Merge branch 'i2c/for-4.4' of git://git.kernel.org/pub/scm/linux/kern…

…el/git/wsa/linux

Pull i2c updates from Wolfram Sang:

 - New drivers: UniPhier (with and without FIFO)

 - some drivers got some bigger rework: ismt, designware, img-scb (rcar
   had to be reverted because issues were showing up just lately)

 - ACPI: reworked the device scanning and added support for muxes

... and quite a lot of driver bugfixes and cleanups this time.  All
files touched outside of the i2c realm have proper acks.

* 'i2c/for-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (70 commits)
  i2c: rcar: Revert the latest refactoring series
  i2c: pnx: remove superfluous assignment
  MAINTAINERS: i2c: drop i2c-pnx maintainer
  MAINTAINERS: i2c: mark also subdirectories as maintained
  i2c: cadence: enable driver for ARM64
  i2c: i801: Document Intel DNV and Broxton
  i2c: at91: manage unexpected RXRDY flag when starting a transfer
  i2c: pnx: Use setup_timer instead of open coding it
  i2c: add ACPI support for I2C mux ports
  acpi: add acpi_preset_companion() stub
  i2c: pxa: Add support for pxa910/988 & new configuration features
  i2c: au1550: Convert to devm_kzalloc and devm_ioremap_resource
  i2c-dev: Fix I2C_SLAVE ioctl comment
  i2c-dev: Fix typo in ioctl name reference
  i2c: sirf: tune the divider to make i2c bus freq more accurate
  i2c: imx: Use -ENXIO as error in the NACK case
  i2c: i801: Add support for Intel Broxton
  i2c: i801: Add support for Intel DNV
  i2c: mediatek: add i2c resume support
  i2c: imx: implement bus recovery
  ...

Documentation/acpi/i2c-muxes.txt

@@ -0,0 +1,58 @@
+ACPI I2C Muxes
+--------------
+
+Describing an I2C device hierarchy that includes I2C muxes requires an ACPI
+Device () scope per mux channel.
+
+Consider this topology:
+
++------+   +------+
+| SMB1 |-->| MUX0 |--CH00--> i2c client A (0x50)
+|      |   | 0x70 |--CH01--> i2c client B (0x50)
++------+   +------+
+
+which corresponds to the following ASL:
+
+Device (SMB1)
+{
+    Name (_HID, ...)
+    Device (MUX0)
+    {
+        Name (_HID, ...)
+        Name (_CRS, ResourceTemplate () {
+            I2cSerialBus (0x70, ControllerInitiated, I2C_SPEED,
+                          AddressingMode7Bit, "^SMB1", 0x00,
+                          ResourceConsumer,,)
+        }
+
+        Device (CH00)
+        {
+            Name (_ADR, 0)
+
+            Device (CLIA)
+            {
+                Name (_HID, ...)
+                Name (_CRS, ResourceTemplate () {
+                    I2cSerialBus (0x50, ControllerInitiated, I2C_SPEED,
+                                  AddressingMode7Bit, "^CH00", 0x00,
+                                  ResourceConsumer,,)
+                }
+            }
+        }
+
+        Device (CH01)
+        {
+            Name (_ADR, 1)
+
+            Device (CLIB)
+            {
+                Name (_HID, ...)
+                Name (_CRS, ResourceTemplate () {
+                    I2cSerialBus (0x50, ControllerInitiated, I2C_SPEED,
+                                  AddressingMode7Bit, "^CH01", 0x00,
+                                  ResourceConsumer,,)
+                }
+            }
+        }
+    }
+}

Documentation/devicetree/bindings/i2c/i2c-davinci.txt

@@ -1,10 +1,10 @@
-* Texas Instruments Davinci I2C
+* Texas Instruments Davinci/Keystone I2C
 
 This file provides information, what the device node for the
-davinci i2c interface contain.
+davinci/keystone i2c interface contains.
 
 Required properties:
-- compatible: "ti,davinci-i2c";
+- compatible: "ti,davinci-i2c" or "ti,keystone-i2c";
 - reg : Offset and length of the register set for the device
 
 Recommended properties :

Documentation/devicetree/bindings/i2c/i2c-imx.txt

@@ -14,6 +14,10 @@ Optional properties:
   The absence of the propoerty indicates the default frequency 100 kHz.
 - dmas: A list of two dma specifiers, one for each entry in dma-names.
 - dma-names: should contain "tx" and "rx".
+- scl-gpios: specify the gpio related to SCL pin
+- sda-gpios: specify the gpio related to SDA pin
+- pinctrl: add extra pinctrl to configure i2c pins to gpio function for i2c
+  bus recovery, call it "gpio" state
 
