[PATCHv3 0/4] Add Altera I2C Controller Driver

[PATCHv3 0/4] Add Altera I2C Controller Driver

[thor.thayer]

From: Thor Thayer <thor.thayer@linux.intel.com>

This patch seris add the Altera I2C Controller driver for use in FPGAs.

Thor Thayer (4):
  ARM: dts: socfpga: Add Altera I2C Controller to CycloneV
  MAINTAINERS: Add Altera I2C Controller Driver
  dt-bindings: i2c: Add Altera I2C Controller
  i2c: altera: Add Altera I2C Controller driver

 .../devicetree/bindings/i2c/i2c-altera.txt         |  39 ++
 MAINTAINERS                                        |   5 +
 arch/arm/boot/dts/socfpga.dtsi                     |  13 +-
 arch/arm/boot/dts/socfpga_cyclone5_socdk.dts       |  28 +-
 drivers/i2c/busses/Kconfig                         |  10 +
 drivers/i2c/busses/Makefile                        |   1 +
 drivers/i2c/busses/i2c-altera.c                    | 509 +++++++++++++++++++++
 7 files changed, 601 insertions(+), 4 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/i2c/i2c-altera.txt
 create mode 100644 drivers/i2c/busses/i2c-altera.c

-- 
2.7.4

[PATCHv3 1/4] ARM: dts: socfpga: Add Altera I2C Controller to CycloneV

[thor.thayer]

From: Thor Thayer <thor.thayer@linux.intel.com>

Add the Altera I2C Controller to the CycloneV SoCFPGA device tree.

Signed-off-by: Thor Thayer <thor.thayer@linux.intel.com>
---
v2  Remove altr, from fifo-size.
    Rename compatible string to "altr,softip-i2c"
v3  Add version to commpatible string "altr,softip-i2c-v1.0"
---
 arch/arm/boot/dts/socfpga.dtsi               | 13 ++++++++++---
 arch/arm/boot/dts/socfpga_cyclone5_socdk.dts | 28 +++++++++++++++++++++++++++-
 2 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/arch/arm/boot/dts/socfpga.dtsi b/arch/arm/boot/dts/socfpga.dtsi
index b2674bd..d69c13d 100644
--- a/arch/arm/boot/dts/socfpga.dtsi
+++ b/arch/arm/boot/dts/socfpga.dtsi
@@ -133,6 +133,13 @@
 					#address-cells = <1>;
 					#size-cells = <0>;
 
+					clk_0: clk_0 {
+						compatible = "fixed-clock";
+						#clock-cells = <0>;
+						clock-frequency = <50000000>;
+						clock-output-names = "clk_0-clk";
+					};
+
 					osc1: osc1 {
 						#clock-cells = <0>;
 						compatible = "fixed-clock";
@@ -529,11 +536,11 @@
 				};
 		};
 
-		fpga_bridge0: fpga_bridge@ff400000 {
+		fpga_bridge0: fpga_bridge@ff200000 {
 			compatible = "altr,socfpga-lwhps2fpga-bridge";
-			reg = <0xff400000 0x100000>;
+			reg = <0xff200000 0x00200000>;
 			resets = <&rst LWHPS2FPGA_RESET>;
-			clocks = <&l4_main_clk>;
+			clocks = <&clk_0>;
 		};
 
 		fpga_bridge1: fpga_bridge@ff500000 {
diff --git a/arch/arm/boot/dts/socfpga_cyclone5_socdk.dts b/arch/arm/boot/dts/socfpga_cyclone5_socdk.dts
index 155829f..f99576b 100644
--- a/arch/arm/boot/dts/socfpga_cyclone5_socdk.dts
+++ b/arch/arm/boot/dts/socfpga_cyclone5_socdk.dts
@@ -68,6 +68,7 @@
 		regulator-min-microvolt = <3300000>;
 		regulator-max-microvolt = <3300000>;
 	};
+
 };
 
 &can0 {
@@ -101,7 +102,7 @@
 };
 
 &i2c0 {
-	status = "okay";
+	status = "disabled";
 	clock-frequency = <100000>;
 
 	/*
@@ -176,3 +177,28 @@
 &usb1 {
 	status = "okay";
 };
+
+&fpga_bridge0 {
+	reg-names = "axi_h2f_lw";
+	#address-cells = <2>;
+	#size-cells = <1>;
+	ranges = <0x00000001 0x00080000 0xff280000 0x00000040>;
+
+	i2c_0: i2c@0x100080000 {
+		compatible = "altr,softip-i2c-v1.0";
+		reg = <0x00000001 0x00080000 0x00000040>;
+		interrupt-parent = <&intc>;
+		interrupts = <0 43 4>;
+		clocks = <&clk_0>;
+		fifo-size = <4>;
+		clock-frequency = <100000>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		eeprom@51 {
+			compatible = "atmel,24c32";
+			reg = <0x51>;
+			pagesize = <32>;
+		};
+	};
+};
-- 
2.7.4

[PATCHv3 2/4] MAINTAINERS: Add Altera I2C Controller Driver

[thor.thayer]

From: Thor Thayer <thor.thayer@linux.intel.com>

Add maintainer for the Altera I2C Controller Driver.

