[PATCH v1 0/2] i2c: microchip: Add driver for PolarFire SoC

[PATCH v1 0/2] i2c: microchip: Add driver for PolarFire SoC

[daire.mcnamara]

From: Daire McNamara <daire.mcnamara@microchip.com>

This patchset adds support for the Microchip PolarFire SoC I2C
hardware block.

Daire McNamara (2):
  dt-bindings: i2c: microchip: Add Microchip PolarFire host binding
  i2c: microchip: Add driver for Microchip PolarFire SoC

 .../bindings/i2c/microchip,mpfs-i2c.yaml      |  74 +++
 drivers/i2c/busses/Kconfig                    |   6 +
 drivers/i2c/busses/Makefile                   |   1 +
 drivers/i2c/busses/i2c-microchip.c            | 519 ++++++++++++++++++
 4 files changed, 600 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/i2c/microchip,mpfs-i2c.yaml
 create mode 100755 drivers/i2c/busses/i2c-microchip.c


base-commit: acd3d28594536e9096c1ea76c5867d8a68babef6
prerequisite-patch-id: 6f7f70120adfa8e938b97517f0c664e43e8745a0
prerequisite-patch-id: 4ea37008d23838aa2e0658811fe15462f6cdbd87
prerequisite-patch-id: 378c9d7495e56454b7bffbdbc430185dc4e36b90
prerequisite-patch-id: b547bbdf0a800c652cdd1a542b8ce725dfd6fcc9
prerequisite-patch-id: 26afc006e51cf743902bf609b537e1558e70f69c
prerequisite-patch-id: 55e615f1af62373acc71366ceb4c27fbcecec60d
prerequisite-patch-id: 6bda20a1c98622e33f3bf0126ae696716c963e4b
-- 
2.25.1

[PATCH v1 1/2] dt-bindings: i2c: microchip: Add Microchip PolarFire host binding

[daire.mcnamara]

From: Daire McNamara <daire.mcnamara@microchip.com>

Add device tree bindings for the Microchip PolarFire I2C controller

Signed-off-by: Daire McNamara <daire.mcnamara@microchip.com>
---
 .../bindings/i2c/microchip,mpfs-i2c.yaml      | 74 +++++++++++++++++++
 1 file changed, 74 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/i2c/microchip,mpfs-i2c.yaml

diff --git a/Documentation/devicetree/bindings/i2c/microchip,mpfs-i2c.yaml b/Documentation/devicetree/bindings/i2c/microchip,mpfs-i2c.yaml
new file mode 100644
index 000000000000..bc4ea4498d35
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/microchip,mpfs-i2c.yaml
@@ -0,0 +1,74 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/i2c/microchip,mpfs-i2c.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Microchip MPFS I2C Controller Device Tree Bindings
+
+maintainers:
+  - Daire McNamara <daire.mcnamara@microchip.com>
+
+description: |
+  This I2C controller is found on the Microchip PolarFire SoC.
+
+allOf:
+  - $ref: /schemas/i2c/i2c-controller.yaml#
+
+properties:
+  compatible:
+    enum:
+      - microchip,mpfs-i2c # Microchip PolarFire SoC compatible SoCs
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    description: Phandle of the clock feeding the I2C controller.
+    minItems: 1
+
+  clock-frequency:
+    description: |
+      Desired I2C bus clock frequency in Hz. As only Standard and Fast
+      modes are supported, possible values are 100000 and 400000.
+    enum: [100000, 400000]
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/microchip,mpfs-clock.h>
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+        i2c@2010a000 {
+            compatible = "microchip,mpfs-i2c";
+            reg = <0 0x2010a000 0 0x1000>;
+            interrupts = <58>;
+            clock-frequency = <100000>;
+            clocks = <&clkcfg CLK_I2C0>;
+        };
+    };
+  - |
+    #include <dt-bindings/clock/microchip,mpfs-clock.h>
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+        i2c@2010b000 {
+            compatible = "microchip,mpfs-i2c";
+            reg = <0 0x2010b000 0 0x1000>;
+            interrupts = <61>;
+            clock-frequency = <100000>;
+            clocks = <&clkcfg CLK_I2C1>;
+        };
+    };
+...
-- 
2.25.1

