--- /dev/null
+/*
+ * Copyright 2011, Netlogic Microsystems Inc.
+ * Copyright 2004, Matt Porter <mporter@kernel.crashing.org>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/ioport.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+
+/* XLR I2C REGISTERS */
+#define XLR_I2C_CFG 0x00
+#define XLR_I2C_CLKDIV 0x01
+#define XLR_I2C_DEVADDR 0x02
+#define XLR_I2C_ADDR 0x03
+#define XLR_I2C_DATAOUT 0x04
+#define XLR_I2C_DATAIN 0x05
+#define XLR_I2C_STATUS 0x06
+#define XLR_I2C_STARTXFR 0x07
+#define XLR_I2C_BYTECNT 0x08
+#define XLR_I2C_HDSTATIM 0x09
+
+/* XLR I2C REGISTERS FLAGS */
+#define XLR_I2C_BUS_BUSY 0x01
+#define XLR_I2C_SDOEMPTY 0x02
+#define XLR_I2C_RXRDY 0x04
+#define XLR_I2C_ACK_ERR 0x08
+#define XLR_I2C_ARB_STARTERR 0x30
+
+/* Register Values */
+#define XLR_I2C_CFG_ADDR 0xF8
+#define XLR_I2C_CFG_NOADDR 0xFA
+#define XLR_I2C_STARTXFR_ND 0x02 /* No Data */
+#define XLR_I2C_STARTXFR_RD 0x01 /* Read */
+#define XLR_I2C_STARTXFR_WR 0x00 /* Write */
+
+#define XLR_I2C_TIMEOUT 10 /* timeout per byte in msec */
+
+/*
+ * On XLR/XLS, we need to use __raw_ IO to read the I2C registers
+ * because they are in the big-endian MMIO area on the SoC.
+ *
+ * The readl/writel implementation on XLR/XLS byteswaps, because
+ * those are for its little-endian PCI space (see arch/mips/Kconfig).
+ */
+static inline void xlr_i2c_wreg(u32 __iomem *base, unsigned int reg, u32 val)
+{
+ __raw_writel(val, base + reg);
+}
+
+static inline u32 xlr_i2c_rdreg(u32 __iomem *base, unsigned int reg)
+{
+ return __raw_readl(base + reg);
+}
+
+struct xlr_i2c_private {
+ struct i2c_adapter adap;
+ u32 __iomem *iobase;
+};
+
+static int xlr_i2c_tx(struct xlr_i2c_private *priv, u16 len,
+ u8 *buf, u16 addr)
+{
+ struct i2c_adapter *adap = &priv->adap;
+ unsigned long timeout, stoptime, checktime;
+ u32 i2c_status;
+ int pos, timedout;
+ u8 offset, byte;
+
+ offset = buf[0];
+ xlr_i2c_wreg(priv->iobase, XLR_I2C_ADDR, offset);
+ xlr_i2c_wreg(priv->iobase, XLR_I2C_DEVADDR, addr);
+ xlr_i2c_wreg(priv->iobase, XLR_I2C_CFG, XLR_I2C_CFG_ADDR);
+ xlr_i2c_wreg(priv->iobase, XLR_I2C_BYTECNT, len - 1);
+
+ timeout = msecs_to_jiffies(XLR_I2C_TIMEOUT);
+ stoptime = jiffies + timeout;
+ timedout = 0;
+ pos = 1;
+retry:
+ if (len == 1) {
+ xlr_i2c_wreg(priv->iobase, XLR_I2C_STARTXFR,
+ XLR_I2C_STARTXFR_ND);
+ } else {
+ xlr_i2c_wreg(priv->iobase, XLR_I2C_DATAOUT, buf[pos]);
+ xlr_i2c_wreg(priv->iobase, XLR_I2C_STARTXFR,
+ XLR_I2C_STARTXFR_WR);
+ }
+
+ while (!timedout) {
+ checktime = jiffies;
+ i2c_status = xlr_i2c_rdreg(priv->iobase, XLR_I2C_STATUS);
+
+ if (i2c_status & XLR_I2C_SDOEMPTY) {
+ pos++;
+ /* need to do a empty dataout after the last byte */
+ byte = (pos < len) ? buf[pos] : 0;
+ xlr_i2c_wreg(priv->iobase, XLR_I2C_DATAOUT, byte);
+
+ /* reset timeout on successful xmit */
+ stoptime = jiffies + timeout;
+ }
+ timedout = time_after(checktime, stoptime);
+
+ if (i2c_status & XLR_I2C_ARB_STARTERR) {
+ if (timedout)
+ break;
+ goto retry;
+ }
+
+ if (i2c_status & XLR_I2C_ACK_ERR)
+ return -EIO;
+
+ if ((i2c_status & XLR_I2C_BUS_BUSY) == 0 && pos >= len)
+ return 0;
+ }
+ dev_err(&adap->dev, "I2C transmit timeout\n");
+ return -ETIMEDOUT;
+}
+
+static int xlr_i2c_rx(struct xlr_i2c_private *priv, u16 len, u8 *buf, u16 addr)
+{
+ struct i2c_adapter *adap = &priv->adap;
+ u32 i2c_status;
+ unsigned long timeout, stoptime, checktime;
