diff options
Diffstat (limited to 'arch/mips/mti-sead3/sead3-i2c-drv.c')
| -rw-r--r-- | arch/mips/mti-sead3/sead3-i2c-drv.c | 405 |
1 files changed, 405 insertions, 0 deletions
diff --git a/arch/mips/mti-sead3/sead3-i2c-drv.c b/arch/mips/mti-sead3/sead3-i2c-drv.c new file mode 100644 index 00000000000..0375ee66bca --- /dev/null +++ b/arch/mips/mti-sead3/sead3-i2c-drv.c @@ -0,0 +1,405 @@ +/* + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 2012 MIPS Technologies, Inc. All rights reserved. + */ +#include <linux/init.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/delay.h> +#include <linux/i2c.h> +#include <linux/platform_device.h> + +#define PIC32_I2CxCON 0x0000 +#define PIC32_I2CCON_ON (1<<15) +#define PIC32_I2CCON_ACKDT (1<<5) +#define PIC32_I2CCON_ACKEN (1<<4) +#define PIC32_I2CCON_RCEN (1<<3) +#define PIC32_I2CCON_PEN (1<<2) +#define PIC32_I2CCON_RSEN (1<<1) +#define PIC32_I2CCON_SEN (1<<0) +#define PIC32_I2CxCONCLR 0x0004 +#define PIC32_I2CxCONSET 0x0008 +#define PIC32_I2CxSTAT 0x0010 +#define PIC32_I2CxSTATCLR 0x0014 +#define PIC32_I2CSTAT_ACKSTAT (1<<15) +#define PIC32_I2CSTAT_TRSTAT (1<<14) +#define PIC32_I2CSTAT_BCL (1<<10) +#define PIC32_I2CSTAT_IWCOL (1<<7) +#define PIC32_I2CSTAT_I2COV (1<<6) +#define PIC32_I2CxBRG 0x0040 +#define PIC32_I2CxTRN 0x0050 +#define PIC32_I2CxRCV 0x0060 + +static DEFINE_SPINLOCK(pic32_bus_lock); + +static void __iomem *bus_xfer = (void __iomem *)0xbf000600; +static void __iomem *bus_status = (void __iomem *)0xbf000060; + +#define DELAY() udelay(100) + +static inline unsigned int ioready(void) +{ + return readl(bus_status) & 1; +} + +static inline void wait_ioready(void) +{ + do { } while (!ioready()); +} + +static inline void wait_ioclear(void) +{ + do { } while (ioready()); +} + +static inline void check_ioclear(void) +{ + if (ioready()) { + do { + (void) readl(bus_xfer); + DELAY(); + } while (ioready()); + } +} + +static u32 pic32_bus_readl(u32 reg) +{ + unsigned long flags; + u32 status, val; + + spin_lock_irqsave(&pic32_bus_lock, flags); + + check_ioclear(); + writel((0x01 << 24) | (reg & 0x00ffffff), bus_xfer); + DELAY(); + wait_ioready(); + status = readl(bus_xfer); + DELAY(); + val = readl(bus_xfer); + wait_ioclear(); + + spin_unlock_irqrestore(&pic32_bus_lock, flags); + + return val; +} + +static void pic32_bus_writel(u32 val, u32 reg) +{ + unsigned long flags; + u32 status; + + spin_lock_irqsave(&pic32_bus_lock, flags); + + check_ioclear(); + writel((0x10 << 24) | (reg & 0x00ffffff), bus_xfer); + DELAY(); + writel(val, bus_xfer); + DELAY(); + wait_ioready(); + status = readl(bus_xfer); + wait_ioclear(); + + spin_unlock_irqrestore(&pic32_bus_lock, flags); +} + +struct pic32_i2c_platform_data { + u32 base; + struct i2c_adapter adap; + u32 xfer_timeout; + u32 ack_timeout; + u32 ctl_timeout; +}; + +static inline void pic32_i2c_start(struct pic32_i2c_platform_data *adap) +{ + pic32_bus_writel(PIC32_I2CCON_SEN, adap->base + PIC32_I2CxCONSET); +} + +static inline void pic32_i2c_stop(struct pic32_i2c_platform_data *adap) +{ + pic32_bus_writel(PIC32_I2CCON_PEN, adap->base + PIC32_I2CxCONSET); +} + +static inline void pic32_i2c_ack(struct pic32_i2c_platform_data *adap) +{ + pic32_bus_writel(PIC32_I2CCON_ACKDT, adap->base + PIC32_I2CxCONCLR); + pic32_bus_writel(PIC32_I2CCON_ACKEN, adap->base + PIC32_I2CxCONSET); +} + +static inline void pic32_i2c_nack(struct pic32_i2c_platform_data *adap) +{ + pic32_bus_writel(PIC32_I2CCON_ACKDT, adap->base + PIC32_I2CxCONSET); + pic32_bus_writel(PIC32_I2CCON_ACKEN, adap->base + PIC32_I2CxCONSET); +} + +static inline int pic32_i2c_idle(struct pic32_i2c_platform_data *adap) +{ + int i; + + for (i = 0; i < adap->ctl_timeout; i++) { + if (((pic32_bus_readl(adap->base + PIC32_I2CxCON) & + (PIC32_I2CCON_ACKEN | PIC32_I2CCON_RCEN | + PIC32_I2CCON_PEN | PIC32_I2CCON_RSEN | + PIC32_I2CCON_SEN)) == 0) && + ((pic32_bus_readl(adap->base + PIC32_I2CxSTAT) & + (PIC32_I2CSTAT_TRSTAT)) == 0)) + return 0; + udelay(1); + } + return -ETIMEDOUT; +} + +static inline u32 pic32_i2c_master_write(struct pic32_i2c_platform_data *adap, + u32 byte) +{ + pic32_bus_writel(byte, adap->base + PIC32_I2CxTRN); + return pic32_bus_readl(adap->base + PIC32_I2CxSTAT) & + PIC32_I2CSTAT_IWCOL; +} + +static inline u32 pic32_i2c_master_read(struct pic32_i2c_platform_data *adap) +{ + pic32_bus_writel(PIC32_I2CCON_RCEN, adap->base + PIC32_I2CxCONSET); + while (pic32_bus_readl(adap->base + PIC32_I2CxCON) & PIC32_I2CCON_RCEN) + ; + pic32_bus_writel(PIC32_I2CSTAT_I2COV, adap->base + PIC32_I2CxSTATCLR); + return pic32_bus_readl(adap->base + PIC32_I2CxRCV); +} + +static int pic32_i2c_address(struct pic32_i2c_platform_data *adap, + unsigned int addr, int rd) +{ + pic32_i2c_idle(adap); + pic32_i2c_start(adap); + pic32_i2c_idle(adap); + + addr <<= 1; + if (rd) + addr |= 1; + + if (pic32_i2c_master_write(adap, addr)) + return -EIO; + pic32_i2c_idle(adap); + if (pic32_bus_readl(adap->base + PIC32_I2CxSTAT) & + PIC32_I2CSTAT_ACKSTAT) + return -EIO; + return 0; +} + +static int sead3_i2c_read(struct pic32_i2c_platform_data *adap, + unsigned char *buf, unsigned int len) +{ + u32 data; + int i; + + i = 0; + while (i < len) { + data = pic32_i2c_master_read(adap); + buf[i++] = data; + if (i < len) + pic32_i2c_ack(adap); + else + pic32_i2c_nack(adap); + } + + pic32_i2c_stop(adap); + pic32_i2c_idle(adap); + return 0; +} + +static int sead3_i2c_write(struct pic32_i2c_platform_data *adap, + unsigned char *buf, unsigned int len) +{ + int i; + u32 data; + + i = 0; + while (i < len) { + data = buf[i]; + if (pic32_i2c_master_write(adap, data)) + return -EIO; + pic32_i2c_idle(adap); + if (pic32_bus_readl(adap->base + PIC32_I2CxSTAT) & + PIC32_I2CSTAT_ACKSTAT) + return -EIO; + i++; + } + + pic32_i2c_stop(adap); + pic32_i2c_idle(adap); + return 0; +} + +static int sead3_pic32_platform_xfer(struct i2c_adapter *i2c_adap, + struct i2c_msg *msgs, int num) +{ + struct pic32_i2c_platform_data *adap = i2c_adap->algo_data; + struct i2c_msg *p; + int i, err = 0; + + for (i = 0; i < num; i++) { +#define __BUFSIZE 80 + int ii; + static char buf[__BUFSIZE]; + char *b = buf; + + p = &msgs[i]; + b += sprintf(buf, " [%d bytes]", p->len); + if ((p->flags & I2C_M_RD) == 0) { + for (ii = 0; ii < p->len; ii++) { + if (b < &buf[__BUFSIZE-4]) { + b += sprintf(b, " %02x", p->buf[ii]); + } else { + strcat(b, "..."); + break; + } + } + } + } + + for (i = 0; !err && i < num; i++) { + p = &msgs[i]; + err = pic32_i2c_address(adap, p->addr, p->flags & I2C_M_RD); + if (err || !p->len) + continue; + if (p->flags & I2C_M_RD) + err = sead3_i2c_read(adap, p->buf, p->len); + else + err = sead3_i2c_write(adap, p->buf, p->len); + } + + /* Return the number of messages processed, or the error code. */ + if (err == 0) + err = num; + + return err; +} + +static u32 sead3_pic32_platform_func(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; +} + +static const struct i2c_algorithm sead3_platform_algo = { + .master_xfer = sead3_pic32_platform_xfer, + .functionality = sead3_pic32_platform_func, +}; + +static void sead3_i2c_platform_setup(struct pic32_i2c_platform_data *priv) +{ + pic32_bus_writel(500, priv->base + PIC32_I2CxBRG); + pic32_bus_writel(PIC32_I2CCON_ON, priv->base + PIC32_I2CxCONCLR); + pic32_bus_writel(PIC32_I2CCON_ON, priv->base + PIC32_I2CxCONSET); + pic32_bus_writel(PIC32_I2CSTAT_BCL | PIC32_I2CSTAT_IWCOL, + priv->base + PIC32_I2CxSTATCLR); +} + +static int __devinit sead3_i2c_platform_probe(struct platform_device *pdev) +{ + struct pic32_i2c_platform_data *priv; + struct resource *r; + int ret; + + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!r) { + ret = -ENODEV; + goto out; + } + + priv = kzalloc(sizeof(struct pic32_i2c_platform_data), GFP_KERNEL); + if (!priv) { + ret = -ENOMEM; + goto out; + } + + priv->base = r->start; + if (!priv->base) { + ret = -EBUSY; + goto out_mem; + } + + priv->xfer_timeout = 200; + priv->ack_timeout = 200; + priv->ctl_timeout = 200; + + priv->adap.nr = pdev->id; + priv->adap.algo = &sead3_platform_algo; + priv->adap.algo_data = priv; + priv->adap.dev.parent = &pdev->dev; + strlcpy(priv->adap.name, "SEAD3 PIC32", sizeof(priv->adap.name)); + + sead3_i2c_platform_setup(priv); + + ret = i2c_add_numbered_adapter(&priv->adap); + if (ret == 0) { + platform_set_drvdata(pdev, priv); + return 0; + } + +out_mem: + kfree(priv); +out: + return ret; +} + +static int __devexit sead3_i2c_platform_remove(struct platform_device *pdev) +{ + struct pic32_i2c_platform_data *priv = platform_get_drvdata(pdev); + + platform_set_drvdata(pdev, NULL); + i2c_del_adapter(&priv->adap); + kfree(priv); + return 0; +} + +#ifdef CONFIG_PM +static int sead3_i2c_platform_suspend(struct platform_device *pdev, + pm_message_t state) +{ + dev_dbg(&pdev->dev, "i2c_platform_disable\n"); + return 0; +} + +static int sead3_i2c_platform_resume(struct platform_device *pdev) +{ + struct pic32_i2c_platform_data *priv = platform_get_drvdata(pdev); + + dev_dbg(&pdev->dev, "sead3_i2c_platform_setup\n"); + sead3_i2c_platform_setup(priv); + + return 0; +} +#else +#define sead3_i2c_platform_suspend NULL +#define sead3_i2c_platform_resume NULL +#endif + +static struct platform_driver sead3_i2c_platform_driver = { + .driver = { + .name = "sead3-i2c", + .owner = THIS_MODULE, + }, + .probe = sead3_i2c_platform_probe, + .remove = __devexit_p(sead3_i2c_platform_remove), + .suspend = sead3_i2c_platform_suspend, + .resume = sead3_i2c_platform_resume, +}; + +static int __init sead3_i2c_platform_init(void) +{ + return platform_driver_register(&sead3_i2c_platform_driver); +} +module_init(sead3_i2c_platform_init); + +static void __exit sead3_i2c_platform_exit(void) +{ + platform_driver_unregister(&sead3_i2c_platform_driver); +} +module_exit(sead3_i2c_platform_exit); + +MODULE_AUTHOR("Chris Dearman, MIPS Technologies INC."); +MODULE_DESCRIPTION("SEAD3 PIC32 I2C driver"); +MODULE_LICENSE("GPL"); |