[PATCH v1 2/2] i2c: microchip: Add driver for Microchip PolarFire SoC

[daire.mcnamara]

From: Daire McNamara <Daire.McNamara@microchip.com>

Add support for i2c on Microchip PolarFire SoC

Signed-off-by: Daire McNamara <daire.mcnamara@microchip.com>
---
 drivers/i2c/busses/Kconfig         |   6 +
 drivers/i2c/busses/Makefile        |   1 +
 drivers/i2c/busses/i2c-microchip.c | 519 +++++++++++++++++++++++++++++
 3 files changed, 526 insertions(+)
 create mode 100755 drivers/i2c/busses/i2c-microchip.c

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 3eec59f1fed3..2a7e3b27cb7f 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -747,6 +747,12 @@ config I2C_MESON
 	  If you say yes to this option, support will be included for the
 	  I2C interface on the Amlogic Meson family of SoCs.
 
+config I2C_MICROCHIP
+	tristate "Microchip I2C"
+	help
+	  If you say yes to this option, support will be included for the
+	  Microchip I2C interface.
+
 config I2C_MPC
 	tristate "MPC107/824x/85xx/512x/52xx/83xx/86xx"
 	depends on PPC
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 615f35e3e31f..0962ce7bfd20 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -73,6 +73,7 @@ obj-$(CONFIG_I2C_JZ4780)	+= i2c-jz4780.o
 obj-$(CONFIG_I2C_KEMPLD)	+= i2c-kempld.o
 obj-$(CONFIG_I2C_LPC2K)		+= i2c-lpc2k.o
 obj-$(CONFIG_I2C_MESON)		+= i2c-meson.o
+obj-$(CONFIG_I2C_MICROCHIP)	+= i2c-microchip.o
 obj-$(CONFIG_I2C_MPC)		+= i2c-mpc.o
 obj-$(CONFIG_I2C_MT65XX)	+= i2c-mt65xx.o
 obj-$(CONFIG_I2C_MT7621)	+= i2c-mt7621.o
diff --git a/drivers/i2c/busses/i2c-microchip.c b/drivers/i2c/busses/i2c-microchip.c
new file mode 100755
index 000000000000..0d75b248b41b
--- /dev/null
+++ b/drivers/i2c/busses/i2c-microchip.c
@@ -0,0 +1,519 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Microchip I2C controller driver
+ *
+ * Copyright (c) 2018 - 2021 Microchip Corporation. All rights reserved.
+ *
+ * Author: Daire McNamara <daire.mcnamara@microchip.com>
+ */
+#include <linux/clk.h>
+#include <linux/clkdev.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/iopoll.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+
+#define MICROCHIP_I2C_TIMEOUT (msecs_to_jiffies(1000))
+
+#define MPFS_I2C_CTRL				(0x00)
+#define   CTRL_CR0				(0x00)
+#define   CTRL_CR1				(0x01)
+#define   CTRL_AA				(0x02)
+#define   CTRL_SI				(0x03)
+#define   CTRL_STO				(0x04)
+#define   CTRL_STA				(0x05)
+#define   CTRL_ENS1				(0x06)
+#define   CTRL_CR2				(0x07)
+#define MPFS_I2C_STATUS				(0x04)
+#define   STATUS_BUS_ERROR			(0x00)
+#define   STATUS_M_START_SENT			(0x08)
+#define   STATUS_M_REPEATED_START_SENT		(0x10)