Signed-off-by: Thor Thayer <thor.thayer@linux.intel.com>
---
v2&3  No change
---
 MAINTAINERS | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 9609ca6..86053d6 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -636,6 +636,11 @@ ALPS PS/2 TOUCHPAD DRIVER
 R:	Pali Rohár <pali.rohar@gmail.com>
 F:	drivers/input/mouse/alps.*
 
+ALTERA I2C CONTROLLER DRIVER
+M:	Thor Thayer <thor.thayer@linux.intel.com>
+S:	Maintained
+F:	drivers/i2c/busses/i2c-altera.c
+
 ALTERA MAILBOX DRIVER
 M:	Ley Foon Tan <lftan@altera.com>
 L:	nios2-dev@lists.rocketboards.org (moderated for non-subscribers)
-- 
2.7.4

[PATCHv3 3/4] dt-bindings: i2c: Add Altera I2C Controller

[thor.thayer]

From: Thor Thayer <thor.thayer@linux.intel.com>

Add the documentation to support the Altera synthesizable
logic I2C Controller in FPGA.

Signed-off-by: Thor Thayer <thor.thayer@linux.intel.com>
---
v2  Change the subject to identify dt-bindings
    Add synthesizable logic to description.
    Change compatible string to "altr,softip-i2c"
    Make description of clock phandle singular since 1 clock.
    Remove altr, from fifo-size
    Specify fifo-size is in bytes.
v3  Add version to compatible string "altr,softip-i2c-v1.0"
    Add for use in FPGA in description.
---
 .../devicetree/bindings/i2c/i2c-altera.txt         | 39 ++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/i2c/i2c-altera.txt

diff --git a/Documentation/devicetree/bindings/i2c/i2c-altera.txt b/Documentation/devicetree/bindings/i2c/i2c-altera.txt
new file mode 100644
index 0000000..767664f
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-altera.txt
@@ -0,0 +1,39 @@
+* Altera I2C Controller
+* This is Altera's synthesizable logic block I2C Controller for use
+* in Altera's FPGAs.
+
+Required properties :
+ - compatible : should be "altr,softip-i2c-v1.0"
+ - reg        : Offset and length of the register set for the device
+ - interrupts : <IRQ> where IRQ is the interrupt number.
+ - clocks     : phandle to input clock.
+ - #address-cells = <1>;
+ - #size-cells = <0>;
+
+Recommended properties :
+ - clock-frequency : desired I2C bus clock frequency in Hz.
+
+Optional properties :
+ - fifo-size : Size of the RX and TX FIFOs in bytes.
+ - Child nodes conforming to i2c bus binding
+
+Example :
+
+	i2c@100080000 {
+		compatible = "altr,softip-i2c-v1.0";
+		reg = <0x00000001 0x00080000 0x00000040>;
+		interrupt-parent = <&intc>;
+		interrupts = <0 43 4>;
+		clocks = <&clk_0>;
+		clock-frequency = <100000>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+		fifo-size = <4>;
+
+		eeprom@51 {
+			compatible = "atmel,24c32";
+			reg = <0x51>;
+			pagesize = <32>;
+		};
+	};
+
-- 
2.7.4

[PATCHv3 4/4] i2c: altera: Add Altera I2C Controller driver

[thor.thayer]

From: Thor Thayer <thor.thayer@linux.intel.com>

Add driver support for the Altera I2C Controller. The I2C
controller is soft IP for use in FPGAs.

Signed-off-by: Thor Thayer <thor.thayer@linux.intel.com>
---
v2  Remove altr, from fifo-size to agree with bindings.
    Change compatible string to "altr,softip-i2c"
v3  Add version to compatible string "altr,softip-i2c-v1.0"
---
 drivers/i2c/busses/Kconfig      |  10 +
 drivers/i2c/busses/Makefile     |   1 +
 drivers/i2c/busses/i2c-altera.c | 509 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 520 insertions(+)
 create mode 100644 drivers/i2c/busses/i2c-altera.c

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 144cbad..981ea48 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -326,6 +326,16 @@ config I2C_POWERMAC
 
 comment "I2C system bus drivers (mostly embedded / system-on-chip)"
 
+config I2C_ALTERA
+	tristate "Altera Soft IP I2C"
+	depends on (ARCH_SOCFPGA || NIOS2) && OF
+	help
+	  If you say yes to this option, support will be included for the
+	  Altera Soft IP I2C interfaces on SoCFPGA and Nios2 architectures.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-altera.
+
 config I2C_AT91
 	tristate "Atmel AT91 I2C Two-Wire interface (TWI)"
 	depends on ARCH_AT91
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 30b6085..4eb5c82 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_I2C_HYDRA)		+= i2c-hydra.o
 obj-$(CONFIG_I2C_POWERMAC)	+= i2c-powermac.o
 
