Loading arch/arm/mach-w90x900/include/mach/i2c.h 0 → 100644 +9 −0 Original line number Diff line number Diff line #ifndef __ASM_ARCH_NUC900_I2C_H #define __ASM_ARCH_NUC900_I2C_H struct nuc900_platform_i2c { int bus_num; unsigned long bus_freq; }; #endif /* __ASM_ARCH_NUC900_I2C_H */ drivers/i2c/busses/Kconfig +7 −0 Original line number Diff line number Diff line Loading @@ -448,6 +448,13 @@ config I2C_NOMADIK If you say yes to this option, support will be included for the I2C interface from ST-Ericsson's Nomadik and Ux500 architectures. config I2C_NUC900 tristate "NUC900 I2C Driver" depends on ARCH_W90X900 help Say Y here to include support for I2C controller in the Winbond/Nuvoton NUC900 based System-on-Chip devices. config I2C_OCORES tristate "OpenCores I2C Controller" depends on EXPERIMENTAL Loading drivers/i2c/busses/Makefile +1 −0 Original line number Diff line number Diff line Loading @@ -43,6 +43,7 @@ obj-$(CONFIG_I2C_IXP2000) += i2c-ixp2000.o obj-$(CONFIG_I2C_MPC) += i2c-mpc.o obj-$(CONFIG_I2C_MV64XXX) += i2c-mv64xxx.o obj-$(CONFIG_I2C_NOMADIK) += i2c-nomadik.o obj-$(CONFIG_I2C_NUC900) += i2c-nuc900.o obj-$(CONFIG_I2C_OCORES) += i2c-ocores.o obj-$(CONFIG_I2C_OMAP) += i2c-omap.o obj-$(CONFIG_I2C_PASEMI) += i2c-pasemi.o Loading drivers/i2c/busses/i2c-nuc900.c 0 → 100644 +709 −0 Original line number Diff line number Diff line /* * linux/drivers/i2c/busses/i2c-nuc900.c * * Copyright (c) 2010 Nuvoton technology corporation. * * This driver based on S3C2410 I2C driver of Ben Dooks <ben-Y5A6D6n0/KfQXOPxS62xeg@public.gmane.org>. * Written by Wan ZongShun <mcuos.com-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation;version 2 of the License. * */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/i2c.h> #include <linux/i2c-id.h> #include <linux/init.h> #include <linux/time.h> #include <linux/interrupt.h> #include <linux/delay.h> #include <linux/errno.h> #include <linux/err.h> #include <linux/platform_device.h> #include <linux/clk.h> #include <linux/cpufreq.h> #include <linux/slab.h> #include <linux/io.h> #include <mach/mfp.h> #include <mach/i2c.h> /* nuc900 i2c registers offset */ #define CSR 0x00 #define DIVIDER 0x04 #define CMDR 0x08 #define SWR 0x0C #define RXR 0x10 #define TXR 0x14 /* nuc900 i2c CSR register bits */ #define IRQEN 0x003 #define I2CBUSY 0x400 #define I2CSTART 0x018 #define IRQFLAG 0x004 #define ARBIT_LOST 0x200 #define SLAVE_ACK 0x800 /* nuc900 i2c CMDR register bits */ #define I2C_CMD_START 0x10 #define I2C_CMD_STOP 0x08 #define I2C_CMD_READ 0x04 #define I2C_CMD_WRITE 0x02 #define I2C_CMD_NACK 0x01 /* i2c controller state */ enum nuc900_i2c_state { STATE_IDLE, STATE_START, STATE_READ, STATE_WRITE, STATE_STOP }; /* i2c controller private data */ struct nuc900_i2c { spinlock_t lock; wait_queue_head_t wait; struct i2c_msg *msg; unsigned int msg_num; unsigned int msg_idx; unsigned int msg_ptr; unsigned int irq; enum nuc900_i2c_state state; void __iomem *regs; struct clk *clk; struct device *dev; struct resource *ioarea; struct i2c_adapter adap; }; /* nuc900_i2c_master_complete * * complete the message and wake up the caller, using the given return code, * or zero to mean ok. */ static inline void nuc900_i2c_master_complete(struct nuc900_i2c *i2c, int ret) { dev_dbg(i2c->dev, "master_complete %d\n", ret); i2c->msg_ptr = 0; i2c->msg = NULL; i2c->msg_idx++; i2c->msg_num = 0; if (ret) i2c->msg_idx = ret; wake_up(&i2c->wait); } /* irq