_rd(bs, BCM2835_SPI_CS);
 
+	/* set clock */
 	spi_hz = tfr->speed_hz;
 	clk_hz = clk_get_rate(bs->clk);
 
 	if (spi_hz >= clk_hz / 2) {
 		cdiv = 2; /* clk_hz/2 is the fastest we can go */
 	} else if (spi_hz) {
-		/* CDIV must be a power of two */
-		cdiv = roundup_pow_of_two(DIV_ROUND_UP(clk_hz, spi_hz));
+		/* CDIV must be a multiple of two */
+		cdiv = DIV_ROUND_UP(clk_hz, spi_hz);
+		cdiv += (cdiv % 2);
 
 		if (cdiv >= 65536)
 			cdiv = 0; /* 0 is the slowest we can go */
-	} else
+	} else {
 		cdiv = 0; /* 0 is the slowest we can go */
+	}
+	spi_used_hz = cdiv ? (clk_hz / cdiv) : (clk_hz / 65536);
+	bcm2835_wr(bs, BCM2835_SPI_CLK, cdiv);
 
+	/* handle all the modes */
+	if ((spi->mode & SPI_3WIRE) && (tfr->rx_buf))
+		cs |= BCM2835_SPI_CS_REN;
 	if (spi->mode & SPI_CPOL)
 		cs |= BCM2835_SPI_CS_CPOL;
 	if (spi->mode & SPI_CPHA)
 		cs |= BCM2835_SPI_CS_CPHA;
 
-	if (!(spi->mode & SPI_NO_CS)) {
-		if (spi->mode & SPI_CS_HIGH) {
-			cs |= BCM2835_SPI_CS_CSPOL;
-			cs |= BCM2835_SPI_CS_CSPOL0 << spi->chip_select;
-		}
-
-		cs |= spi->chip_select;
-	}
+	/* for gpio_cs set dummy CS so that no HW-CS get changed
+	 * we can not run this in bcm2835_spi_set_cs, as it does
+	 * not get called for cs_gpio cases, so we need to do it here
+	 */
+	if (gpio_is_valid(spi->cs_gpio) || (spi->mode & SPI_NO_CS))
+		cs |= BCM2835_SPI_CS_CS_10 | BCM2835_SPI_CS_CS_01;
 
-	reinit_completion(&bs->done);
+	/* set transmit buffers and length */
 	bs->tx_buf = tfr->tx_buf;
 	bs->rx_buf = tfr->rx_buf;
-	bs->len = tfr->len;
+	bs->tx_len = tfr->len;
+	bs->rx_len = tfr->len;
 
-	bcm2835_wr(bs, BCM2835_SPI_CLK, cdiv);
-	/*
-	 * Enable the HW block. This will immediately trigger a DONE (TX
-	 * empty) interrupt, upon which we will fill the TX FIFO with the
-	 * first TX bytes. Pre-filling the TX FIFO here to avoid the
-	 * interrupt doesn't work:-(
-	 */
-	bcm2835_wr(bs, BCM2835_SPI_CS, cs);
+	/* calculate the estimated time in us the transfer runs */
+	xfer_time_us = tfr->len
+		* 9 /* clocks/byte - SPI-HW waits 1 clock after each byte */
+		* 1000000 / spi_used_hz;
 
-	return 0;
+	/* for short requests run polling*/
+	if (xfer_time_us <= BCM2835_SPI_POLLING_LIMIT_US)
+		return bcm2835_spi_transfer_one_poll(master, spi, tfr,
+						     cs, xfer_time_us);
+
+	return bcm2835_spi_transfer_one_irq(master, spi, tfr, cs);
 }
 