 # Embedded system I2C/SMBus host controller drivers
+obj-$(CONFIG_I2C_ALTERA)	+= i2c-altera.o
 obj-$(CONFIG_I2C_AT91)		+= i2c-at91.o
 obj-$(CONFIG_I2C_AU1550)	+= i2c-au1550.o
 obj-$(CONFIG_I2C_AXXIA)		+= i2c-axxia.o
diff --git a/drivers/i2c/busses/i2c-altera.c b/drivers/i2c/busses/i2c-altera.c
new file mode 100644
index 0000000..0c7717d
--- /dev/null
+++ b/drivers/i2c/busses/i2c-altera.c
@@ -0,0 +1,509 @@
+/*
+ *  Copyright Intel Corporation (C) 2017.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Based on the i2c-axxia.c driver.
+ */
+#include <linux/clk.h>
+#include <linux/clkdev.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+
+#define ALTR_I2C_TFR_CMD	0x00	/* Transfer Command register */
+#define     ALTR_I2C_TFR_CMD_STA	BIT(9)	/* send START before byte */
+#define     ALTR_I2C_TFR_CMD_STO	BIT(8)	/* send STOP after byte */
+#define     ALTR_I2C_TFR_CMD_RW_D	BIT(0)	/* Direction of transfer */
+#define ALTR_I2C_RX_DATA	0x04	/* RX data FIFO register */
+#define ALTR_I2C_CTRL		0x08	/* Control register */
+#define	    ALTR_I2C_CTRL_RXT_SHFT	4	/* RX FIFO Threshold */
+#define     ALTR_I2C_CTRL_TCT_SHFT	2	/* TFER CMD FIFO Threshold */
+#define     ALTR_I2C_CTRL_BSPEED	BIT(1)	/* Bus Speed (1=Fast) */
+#define     ALTR_I2C_CTRL_EN	BIT(0)	/* Enable Core (1=Enable) */
+#define ALTR_I2C_ISER		0x0C	/* Interrupt Status Enable register */
+#define     ALTR_I2C_ISER_RXOF_EN	BIT(4)	/* Enable RX OVERFLOW IRQ */
+#define     ALTR_I2C_ISER_ARB_EN	BIT(3)	/* Enable ARB LOST IRQ */
+#define     ALTR_I2C_ISER_NACK_EN	BIT(2)	/* Enable NACK DET IRQ */
+#define     ALTR_I2C_ISER_RXRDY_EN	BIT(1)	/* Enable RX Ready IRQ */
+#define     ALTR_I2C_ISER_TXRDY_EN	BIT(0)	/* Enable TX Ready IRQ */
+#define ALTR_I2C_ISR		0x10	/* Interrupt Status register */
+#define     ALTR_I2C_ISR_RXOF		BIT(4)	/* RX OVERFLOW IRQ */
+#define     ALTR_I2C_ISR_ARB		BIT(3)	/* ARB LOST IRQ */
+#define     ALTR_I2C_ISR_NACK		BIT(2)	/* NACK DET IRQ */
+#define     ALTR_I2C_ISR_RXRDY		BIT(1)	/* RX Ready IRQ */
+#define     ALTR_I2C_ISR_TXRDY		BIT(0)	/* TX Ready IRQ */
+#define ALTR_I2C_STATUS		0x14	/* Status register */
+#define	    ALTR_I2C_STAT_CORE		BIT(0)	/* Core Status (0=idle) */
+#define ALTR_I2C_TC_FIFO_LVL	0x18	/* Transfer FIFO LVL register */
+#define ALTR_I2C_RX_FIFO_LVL	0x1C	/* Receive FIFO LVL register */
+#define ALTR_I2C_SCL_LOW	0x20	/* SCL low count register */
+#define ALTR_I2C_SCL_HIGH	0x24	/* SCL high count register */
+#define ALTR_I2C_SDA_HOLD	0x28	/* SDA hold count register */
+
+#define ALTR_I2C_ALL_IRQ	(ALTR_I2C_ISR_RXOF | ALTR_I2C_ISR_ARB | \
+				 ALTR_I2C_ISR_NACK | ALTR_I2C_ISR_RXRDY | \
+				 ALTR_I2C_ISR_TXRDY)
+
+#define ALTR_I2C_THRESHOLD	0	/*IRQ Threshold at 1 element */
+#define ALTR_I2C_DFLT_FIFO_SZ	4
+#define ALTR_I2C_TIMEOUT	100
+#define ALTR_I2C_XFER_TIMEOUT	(msecs_to_jiffies(250))
+
+/**
+ * altr_i2c_dev - I2C device context
+ * @base: pointer to register struct
+ * @msg: pointer to current message
+ * @msg_len: number of bytes transferred in msg
+ * @msg_err: error code for completed message
+ * @msg_complete: xfer completion object
+ * @dev: device reference
+ * @adapter: core i2c abstraction
+ * @i2c_clk: clock reference for i2c input clock
+ * @bus_clk_rate: current i2c bus clock rate
+ * @buf: ptr to msg buffer for easier use.
+ * @fifo_size: size of the FIFO passed in.
+ */
+struct altr_i2c_dev {
+	void __iomem *base;
+	struct i2c_msg *msg;
+	size_t msg_len;
+	int msg_err;
+	struct completion msg_complete;
+	struct device *dev;
+	struct i2c_adapter adapter;
+	struct clk *i2c_clk;
+	u32 bus_clk_rate;
+	u8 *buf;
+	unsigned int fifo_size;
+};
+
+static void i2c_int_disable(struct altr_i2c_dev *idev, u32 mask)