enable/disable functions */ static inline void nuc900_i2c_disable_irq(struct nuc900_i2c *i2c) { unsigned long tmp; tmp = readl(i2c->regs + CSR); writel(tmp & ~IRQEN, i2c->regs + CSR); } static inline void nuc900_i2c_enable_irq(struct nuc900_i2c *i2c) { unsigned long tmp; tmp = readl(i2c->regs + CSR); writel(tmp | IRQEN, i2c->regs + CSR); } /* nuc900_i2c_message_start * * put the start of a message onto the bus */ static void nuc900_i2c_message_start(struct nuc900_i2c *i2c, struct i2c_msg *msg) { unsigned int addr = (msg->addr & 0x7f) << 1; if (msg->flags & I2C_M_RD) addr |= 0x1; writel(addr & 0xff, i2c->regs + TXR); writel(I2C_CMD_START | I2C_CMD_WRITE, i2c->regs + CMDR); } static inline void nuc900_i2c_stop(struct nuc900_i2c *i2c, int ret) { dev_dbg(i2c->dev, "STOP\n"); /* stop the transfer */ i2c->state = STATE_STOP; writel(I2C_CMD_STOP, i2c->regs + CMDR); nuc900_i2c_master_complete(i2c, ret); nuc900_i2c_disable_irq(i2c); } /* helper functions to determine the current state in the set of * messages we are sending */ /* is_lastmsg() * * returns TRUE if the current message is the last in the set */ static inline int is_lastmsg(struct nuc900_i2c *i2c) { return i2c->msg_idx >= (i2c->msg_num - 1); } /* is_msglast * * returns TRUE if we this is the last byte in the current message */ static inline int is_msglast(struct nuc900_i2c *i2c) { return i2c->msg_ptr == i2c->msg->len-1; } /* is_msgend * * returns TRUE if we reached the end of the current message */ static inline int is_msgend(struct nuc900_i2c *i2c) { return i2c->msg_ptr >= i2c->msg->len; } /* i2c_nuc900_irq_nextbyte * * process an interrupt and work out what to do */ static void i2c_nuc900_irq_nextbyte(struct nuc900_i2c *i2c, unsigned long iicstat) { unsigned char byte; switch (i2c->state) { case STATE_IDLE: dev_err(i2c->dev, "%s: called in STATE_IDLE\n", __func__); break; case STATE_STOP: dev_err(i2c->dev, "%s: called in STATE_STOP\n", __func__); nuc900_i2c_disable_irq(i2c); break; case STATE_START: /* last thing we did was send a start condition on the * bus, or started a new i2c message */ if (iicstat & SLAVE_ACK && !(i2c->msg->flags & I2C_M_IGNORE_NAK)) { /* ack was not received... */ dev_dbg(i2c->dev, "ack was not received\n"); nuc900_i2c_stop(i2c, -ENXIO); break; } if (i2c->msg->flags & I2C_M_RD) i2c->state = STATE_READ; else i2c->state = STATE_WRITE; /* terminate the transfer if there is nothing to do * as this is used by the i2c probe to find devices. */ if (is_lastmsg(i2c) && i2c->msg->len == 0) { nuc900_i2c_stop(i2c, 0); break; } if (i2c->state == STATE_READ) goto prepare_read; /* fall through to the write state, as we will need to * send a byte as well */ case STATE_WRITE: /* we are writing data to the device... check for the * end of the message, and if so, work out what to do */ if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) { if (iicstat & SLAVE_ACK) { dev_dbg(i2c->dev, "WRITE: No Ack\n"); nuc900_i2c_stop(i2c, -ECONNREFUSED); break; } } retry_write: if (!is_msgend(i2c)) { byte = i2c->msg->buf[i2c->msg_ptr++]; writeb(byte, i2c->regs + TXR); writel(I2C_CMD_WRITE, i2c->regs + CMDR); } else if (!is_lastmsg(i2c)) { /* we need to go to the next i2c message */ dev_dbg(i2c->dev, "WRITE: Next Message\n"); i2c->msg_ptr = 0; i2c->msg_idx++; i2c->msg++; /* check to see if we need to do another message */ if (i2c->msg->flags & I2C_M_NOSTART) { if (i2c->msg->flags & I2C_M_RD) { /* cannot do