+#define   STATUS_M_SLAW_ACK			(0x18)
+#define   STATUS_M_SLAW_NACK			(0x20)
+#define   STATUS_M_TX_DATA_ACK			(0x28)
+#define   STATUS_M_TX_DATA_NACK			(0x30)
+#define   STATUS_M_ARB_LOST			(0x38)
+#define   STATUS_M_SLAR_ACK			(0x40)
+#define   STATUS_M_SLAR_NACK			(0x48)
+#define   STATUS_M_RX_DATA_ACKED		(0x50)
+#define   STATUS_M_RX_DATA_NACKED		(0x58)
+#define   STATUS_S_SLAW_ACKED			(0x60)
+#define   STATUS_S_ARB_LOST_SLAW_ACKED		(0x68)
+#define   STATUS_S_GENERAL_CALL_ACKED		(0x70)
+#define   STATUS_S_ARB_LOST_GENERAL_CALL_ACKED	(0x78)
+#define   STATUS_S_RX_DATA_ACKED		(0x80)
+#define   STATUS_S_RX_DATA_NACKED		(0x88)
+#define   STATUS_S_GENERAL_CALL_RX_DATA_ACKED	(0x90)
+#define   STATUS_S_GENERAL_CALL_RX_DATA_NACKED	(0x98)
+#define   STATUS_S_RX_STOP			(0xA0)
+#define   STATUS_S_SLAR_ACKED			(0xA8)
+#define   STATUS_S_ARB_LOST_SLAR_ACKED		(0xB0)
+#define   STATUS_S_TX_DATA_ACK			(0xb8)
+#define   STATUS_S_TX_DATA_NACK			(0xC0)
+#define   STATUS_LAST_DATA_ACK			(0xC8)
+#define   STATUS_M_SMB_MASTER_RESET		(0xD0)
+#define   STATUS_S_SCL_LOW_TIMEOUT		(0xD8) /* 25 ms */
+#define   STATUS_NO_STATE_INFO			(0xF8)
+#define MPFS_I2C_DATA				(0x08)
+#define   WRITE_BIT				(0)
+#define   READ_BIT				BIT(0)
+#define   SLAVE_ADDR_SHIFT			(1)
+#define MPFS_I2C_SLAVE0_ADDR			(0x0c)
+#define   GENERAL_CALL_BIT			BIT(0)
+#define MPFS_I2C_SMBUS				(0x10)
+#define   SMBALERT_INT_ENB			(0)
+#define   SMBSUS_INT_ENB			(1)
+#define   SMBUS_ENB				(2)
+#define   SMBALERT_NI_STATUS			(3)
+#define   SMBALERT_NO_CTRL			(4)
+#define   SMBSUS_NI_STATUS			(5)
+#define   SMBSUS_NO_CTRL			(6)
+#define   SMBUS_RESET				(7)
+#define MPFS_I2C_FREQ				(0x14)
+#define MPFS_I2C_GLITCHREG			(0x18)
+#define MPFS_I2C_SLAVE1_ADDR			(0x1c)
+
+#define PCLK_DIV_256  ((0 << CTRL_CR0) | (0 << CTRL_CR1) | (0 << CTRL_CR2))
+#define PCLK_DIV_224  ((1 << CTRL_CR0) | (0 << CTRL_CR1) | (0 << CTRL_CR2))
+#define PCLK_DIV_192  ((0 << CTRL_CR0) | (1 << CTRL_CR1) | (0 << CTRL_CR2))
+#define PCLK_DIV_160  ((1 << CTRL_CR0) | (1 << CTRL_CR1) | (0 << CTRL_CR2))
+#define PCLK_DIV_960  ((0 << CTRL_CR0) | (0 << CTRL_CR1) | (1 << CTRL_CR2))
+#define PCLK_DIV_120  ((1 << CTRL_CR0) | (0 << CTRL_CR1) | (1 << CTRL_CR2))
+#define PCLK_DIV_60   ((0 << CTRL_CR0) | (1 << CTRL_CR1) | (1 << CTRL_CR2))
+#define BCLK_DIV_8    ((1 << CTRL_CR0) | (1 << CTRL_CR1) | (1 << CTRL_CR2))
+#define CLK_MASK      ((1 << CTRL_CR0) | (1 << CTRL_CR1) | (1 << CTRL_CR2))
+
+/*
+ * mpfs_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.
+ * @isr_status: cached copy of local ISR status.
+ * @lock: spinlock for IRQ synchronization.
+ */
+struct mpfs_i2c_dev {
+	void __iomem *base;