+{
+	u32 int_en = readl(idev->base + ALTR_I2C_ISER);
+
+	writel(int_en & ~mask, idev->base + ALTR_I2C_ISER);
+}
+
+static void i2c_int_enable(struct altr_i2c_dev *idev, u32 mask)
+{
+	u32 int_en = readl(idev->base + ALTR_I2C_ISER);
+
+	writel(int_en | mask, idev->base + ALTR_I2C_ISER);
+}
+
+static void i2c_int_clear(struct altr_i2c_dev *idev, u32 mask)
+{
+	u32 int_en = readl(idev->base + ALTR_I2C_ISR);
+
+	writel(int_en | mask, idev->base + ALTR_I2C_ISR);
+}
+
+static void altr_i2c_core_disable(struct altr_i2c_dev *idev)
+{
+	u32 tmp = readl(idev->base + ALTR_I2C_CTRL);
+
+	writel(tmp & ~ALTR_I2C_CTRL_EN, idev->base + ALTR_I2C_CTRL);
+}
+
+static void altr_i2c_core_enable(struct altr_i2c_dev *idev)
+{
+	u32 tmp = readl(idev->base + ALTR_I2C_CTRL);
+
+	writel(tmp | ALTR_I2C_CTRL_EN, idev->base + ALTR_I2C_CTRL);
+}
+
+static void altr_i2c_reset(struct altr_i2c_dev *idev)
+{
+	altr_i2c_core_disable(idev);
+	altr_i2c_core_enable(idev);
+}
+
+static void altr_i2c_recover(struct altr_i2c_dev *idev)
+{
+	altr_i2c_reset(idev);
+	/* Clock start bit + 8 bits + stop bit out */
+	writel(ALTR_I2C_TFR_CMD_STA | ALTR_I2C_TFR_CMD_STO,
+	       idev->base + ALTR_I2C_TFR_CMD);
+	altr_i2c_reset(idev);
+
+	i2c_recover_bus(&idev->adapter);
+}
+
+static inline void altr_i2c_stop(struct altr_i2c_dev *idev)
+{
+	writel(ALTR_I2C_TFR_CMD_STO, idev->base + ALTR_I2C_TFR_CMD);
+}
+
+static void altr_i2c_init(struct altr_i2c_dev *idev)
+{
+	u32 divisor = clk_get_rate(idev->i2c_clk) / idev->bus_clk_rate;
+	u32 clk_mhz = clk_get_rate(idev->i2c_clk) / 1000000;
+	u32 tmp = (ALTR_I2C_THRESHOLD << ALTR_I2C_CTRL_RXT_SHFT) |
+		  (ALTR_I2C_THRESHOLD << ALTR_I2C_CTRL_TCT_SHFT);
+	u32 t_high, t_low;
+
+	if (idev->bus_clk_rate <= 100000) {
+		tmp &= ~ALTR_I2C_CTRL_BSPEED;
+		/* Standard mode SCL 50/50 */
+		t_high = divisor * 1 / 2;
+		t_low = divisor * 1 / 2;
+	} else {
+		tmp |= ALTR_I2C_CTRL_BSPEED;
+		/* Fast mode SCL 33/66 */
+		t_high = divisor * 1 / 3;
+		t_low = divisor * 2 / 3;
+	}
+	writel(tmp, idev->base + ALTR_I2C_CTRL);
+
+	dev_dbg(idev->dev, "rate=%uHz per_clk=%uMHz -> ratio=1:%u\n",
+		idev->bus_clk_rate, clk_mhz, divisor);
+
+	/* Reset controller */
+	altr_i2c_reset(idev);
+
+	/* SCL High Time */
+	writel(t_high, idev->base + ALTR_I2C_SCL_HIGH);
+	/* SCL Low Time */
+	writel(t_low, idev->base + ALTR_I2C_SCL_LOW);
+	/* SDA Hold Time, 300ns */
+	writel(div_u64(300 * clk_mhz, 1000), idev->base + ALTR_I2C_SDA_HOLD);
+
+	/* Mask all master interrupt bits */
+	i2c_int_disable(idev, ~0);
+}
+
+static int i2c_m_rd(const struct i2c_msg *msg)
+{
+	return (msg->flags & I2C_M_RD) != 0;
+}
+
+/**
+ * altr_i2c_empty_rx_fifo - Fetch data from RX FIFO until end of
+ * transfer. Send a Stop bit on the last byte.
+ */
+static void altr_i2c_empty_rx_fifo(struct altr_i2c_dev *idev)
+{
+	size_t rx_fifo_avail = readl(idev->base + ALTR_I2C_RX_FIFO_LVL);
+	int bytes_to_transfer = min(rx_fifo_avail, idev->msg_len);
+
+	while (bytes_to_transfer-- > 0) {
+		*idev->buf++ = readl(idev->base + ALTR_I2C_RX_DATA);
+		if (idev->msg_len == 1)
+			altr_i2c_stop(idev);
+		else
+			writel(0, idev->base + ALTR_I2C_TFR_CMD);
+
+		idev->msg_len--;
+	}
+}
+
+/**
+ * altr_i2c_fill_tx_fifo - Fill TX FIFO from current message buffer.
+ * @return: Number of bytes left to transfer.
+ */
+static int altr_i2c_fill_tx_fifo(struct altr_i2c_dev *idev)
+{
+	size_t tx_fifo_avail = idev->fifo_size - readl(idev->base +
+						       ALTR_I2C_TC_FIFO_LVL);
+	int bytes_to_transfer = min(tx_fifo_avail, idev->msg_len);
+	int ret = idev->msg_len - bytes_to_transfer;
+
+	while (bytes_to_transfer-- > 0) {
+		if (idev->msg_len == 1)
