Merge branch 'for-next/spi'

3 files changed, 209 insertions, 77 deletions

diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c
index 43aec8e30b..793933eefb 100644
--- a/drivers/spi/atmel_spi.c
+++ b/drivers/spi/atmel_spi.c
@@ -66,6 +66,106 @@ static inline bool atmel_spi_is_v2(void)
 	return !cpu_is_at91rm9200();
 }
 
+/*
+ * Earlier SPI controllers (e.g. on at91rm9200) have a design bug whereby
+ * they assume that spi slave device state will not change on deselect, so
+ * that automagic deselection is OK.  ("NPCSx rises if no data is to be
+ * transmitted")  Not so!  Workaround uses nCSx pins as GPIOs; or newer
+ * controllers have CSAAT and friends.
+ *
+ * Since the CSAAT functionality is a bit weird on newer controllers as
+ * well, we use GPIO to control nCSx pins on all controllers, updating
+ * MR.PCS to avoid confusing the controller.  Using GPIOs also lets us
+ * support active-high chipselects despite the controller's belief that
+ * only active-low devices/systems exists.
+ *
+ * However, at91rm9200 has a second erratum whereby nCS0 doesn't work
+ * right when driven with GPIO.  ("Mode Fault does not allow more than one
+ * Master on Chip Select 0.")  No workaround exists for that ... so for
+ * nCS0 on that chip, we (a) don't use the GPIO, (b) can't support CS_HIGH,
+ * and (c) will trigger that first erratum in some cases.
+ *
+ * TODO: Test if the atmel_spi_is_v2() branch below works on
+ * AT91RM9200 if we use some other register than CSR0. However, don't
+ * do this unconditionally since AP7000 has an errata where the BITS
+ * field in CSR0 overrides all other CSRs.
+ */
+
+static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
+{
+	struct spi_master *master = &as->master;
+	int npcs_pin;
+	unsigned active = spi->mode & SPI_CS_HIGH;
+	u32 mr, csr;
+
+	BUG_ON(spi->chip_select >= master->num_chipselect);
+	npcs_pin = as->cs_pins[spi->chip_select];
+
+	csr = (u32)spi->controller_data;
+
+	if (atmel_spi_is_v2()) {
+		/*
+		 * Always use CSR0. This ensures that the clock
+		 * switches to the correct idle polarity before we
+		 * toggle the CS.
+		 */
+		spi_writel(as, CSR0, csr);
+		spi_writel(as, MR, SPI_BF(PCS, 0x0e) | SPI_BIT(MODFDIS)
+				| SPI_BIT(MSTR));
+		mr = spi_readl(as, MR);
+		gpio_set_value(npcs_pin, active);
+	} else {
+		u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0;
+		int i;
+		u32 csr;
+
+		/* Make sure clock polarity is correct */
+		for (i = 0; i < spi->master->num_chipselect; i++) {
+			csr = spi_readl(as, CSR0 + 4 * i);
+			if ((csr ^ cpol) & SPI_BIT(CPOL))
+				spi_writel(as, CSR0 + 4 * i,
+						csr ^ SPI_BIT(CPOL));
+		}
+
+		mr = spi_readl(as, MR);
+		mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr);
+		if (npcs_pin != AT91_PIN_PA3)
+			gpio_set_value(npcs_pin, active);
+		spi_writel(as, MR, mr);
+	}
+
+	dev_dbg(&spi->dev, "activate %u%s, mr %08x\n",
+			npcs_pin, active ? " (high)" : "",
+			mr);
+}
+
+static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
+{
+	struct spi_master *master = &as->master;
+	int npcs_pin;
+	unsigned active = spi->mode & SPI_CS_HIGH;
+	u32 mr;
+
+	BUG_ON(spi->chip_select >= master->num_chipselect);
+	npcs_pin = as->cs_pins[spi->chip_select];
+
+	/* only deactivate *this* device; sometimes transfers to
+	 * another device may be active when this routine is called.
+	 */
+	mr = spi_readl(as, MR);
+	if (~SPI_BFEXT(PCS, mr) & (1 << spi->chip_select)) {
+		mr = SPI_BFINS(PCS, 0xf, mr);
+		spi_writel(as, MR, mr);
+	}
+
+	dev_dbg(&spi->dev, "DEactivate %u%s, mr %08x\n",
+			npcs_pin, active ? " (low)" : "",
+			mr);
+
+	if (atmel_spi_is_v2() || npcs_pin != AT91_PIN_PA3)
+		gpio_set_value(npcs_pin, !active);
+}
+
 static int atmel_spi_setup(struct spi_device *spi)
 {
 	struct spi_master	*master = spi->master;
@@ -75,10 +175,18 @@ static int atmel_spi_setup(struct spi_device *spi)
 	unsigned int		bits = spi->bits_per_word;
 	unsigned long		bus_hz;
 