+	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;
+	u8 addr;
+	u32 msg_read;
+	u32 isr_status;
+	spinlock_t lock;	/* IRQ synchronization */
+};
+
+static void mpfs_i2c_int_clear(struct mpfs_i2c_dev *idev)
+{
+	u8 ctrl = readl(idev->base + MPFS_I2C_CTRL);
+
+	ctrl &= ~(1 << CTRL_SI);
+	writel(ctrl, idev->base + MPFS_I2C_CTRL);
+}
+
+static void mpfs_i2c_core_disable(struct mpfs_i2c_dev *idev)
+{
+	u8 ctrl = readl(idev->base + MPFS_I2C_CTRL);
+
+	ctrl &= ~(1 << CTRL_ENS1);
+	writel(ctrl, idev->base + MPFS_I2C_CTRL);
+}
+
+static void mpfs_i2c_core_enable(struct mpfs_i2c_dev *idev)
+{
+	u8 ctrl = readl(idev->base + MPFS_I2C_CTRL);
+
+	ctrl |= (1 << CTRL_ENS1);
+	writel(ctrl, idev->base + MPFS_I2C_CTRL);
+}
+
+static void mpfs_i2c_reset(struct mpfs_i2c_dev *idev)
+{
+	mpfs_i2c_core_disable(idev);
+	mpfs_i2c_core_enable(idev);
+}
+
+static inline void mpfs_i2c_stop(struct mpfs_i2c_dev *idev)
+{
+	u8 ctrl = readl(idev->base + MPFS_I2C_CTRL);
+
+	ctrl |= (1 << CTRL_STO);
+	writel(ctrl, idev->base + MPFS_I2C_CTRL);
+}
+
+static inline int mpfs_generate_divisor(u32 rate, u8 *code)
+{
+	int ret = 0;
+
+	if (rate >= 960)
+		*code = PCLK_DIV_960;
+	else if (rate >= 256)
+		*code = PCLK_DIV_256;
+	else if (rate >= 224)
+		*code = PCLK_DIV_224;
+	else if (rate >= 192)
+		*code = PCLK_DIV_192;
+	else if (rate >= 160)
+		*code = PCLK_DIV_160;
+	else if (rate >= 120)
+		*code = PCLK_DIV_120;
+	else if (rate >= 60)
+		*code = PCLK_DIV_60;
+	else if (rate >= 8)
+		*code = BCLK_DIV_8;
+	else
+		ret = -1;
+
+	return ret;
+}
+
+static int mpfs_i2c_init(struct mpfs_i2c_dev *idev)
+{
+	u32 clk_rate = clk_get_rate(idev->i2c_clk);
+	u32 divisor = clk_rate / idev->bus_clk_rate;
+	u8 clkval;
+	int ret;
+	u8 ctrl = readl(idev->base + MPFS_I2C_CTRL);
+
+	ctrl &= ~CLK_MASK;
+
+	ret = mpfs_generate_divisor(divisor, &clkval);
+
+	if (ret)
+		return -1;
+
+	ctrl |= clkval;
+
+	writel(ctrl, idev->base + MPFS_I2C_CTRL);
+
+	ctrl = readl(idev->base + MPFS_I2C_CTRL);
+
+	/* Reset controller */
+	mpfs_i2c_reset(idev);
+
+	return 0;
+}
+
+static void mpfs_i2c_transfer(struct mpfs_i2c_dev *idev, u32 data)
+{
+	if (idev->msg_len > 0)
+		writel(data, idev->base + MPFS_I2C_DATA);
+}
+
+static void mpfs_i2c_empty_rx(struct mpfs_i2c_dev *idev)
+{
+	u8 ctrl;
+
+	if (idev->msg_len > 0) {
+		*idev->buf++ = readl(idev->base + MPFS_I2C_DATA);
+		idev->msg_len--;
+	}
+
+	if (idev->msg_len == 0) {
+		ctrl = readl(idev->base + MPFS_I2C_CTRL);
+		ctrl &= ~(1 << CTRL_AA);
+		writel(ctrl, idev->base + MPFS_I2C_CTRL);
+	}
+}
+
+static int mpfs_i2c_fill_tx(struct mpfs_i2c_dev *idev)
+{
+	mpfs_i2c_transfer(idev, *idev->buf++);
+	idev->msg_len--;