 Examples:
 
@@ -37,4 +41,9 @@ i2c0: i2c@40066000 { /* i2c0 on vf610 */
 	dmas = <&edma0 0 50>,
 		<&edma0 0 51>;
 	dma-names = "rx","tx";
+	pinctrl-names = "default", "gpio";
+	pinctrl-0 = <&pinctrl_i2c1>;
+	pinctrl-1 = <&pinctrl_i2c1_gpio>;
+	scl-gpios = <&gpio5 26 GPIO_ACTIVE_HIGH>;
+	sda-gpios = <&gpio5 27 GPIO_ACTIVE_HIGH>;
 };

Documentation/devicetree/bindings/i2c/i2c-rcar.txt

@@ -10,6 +10,7 @@ Required properties:
 	"renesas,i2c-r8a7792"
 	"renesas,i2c-r8a7793"
 	"renesas,i2c-r8a7794"
+	"renesas,i2c-r8a7795"
 - reg: physical base address of the controller and length of memory mapped
   region.
 - interrupts: interrupt specifier.

Documentation/devicetree/bindings/i2c/i2c-sh_mobile.txt

@@ -10,6 +10,7 @@ Required properties:
 			- "renesas,iic-r8a7792" (R-Car V2H)
 			- "renesas,iic-r8a7793" (R-Car M2-N)
 			- "renesas,iic-r8a7794" (R-Car E2)
+			- "renesas,iic-r8a7795" (R-Car H3)
 			- "renesas,iic-sh73a0" (SH-Mobile AG5)
 - reg             : address start and address range size of device
 - interrupts      : interrupt of device

Documentation/devicetree/bindings/i2c/i2c-uniphier-f.txt

@@ -0,0 +1,25 @@
+UniPhier I2C controller (FIFO-builtin)
+
+Required properties:
+- compatible: should be "socionext,uniphier-fi2c".
+- #address-cells: should be 1.
+- #size-cells: should be 0.
+- reg: offset and length of the register set for the device.
+- interrupts: a single interrupt specifier.
+- clocks: phandle to the input clock.
+
+Optional properties:
+- clock-frequency: desired I2C bus frequency in Hz.  The maximum supported
+  value is 400000.  Defaults to 100000 if not specified.
+
+Examples:
+
+	i2c0: i2c@58780000 {
+		compatible = "socionext,uniphier-fi2c";
+		reg = <0x58780000 0x80>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+		interrupts = <0 41 4>;
+		clocks = <&i2c_clk>;
+		clock-frequency = <100000>;
+	};

Documentation/devicetree/bindings/i2c/i2c-uniphier.txt

@@ -0,0 +1,25 @@
+UniPhier I2C controller (FIFO-less)
+
+Required properties:
+- compatible: should be "socionext,uniphier-i2c".
+- #address-cells: should be 1.
+- #size-cells: should be 0.
+- reg: offset and length of the register set for the device.
+- interrupts: a single interrupt specifier.
+- clocks: phandle to the input clock.
+
+Optional properties:
+- clock-frequency: desired I2C bus frequency in Hz.  The maximum supported
+  value is 400000.  Defaults to 100000 if not specified.
+
+Examples:
+
+	i2c0: i2c@58400000 {
+		compatible = "socionext,uniphier-i2c";
+		reg = <0x58400000 0x40>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+		interrupts = <0 41 1>;
+		clocks = <&i2c_clk>;
+		clock-frequency = <100000>;
+	};

Documentation/i2c/busses/i2c-i801

@@ -30,6 +30,8 @@ Supported adapters:
   * Intel BayTrail (SOC)
   * Intel Sunrise Point-H (PCH)
   * Intel Sunrise Point-LP (PCH)
+  * Intel DNV (SOC)
+  * Intel Broxton (SOC)
    Datasheets: Publicly available at the Intel website
 
 On Intel Patsburg and later chipsets, both the normal host SMBus controller

MAINTAINERS

@@ -1626,6 +1626,7 @@ L:	[email protected] (moderated for non-subscribers)
 S:	Maintained
 F:	arch/arm/boot/dts/uniphier*
 F:	arch/arm/mach-uniphier/
+F:	drivers/i2c/busses/i2c-uniphier*
 F:	drivers/pinctrl/uniphier/
 F:	drivers/tty/serial/8250/8250_uniphier.c
 N:	uniphier
@@ -5163,6 +5164,7 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/i2c/
 F:	Documentation/i2c/
 F:	drivers/i2c/
+F:	drivers/i2c/*/
 F:	include/linux/i2c.h
 F:	include/linux/i2c-*.h
 F:	include/uapi/linux/i2c.h
@@ -8418,12 +8420,6 @@ M:	"Rafael J. Wysocki" <[email protected]>
 S:	Maintained
 F:	drivers/pnp/
 