-static int bcm2835_spi_finish_transfer(struct spi_device *spi,
-		struct spi_transfer *tfr, bool cs_change)
+static void bcm2835_spi_handle_err(struct spi_master *master,
+				   struct spi_message *msg)
 {
-	struct bcm2835_spi *bs = spi_master_get_devdata(spi->master);
-	u32 cs = bcm2835_rd(bs, BCM2835_SPI_CS);
+	bcm2835_spi_reset_hw(master);
+}
+
+static void bcm2835_spi_set_cs(struct spi_device *spi, bool gpio_level)
+{
+	/*
+	 * we can assume that we are "native" as per spi_set_cs
+	 *   calling us ONLY when cs_gpio is not set
+	 * we can also assume that we are CS < 3 as per bcm2835_spi_setup
+	 *   we would not get called because of error handling there.
+	 * the level passed is the electrical level not enabled/disabled
+	 *   so it has to get translated back to enable/disable
+	 *   see spi_set_cs in spi.c for the implementation
+	 */
 
-	/* Drain RX FIFO */
-	while (cs & BCM2835_SPI_CS_RXD) {
-		bcm2835_rd_fifo(bs, 1);
-		cs = bcm2835_rd(bs, BCM2835_SPI_CS);
+	struct spi_master *master = spi->master;
+	struct bcm2835_spi *bs = spi_master_get_devdata(master);
+	u32 cs = bcm2835_rd(bs, BCM2835_SPI_CS);
+	bool enable;
+
+	/* calculate the enable flag from the passed gpio_level */
+	enable = (spi->mode & SPI_CS_HIGH) ? gpio_level : !gpio_level;
+
+	/* set flags for "reverse" polarity in the registers */
+	if (spi->mode & SPI_CS_HIGH) {
+		/* set the correct CS-bits */
+		cs |= BCM2835_SPI_CS_CSPOL;
+		cs |= BCM2835_SPI_CS_CSPOL0 << spi->chip_select;
+	} else {
+		/* clean the CS-bits */
+		cs &= ~BCM2835_SPI_CS_CSPOL;
+		cs &= ~(BCM2835_SPI_CS_CSPOL0 << spi->chip_select);
 	}
 
-	if (tfr->delay_usecs)
-		udelay(tfr->delay_usecs);
+	/* select the correct chip_select depending on disabled/enabled */
+	if (enable) {
+		/* set cs correctly */
+		if (spi->mode & SPI_NO_CS) {
+			/* use the "undefined" chip-select */
+			cs |= BCM2835_SPI_CS_CS_10 | BCM2835_SPI_CS_CS_01;
+		} else {
+			/* set the chip select */
+			cs &= ~(BCM2835_SPI_CS_CS_10 | BCM2835_SPI_CS_CS_01);
+			cs |= spi->chip_select;
+		}
+	} else {
+		/* disable CSPOL which puts HW-CS into deselected state */
+		cs &= ~BCM2835_SPI_CS_CSPOL;
+		/* use the "undefined" chip-select as precaution */
+		cs |= BCM2835_SPI_CS_CS_10 | BCM2835_SPI_CS_CS_01;
+	}
 
-	if (cs_change)
-		/* Clear TA flag */
-		bcm2835_wr(bs, BCM2835_SPI_CS, cs & ~BCM2835_SPI_CS_TA);
+	/* finally set the calculated flags in SPI_CS */
+	bcm2835_wr(bs, BCM2835_SPI_CS, cs);
+}
 
-	return 0;
+static int chip_match_name(struct gpio_chip *chip, void *data)
+{
+	return !strcmp(chip->label, data);
 }
 
-static int bcm2835_spi_transfer_one(struct spi_master *master,
-		struct spi_message *mesg)
+static int bcm2835_spi_setup(struct spi_device *spi)
 {
-	struct bcm2835_spi *bs = spi_master_get_devdata(master);
-	struct spi_transfer *tfr;
-	struct spi_device *spi = mesg->spi;
-	int err = 0;
-	unsigned int timeout;
-	bool cs_change;
-
-	list_for_each_entry(tfr, &mesg->transfers, transfer_list) {
-		err = bcm2835_spi_start_transfer(spi, tfr);
-		if (err)
-			goto out;
-
-		timeout = wait_for_completion_timeout(&bs->done,
-				msecs_to_jiffies(BCM2835_SPI_TIMEOUT_MS));
-		if (!timeout) {
-			err = -ETIMEDOUT;
-			goto out;
-		}
+	int err;
+	struct gpio_chip *chip;
+	/*
+	 * sanity checking the native-chipselects
+	 */
+	if (spi->mode & SPI_NO_CS)
+		return 0;
+	if (gpio_is_valid(spi->cs_gpio))
+		return 0;
+	if (spi->chip_select > 1) {
+		/* error in the case of native CS requested with CS > 1
+		 * officially there is a CS2, but it is not documented
+		 * which GPIO is connected with that...
+		 */
+		dev_err(&spi->dev,
+			"setup: only two native chip-selects are supported\n");
+		return -EINVAL;
+	}
+	/* now translate native cs to GPIO */
 