this, the controller * forces us to send a new START * when we change direction */ nuc900_i2c_stop(i2c, -EINVAL); } goto retry_write; } else { /* send the new start */ nuc900_i2c_message_start(i2c, i2c->msg); i2c->state = STATE_START; } } else { /* send stop */ nuc900_i2c_stop(i2c, 0); } break; case STATE_READ: /* we have a byte of data in the data register, do * something with it, and then work out wether we are * going to do any more read/write */ byte = readb(i2c->regs + RXR); i2c->msg->buf[i2c->msg_ptr++] = byte; prepare_read: if (is_msglast(i2c)) { /* last byte of buffer */ if (is_lastmsg(i2c)) writel(I2C_CMD_READ | I2C_CMD_NACK, i2c->regs + CMDR); } else if (is_msgend(i2c)) { /* ok, we've read the entire buffer, see if there * is anything else we need to do */ if (is_lastmsg(i2c)) { /* last message, send stop and complete */ dev_dbg(i2c->dev, "READ: Send Stop\n"); nuc900_i2c_stop(i2c, 0); } else { /* go to the next transfer */ dev_dbg(i2c->dev, "READ: Next Transfer\n"); i2c->msg_ptr = 0; i2c->msg_idx++; i2c->msg++; writel(I2C_CMD_READ, i2c->regs + CMDR); } } else { writel(I2C_CMD_READ, i2c->regs + CMDR); } break; } } /* nuc900_i2c_irq * * top level IRQ servicing routine */ static irqreturn_t nuc900_i2c_irq(int irqno, void *dev_id) { struct nuc900_i2c *i2c = dev_id; unsigned long status; status = readl(i2c->regs + CSR); writel(status | IRQFLAG, i2c->regs + CSR); if (status & ARBIT_LOST) { /* deal with arbitration loss */ dev_err(i2c->dev, "deal with arbitration loss\n"); goto out; } if (i2c->state == STATE_IDLE) { dev_dbg(i2c->dev, "IRQ: error i2c->state == IDLE\n"); goto out; } /* pretty much this leaves us with the fact that we've * transmitted or received whatever byte we last sent */ i2c_nuc900_irq_nextbyte(i2c, status); out: return IRQ_HANDLED; } /* nuc900_i2c_set_master * * get the i2c bus for a master transaction */ static int nuc900_i2c_set_master(struct nuc900_i2c *i2c) { int timeout = 400; while (timeout-- > 0) { if (((readl(i2c->regs + SWR) & I2CSTART) == I2CSTART) && ((readl(i2c->regs + CSR) & I2CBUSY) == 0)) { return 0; } msleep(1); } return -ETIMEDOUT; } /* nuc900_i2c_doxfer * * this starts an i2c transfer */ static int nuc900_i2c_doxfer(struct nuc900_i2c *i2c, struct i2c_msg *msgs, int num) { unsigned long iicstat, timeout; int spins = 20; int ret; ret = nuc900_i2c_set_master(i2c); if (ret != 0) { dev_err(i2c->dev, "cannot get bus (error %d)\n", ret); ret = -EAGAIN; goto out; } spin_lock_irq(&i2c->lock); i2c->msg = msgs; i2c->msg_num = num; i2c->msg_ptr = 0; i2c->msg_idx = 0; i2c->state = STATE_START; nuc900_i2c_message_start(i2c, msgs); spin_unlock_irq(&i2c->lock); timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5); ret = i2c->msg_idx; /* having these next two as dev_err() makes life very * noisy when doing an i2cdetect */ if (timeout == 0) dev_dbg(i2c->dev, "timeout\n"); else if (ret != num) dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret); /* ensure the stop has been through the bus */ dev_dbg(i2c->dev, "waiting for bus idle\n"); /* first, try busy waiting briefly */ do { iicstat = readl(i2c->regs + CSR); } while ((iicstat & I2CBUSY) && --spins); /* if that timed out sleep */ if (!spins) { msleep(1); iicstat = readl(i2c->regs + CSR); } if (iicstat & I2CBUSY) dev_warn(i2c->dev, "timeout waiting for bus idle\n"); out: return ret; } /* nuc900_i2c_xfer * * first port of call from the i2c bus code when an message needs * transferring across the i2c bus. */ static int nuc900_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) { struct nuc900_i2c *i2c = (struct nuc900_i2c *)adap->algo_data; int retry; int ret; nuc900_i2c_enable_irq(i2c); for (retry = 0; retry < adap->retries; retry++) { ret = nuc900_i2c_doxfer(i2c, msgs, num); if (ret != -EAGAIN) return ret; dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry); udelay(100); } return -EREMOTEIO; } /* declare our i2c functionality */ static u32 nuc900_i2c_func(struct i2c_adapter *adap) { return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING; } /* i2c bus registration info */ static const struct i2c_algorithm nuc900_i2c_algorithm = { .master_xfer = nuc900_i2c_xfer, .functionality = nuc900_i2c_func, }; /* nuc900_i2c_probe * * called by the bus driver when a suitable device is found */ static int __devinit nuc900_i2c_probe(struct platform_device *pdev) { struct nuc900_i2c *i2c; struct nuc900_platform_i2c *pdata; struct resource *res; int ret; pdata = pdev->dev.platform_data; if (!pdata) { dev_err(&pdev->dev, "no platform data\n"); return -EINVAL; } i2c = kzalloc(sizeof(struct nuc900_i2c), GFP_KERNEL); if (!i2c) { dev_err(&pdev->dev, "no memory for state\n"); return -ENOMEM; } strlcpy(i2c->adap.name, "nuc900-i2c0", sizeof(i2c->adap.name)); i2c->adap.owner = THIS_MODULE; i2c->adap.algo = &nuc900_i2c_algorithm; i2c->adap.retries = 2; i2c->adap.class = I2C_CLASS_HWMON | I2C_CLASS_SPD; spin_lock_init(&i2c->lock); init_waitqueue_head(&i2c->wait); /* find the clock and enable it */ i2c->dev = &pdev->dev; i2c->clk = clk_get(&pdev->dev, NULL); if (IS_ERR(i2c->clk)) { dev_err(&pdev->dev, "cannot get clock\n"); ret = -ENOENT; goto err_noclk; } dev_dbg(&pdev->dev, "clock source %p\n", i2c->clk); clk_enable(i2c->clk); /* map the registers */ res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (res == NULL) { dev_err(&pdev->dev, "cannot find IO resource\n"); ret = -ENOENT; goto err_clk; } i2c->ioarea = request_mem_region(res->start, resource_size(res), pdev->name); if (i2c->ioarea == NULL) { dev_err(&pdev->dev, "cannot request IO\n"); ret = -ENXIO; goto err_clk; } i2c->regs = ioremap(res->start, resource_size(res)); if (i2c->regs == NULL) { dev_err(&pdev->dev, "cannot map IO\n"); ret = -ENXIO; goto err_ioarea; } dev_dbg(&pdev->dev, "registers %p (%p, %p)\n", i2c->regs, i2c->ioarea, res); /* setup info block for the i2c core */ i2c->adap.algo_data = i2c; i2c->adap.dev.parent = &pdev->dev; mfp_set_groupg(&pdev->dev); clk_get_rate(i2c->clk); ret = (i2c->clk.apbfreq)/(pdata->bus_freq * 5) - 1; writel(ret & 0xffff, i2c->regs + DIVIDER); /* find the IRQ for this unit (note, this relies on the init call to * ensure no current IRQs pending */ i2c->irq = ret = platform_get_irq(pdev, 0); if (ret <= 0) { dev_err(&pdev->dev, "cannot find IRQ\n"); goto err_iomap; } ret = request_irq(i2c->irq, nuc900_i2c_irq, IRQF_DISABLED | IRQF_SHARED, dev_name(&pdev->dev), i2c); if (ret != 0) { dev_err(&pdev->dev, "cannot claim IRQ %d\n", i2c->irq); goto err_iomap; } /* Note, previous versions of the driver used i2c_add_adapter() * to add the bus at any number. We now pass the bus number via * the platform data, so if unset it will now default to always * being bus 0. */ i2c->adap.nr = pdata->bus_num; ret = i2c_add_numbered_adapter(&i2c->adap); if (ret < 0) { dev_err(&pdev->dev, "failed to add bus to i2c core\n"); goto