-	if (spi->controller_data) {
-		csr = (u32)spi->controller_data;
-		spi_writel(as, CSR0, csr);
-		return 0;
+	if (spi->chip_select > spi->master->num_chipselect) {
+		dev_dbg(&spi->dev,
+				"setup: invalid chipselect %u (%u defined)\n",
+				spi->chip_select, spi->master->num_chipselect);
+		return -EINVAL;
+	}
+
+	if (bits < 8 || bits > 16) {
+		dev_dbg(&spi->dev,
+				"setup: invalid bits_per_word %u (8 to 16)\n",
+				bits);
+		return -EINVAL;
 	}
 
 	dev_dbg(master->dev, "%s mode 0x%08x bits_per_word: %d speed: %d\n",
@@ -131,28 +239,14 @@ static int atmel_spi_setup(struct spi_device *spi)
 		"setup: %lu Hz bpw %u mode 0x%x -> csr%d %08x\n",
 		bus_hz / scbr, bits, spi->mode, spi->chip_select, csr);
 
-	spi_writel(as, CSR0, csr);
-
-	/*
-	 * store the csr-setting when bits are defined. This happens usually
-	 * after the specific spi_device driver has been probed.
-	 */
-	if (bits > 0)
-		spi->controller_data = (void *)csr;
-
-	return 0;
-}
+	spi->controller_data = (void *)csr;
 
-static void atmel_spi_chipselect(struct spi_device *spi, struct atmel_spi *as, int on)
-{
-	struct spi_master *master = &as->master;
-	int cs_pin;
-	int val = ((spi->mode & SPI_CS_HIGH) != 0) == on;
+	cs_deactivate(as, spi);
 
-	BUG_ON(spi->chip_select >= master->num_chipselect);
-	cs_pin = as->cs_pins[spi->chip_select];
+	if (!atmel_spi_is_v2())
+		spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
 
-	gpio_direction_output(cs_pin, val);
+	return 0;
 }
 
 static int atmel_spi_xchg(struct atmel_spi *as, u32 tx_val)
@@ -178,20 +272,57 @@ static int atmel_spi_xchg(struct atmel_spi *as, u32 tx_val)
 	return spi_readl(as, RDR) & 0xffff;
 }
 
+static int atmel_spi_do_xfer(struct spi_device *spi, struct atmel_spi *as,
+			     struct spi_transfer *t)
+{
+	unsigned int bits = spi->bits_per_word;
+	u32 tx_val;
+	int i = 0, rx_val;
+
+	if (bits <= 8) {
+		const u8 *txbuf = t->tx_buf;
+		u8 *rxbuf = t->rx_buf;
+
+		while (i < t->len) {
+			tx_val = txbuf ? txbuf[i] : 0;
+
+			rx_val = atmel_spi_xchg(as, tx_val);
+			if (rx_val < 0)
+				return rx_val;
+
+			if (rxbuf)
+				rxbuf[i] = rx_val;
+			i++;
+		}
+	} else if (bits <= 16) {
+		const u16 *txbuf = t->tx_buf;
+		u16 *rxbuf = t->rx_buf;
+
+		while (i < t->len >> 1) {
+			tx_val = txbuf ? txbuf[i] : 0;
+
+			rx_val = atmel_spi_xchg(as, tx_val);
+			if (rx_val < 0)
+				return rx_val;
+
+			if (rxbuf)
+				rxbuf[i] = rx_val;
+			i++;
+		}
+	}
+
+	return t->len;
+}
+
 static int atmel_spi_transfer(struct spi_device *spi, struct spi_message *mesg)
 {
 	int ret;
 	struct spi_master *master	= spi->master;
 	struct atmel_spi *as		= to_atmel_spi(master);
 	struct spi_transfer *t		= NULL;
-	unsigned int bits		= spi->bits_per_word;
+	unsigned int cs_change;
 
 	mesg->actual_length = 0;
-	ret = master->setup(spi);
-	if (ret < 0) {
-		dev_dbg(master->dev, "transfer: master setup failed\n");
-		return ret;
-	}
 
 	dev_dbg(master->dev, "  csr0: %08x\n", spi_readl(as, CSR0));
 