+			writel(ALTR_I2C_TFR_CMD_STO | *idev->buf++,
+			       idev->base + ALTR_I2C_TFR_CMD);
+		else
+			writel(*idev->buf++, idev->base + ALTR_I2C_TFR_CMD);
+		idev->msg_len--;
+	}
+
+	return ret;
+}
+
+/**
+ * altr_i2c_wait_for_core_idle - After TX, check core idle for all bytes TX.
+ * @return: 0 on success or -ETIMEDOUT on timeout.
+ */
+static int altr_i2c_wait_for_core_idle(struct altr_i2c_dev *idev)
+{
+	unsigned long timeout = jiffies + msecs_to_jiffies(ALTR_I2C_TIMEOUT);
+
+	do {
+		if (time_after(jiffies, timeout)) {
+			dev_err(idev->dev, "Core Idle timeout\n");
+			return -ETIMEDOUT;
+		}
+	} while (readl(idev->base + ALTR_I2C_STATUS) & ALTR_I2C_STAT_CORE);
+
+	return 0;
+}
+
+static irqreturn_t altr_i2c_isr(int irq, void *_dev)
+{
+	struct altr_i2c_dev *idev = _dev;
+	/* Read IRQ status but only interested in Enabled IRQs. */
+	u32 status = readl(idev->base + ALTR_I2C_ISR) &
+		     readl(idev->base + ALTR_I2C_ISER);
+
+	if (!idev->msg) {
+		dev_warn(idev->dev, "unexpected interrupt\n");
+		goto out;
+	}
+
+	/* handle Lost Arbitration */
+	if (unlikely(status & ALTR_I2C_ISR_ARB)) {
+		dev_err(idev->dev, "%s: arbitration lost\n", __func__);
+		i2c_int_clear(idev, ALTR_I2C_ISR_ARB);
+		idev->msg_err = -EAGAIN;
+		goto complete;
+	}
+
+	if (unlikely(status & ALTR_I2C_ISR_NACK)) {
+		dev_dbg(idev->dev, "%s: could not get ACK\n", __func__);
+		idev->msg_err = -ENXIO;
+		i2c_int_clear(idev, ALTR_I2C_ISR_NACK);
+		altr_i2c_stop(idev);
+		goto complete;
+	}
+
+	/* handle RX FIFO Overflow */
+	if (i2c_m_rd(idev->msg) && unlikely(status & ALTR_I2C_ISR_RXOF)) {
+		altr_i2c_empty_rx_fifo(idev);
+		i2c_int_clear(idev, ALTR_I2C_ISR_RXRDY);
+		altr_i2c_stop(idev);
+		dev_err(idev->dev, "%s: RX FIFO Overflow\n", __func__);
+		goto complete;
+	}
+
+	/* RX FIFO needs service? */
+	if (i2c_m_rd(idev->msg) && (status & ALTR_I2C_ISR_RXRDY)) {
+		altr_i2c_empty_rx_fifo(idev);
+		i2c_int_clear(idev, ALTR_I2C_ISR_RXRDY);
+		if (!idev->msg_len)
+			goto complete;
+
+		goto out;
+	}
+
+	/* TX FIFO needs service? */
+	if (!i2c_m_rd(idev->msg) && (status & ALTR_I2C_ISR_TXRDY)) {
+		i2c_int_clear(idev, ALTR_I2C_ISR_TXRDY);
+		if (!altr_i2c_fill_tx_fifo(idev))
+			goto complete;
+
+		goto out;
+	}
+
+complete:
+	dev_dbg(idev->dev, "%s: Message Complete\n", __func__);
+	if (altr_i2c_wait_for_core_idle(idev))
+		dev_err(idev->dev, "%s: message timeout\n", __func__);
+	i2c_int_disable(idev, ALTR_I2C_ALL_IRQ);
+	i2c_int_clear(idev, ALTR_I2C_ALL_IRQ);
+	complete(&idev->msg_complete);
+
+out:
+	return IRQ_HANDLED;
+}
+
+static int altr_i2c_xfer_msg(struct altr_i2c_dev *idev, struct i2c_msg *msg)
+{
+	u32 int_mask = ALTR_I2C_ISR_RXOF | ALTR_I2C_ISR_ARB | ALTR_I2C_ISR_NACK;
+	u32 addr = (msg->addr << 1) & 0xFF;
+	unsigned long time_left;
+
+	idev->msg = msg;
+	idev->msg_len = msg->len;
+	idev->buf = msg->buf;
+	idev->msg_err = 0;
+	reinit_completion(&idev->msg_complete);
+	altr_i2c_core_enable(idev);
+
+	if (i2c_m_rd(msg)) {
+		/* Dummy read to ensure RX FIFO is empty */
+		readl(idev->base + ALTR_I2C_RX_DATA);
+		addr |= ALTR_I2C_TFR_CMD_RW_D;
+	}
+
+	writel(ALTR_I2C_TFR_CMD_STA | addr, idev->base + ALTR_I2C_TFR_CMD);
+
+	if (i2c_m_rd(msg)) {
+		/* write the first byte to start the RX */
+		writel(0, idev->base + ALTR_I2C_TFR_CMD);
+		int_mask |= ALTR_I2C_ISER_RXOF_EN | ALTR_I2C_ISER_RXRDY_EN;
+	} else {
+		altr_i2c_fill_tx_fifo(idev);
+		int_mask |= ALTR_I2C_ISR_TXRDY;
+	}
+	i2c_int_enable(idev, int_mask);
+
+	time_left = wait_for_completion_timeout(&idev->msg_complete,
+						ALTR_I2C_XFER_TIMEOUT);
+
+	i2c_int_disable(idev, int_mask);
+
+	if (readl(idev->base + ALTR_I2C_STATUS) & ALTR_I2C_STAT_CORE)
