--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Actions Semiconductor Owl SoC's I2C driver
+ *
+ * Copyright (c) 2014 Actions Semi Inc.
+ * Author: David Liu <liuwei@actions-semi.com>
+ *
+ * Copyright (c) 2018 Linaro Ltd.
+ * Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+
+/* I2C registers */
+#define OWL_I2C_REG_CTL 0x0000
+#define OWL_I2C_REG_CLKDIV 0x0004
+#define OWL_I2C_REG_STAT 0x0008
+#define OWL_I2C_REG_ADDR 0x000C
+#define OWL_I2C_REG_TXDAT 0x0010
+#define OWL_I2C_REG_RXDAT 0x0014
+#define OWL_I2C_REG_CMD 0x0018
+#define OWL_I2C_REG_FIFOCTL 0x001C
+#define OWL_I2C_REG_FIFOSTAT 0x0020
+#define OWL_I2C_REG_DATCNT 0x0024
+#define OWL_I2C_REG_RCNT 0x0028
+
+/* I2Cx_CTL Bit Mask */
+#define OWL_I2C_CTL_RB BIT(1)
+#define OWL_I2C_CTL_GBCC(x) (((x) & 0x3) << 2)
+#define OWL_I2C_CTL_GBCC_NONE OWL_I2C_CTL_GBCC(0)
+#define OWL_I2C_CTL_GBCC_START OWL_I2C_CTL_GBCC(1)
+#define OWL_I2C_CTL_GBCC_STOP OWL_I2C_CTL_GBCC(2)
+#define OWL_I2C_CTL_GBCC_RSTART OWL_I2C_CTL_GBCC(3)
+#define OWL_I2C_CTL_IRQE BIT(5)
+#define OWL_I2C_CTL_EN BIT(7)
+#define OWL_I2C_CTL_AE BIT(8)
+#define OWL_I2C_CTL_SHSM BIT(10)
+
+#define OWL_I2C_DIV_FACTOR(x) ((x) & 0xff)
+
+/* I2Cx_STAT Bit Mask */
+#define OWL_I2C_STAT_RACK BIT(0)
+#define OWL_I2C_STAT_BEB BIT(1)
+#define OWL_I2C_STAT_IRQP BIT(2)
+#define OWL_I2C_STAT_LAB BIT(3)
+#define OWL_I2C_STAT_STPD BIT(4)
+#define OWL_I2C_STAT_STAD BIT(5)
+#define OWL_I2C_STAT_BBB BIT(6)
+#define OWL_I2C_STAT_TCB BIT(7)
+#define OWL_I2C_STAT_LBST BIT(8)
+#define OWL_I2C_STAT_SAMB BIT(9)
+#define OWL_I2C_STAT_SRGC BIT(10)
+
+/* I2Cx_CMD Bit Mask */
+#define OWL_I2C_CMD_SBE BIT(0)
+#define OWL_I2C_CMD_RBE BIT(4)
+#define OWL_I2C_CMD_DE BIT(8)
+#define OWL_I2C_CMD_NS BIT(9)
+#define OWL_I2C_CMD_SE BIT(10)
+#define OWL_I2C_CMD_MSS BIT(11)
+#define OWL_I2C_CMD_WRS BIT(12)
+#define OWL_I2C_CMD_SECL BIT(15)
+
+#define OWL_I2C_CMD_AS(x) (((x) & 0x7) << 1)
+#define OWL_I2C_CMD_SAS(x) (((x) & 0x7) << 5)
+
+/* I2Cx_FIFOCTL Bit Mask */
+#define OWL_I2C_FIFOCTL_NIB BIT(0)
+#define OWL_I2C_FIFOCTL_RFR BIT(1)
+#define OWL_I2C_FIFOCTL_TFR BIT(2)
+
+/* I2Cc_FIFOSTAT Bit Mask */
+#define OWL_I2C_FIFOSTAT_RNB BIT(1)
+#define OWL_I2C_FIFOSTAT_RFE BIT(2)
+#define OWL_I2C_FIFOSTAT_TFF BIT(5)
+#define OWL_I2C_FIFOSTAT_TFD GENMASK(23, 16)
+#define OWL_I2C_FIFOSTAT_RFD GENMASK(15, 8)
+
+/* I2C bus timeout */
+#define OWL_I2C_TIMEOUT msecs_to_jiffies(4 * 1000)
+
+#define OWL_I2C_MAX_RETRIES 50
+
+#define OWL_I2C_DEF_SPEED_HZ 100000
+#define OWL_I2C_MAX_SPEED_HZ 400000
+
+struct owl_i2c_dev {
+ struct i2c_adapter adap;
+ struct i2c_msg *msg;
+ struct completion msg_complete;
+ struct clk *clk;
+ spinlock_t lock;
+ void __iomem *base;
+ unsigned long clk_rate;
+ u32 bus_freq;
+ u32 msg_ptr;
+ int err;
+};
+
+static void owl_i2c_update_reg(void __iomem *reg, unsigned int val, bool state)
+{
+ unsigned int regval;
+
+ regval = readl(reg);
+
+ if (state)
+ regval |= val;
+ else
+ regval &= ~val;
+
+ writel(regval, reg);
+}
+
+static void owl_i2c_reset(struct owl_i2c_dev *i2c_dev)
+{
+ owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL,
+ OWL_I2C_CTL_EN, false);
+ mdelay(1);
+ owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL,
+ OWL_I2C_CTL_EN, true);