-		cs_change = tfr->cs_change ||
-			list_is_last(&tfr->transfer_list, &mesg->transfers);
+	/* get the gpio chip for the base */
+	chip = gpiochip_find("pinctrl-bcm2835", chip_match_name);
+	if (!chip)
+		return 0;
 
-		err = bcm2835_spi_finish_transfer(spi, tfr, cs_change);
-		if (err)
-			goto out;
+	/* and calculate the real CS */
+	spi->cs_gpio = chip->base + 8 - spi->chip_select;
 
-		mesg->actual_length += (tfr->len - bs->len);
-	}
+	/* and set up the "mode" and level */
+	dev_info(&spi->dev, "setting up native-CS%i as GPIO %i\n",
+		 spi->chip_select, spi->cs_gpio);
 
-out:
-	/* Clear FIFOs, and disable the HW block */
-	bcm2835_wr(bs, BCM2835_SPI_CS,
-		   BCM2835_SPI_CS_CLEAR_RX | BCM2835_SPI_CS_CLEAR_TX);
-	mesg->status = err;
-	spi_finalize_current_message(master);
+	/* set up GPIO as output and pull to the correct level */
+	err = gpio_direction_output(spi->cs_gpio,
+				    (spi->mode & SPI_CS_HIGH) ? 0 : 1);
+	if (err) {
+		dev_err(&spi->dev,
+			"could not set CS%i gpio %i as output: %i",
+			spi->chip_select, spi->cs_gpio, err);
+		return err;
+	}
+	/* the implementation of pinctrl-bcm2835 currently does not
+	 * set the GPIO value when using gpio_direction_output
+	 * so we are setting it here explicitly
+	 */
+	gpio_set_value(spi->cs_gpio, (spi->mode & SPI_CS_HIGH) ? 0 : 1);
 
 	return 0;
 }
@@ -312,13 +426,14 @@ static int bcm2835_spi_probe(struct platform_device *pdev)
 	master->mode_bits = BCM2835_SPI_MODE_BITS;
 	master->bits_per_word_mask = SPI_BPW_MASK(8);
 	master->num_chipselect = 3;
-	master->transfer_one_message = bcm2835_spi_transfer_one;
+	master->setup = bcm2835_spi_setup;
+	master->set_cs = bcm2835_spi_set_cs;
+	master->transfer_one = bcm2835_spi_transfer_one;
+	master->handle_err = bcm2835_spi_handle_err;
 	master->dev.of_node = pdev->dev.of_node;
 
 	bs = spi_master_get_devdata(master);
 
-	init_completion(&bs->done);
-
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	bs->regs = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(bs->regs)) {
@@ -343,13 +458,13 @@ static int bcm2835_spi_probe(struct platform_device *pdev)
 	clk_prepare_enable(bs->clk);
 
 	err = devm_request_irq(&pdev->dev, bs->irq, bcm2835_spi_interrupt, 0,
-				dev_name(&pdev->dev), master);
+			       dev_name(&pdev->dev), master);
 	if (err) {
 		dev_err(&pdev->dev, "could not request IRQ: %d\n", err);
 		goto out_clk_disable;
 	}
 
-	/* initialise the hardware */
+	/* initialise the hardware with the default polarities */
 	bcm2835_wr(bs, BCM2835_SPI_CS,
 		   BCM2835_SPI_CS_CLEAR_RX | BCM2835_SPI_CS_CLEAR_TX);