+
+	return 0;
+}
+
+static irqreturn_t mpfs_i2c_handle_isr(int irq, void *_dev)
+{
+	bool read, finish = false;
+	struct mpfs_i2c_dev *idev = _dev;
+	u32 status = idev->isr_status;
+	u8 ctrl;
+
+	if (!idev->buf) {
+		dev_warn(idev->dev, "unexpected interrupt\n");
+		return IRQ_HANDLED;
+	}
+
+	read = idev->msg_read ? 1 : 0;
+
+	switch (status) {
+	case STATUS_M_START_SENT:
+	case STATUS_M_REPEATED_START_SENT:
+		ctrl = readl(idev->base + MPFS_I2C_CTRL);
+		ctrl &= ~(1 << CTRL_STA);
+		writel(idev->addr, idev->base + MPFS_I2C_DATA);
+		writel(ctrl, idev->base + MPFS_I2C_CTRL);
+		if (idev->msg_len <= 0)
+			finish = true;
+		break;
+	case STATUS_M_ARB_LOST:
+		/* handle Lost Arbitration */
+		idev->msg_err = -EAGAIN;
+		finish = true;
+		break;
+	case  STATUS_M_SLAW_ACK:
+		if (idev->msg_len > 0) {
+			mpfs_i2c_fill_tx(idev);
+		} else {
+			/* On the last byte to be transmitted, send STOP */
+			mpfs_i2c_stop(idev);
+			finish = true;
+		}
+		break;
+	case STATUS_M_TX_DATA_NACK:
+	case STATUS_M_RX_DATA_NACKED:
+	case STATUS_M_SLAR_NACK:
+	case STATUS_M_SLAW_NACK:
+		idev->msg_err = -ENXIO;
+		mpfs_i2c_stop(idev);
+		finish = true;
+		break;
+	case STATUS_M_TX_DATA_ACK:
+		if (idev->msg_len > 0) {
+			mpfs_i2c_fill_tx(idev);
+		} else {
+			/* On the last byte to be transmitted, send STOP */
+			mpfs_i2c_stop(idev);
+			finish = true;
+		}
+		break;
+	case STATUS_M_SLAR_ACK:
+		ctrl = readl(idev->base + MPFS_I2C_CTRL);
+		ctrl |= (1 << CTRL_AA);
+		writel(ctrl, idev->base + MPFS_I2C_CTRL);
+		if (idev->msg_len == 0) {
+			/* On the last byte to be transmitted, send STOP */
+			mpfs_i2c_stop(idev);
+			finish = true;
+		}
+		break;
+	case STATUS_M_RX_DATA_ACKED:
+		mpfs_i2c_empty_rx(idev);
+		if (idev->msg_len == 0) {
+			/* On the last byte to be transmitted, send STOP */
+			mpfs_i2c_stop(idev);
+			finish = true;
+		}
+		break;
+	default:
+		break;
+	}
+
+	if (finish) {
+		ctrl = readl(idev->base + MPFS_I2C_CTRL);
+		ctrl &= ~(1 << CTRL_AA);
+		writel(ctrl, idev->base + MPFS_I2C_CTRL);
+		complete(&idev->msg_complete);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t mpfs_i2c_isr(int irq, void *_dev)
+{
+	struct mpfs_i2c_dev *idev = _dev;
+	irqreturn_t ret = IRQ_NONE;
+	int si_bit = 0;
+
+	si_bit = readl(idev->base + MPFS_I2C_CTRL);
+	if (si_bit & (1 << CTRL_SI)) {
+		idev->isr_status = readl(idev->base + MPFS_I2C_STATUS);
+		ret = mpfs_i2c_handle_isr(irq, idev);
+	}
+
+	// Clear the si flag
+	mpfs_i2c_int_clear(idev);
+
+	return ret;
+}
+
+static int mpfs_i2c_xfer_msg(struct mpfs_i2c_dev *idev, struct i2c_msg *msg)
+{
+	u8 ctrl;
+	unsigned long time_left;
+
+	if (msg->len == 0)