+ int nbytes, timedout;
+ u8 byte;
+
+ xlr_i2c_wreg(priv->iobase, XLR_I2C_CFG, XLR_I2C_CFG_NOADDR);
+ xlr_i2c_wreg(priv->iobase, XLR_I2C_BYTECNT, len);
+ xlr_i2c_wreg(priv->iobase, XLR_I2C_DEVADDR, addr);
+
+ timeout = msecs_to_jiffies(XLR_I2C_TIMEOUT);
+ stoptime = jiffies + timeout;
+ timedout = 0;
+ nbytes = 0;
+retry:
+ xlr_i2c_wreg(priv->iobase, XLR_I2C_STARTXFR, XLR_I2C_STARTXFR_RD);
+
+ while (!timedout) {
+ checktime = jiffies;
+ i2c_status = xlr_i2c_rdreg(priv->iobase, XLR_I2C_STATUS);
+ if (i2c_status & XLR_I2C_RXRDY) {
+ if (nbytes > len)
+ return -EIO; /* should not happen */
+
+ /* we need to do a dummy datain when nbytes == len */
+ byte = xlr_i2c_rdreg(priv->iobase, XLR_I2C_DATAIN);
+ if (nbytes < len)
+ buf[nbytes] = byte;
+ nbytes++;
+
+ /* reset timeout on successful read */
+ stoptime = jiffies + timeout;
+ }
+
+ timedout = time_after(checktime, stoptime);
+ if (i2c_status & XLR_I2C_ARB_STARTERR) {
+ if (timedout)
+ break;
+ goto retry;
+ }
+
+ if (i2c_status & XLR_I2C_ACK_ERR)
+ return -EIO;
+
+ if ((i2c_status & XLR_I2C_BUS_BUSY) == 0)
+ return 0;
+ }
+
+ dev_err(&adap->dev, "I2C receive timeout\n");
+ return -ETIMEDOUT;
+}
+
+static int xlr_i2c_xfer(struct i2c_adapter *adap,
+ struct i2c_msg *msgs, int num)
+{
+ struct i2c_msg *msg;
+ int i;
+ int ret = 0;
+ struct xlr_i2c_private *priv = i2c_get_adapdata(adap);
+
+ for (i = 0; ret == 0 && i < num; i++) {
+ msg = &msgs[i];
+ if (msg->flags & I2C_M_RD)
+ ret = xlr_i2c_rx(priv, msg->len, &msg->buf[0],
+ msg->addr);
+ else
+ ret = xlr_i2c_tx(priv, msg->len, &msg->buf[0],
+ msg->addr);
+ }
+
+ return (ret != 0) ? ret : num;
+}
+
+static u32 xlr_func(struct i2c_adapter *adap)
+{
+ /* Emulate SMBUS over I2C */
+ return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C;
+}
+
+static struct i2c_algorithm xlr_i2c_algo = {
+ .master_xfer = xlr_i2c_xfer,
+ .functionality = xlr_func,
+};
+
+static int xlr_i2c_probe(struct platform_device *pdev)
+{
+ struct xlr_i2c_private *priv;
+ struct resource *res;
+ int ret;
+
+ priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ priv->iobase = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(priv->iobase))
+ return PTR_ERR(priv->iobase);
+
+ priv->adap.dev.parent = &pdev->dev;
+ priv->adap.owner = THIS_MODULE;
+ priv->adap.algo_data = priv;
+ priv->adap.algo = &xlr_i2c_algo;
+ priv->adap.nr = pdev->id;
+ priv->adap.class = I2C_CLASS_HWMON;
+ snprintf(priv->adap.name, sizeof(priv->adap.name), "xlr-i2c");
+
+ i2c_set_adapdata(&priv->adap, priv);
+ ret = i2c_add_numbered_adapter(&priv->adap);
+ if (ret < 0) {
+ dev_err(&priv->adap.dev, "Failed to add i2c bus.\n");
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, priv);
+ dev_info(&priv->adap.dev, "Added I2C Bus.\n");
+ return 0;
+}
+
+static int xlr_i2c_remove(struct platform_device *pdev)
+{
+ struct xlr_i2c_private *priv;
+
+ priv = platform_get_drvdata(pdev);
+ i2c_del_adapter(&priv->adap);
+ return 0;
+}
+
+static struct platform_driver xlr_i2c_driver = {
+ .probe = xlr_i2c_probe,
+ .remove = xlr_i2c_remove,
+ .driver = {
+ .name = "xlr-i2cbus",
+ },
+};
+
+module_platform_driver(xlr_i2c_driver);
+
+MODULE_AUTHOR("Ganesan Ramalingam <ganesanr@netlogicmicro.com>");
+MODULE_DESCRIPTION("XLR/XLS SoC I2C Controller driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:xlr-i2cbus");
Code Review / kvmfornfv.git / blobdiff