@@ -202,50 +333,38 @@ static int atmel_spi_transfer(struct spi_device *spi, struct spi_message *mesg)
 			t, t->len, t->tx_buf, t->rx_buf);
 	}
 #endif
-	atmel_spi_chipselect(spi, as, 1);
+
+	cs_activate(as, spi);
+
+	cs_change = 0;
+
 	list_for_each_entry(t, &mesg->transfers, transfer_list) {
-		u32 tx_val;
-		int i = 0, rx_val;
-
-		mesg->actual_length += t->len;
-		if (bits <= 8) {
-			const u8 *txbuf = t->tx_buf;
-			u8 *rxbuf = t->rx_buf;
-
-			while (i < t->len) {
-				tx_val = txbuf ? txbuf[i] : 0;
-
-				rx_val = atmel_spi_xchg(as, tx_val);
-				if (rx_val < 0) {
-					ret = rx_val;
-					goto out;
-				}
-
-				if (rxbuf)
-					rxbuf[i] = rx_val;
-				i++;
-			}
-		} else if (bits <= 16) {
-			const u16 *txbuf = t->tx_buf;
-			u16 *rxbuf = t->rx_buf;
-
-			while (i < t->len >> 1) {
-				tx_val = txbuf ? txbuf[i] : 0;
-
-				rx_val = atmel_spi_xchg(as, tx_val);
-				if (rx_val < 0) {
-					ret = rx_val;
-					goto out;
-				}
-
-				if (rxbuf)
-					rxbuf[i] = rx_val;
-				i++;
-			}
+
+		if (cs_change) {
+			udelay(1);
+			cs_deactivate(as, spi);
+			udelay(1);
+			cs_activate(as, spi);
 		}
+
+		cs_change = t->cs_change;
+
+		ret = atmel_spi_do_xfer(spi, as, t);
+		if (ret < 0)
+			goto err;
+		mesg->actual_length += ret;
+
+		if (cs_change)
+			cs_activate(as, spi);
 	}
-out:
-	atmel_spi_chipselect(spi, as, 0);
+
+	if (!cs_change)
+		cs_deactivate(as, spi);
+
+	return 0;
+
+err:
+	cs_deactivate(as, spi);
 	return ret;
 }
 
@@ -265,6 +384,7 @@ static int atmel_spi_probe(struct device_d *dev)
 
 	master = &as->master;
 	master->dev = dev;
+	master->bus_num = dev->id;
 
 	as->clk = clk_get(dev, "spi_clk");
 	if (IS_ERR(as->clk)) {
diff --git a/drivers/spi/omap3_spi.c b/drivers/spi/omap3_spi.c
index 29cb69ae2f..f81b4aa9d1 100644
--- a/drivers/spi/omap3_spi.c
+++ b/drivers/spi/omap3_spi.c
@@ -327,10 +327,10 @@ static int omap3_spi_setup(struct spi_device *spi)
 {
 	struct spi_master *master = spi->master;
 
-	if (((master->bus_num == 0) && (spi->chip_select > 3)) ||
-			((master->bus_num == 1) && (spi->chip_select > 1)) ||
+	if (((master->bus_num == 1) && (spi->chip_select > 3)) ||
 			((master->bus_num == 2) && (spi->chip_select > 1)) ||
-			((master->bus_num == 3) && (spi->chip_select > 0))) {
+			((master->bus_num == 3) && (spi->chip_select > 1)) ||
+			((master->bus_num == 4) && (spi->chip_select > 0))) {
 		printf("SPI error: unsupported chip select %i \
 			on bus %i\n", spi->chip_select, master->bus_num);
 		return -EINVAL;
@@ -363,10 +363,10 @@ static int omap3_spi_probe(struct device_d *dev)
 	/*
 	 * OMAP3 McSPI (MultiChannel SPI) has 4 busses (modules)
 	 * with different number of chip selects (CS, channels):
-	 * McSPI1 has 4 CS (bus 0, cs 0 - 3)
-	 * McSPI2 has 2 CS (bus 1, cs 0 - 1)
-	 * McSPI3 has 2 CS (bus 2, cs 0 - 1)
-	 * McSPI4 has 1 CS (bus 3, cs 0)
+	 * McSPI1 has 4 CS (bus 1, cs 0 - 3)
+	 * McSPI2 has 2 CS (bus 2, cs 0 - 1)
+	 * McSPI3 has 2 CS (bus 3, cs 0 - 1)
+	 * McSPI4 has 1 CS (bus 4, cs 0)
 	 *
 	 * The board code has to make sure that it does not use
 	 * invalid buses or chip selects.
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 44040e5f62..6a5bd6d2b8 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -219,6 +219,18 @@ int spi_register_master(struct spi_master *master)
 }
 EXPORT_SYMBOL(spi_register_master);
 
+struct spi_master *spi_get_master(int bus)
+{
+	struct spi_master* m;
+
+	list_for_each_entry(m, &spi_master_list, list) {
+		if (m->bus_num == bus)
+			return m;
+	}
+
+	return NULL;
+}
+
 int spi_sync(struct spi_device *spi, struct spi_message *message)
 {
 	return spi->master->transfer(spi, message);