+
+ /* Clear status registers */
+ writel(0, i2c_dev->base + OWL_I2C_REG_STAT);
+}
+
+static int owl_i2c_reset_fifo(struct owl_i2c_dev *i2c_dev)
+{
+ unsigned int val, timeout = 0;
+
+ /* Reset FIFO */
+ owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_FIFOCTL,
+ OWL_I2C_FIFOCTL_RFR | OWL_I2C_FIFOCTL_TFR,
+ true);
+
+ /* Wait 50ms for FIFO reset complete */
+ do {
+ val = readl(i2c_dev->base + OWL_I2C_REG_FIFOCTL);
+ if (!(val & (OWL_I2C_FIFOCTL_RFR | OWL_I2C_FIFOCTL_TFR)))
+ break;
+ usleep_range(500, 1000);
+ } while (timeout++ < OWL_I2C_MAX_RETRIES);
+
+ if (timeout > OWL_I2C_MAX_RETRIES) {
+ dev_err(&i2c_dev->adap.dev, "FIFO reset timeout\n");
+ return -ETIMEDOUT;
+ }
+
+ return 0;
+}
+
+static void owl_i2c_set_freq(struct owl_i2c_dev *i2c_dev)
+{
+ unsigned int val;
+
+ val = DIV_ROUND_UP(i2c_dev->clk_rate, i2c_dev->bus_freq * 16);
+
+ /* Set clock divider factor */
+ writel(OWL_I2C_DIV_FACTOR(val), i2c_dev->base + OWL_I2C_REG_CLKDIV);
+}
+
+static irqreturn_t owl_i2c_interrupt(int irq, void *_dev)
+{
+ struct owl_i2c_dev *i2c_dev = _dev;
+ struct i2c_msg *msg = i2c_dev->msg;
+ unsigned long flags;
+ unsigned int stat, fifostat;
+
+ spin_lock_irqsave(&i2c_dev->lock, flags);
+
+ i2c_dev->err = 0;
+
+ /* Handle NACK from slave */
+ fifostat = readl(i2c_dev->base + OWL_I2C_REG_FIFOSTAT);
+ if (fifostat & OWL_I2C_FIFOSTAT_RNB) {
+ i2c_dev->err = -ENXIO;
+ goto stop;
+ }
+
+ /* Handle bus error */
+ stat = readl(i2c_dev->base + OWL_I2C_REG_STAT);
+ if (stat & OWL_I2C_STAT_BEB) {
+ i2c_dev->err = -EIO;
+ goto stop;
+ }
+
+ /* Handle FIFO read */
+ if (msg->flags & I2C_M_RD) {
+ while ((readl(i2c_dev->base + OWL_I2C_REG_FIFOSTAT) &
+ OWL_I2C_FIFOSTAT_RFE) && i2c_dev->msg_ptr < msg->len) {
+ msg->buf[i2c_dev->msg_ptr++] = readl(i2c_dev->base +
+ OWL_I2C_REG_RXDAT);
+ }
+ } else {
+ /* Handle the remaining bytes which were not sent */
+ while (!(readl(i2c_dev->base + OWL_I2C_REG_FIFOSTAT) &
+ OWL_I2C_FIFOSTAT_TFF) && i2c_dev->msg_ptr < msg->len) {
+ writel(msg->buf[i2c_dev->msg_ptr++],
+ i2c_dev->base + OWL_I2C_REG_TXDAT);
+ }
+ }
+
+stop:
+ /* Clear pending interrupts */
+ owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_STAT,
+ OWL_I2C_STAT_IRQP, true);
+
+ complete_all(&i2c_dev->msg_complete);
+ spin_unlock_irqrestore(&i2c_dev->lock, flags);
+
+ return IRQ_HANDLED;
+}
+
+static u32 owl_i2c_func(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static int owl_i2c_check_bus_busy(struct i2c_adapter *adap)
+{
+ struct owl_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
+ unsigned long timeout;
+
+ /* Check for Bus busy */
+ timeout = jiffies + OWL_I2C_TIMEOUT;
+ while (readl(i2c_dev->base + OWL_I2C_REG_STAT) & OWL_I2C_STAT_BBB) {
+ if (time_after(jiffies, timeout)) {
+ dev_err(&adap->dev, "Bus busy timeout\n");
+ return -ETIMEDOUT;
+ }
+ }
+
+ return 0;
+}
+
+static int owl_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
+ int num)
+{
+ struct owl_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
+ struct i2c_msg *msg;
+ unsigned long time_left, flags;
+ unsigned int i2c_cmd, val;
+ unsigned int addr;
+ int ret, idx;
+
+ spin_lock_irqsave(&i2c_dev->lock, flags);
+
+ /* Reset I2C controller */
+ owl_i2c_reset(i2c_dev);
+
