i2c: phytium: Add i2c driver for Phytium I2C adapter

Add a driver for Phytium I2C controller with SMBus alert interrupt support.

Signed-off-by: Cheng Quan <[email protected]>
Signed-off-by: Feng Jun <[email protected]>
Signed-off-by: Chen Baozi <[email protected]>
Signed-off-by: Wang Yinfeng <[email protected]>
Signed-off-by: Jiakun Shuai <[email protected]>

Author: JiakunShuai

drivers/i2c/busses/Kconfig

@@ -938,6 +938,34 @@ config I2C_PCA_PLATFORM
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-pca-platform.
 
+config I2C_PHYTIUM_CORE
+	tristate
+
+config I2C_PHYTIUM_PCI
+	tristate "Phytium I2C PCI"
+	depends on PCI && ARCH_PHYTIUM
+	select I2C_PHYTIUM_CORE
+	select I2C_SMBUS
+	help
+	  If you say yes to this option, support will be included for the
+	  Phytium I2C adapter. Only master mode is supported.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-phytium-pci.
+
+config I2C_PHYTIUM_PLATFORM
+	tristate "Phytium I2C Platform"
+	depends on (ACPI && COMMON_CLK) || !ACPI
+	select I2C_SLAVE
+	select I2C_PHYTIUM_CORE
+	select I2C_SMBUS
+	help
+	  If you say yes to this option, support will be included for the
+	  Phytium I2C adapter. Only master mode is supported.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-phytium-platform.
+
 config I2C_PNX
 	tristate "I2C bus support for Philips PNX and NXP LPC targets"
 	depends on ARCH_LPC32XX || COMPILE_TEST

drivers/i2c/busses/Makefile

@@ -93,6 +93,10 @@ obj-$(CONFIG_I2C_OWL)		+= i2c-owl.o
 obj-$(CONFIG_I2C_PASEMI)	+= i2c-pasemi-core.o i2c-pasemi-pci.o
 obj-$(CONFIG_I2C_APPLE)		+= i2c-pasemi-core.o i2c-pasemi-platform.o
 obj-$(CONFIG_I2C_PCA_PLATFORM)	+= i2c-pca-platform.o
+obj-$(CONFIG_I2C_PHYTIUM_CORE)	+= i2c-phytium-core.o
+i2c-phytium-core-objs := i2c-phytium-common.o i2c-phytium-master.o i2c-phytium-slave.o
+obj-$(CONFIG_I2C_PHYTIUM_PCI)	+= i2c-phytium-pci.o
+obj-$(CONFIG_I2C_PHYTIUM_PLATFORM)	+= i2c-phytium-platform.o
 obj-$(CONFIG_I2C_PNX)		+= i2c-pnx.o
 obj-$(CONFIG_I2C_PXA)		+= i2c-pxa.o
 obj-$(CONFIG_I2C_PXA_PCI)	+= i2c-pxa-pci.o