+		return -EINVAL;
+
+	idev->addr = i2c_8bit_addr_from_msg(msg);
+	idev->msg_len = msg->len;
+	idev->buf = msg->buf;
+	idev->msg_err = 0;
+	idev->msg_read = (msg->flags & I2C_M_RD);
+
+	reinit_completion(&idev->msg_complete);
+
+	mpfs_i2c_core_enable(idev);
+
+	ctrl = readl(idev->base + MPFS_I2C_CTRL);
+
+	ctrl |= (1 << CTRL_STA);
+
+	writel(ctrl, idev->base + MPFS_I2C_CTRL);
+
+	time_left = wait_for_completion_timeout(&idev->msg_complete,
+						MICROCHIP_I2C_TIMEOUT);
+
+	if (time_left == 0)
+		return -ETIMEDOUT;
+
+	return idev->msg_err;
+}
+
+static int mpfs_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
+{
+	struct mpfs_i2c_dev *idev = i2c_get_adapdata(adap);
+	int i, ret;
+
+	for (i = 0; i < num; i++) {
+		ret = mpfs_i2c_xfer_msg(idev, msgs++);
+		if (ret)
+			return ret;
+	}
+
+	return num;
+}
+
+static u32 mpfs_i2c_func(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm mpfs_i2c_algo = {
+	.master_xfer = mpfs_i2c_xfer,
+	.functionality = mpfs_i2c_func,
+};
+
+static int mpfs_i2c_probe(struct platform_device *pdev)
+{
+	struct mpfs_i2c_dev *idev = NULL;
+	struct resource *res;
+	int irq, ret;
+	u32 val;
+
+	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);
+	spin_lock_init(&idev->lock);
+
+	val = device_property_read_u32(idev->dev, "clock-frequency",
+				       &idev->bus_clk_rate);
+	if (val) {
+		dev_info(&pdev->dev, "default to 100kHz\n");
+		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, mpfs_i2c_isr,
+			       IRQF_SHARED, 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;
+	}
+
+	ret = mpfs_i2c_init(idev);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to program clock divider\n");
+		return ret;
+	}
+
+	i2c_set_adapdata(&idev->adapter, idev);
+	snprintf(idev->adapter.name, sizeof(idev->adapter.name),
+		 "Microchip I2C hw bus");
+	idev->adapter.owner = THIS_MODULE;
+	idev->adapter.algo = &mpfs_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, "Microchip I2C Probe Complete\n");
+
+	return 0;
+}
+
+static int mpfs_i2c_remove(struct platform_device *pdev)
+{
+	struct mpfs_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 mpfs_i2c_of_match[] = {
+	{ .compatible = "microchip,mpfs-i2c" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, mpfs_i2c_of_match);
+
+static struct platform_driver mpfs_i2c_driver = {
+	.probe = mpfs_i2c_probe,
+	.remove = mpfs_i2c_remove,
+	.driver = {
+		.name = "microchip-mpfs-i2c",
+		.of_match_table = mpfs_i2c_of_match,
+	},
+};
+
+module_platform_driver(mpfs_i2c_driver);
+
+MODULE_DESCRIPTION("Microchip I2C bus driver");
+MODULE_AUTHOR("Microchip Corporation");
+MODULE_LICENSE("GPL v2");
-- 
2.25.1