err_irq; } platform_set_drvdata(pdev, i2c); dev_info(&pdev->dev, "%s: NUC900 I2C adapter\n", dev_name(&i2c->adap.dev)); return 0; err_irq: free_irq(i2c->irq, i2c); err_iomap: iounmap(i2c->regs); err_ioarea: release_resource(i2c->ioarea); kfree(i2c->ioarea); err_clk: clk_disable(i2c->clk); clk_put(i2c->clk); err_noclk: kfree(i2c); return ret; } /* nuc900_i2c_remove * * called when device is removed from the bus */ static int __devexit nuc900_i2c_remove(struct platform_device *pdev) { struct nuc900_i2c *i2c = platform_get_drvdata(pdev); i2c_del_adapter(&i2c->adap); free_irq(i2c->irq, i2c); clk_disable(i2c->clk); clk_put(i2c->clk); iounmap(i2c->regs); release_resource(i2c->ioarea); kfree(i2c->ioarea); kfree(i2c); return 0; } static struct platform_driver nuc900_i2c_driver = { .probe = nuc900_i2c_probe, .remove = __devexit_p(nuc900_i2c_remove), .driver = { .owner = THIS_MODULE, .name = "nuc900-i2c0", }, }; static int __init i2c_adap_nuc900_init(void) { return platform_driver_register(&nuc900_i2c_driver); } static void __exit i2c_adap_nuc900_exit(void) { platform_driver_unregister(&nuc900_i2c_driver); } subsys_initcall(i2c_adap_nuc900_init); module_exit(i2c_adap_nuc900_exit); MODULE_DESCRIPTION("NUC900 I2C Bus driver"); MODULE_AUTHOR("Wan ZongShun, <mcuos.com-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:nuc900-i2c0"); Loading
arch/arm/mach-w90x900/include/mach/i2c.h 0 → 100644 +9 −0 Original line number Diff line number Diff line #ifndef __ASM_ARCH_NUC900_I2C_H #define __ASM_ARCH_NUC900_I2C_H struct nuc900_platform_i2c { int bus_num; unsigned long bus_freq; }; #endif /* __ASM_ARCH_NUC900_I2C_H */
drivers/i2c/busses/Kconfig +7 −0 Original line number Diff line number Diff line Loading @@ -448,6 +448,13 @@ config I2C_NOMADIK If you say yes to this option, support will be included for the I2C interface from ST-Ericsson's Nomadik and Ux500 architectures. config I2C_NUC900 tristate "NUC900 I2C Driver" depends on ARCH_W90X900 help Say Y here to include support for I2C controller in the Winbond/Nuvoton NUC900 based System-on-Chip devices. config I2C_OCORES tristate "OpenCores I2C Controller" depends on EXPERIMENTAL Loading
drivers/i2c/busses/Makefile +1 −0 Original line number Diff line number Diff line Loading @@ -43,6 +43,7 @@ obj-$(CONFIG_I2C_IXP2000) += i2c-ixp2000.o obj-$(CONFIG_I2C_MPC) += i2c-mpc.o obj-$(CONFIG_I2C_MV64XXX) += i2c-mv64xxx.o obj-$(CONFIG_I2C_NOMADIK) += i2c-nomadik.o obj-$(CONFIG_I2C_NUC900) += i2c-nuc900.o obj-$(CONFIG_I2C_OCORES) += i2c-ocores.o obj-$(CONFIG_I2C_OMAP) += i2c-omap.o obj-$(CONFIG_I2C_PASEMI) += i2c-pasemi.o Loading
drivers/i2c/busses/i2c-nuc900.c 0 → 100644 +709 −0 Original line number Diff line number Diff line /* * linux/drivers/i2c/busses/i2c-nuc900.c * * Copyright (c) 2010 Nuvoton technology corporation. * * This driver based on S3C2410 I2C driver of Ben Dooks <ben-Y5A6D6n0/KfQXOPxS62xeg@public.gmane.org>. * Written by Wan ZongShun <mcuos.com-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation;version 2 of the License. * */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/i2c.h> #include <linux/i2c-id.h> #include <linux/init.h> #include <linux/time.h> #include <linux/interrupt.h> #include <linux/delay.h> #include <linux/errno.h> #include <linux/err.h> #include <linux/platform_device.h> #include <linux/clk.h> #include <linux/cpufreq.h> #include <linux/slab.h> #include <linux/io.h> #include <mach/mfp.h> #include <mach/i2c.h> /* nuc900 