+		dev_err(idev->dev, "%s: Core Status not IDLE...\n", __func__);
+
+	if (time_left == 0) {
+		idev->msg_err = -ETIMEDOUT;
+		dev_err(idev->dev, "%s: Transaction timed out.\n", __func__);
+		altr_i2c_recover(idev);
+	}
+
+	if (unlikely(idev->msg_err) && idev->msg_err != -ENXIO)
+		altr_i2c_init(idev);
+
+	altr_i2c_core_disable(idev);
+
+	return idev->msg_err;
+}
+
+static int
+altr_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
+{
+	struct altr_i2c_dev *idev = i2c_get_adapdata(adap);
+	int i;
+	int ret = 0;
+
+	for (i = 0; ret == 0 && i < num; ++i)
+		ret = altr_i2c_xfer_msg(idev, &msgs[i]);
+
+	return ret ? : i;
+}
+
+static u32 altr_i2c_func(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C;
+}
+
+static const struct i2c_algorithm altr_i2c_algo = {
+	.master_xfer = altr_i2c_xfer,
+	.functionality = altr_i2c_func,
+};
+
+static int altr_i2c_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct altr_i2c_dev *idev = NULL;
+	struct resource *res;
+	int irq;
+	int ret = 0;
+
+	idev = devm_kzalloc(&pdev->dev, sizeof(*idev), GFP_KERNEL);
+	if (!idev)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	idev->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(idev->base))
+		return PTR_ERR(idev->base);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(&pdev->dev, "missing interrupt resource\n");
+		return irq;
+	}
+
+	idev->i2c_clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(idev->i2c_clk)) {
+		dev_err(&pdev->dev, "missing clock\n");
+		return PTR_ERR(idev->i2c_clk);
+	}
+
+	idev->dev = &pdev->dev;
+	init_completion(&idev->msg_complete);
+
+	if (of_property_read_u32(np, "fifo-size", &idev->fifo_size))
+		idev->fifo_size = ALTR_I2C_DFLT_FIFO_SZ;
+
+	if (of_property_read_u32(np, "clock-frequency", &idev->bus_clk_rate))
+		idev->bus_clk_rate = 100000;	/* default clock rate */
+
+	if (idev->bus_clk_rate > 400000) {
+		dev_err(&pdev->dev, "invalid clock-frequency %d\n",
+			idev->bus_clk_rate);
+		return -EINVAL;
+	}
+
+	ret = devm_request_irq(&pdev->dev, irq, altr_i2c_isr, 0,
+			       pdev->name, idev);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to claim IRQ%d\n", irq);
+		return ret;
+	}
+
+	ret = clk_prepare_enable(idev->i2c_clk);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to enable clock\n");
+		return ret;
+	}
+
+	altr_i2c_init(idev);
+
+	i2c_set_adapdata(&idev->adapter, idev);
+	strlcpy(idev->adapter.name, pdev->name, sizeof(idev->adapter.name));
+	idev->adapter.owner = THIS_MODULE;
+	idev->adapter.algo = &altr_i2c_algo;
+	idev->adapter.dev.parent = &pdev->dev;
+	idev->adapter.dev.of_node = pdev->dev.of_node;
+
+	platform_set_drvdata(pdev, idev);
+
+	ret = i2c_add_adapter(&idev->adapter);
+	if (ret) {
+		clk_disable_unprepare(idev->i2c_clk);
+		return ret;
+	}
+	dev_info(&pdev->dev, "Altera SoftIP I2C Probe Complete\n");
+
+	return 0;
+}
+
+static int altr_i2c_remove(struct platform_device *pdev)
+{
+	struct altr_i2c_dev *idev = platform_get_drvdata(pdev);
+
+	clk_disable_unprepare(idev->i2c_clk);
+	i2c_del_adapter(&idev->adapter);
+
+	return 0;
+}
+
+/* Match table for of_platform binding */
+static const struct of_device_id altr_i2c_of_match[] = {
+	{ .compatible = "altr,softip-i2c-v1.0" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, altr_i2c_of_match);
+
+static struct platform_driver altr_i2c_driver = {
+	.probe = altr_i2c_probe,
+	.remove = altr_i2c_remove,
+	.driver = {
+		.name = "altera-i2c",
+		.of_match_table = altr_i2c_of_match,
+	},
+};
+
+module_platform_driver(altr_i2c_driver);
+
+MODULE_DESCRIPTION("Altera Soft IP I2C bus driver");
+MODULE_AUTHOR("Thor Thayer <thor.thayer@linux.intel.com>");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4