Re: [PATCH v1 1/2] dt-bindings: i2c: microchip: Add Microchip PolarFire host binding

[Rob Herring]

On Wed, 12 May 2021 12:20:23 +0100, daire.mcnamara@microchip.com wrote:
> From: Daire McNamara <daire.mcnamara@microchip.com>
> 
> Add device tree bindings for the Microchip PolarFire I2C controller
> 
> Signed-off-by: Daire McNamara <daire.mcnamara@microchip.com>
> ---
>  .../bindings/i2c/microchip,mpfs-i2c.yaml      | 74 +++++++++++++++++++
>  1 file changed, 74 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/i2c/microchip,mpfs-i2c.yaml
> 

My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check'
on your patch (DT_CHECKER_FLAGS is new in v5.13):

yamllint warnings/errors:

dtschema/dtc warnings/errors:
Documentation/devicetree/bindings/i2c/microchip,mpfs-i2c.example.dts:19:18: fatal error: dt-bindings/clock/microchip,mpfs-clock.h: No such file or directory
   19 |         #include <dt-bindings/clock/microchip,mpfs-clock.h>
      |                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.
make[1]: *** [scripts/Makefile.lib:380: Documentation/devicetree/bindings/i2c/microchip,mpfs-i2c.example.dt.yaml] Error 1
make[1]: *** Waiting for unfinished jobs....
make: *** [Makefile:1416: dt_binding_check] Error 2

See https://patchwork.ozlabs.org/patch/1477553

This check can fail if there are any dependencies. The base for a patch
series is generally the most recent rc1.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit.

Re: [PATCH v1 2/2] i2c: microchip: Add driver for Microchip PolarFire SoC

[Wolfram Sang]

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Hi Daire,

thanks for your driver! Some issues, but nothing major.

some checkpatch errors first:

ERROR: do not set execute permissions for source files
#47: FILE: drivers/i2c/busses/i2c-microchip.c

This must be fixed.


WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?

Are you interested in maintaining the driver? Then, please add a section
to MAINTAINERS as well.

WARNING: From:/Signed-off-by: email address mismatch: 'From: Daire McNamara <Daire.McNamara@microchip.com>' != 'Signed-off-by: Daire McNamara <daire.mcnamara@microchip.com>'

Would be nice to have this consistent as well!


> +config I2C_MICROCHIP
> +	tristate "Microchip I2C"
> +	help
> +	  If you say yes to this option, support will be included for the
> +	  Microchip I2C interface.
> +

Document the module name?

> @@ -0,0 +1,519 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Microchip I2C controller driver
> + *
> + * Copyright (c) 2018 - 2021 Microchip Corporation. All rights reserved.
> + *
> + * Author: Daire McNamara <daire.mcnamara@microchip.com>
> + */
> +#include <linux/clk.h>
> +#include <linux/clkdev.h>
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/iopoll.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/platform_device.h>
> +
> +#define MICROCHIP_I2C_TIMEOUT (msecs_to_jiffies(1000))
> +
> +#define MPFS_I2C_CTRL				(0x00)
> +#define   CTRL_CR0				(0x00)
> +#define   CTRL_CR1				(0x01)
> +#define   CTRL_AA				(0x02)
> +#define   CTRL_SI				(0x03)
> +#define   CTRL_STO				(0x04)
> +#define   CTRL_STA				(0x05)
> +#define   CTRL_ENS1				(0x06)
> +#define   CTRL_CR2				(0x07)

Using the BIT() macros, this would remove a lot of "1 << " from the
driver and make it quite more readable, I'd say.

> +static int mpfs_i2c_init(struct mpfs_i2c_dev *idev)
> +{
> +	u32 clk_rate = clk_get_rate(idev->i2c_clk);
> +	u32 divisor = clk_rate / idev->bus_clk_rate;

Not protected against division by zero, or?

> +	u8 clkval;
> +	int ret;
> +	u8 ctrl = readl(idev->base + MPFS_I2C_CTRL);
> +
> +	ctrl &= ~CLK_MASK;
> +
> +	ret = mpfs_generate_divisor(divisor, &clkval);
> +
> +	if (ret)
> +		return -1;

-EINVAL instead of -1? In mpfs_generate_divisor as well.