i2c registers offset */ #define CSR 0x00 #define DIVIDER 0x04 #define CMDR 0x08 #define SWR 0x0C #define RXR 0x10 #define TXR 0x14 /* nuc900 i2c CSR register bits */ #define IRQEN 0x003 #define I2CBUSY 0x400 #define I2CSTART 0x018 #define IRQFLAG 0x004 #define ARBIT_LOST 0x200 #define SLAVE_ACK 0x800 /* nuc900 i2c CMDR register bits */ #define I2C_CMD_START 0x10 #define I2C_CMD_STOP 0x08 #define I2C_CMD_READ 0x04 #define I2C_CMD_WRITE 0x02 #define I2C_CMD_NACK 0x01 /* i2c controller state */ enum nuc900_i2c_state { STATE_IDLE, STATE_START, STATE_READ, STATE_WRITE, STATE_STOP }; /* i2c controller private data */ struct nuc900_i2c { spinlock_t lock; wait_queue_head_t wait; struct i2c_msg *msg; unsigned int msg_num; unsigned int msg_idx; unsigned int msg_ptr; unsigned int irq; enum nuc900_i2c_state state; void __iomem *regs; struct clk *clk; struct device *dev; struct resource *ioarea; struct i2c_adapter adap; }; /* nuc900_i2c_master_complete * * complete the message and wake up the caller, using the given return code, * or zero to mean ok. */ static inline void nuc900_i2c_master_complete(struct nuc900_i2c *i2c, int ret) { dev_dbg(i2c->dev, "master_complete %d\n", ret); i2c->msg_ptr = 0; i2c->msg = NULL; i2c->msg_idx++; i2c->msg_num = 0; if (ret) i2c->msg_idx = ret; wake_up(&i2c->wait); } /* irq enable/disable functions */ static inline void nuc900_i2c_disable_irq(struct nuc900_i2c *i2c) { unsigned long tmp; tmp = readl(i2c->regs + CSR); writel(tmp & ~IRQEN, i2c->regs + CSR); } static inline void nuc900_i2c_enable_irq(struct nuc900_i2c *i2c) { unsigned long tmp; tmp = readl(i2c->regs + CSR); writel(tmp | IRQEN, i2c->regs + CSR); } /* nuc900_i2c_message_start * * put the start of a message onto the bus */ static void nuc900_i2c_message_start(struct nuc900_i2c *i2c, struct i2c_msg *msg) { unsigned int addr = (msg->addr & 0x7f) << 1; if (msg->flags & I2C_M_RD) addr |= 0x1; writel(addr & 0xff, i2c->regs + TXR); writel(I2C_CMD_START | I2C_CMD_WRITE, i2c->regs + CMDR); } static inline void nuc900_i2c_stop(struct nuc900_i2c *i2c, int ret) { dev_dbg(i2c->dev, "STOP\n"); /* stop the transfer */ i2c->state = STATE_STOP; writel(I2C_CMD_STOP, i2c->regs + CMDR); nuc900_i2c_master_complete(i2c, ret); nuc900_i2c_disable_irq(i2c); } /* helper functions to determine the current state in the set of * messages we are sending */ /* is_lastmsg() * * returns TRUE if the current message is the last in the set */ static inline int is_lastmsg(struct nuc900_i2c *i2c) { return i2c->msg_idx >= (i2c->msg_num - 1); } /* is_msglast * * returns TRUE if we this is the last byte in the current message */ static inline int is_msglast(struct nuc900_i2c *i2c) { return i2c->msg_ptr == i2c->msg->len-1; } /* is_msgend * * returns TRUE if we reached the end of the current message */ static inline int is_msgend(struct nuc900_i2c *i2c) { return i2c->msg_ptr >= i2c->msg->len; } /* i2c_nuc900_irq_nextbyte * * process an interrupt and work out what to do */ static void i2c_nuc900_irq_nextbyte(struct nuc900_i2c *i2c, unsigned long iicstat) { unsigned char byte; switch (i2c->state) { case STATE_IDLE: dev_err(i2c->dev, "%s: called in STATE_IDLE\n", __func__); break; case STATE_STOP: dev_err(i2c->dev, "%s: called in STATE_STOP\n", __func__); nuc900_i2c_disable_irq(i2c); break; case STATE_START: /* last thing we did was send a start condition on the * bus, or started a new i2c message */ if (iicstat & SLAVE_ACK && !