+ /* Set bus frequency */
+ owl_i2c_set_freq(i2c_dev);
+
+ /*
+ * Spinlock should be released before calling reset FIFO and
+ * bus busy check since those functions may sleep
+ */
+ spin_unlock_irqrestore(&i2c_dev->lock, flags);
+
+ /* Reset FIFO */
+ ret = owl_i2c_reset_fifo(i2c_dev);
+ if (ret)
+ goto unlocked_err_exit;
+
+ /* Check for bus busy */
+ ret = owl_i2c_check_bus_busy(adap);
+ if (ret)
+ goto unlocked_err_exit;
+
+ spin_lock_irqsave(&i2c_dev->lock, flags);
+
+ /* Check for Arbitration lost */
+ val = readl(i2c_dev->base + OWL_I2C_REG_STAT);
+ if (val & OWL_I2C_STAT_LAB) {
+ val &= ~OWL_I2C_STAT_LAB;
+ writel(val, i2c_dev->base + OWL_I2C_REG_STAT);
+ ret = -EAGAIN;
+ goto err_exit;
+ }
+
+ reinit_completion(&i2c_dev->msg_complete);
+
+ /* Enable I2C controller interrupt */
+ owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL,
+ OWL_I2C_CTL_IRQE, true);
+
+ /*
+ * Select: FIFO enable, Master mode, Stop enable, Data count enable,
+ * Send start bit
+ */
+ i2c_cmd = OWL_I2C_CMD_SECL | OWL_I2C_CMD_MSS | OWL_I2C_CMD_SE |
+ OWL_I2C_CMD_NS | OWL_I2C_CMD_DE | OWL_I2C_CMD_SBE;
+
+ /* Handle repeated start condition */
+ if (num > 1) {
+ /* Set internal address length and enable repeated start */
+ i2c_cmd |= OWL_I2C_CMD_AS(msgs[0].len + 1) |
+ OWL_I2C_CMD_SAS(1) | OWL_I2C_CMD_RBE;
+
+ /* Write slave address */
+ addr = i2c_8bit_addr_from_msg(&msgs[0]);
+ writel(addr, i2c_dev->base + OWL_I2C_REG_TXDAT);
+
+ /* Write internal register address */
+ for (idx = 0; idx < msgs[0].len; idx++)
+ writel(msgs[0].buf[idx],
+ i2c_dev->base + OWL_I2C_REG_TXDAT);
+
+ msg = &msgs[1];
+ } else {
+ /* Set address length */
+ i2c_cmd |= OWL_I2C_CMD_AS(1);
+ msg = &msgs[0];
+ }
+
+ i2c_dev->msg = msg;
+ i2c_dev->msg_ptr = 0;
+
+ /* Set data count for the message */
+ writel(msg->len, i2c_dev->base + OWL_I2C_REG_DATCNT);
+
+ addr = i2c_8bit_addr_from_msg(msg);
+ writel(addr, i2c_dev->base + OWL_I2C_REG_TXDAT);
+
+ if (!(msg->flags & I2C_M_RD)) {
+ /* Write data to FIFO */
+ for (idx = 0; idx < msg->len; idx++) {
+ /* Check for FIFO full */
+ if (readl(i2c_dev->base + OWL_I2C_REG_FIFOSTAT) &
+ OWL_I2C_FIFOSTAT_TFF)
+ break;
+
+ writel(msg->buf[idx],
+ i2c_dev->base + OWL_I2C_REG_TXDAT);
+ }
+
+ i2c_dev->msg_ptr = idx;
+ }
+
+ /* Ignore the NACK if needed */
+ if (msg->flags & I2C_M_IGNORE_NAK)
+ owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_FIFOCTL,
+ OWL_I2C_FIFOCTL_NIB, true);
+ else
+ owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_FIFOCTL,
+ OWL_I2C_FIFOCTL_NIB, false);
+
+ /* Start the transfer */
+ writel(i2c_cmd, i2c_dev->base + OWL_I2C_REG_CMD);
+
+ spin_unlock_irqrestore(&i2c_dev->lock, flags);
+
+ time_left = wait_for_completion_timeout(&i2c_dev->msg_complete,
+ adap->timeout);
+
+ spin_lock_irqsave(&i2c_dev->lock, flags);
+ if (time_left == 0) {
+ dev_err(&adap->dev, "Transaction timed out\n");
+ /* Send stop condition and release the bus */
+ owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL,
+ OWL_I2C_CTL_GBCC_STOP | OWL_I2C_CTL_RB,
+ true);
+ ret = -ETIMEDOUT;
+ goto err_exit;
+ }
+
+ ret = i2c_dev->err < 0 ? i2c_dev->err : num;
+
+err_exit:
+ spin_unlock_irqrestore(&i2c_dev->lock, flags);
+
+unlocked_err_exit:
+ /* Disable I2C controller */
+ owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL,
+ OWL_I2C_CTL_EN, false);
+
+ return ret;
+}
+
+static const struct i2c_algorithm owl_i2c_algorithm = {
+ .master_xfer = owl_i2c_master_xfer,
+ .functionality = owl_i2c_func,
+};
+
+static const struct i2c_adapter_quirks owl_i2c_quirks = {
+ .flags = I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST,
+ .max_read_len = 240,
+ .max_write_len = 240,
+ .max_comb_1st_msg_len = 6,
+ .max_comb_2nd_msg_len = 240,
+};
+
+static int owl_i2c_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct owl_i2c_dev *i2c_dev;
+ struct resource *res;
+ int ret, irq;
+
+ i2c_dev = devm_kzalloc(dev, sizeof(*i2c_dev), GFP_KERNEL);
+ if (!i2c_dev)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ i2c_dev->base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(i2c_dev->base))
+ return PTR_ERR(i2c_dev->base);
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0) {
+ dev_err(dev, "failed to get IRQ number\n");
+ return irq;
+ }
+
+ if (of_property_read_u32(dev->of_node, "clock-frequency",
+ &i2c_dev->bus_freq))
+ i2c_dev->bus_freq = OWL_I2C_DEF_SPEED_HZ;
+
+ /* We support only frequencies of 100k and 400k for now */
+ if (i2c_dev->bus_freq != OWL_I2C_DEF_SPEED_HZ &&
+ i2c_dev->bus_freq != OWL_I2C_MAX_SPEED_HZ) {
+ dev_err(dev, "invalid clock-frequency %d\n", i2c_dev->bus_freq);
+ return -EINVAL;
+ }
+
+ i2c_dev->clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(i2c_dev->clk)) {
+ dev_err(dev, "failed to get clock\n");
+ return PTR_ERR(i2c_dev->clk);
+ }
+
+ ret = clk_prepare_enable(i2c_dev->clk);
+ if (ret)
+ return ret;
+
+ i2c_dev->clk_rate = clk_get_rate(i2c_dev->clk);
+ if (!i2c_dev->clk_rate) {
+ dev_err(dev, "input clock rate should not be zero\n");
+ ret = -EINVAL;
+ goto disable_clk;
+ }
+
+ init_completion(&i2c_dev->msg_complete);
+ spin_lock_init(&i2c_dev->lock);
+ i2c_dev->adap.owner = THIS_MODULE;
+ i2c_dev->adap.algo = &owl_i2c_algorithm;
+ i2c_dev->adap.timeout = OWL_I2C_TIMEOUT;
+ i2c_dev->adap.quirks = &owl_i2c_quirks;
+ i2c_dev->adap.dev.parent = dev;
+ i2c_dev->adap.dev.of_node = dev->of_node;
+ snprintf(i2c_dev->adap.name, sizeof(i2c_dev->adap.name),
+ "%s", "OWL I2C adapter");
+ i2c_set_adapdata(&i2c_dev->adap, i2c_dev);
+
+ platform_set_drvdata(pdev, i2c_dev);
+
+ ret = devm_request_irq(dev, irq, owl_i2c_interrupt, 0, pdev->name,
+ i2c_dev);
+ if (ret) {
+ dev_err(dev, "failed to request irq %d\n", irq);
+ goto disable_clk;
+ }
+
+ return i2c_add_adapter(&i2c_dev->adap);
+
+disable_clk:
+ clk_disable_unprepare(i2c_dev->clk);
+
+ return ret;
+}
+
+static const struct of_device_id owl_i2c_of_match[] = {
+ { .compatible = "actions,s900-i2c" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, owl_i2c_of_match);
+
+static struct platform_driver owl_i2c_driver = {
+ .probe = owl_i2c_probe,
+ .driver = {
+ .name = "owl-i2c",
+ .of_match_table = of_match_ptr(owl_i2c_of_match),
+ },
+};
+module_platform_driver(owl_i2c_driver);
+
+MODULE_AUTHOR("David Liu <liuwei@actions-semi.com>");
+MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>");
+MODULE_DESCRIPTION("Actions Semiconductor Owl SoC's I2C driver");
+MODULE_LICENSE("GPL");
projects / openwrt / staging / blogic.git / commitdiff