> +
> +	ctrl |= clkval;
> +
> +	writel(ctrl, idev->base + MPFS_I2C_CTRL);
> +
> +	ctrl = readl(idev->base + MPFS_I2C_CTRL);
> +
> +	/* Reset controller */

Very obvious comment :)

> +	mpfs_i2c_reset(idev);
> +
> +	return 0;
> +}

> +static irqreturn_t mpfs_i2c_handle_isr(int irq, void *_dev)
> +{
> +	bool read, finish = false;

drivers/i2c/busses/i2c-microchip.c: In function ‘mpfs_i2c_handle_isr’:
drivers/i2c/busses/i2c-microchip.c:244:7: warning: variable ‘read’ set but not used [-Wunused-but-set-variable]

> +	struct mpfs_i2c_dev *idev = _dev;
> +	u32 status = idev->isr_status;
> +	u8 ctrl;
> +
> +	if (!idev->buf) {
> +		dev_warn(idev->dev, "unexpected interrupt\n");
> +		return IRQ_HANDLED;
> +	}
> +
> +	read = idev->msg_read ? 1 : 0;
> +
> +	switch (status) {
> +	case STATUS_M_START_SENT:
> +	case STATUS_M_REPEATED_START_SENT:
> +		ctrl = readl(idev->base + MPFS_I2C_CTRL);
> +		ctrl &= ~(1 << CTRL_STA);
> +		writel(idev->addr, idev->base + MPFS_I2C_DATA);
> +		writel(ctrl, idev->base + MPFS_I2C_CTRL);
> +		if (idev->msg_len <= 0)

    CPPCHECK
drivers/i2c/busses/i2c-microchip.c:263:21: warning: Checking if unsigned expression 'idev->msg_len' is less than zero. [unsignedLessThanZero]

...

> +static int mpfs_i2c_xfer_msg(struct mpfs_i2c_dev *idev, struct i2c_msg *msg)
> +{
> +	u8 ctrl;
> +	unsigned long time_left;
> +
> +	if (msg->len == 0)
> +		return -EINVAL;

Use a 'struct i2c_adapter_quirks' with the I2C_AQ_NO_ZERO_LEN flag and
the core will check that for you.

> +static u32 mpfs_i2c_func(struct i2c_adapter *adap)
> +{
> +	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
> +}

If you can't do zero lenght transfers, you'll need
(I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK).

> +static int mpfs_i2c_probe(struct platform_device *pdev)
> +{
> +	struct mpfs_i2c_dev *idev = NULL;

Initialization not needed.

> +	idev->dev = &pdev->dev;
> +	init_completion(&idev->msg_complete);
> +	spin_lock_init(&idev->lock);

This spinlock is not used anywhere? It seems that everything spinlock
related can go?

> +
> +	val = device_property_read_u32(idev->dev, "clock-frequency",
> +				       &idev->bus_clk_rate);
> +	if (val) {
> +		dev_info(&pdev->dev, "default to 100kHz\n");
> +		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, mpfs_i2c_isr,
> +			       IRQF_SHARED, 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;
> +	}
> +
> +	ret = mpfs_i2c_init(idev);
> +	if (ret) {
> +		dev_err(&pdev->dev, "failed to program clock divider\n");
> +		return ret;
> +	}
> +
> +	i2c_set_adapdata(&idev->adapter, idev);
> +	snprintf(idev->adapter.name, sizeof(idev->adapter.name),
> +		 "Microchip I2C hw bus");

Most people add the base address of the registers here to be able to
differentiate multiple adapters in one system.

> +	idev->adapter.owner = THIS_MODULE;
> +	idev->adapter.algo = &mpfs_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, "Microchip I2C Probe Complete\n");
> +
> +	return 0;
> +}

But this is all pretty minor stuff. It looks quite good actually!

Happy hacking,

   Wolfram


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Re: [PATCH v1 1/2] dt-bindings: i2c: microchip: Add Microchip PolarFire host binding

[Wolfram Sang]

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Hi Rob,

> Documentation/devicetree/bindings/i2c/microchip,mpfs-i2c.example.dts:19:18: fatal error: dt-bindings/clock/microchip,mpfs-clock.h: No such file or directory
>    19 |         #include <dt-bindings/clock/microchip,mpfs-clock.h>
>       |                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> compilation terminated.

I'd think this is only because the file has not hit -next yet?

Would you be so kind and review the bindings nonetheless?

Thank you and kind regards,

   Wolfram


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