Re: [PATCHv3 1/4] ARM: dts: socfpga: Add Altera I2C Controller to CycloneV

[Steffen Trumtrar]

Hi!

thor.thayer@linux.intel.com writes:

> From: Thor Thayer <thor.thayer@linux.intel.com>
>
> Add the Altera I2C Controller to the CycloneV SoCFPGA device tree.
>
> Signed-off-by: Thor Thayer <thor.thayer@linux.intel.com>
> ---
> v2  Remove altr, from fifo-size.
>     Rename compatible string to "altr,softip-i2c"
> v3  Add version to commpatible string "altr,softip-i2c-v1.0"
> ---
>  arch/arm/boot/dts/socfpga.dtsi               | 13 ++++++++++---
>  arch/arm/boot/dts/socfpga_cyclone5_socdk.dts | 28 +++++++++++++++++++++++++++-
>  2 files changed, 37 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm/boot/dts/socfpga.dtsi b/arch/arm/boot/dts/socfpga.dtsi
> index b2674bd..d69c13d 100644
> --- a/arch/arm/boot/dts/socfpga.dtsi
> +++ b/arch/arm/boot/dts/socfpga.dtsi
> @@ -133,6 +133,13 @@
>  					#address-cells = <1>;
>  					#size-cells = <0>;
>  
> +					clk_0: clk_0 {
> +						compatible = "fixed-clock";
> +						#clock-cells = <0>;
> +						clock-frequency = <50000000>;
> +						clock-output-names = "clk_0-clk";
> +					};
> +
>  					osc1: osc1 {
>  						#clock-cells = <0>;
>  						compatible = "fixed-clock";
> @@ -529,11 +536,11 @@
>  				};
>  		};
>  
> -		fpga_bridge0: fpga_bridge@ff400000 {
> +		fpga_bridge0: fpga_bridge@ff200000 {
>  			compatible = "altr,socfpga-lwhps2fpga-bridge";
> -			reg = <0xff400000 0x100000>;
> +			reg = <0xff200000 0x00200000>;
>  			resets = <&rst LWHPS2FPGA_RESET>;
> -			clocks = <&l4_main_clk>;
> +			clocks = <&clk_0>;
>  		};
>

Why this change? This looks wrong and unrelated. The LWHPS2FPGA bridge
is at 0xff400000, so it is correct the way it is or not?

>  		fpga_bridge1: fpga_bridge@ff500000 {
> diff --git a/arch/arm/boot/dts/socfpga_cyclone5_socdk.dts b/arch/arm/boot/dts/socfpga_cyclone5_socdk.dts
> index 155829f..f99576b 100644
> --- a/arch/arm/boot/dts/socfpga_cyclone5_socdk.dts
> +++ b/arch/arm/boot/dts/socfpga_cyclone5_socdk.dts
> @@ -68,6 +68,7 @@
>  		regulator-min-microvolt = <3300000>;
>  		regulator-max-microvolt = <3300000>;
>  	};
> +
>  };

???