drivers/i2c/busses/i2c-phytium-common.c

@@ -0,0 +1,206 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Phytium I2C adapter driver.
+ *
+ * Derived from Synopysys I2C driver.
+ *   Copyright (C) 2006 Texas Instruments.
+ *   Copyright (C) 2007 MontaVista Software Inc.
+ *   Copyright (C) 2009 Provigent Ltd.
+ *
+ * Copyright (C) 2021-2023, Phytium Technology Co., Ltd.
+ */
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/export.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+#include <linux/swab.h>
+
+#include "i2c-phytium-core.h"
+
+static char *abort_sources[] = {
+	[ABRT_7B_ADDR_NOACK] =
+		"slave address not acknowledged (7bit mode)",
+	[ABRT_10ADDR1_NOACK] =
+		"first address byte not acknowledged (10bit mode)",
+	[ABRT_10ADDR2_NOACK] =
+		"second address byte not acknowledged (10bit mode)",
+	[ABRT_TXDATA_NOACK] =
+		"data not acknowledged",
+	[ABRT_GCALL_NOACK] =
+		"no acknowledgment for a general call",
+	[ABRT_GCALL_READ] =
+		"read after general call",
+	[ABRT_SBYTE_ACKDET] =
+		"start byte acknowledged",
+	[ABRT_SBYTE_NORSTRT] =
+		"trying to send start byte when restart is disabled",
+	[ABRT_10B_RD_NORSTRT] =
+		"trying to read when restart is disabled (10bit mode)",
+	[ABRT_MASTER_DIS] =
+		"trying to use disabled adapter",
+	[ARB_LOST] =
+		"lost arbitration",
+	[ABRT_SLAVE_FLUSH_TXFIFO] =
+		"read command so flush old data in the TX FIFO",
+	[ABRT_SLAVE_ARBLOST] =
+		"slave lost the bus while transmitting data to a remote master",
+	[ABRT_SLAVE_RD_INTX] =
+		"incorrect slave-transmitter mode configuration",
+};
+
+u32 phytium_readl(struct phytium_i2c_dev *dev, int offset)
+{
+	return readl_relaxed(dev->base + offset);
+}
+
+void phytium_writel(struct phytium_i2c_dev *dev, u32 b, int offset)
+{
+	writel_relaxed(b, dev->base + offset);
+}
+
+u32 i2c_phytium_scl_hcnt(u32 ic_clk, u32 tSYMBOL, u32 tf, int cond, int offset)
+{
+	if (cond)
+		return (ic_clk * tSYMBOL + 500000) / 1000000 - 8 + offset;
+	else
+		return (ic_clk * (tSYMBOL + tf) + 500000) / 1000000 - 3 + offset;
+}
+
+u32 i2c_phytium_scl_lcnt(u32 ic_clk, u32 tLOW, u32 tf, int offset)
+{
+	return ((ic_clk * (tLOW + tf) + 500000) / 1000000) - 1 + offset;
+}
+
+int i2c_phytium_set_sda_hold(struct phytium_i2c_dev *dev)
+{
+	if (!dev->sda_hold_time) {
+		/* Keep previous hold time setting if no one set it */
+		dev->sda_hold_time = phytium_readl(dev, IC_SDA_HOLD);
+	}
+
+	if (!(dev->sda_hold_time & IC_SDA_HOLD_RX_MASK))
+		dev->sda_hold_time |= 1 << IC_SDA_HOLD_RX_SHIFT;
+
+	dev_dbg(dev->dev, "SDA Hold Time TX:RX = %d:%d\n",
+		dev->sda_hold_time & ~(u32)IC_SDA_HOLD_RX_MASK,
+		dev->sda_hold_time >> IC_SDA_HOLD_RX_SHIFT);
+
+	return 0;
+}
+
+void __i2c_phytium_disable(struct phytium_i2c_dev *dev)
+{
+	int timeout = 100;
+
+	do {
+		__i2c_phytium_disable_nowait(dev);
+		if ((phytium_readl(dev, IC_ENABLE_STATUS) & 1) == 0)
+			return;
+
+		/*
+		 * Wait 10 times the signaling period of the highest I2C
+		 * transfer supported by the driver (for 400KHz this is
+		 * 25us).
+		 */
+		usleep_range(25, 250);
+	} while (timeout--);
+
+	dev_warn(dev->dev, "timeout in disabling adapter\n");
+}
+
+unsigned long i2c_phytium_clk_rate(struct phytium_i2c_dev *dev)
+{
+	if (WARN_ON_ONCE(!dev->get_clk_rate_khz))
+		return 0;
+	return dev->get_clk_rate_khz(dev);
+}
+
+int i2c_phytium_prepare_clk(struct phytium_i2c_dev *dev, bool prepare)
+{
+	if (IS_ERR(dev->clk))
+		return PTR_ERR(dev->clk);
+
+	if (prepare)
+		return clk_prepare_enable(dev->clk);
+
+	clk_disable_unprepare(dev->clk);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(i2c_phytium_prepare_clk);
+
+int i2c_phytium_wait_bus_not_busy(struct phytium_i2c_dev *dev)
+{
+	int timeout = 20; /* 20 ms */
+
+	while (phytium_readl(dev, IC_STATUS) & IC_STATUS_ACTIVITY) {
+		if (timeout <= 0) {
+			dev_warn(dev->dev, "timeout waiting for bus ready\n");
+			i2c_recover_bus(&dev->adapter);
+
+			if (phytium_readl(dev, IC_STATUS) & IC_STATUS_ACTIVITY)
+				return -ETIMEDOUT;
+			return 0;
+		}
+		timeout--;
+		usleep_range(1000, 1100);
+	}
+
+	return 0;
+}
+
+int i2c_phytium_handle_tx_abort(struct phytium_i2c_dev *dev)
+{
+	unsigned long abort_source = dev->abort_source;
+	int i;
+
+	if (abort_source & IC_TX_ABRT_NOACK) {
+		for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources))
+			dev_dbg(dev->dev,
+				"%s: %s\n", __func__, abort_sources[i]);
+		return -EREMOTEIO;
+	}
+
+	for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources))
+		dev_err(dev->dev, "%s: %s\n", __func__, abort_sources[i]);
+
+	if (abort_source & IC_TX_ARB_LOST)
+		return -EAGAIN;
+	else if (abort_source & IC_TX_ABRT_GCALL_READ)
+		return -EINVAL;
+	else
+		return -EIO;
+
+	return 0;
+}
+
+u32 i2c_phytium_func(struct i2c_adapter *adapter)
+{
+	struct phytium_i2c_dev *dev = i2c_get_adapdata(adapter);
+
+	return dev->functionality;
+}
+
+void i2c_phytium_disable(struct phytium_i2c_dev *dev)
+{
+	/* Disable controller */
+	__i2c_phytium_disable(dev);
+
+	/* Disable all interrupts */
+	phytium_writel(dev, 0, IC_INTR_MASK);
+	phytium_readl(dev, IC_CLR_INTR);
+}
+
+void i2c_phytium_disable_int(struct phytium_i2c_dev *dev)
+{
+	phytium_writel(dev, 0, IC_INTR_MASK);
+}
+
+MODULE_AUTHOR("Cheng Quan <[email protected]>");
+MODULE_DESCRIPTION("Phytium I2C bus adapter core");
+MODULE_LICENSE("GPL");