/* * 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/init.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", .owner = THIS_MODULE, }, }; 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");