-PNXxxxx I2C DRIVER
-M:	Vitaly Wool <[email protected]>
-L:	[email protected]
-S:	Maintained
-F:	drivers/i2c/busses/i2c-pnx.c
-
 PPP PROTOCOL DRIVERS AND COMPRESSORS
 M:	Paul Mackerras <[email protected]>
 L:	[email protected]

drivers/i2c/busses/Kconfig

@@ -124,6 +124,8 @@ config I2C_I801
 	    BayTrail (SOC)
 	    Sunrise Point-H (PCH)
 	    Sunrise Point-LP (PCH)
+	    DNV (SOC)
+	    Broxton (SOC)
 
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-i801.
@@ -422,7 +424,7 @@ config I2C_BLACKFIN_TWI_CLK_KHZ
 
 config I2C_CADENCE
 	tristate "Cadence I2C Controller"
-	depends on ARCH_ZYNQ
+	depends on ARCH_ZYNQ || ARM64
 	help
 	  Say yes here to select Cadence I2C Host Controller. This controller is
 	  e.g. used by Xilinx Zynq.
@@ -582,10 +584,10 @@ config I2C_IMG
 
 config I2C_IMX
 	tristate "IMX I2C interface"
-	depends on ARCH_MXC
+	depends on ARCH_MXC || ARCH_LAYERSCAPE
 	help
 	  Say Y here if you want to use the IIC bus controller on
-	  the Freescale i.MX/MXC processors.
+	  the Freescale i.MX/MXC or Layerscape processors.
 
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-imx.
@@ -902,6 +904,22 @@ config I2C_TEGRA
 	  If you say yes to this option, support will be included for the
 	  I2C controller embedded in NVIDIA Tegra SOCs
 
+config I2C_UNIPHIER
+	tristate "UniPhier FIFO-less I2C controller"
+	depends on ARCH_UNIPHIER
+	help
+	  If you say yes to this option, support will be included for
+	  the UniPhier FIFO-less I2C interface embedded in PH1-LD4, PH1-sLD8,
+	  or older UniPhier SoCs.
+
+config I2C_UNIPHIER_F
+	tristate "UniPhier FIFO-builtin I2C controller"
+	depends on ARCH_UNIPHIER
+	help
+	  If you say yes to this option, support will be included for
+	  the UniPhier FIFO-builtin I2C interface embedded in PH1-Pro4,
+	  PH1-Pro5, or newer UniPhier SoCs.
+
 config I2C_VERSATILE
 	tristate "ARM Versatile/Realview I2C bus support"
 	depends on ARCH_VERSATILE || ARCH_REALVIEW || ARCH_VEXPRESS

drivers/i2c/busses/Makefile

@@ -87,6 +87,8 @@ obj-$(CONFIG_I2C_ST)		+= i2c-st.o
 obj-$(CONFIG_I2C_STU300)	+= i2c-stu300.o
 obj-$(CONFIG_I2C_SUN6I_P2WI)	+= i2c-sun6i-p2wi.o
 obj-$(CONFIG_I2C_TEGRA)		+= i2c-tegra.o
+obj-$(CONFIG_I2C_UNIPHIER)	+= i2c-uniphier.o
+obj-$(CONFIG_I2C_UNIPHIER_F)	+= i2c-uniphier-f.o
 obj-$(CONFIG_I2C_VERSATILE)	+= i2c-versatile.o
 obj-$(CONFIG_I2C_WMT)		+= i2c-wmt.o
 obj-$(CONFIG_I2C_OCTEON)	+= i2c-octeon.o

drivers/i2c/busses/i2c-at91.c

@@ -347,8 +347,14 @@ static void at91_twi_write_data_dma(struct at91_twi_dev *dev)
 
 static void at91_twi_read_next_byte(struct at91_twi_dev *dev)
 {
-	if (!dev->buf_len)
+	/*
+	 * If we are in this case, it means there is garbage data in RHR, so
+	 * delete them.
+	 */
+	if (!dev->buf_len) {
+		at91_twi_read(dev, AT91_TWI_RHR);
 		return;
+	}
 