(...)


Best regards,
Steffen

-- 
Pengutronix e.K.                           | Steffen Trumtrar            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

Re: [PATCHv3 1/4] ARM: dts: socfpga: Add Altera I2C Controller to CycloneV

[Thor Thayer]

Hi Steffen,

On 06/06/2017 01:40 AM, Steffen Trumtrar wrote:
> 
> Hi!
> 
> thor.thayer@linux.intel.com writes:
> 
>> From: Thor Thayer <thor.thayer@linux.intel.com>
>>
>> Add the Altera I2C Controller to the CycloneV SoCFPGA device tree.
>>
>> Signed-off-by: Thor Thayer <thor.thayer@linux.intel.com>
>> ---
>> v2  Remove altr, from fifo-size.
>>      Rename compatible string to "altr,softip-i2c"
>> v3  Add version to commpatible string "altr,softip-i2c-v1.0"
>> ---
>>   arch/arm/boot/dts/socfpga.dtsi               | 13 ++++++++++---
>>   arch/arm/boot/dts/socfpga_cyclone5_socdk.dts | 28 +++++++++++++++++++++++++++-
>>   2 files changed, 37 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/arm/boot/dts/socfpga.dtsi b/arch/arm/boot/dts/socfpga.dtsi
>> index b2674bd..d69c13d 100644
>> --- a/arch/arm/boot/dts/socfpga.dtsi
>> +++ b/arch/arm/boot/dts/socfpga.dtsi
>> @@ -133,6 +133,13 @@
>>   					#address-cells = <1>;
>>   					#size-cells = <0>;
>>   
>> +					clk_0: clk_0 {
>> +						compatible = "fixed-clock";
>> +						#clock-cells = <0>;
>> +						clock-frequency = <50000000>;
>> +						clock-output-names = "clk_0-clk";
>> +					};
>> +
>>   					osc1: osc1 {
>>   						#clock-cells = <0>;
>>   						compatible = "fixed-clock";
>> @@ -529,11 +536,11 @@
>>   				};
>>   		};
>>   
>> -		fpga_bridge0: fpga_bridge@ff400000 {
>> +		fpga_bridge0: fpga_bridge@ff200000 {
>>   			compatible = "altr,socfpga-lwhps2fpga-bridge";
>> -			reg = <0xff400000 0x100000>;
>> +			reg = <0xff200000 0x00200000>;
>>   			resets = <&rst LWHPS2FPGA_RESET>;
>> -			clocks = <&l4_main_clk>;
>> +			clocks = <&clk_0>;
>>   		};
>>
> 
> Why this change? This looks wrong and unrelated. The LWHPS2FPGA bridge
> is at 0xff400000, so it is correct the way it is or not?
> 
Yes, good point. I was using the LWHPS2FPGA slave bus so I shouldn't 
change this one. I'll add the slave version.

Thanks,

Thor
>>   		fpga_bridge1: fpga_bridge@ff500000 {
>> diff --git a/arch/arm/boot/dts/socfpga_cyclone5_socdk.dts b/arch/arm/boot/dts/socfpga_cyclone5_socdk.dts
>> index 155829f..f99576b 100644
>> --- a/arch/arm/boot/dts/socfpga_cyclone5_socdk.dts
>> +++ b/arch/arm/boot/dts/socfpga_cyclone5_socdk.dts
>> @@ -68,6 +68,7 @@
>>   		regulator-min-microvolt = <3300000>;
>>   		regulator-max-microvolt = <3300000>;
>>   	};
>> +
>>   };
> 
> ???
> 
Whoops. I should remove the extra space. Thanks!

> 
> (...)
> 
> 
> Best regards,
> Steffen
> 

Re: [PATCHv3 3/4] dt-bindings: i2c: Add Altera I2C Controller

[Rob Herring]

On Fri, Jun 02, 2017 at 06:52:38PM -0500, thor.thayer@linux.intel.com wrote:
> From: Thor Thayer <thor.thayer@linux.intel.com>
> 
> Add the documentation to support the Altera synthesizable
> logic I2C Controller in FPGA.
> 
> Signed-off-by: Thor Thayer <thor.thayer@linux.intel.com>
> ---
> v2  Change the subject to identify dt-bindings
>     Add synthesizable logic to description.
>     Change compatible string to "altr,softip-i2c"
>     Make description of clock phandle singular since 1 clock.
>     Remove altr, from fifo-size
>     Specify fifo-size is in bytes.
> v3  Add version to compatible string "altr,softip-i2c-v1.0"
>     Add for use in FPGA in description.
> ---
>  .../devicetree/bindings/i2c/i2c-altera.txt         | 39 ++++++++++++++++++++++
>  1 file changed, 39 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/i2c/i2c-altera.txt

Acked-by: Rob Herring <robh@kernel.org>