 	/* 8bit read works with and without FIFO */
 	*dev->buf = readb_relaxed(dev->base + AT91_TWI_RHR);
@@ -465,19 +471,73 @@ static irqreturn_t atmel_twi_interrupt(int irq, void *dev_id)
 
 	if (!irqstatus)
 		return IRQ_NONE;
-	else if (irqstatus & AT91_TWI_RXRDY)
+	/*
+	 * In reception, the behavior of the twi device (before sama5d2) is
+	 * weird. There is some magic about RXRDY flag! When a data has been
+	 * almost received, the reception of a new one is anticipated if there
+	 * is no stop command to send. That is the reason why ask for sending
+	 * the stop command not on the last data but on the second last one.
+	 *
+	 * Unfortunately, we could still have the RXRDY flag set even if the
+	 * transfer is done and we have read the last data. It might happen
+	 * when the i2c slave device sends too quickly data after receiving the
+	 * ack from the master. The data has been almost received before having
+	 * the order to send stop. In this case, sending the stop command could
+	 * cause a RXRDY interrupt with a TXCOMP one. It is better to manage
+	 * the RXRDY interrupt first in order to not keep garbage data in the
+	 * Receive Holding Register for the next transfer.
+	 */
+	if (irqstatus & AT91_TWI_RXRDY)
 		at91_twi_read_next_byte(dev);
-	else if (irqstatus & AT91_TWI_TXRDY)
-		at91_twi_write_next_byte(dev);
-
-	/* catch error flags */
-	dev->transfer_status |= status;
 
+	/*
+	 * When a NACK condition is detected, the I2C controller sets the NACK,
+	 * TXCOMP and TXRDY bits all together in the Status Register (SR).
+	 *
+	 * 1 - Handling NACK errors with CPU write transfer.
+	 *
+	 * In such case, we should not write the next byte into the Transmit
+	 * Holding Register (THR) otherwise the I2C controller would start a new
+	 * transfer and the I2C slave is likely to reply by another NACK.
+	 *
+	 * 2 - Handling NACK errors with DMA write transfer.
+	 *
+	 * By setting the TXRDY bit in the SR, the I2C controller also triggers
+	 * the DMA controller to write the next data into the THR. Then the
+	 * result depends on the hardware version of the I2C controller.
+	 *
+	 * 2a - Without support of the Alternative Command mode.
+	 *
+	 * This is the worst case: the DMA controller is triggered to write the
+	 * next data into the THR, hence starting a new transfer: the I2C slave
+	 * is likely to reply by another NACK.
+	 * Concurrently, this interrupt handler is likely to be called to manage
+	 * the first NACK before the I2C controller detects the second NACK and
+	 * sets once again the NACK bit into the SR.
+	 * When handling the first NACK, this interrupt handler disables the I2C
+	 * controller interruptions, especially the NACK interrupt.
+	 * Hence, the NACK bit is pending into the SR. This is why we should
+	 * read the SR to clear all pending interrupts at the beginning of
+	 * at91_do_twi_transfer() before actually starting a new transfer.
+	 *
+	 * 2b - With support of the Alternative Command mode.
+	 *
+	 * When a NACK condition is detected, the I2C controller also locks the
+	 * THR (and sets the LOCK bit in the SR): even though the DMA controller
+	 * is triggered by the TXRDY bit to write the next data into the THR,
+	 * this data actually won't go on the I2C bus hence a second NACK is not
+	 * generated.
+	 */
 	if (irqstatus & (AT91_TWI_TXCOMP | AT91_TWI_NACK)) {
 		at91_disable_twi_interrupts(dev);
 		complete(&dev->cmd_complete);
+	} else if (irqstatus & AT91_TWI_TXRDY) {
+		at91_twi_write_next_byte(dev);
 	}
 
+	/* catch error flags */
+	dev->transfer_status |= status;
+
 	return IRQ_HANDLED;
 }
 
@@ -537,6 +597,9 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev)
 	reinit_completion(&dev->cmd_complete);
 	dev->transfer_status = 0;
 
+	/* Clear pending interrupts, such as NACK. */
+	at91_twi_read(dev, AT91_TWI_SR);
+
 	if (dev->fifo_size) {
 		unsigned fifo_mr = at91_twi_read(dev, AT91_TWI_FMR);
 
@@ -558,11 +621,6 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev)
 	} else if (dev->msg->flags & I2C_M_RD) {
 		unsigned start_flags = AT91_TWI_START;
 
-		if (at91_twi_read(dev, AT91_TWI_SR) & AT91_TWI_RXRDY) {
-			dev_err(dev->dev, "RXRDY still set!");
-			at91_twi_read(dev, AT91_TWI_RHR);
-		}
-
 		/* if only one byte is to be read, immediately stop transfer */
 		if (!has_alt_cmd && dev->buf_len <= 1 &&
 		    !(dev->msg->flags & I2C_M_RECV_LEN))