(i2c->msg->flags & I2C_M_IGNORE_NAK)) { /* ack was not received... */ dev_dbg(i2c->dev, "ack was not received\n"); nuc900_i2c_stop(i2c, -ENXIO); break; } if (i2c->msg->flags & I2C_M_RD) i2c->state = STATE_READ; else i2c->state = STATE_WRITE; /* terminate the transfer if there is nothing to do * as this is used by the i2c probe to find devices. */ if (is_lastmsg(i2c) && i2c->msg->len == 0) { nuc900_i2c_stop(i2c, 0); break; } if (i2c->state == STATE_READ) goto prepare_read; /* fall through to the write state, as we will need to * send a byte as well */ case STATE_WRITE: /* we are writing data to the device... check for the * end of the message, and if so, work out what to do */ if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) { if (iicstat & SLAVE_ACK) { dev_dbg(i2c->dev, "WRITE: No Ack\n"); nuc900_i2c_stop(i2c, -ECONNREFUSED); break; } } retry_write: if (!is_msgend(i2c)) { byte = i2c->msg->buf[i2c->msg_ptr++]; writeb(byte, i2c->regs + TXR); writel(I2C_CMD_WRITE, i2c->regs + CMDR); } else if (!is_lastmsg(i2c)) { /* we need to go to the next i2c message */ dev_dbg(i2c->dev, "WRITE: Next Message\n"); i2c->msg_ptr = 0; i2c->msg_idx++; i2c->msg++; /* check to see if we need to do another message */ if (i2c->msg->flags & I2C_M_NOSTART) { if (i2c->msg->flags & I2C_M_RD) { /* cannot do this, the controller * forces us to send a new START * when we change direction */ nuc900_i2c_stop(i2c, -EINVAL); } goto retry_write; } else { /* send the new start */ nuc900_i2c_message_start(i2c, i2c->msg); i2c->state = STATE_START; } } else { /* send stop */ nuc900_i2c_stop(i2c, 0); } break; case STATE_READ: /* we have a byte of data in the data register, do * something with it, and then work out wether we are * going to do any more read/write */ byte = readb(i2c->regs + RXR); i2c->msg->buf[i2c->msg_ptr++] = byte; prepare_read: if (is_msglast(i2c)) { /* last byte of buffer */ if (is_lastmsg(i2c)) writel(I2C_CMD_READ | I2C_CMD_NACK, i2c->regs + CMDR); } else if (is_msgend(i2c)) { /* ok, we've read the entire buffer, see if there * is anything else we need to do */ if (is_lastmsg(i2c)) { /* last message, send stop and complete */ dev_dbg(i2c->dev, "READ: Send Stop\n"); nuc900_i2c_stop(i2c, 0); } else { /* go to the next transfer */ dev_dbg(i2c->dev, "READ: Next Transfer\n"); i2c->msg_ptr = 0; i2c->msg_idx++; i2c->msg++; writel(I2C_CMD_READ, i2c->regs + CMDR); } } else { writel(I2C_CMD_READ, i2c->regs + CMDR); } break; } } /* nuc900_i2c_irq * * top level IRQ servicing routine */ static irqreturn_t nuc900_i2c_irq(int irqno, void *dev_id) { struct nuc900_i2c *i2c = dev_id; unsigned long status; status = readl(i2c->regs + CSR); writel(status | IRQFLAG, i2c->regs + CSR); if (status & ARBIT_LOST) { /* deal with arbitration loss */ dev_err(i2c->dev, "deal with arbitration loss\n"); goto out; } if (i2c->state == STATE_IDLE) { dev_dbg(i2c->dev, "IRQ: error i2c->state == IDLE\n"); goto out; } /* pretty much this leaves us with the fact that we've * transmitted or received whatever byte we last sent */ i2c_nuc900_irq_nextbyte(i2c, status); out: return IRQ_HANDLED; } /* nuc900_i2c_set_master * * get the i2c bus for a master transaction */ static int nuc900_i2c_set_master(struct nuc900_i2c *i2c) { int timeout = 400; while (timeout-- > 0) { if (((readl(i2c->regs + SWR) & I2CSTART) == I2CSTART) && ((readl(i2c->regs + CSR) & I2CBUSY) == 0)) { return 0; } msleep(1); } return -ETIMEDOUT; } /* nuc900_i2c_doxfer * * this starts an i2c transfer */ static int nuc900_i2c_doxfer(struct nuc900_i2c *i2c, struct i2c_msg *msgs, int num) { unsigned long iicstat, timeout; int spins = 20; int ret; ret = nuc900_i2c_set_master(i2c); if (ret != 0) { dev_err(i2c->dev, "cannot get bus (error %d)\n", ret); ret = -EAGAIN; goto out; } spin_lock_irq(&i2c->lock); i2c->msg = msgs; i2c->msg_num = num; i2c->msg_ptr = 0; i2c->msg_idx = 0; i2c->state = STATE_START; nuc900_i2c_message_start(i2c, msgs); spin_unlock_irq(&i2c->lock); timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5); ret = i2c->msg_idx; /* having these next two as dev_err() makes life very * noisy when doing an i2cdetect */ if (timeout == 0) dev_dbg(i2c->dev, "timeout\n"); else if (ret != num) dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret); /* ensure the stop has been through the bus */ dev_dbg(i2c->dev, "waiting for bus idle\n"); /* first, try busy waiting briefly */ do { iicstat = readl(i2c->regs + CSR); } while ((iicstat & I2CBUSY) && --spins); /* if that timed out sleep */ if (!spins) { msleep(1); iicstat = readl(i2c->regs + CSR); } if (iicstat & I2CBUSY) dev_warn(i2c->dev, "timeout waiting for bus idle\n"); out: return ret; } /* nuc900_i2c_xfer * * first port of call from the i2c bus code when an message needs * transferring across the i2c bus. */ static int nuc900_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) { struct nuc900_i2c *i2c = (struct nuc900_i2c *)adap->algo_data; int retry; int ret; nuc900_i2c_enable_irq(i2c); for (retry = 0; retry < adap->retries; retry++) { ret = nuc900_i2c_doxfer(i2c, msgs, num); if (ret != -EAGAIN) return ret; dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry); udelay(100); } return -EREMOTEIO; } /* declare our i2c functionality */ static u32 nuc900_i2c_func(struct i2c_adapter *adap) { return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING; } /* i2c bus registration info */ static const struct i2c_algorithm nuc900_i2c_algorithm = { .master_xfer = nuc900_i2c_xfer, .functionality = nuc900_i2c_func, }; /* nuc900_i2c_probe * * called by the bus driver when a suitable device is found */ static int __devinit nuc900_i2c_probe(struct platform_device *pdev) { struct nuc900_i2c *i2c; struct nuc900_platform_i2c *pdata; struct resource *res; int ret; pdata = pdev->dev.platform_data; if (!pdata) { dev_err(&pdev->dev, "no platform data\n"); return -EINVAL; } i2c = kzalloc(sizeof(struct nuc900_i2c), GFP_KERNEL); if (!i2c) { dev_err(&pdev->dev, "no memory for state\n"); return -ENOMEM; } strlcpy(i2c->adap.name, "nuc900-i2c0", sizeof(i2c->adap.name)); i2c->adap.owner = THIS_MODULE; i2c->adap.algo = &nuc900_i2c_algorithm; i2c->adap.retries = 2; i2c->adap.class = I2C_CLASS_HWMON | I2C_CLASS_SPD; spin_lock_init(&i2c->lock); init_waitqueue_head(&i2c->wait); /* find the clock and enable it */ i2c->dev = &pdev->dev; i2c->clk = clk_get(&pdev->dev, NULL); if (IS_ERR(i2c->clk)) { dev_err(&pdev->dev, "cannot get clock\n"); ret = -ENOENT; goto err_noclk; } dev_dbg(&pdev->dev, "clock source %p\n", i2c->clk); clk_enable(i2c->clk); /* map the registers */ res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (res == NULL) { dev_err(&pdev->dev, "cannot find IO resource\n"); ret = -ENOENT; goto err_clk; } i2c->ioarea = request_mem_region(res->start, resource_size(res), pdev->name); if (i2c->ioarea == NULL) { dev_err(&pdev->dev, "cannot request IO\n"); ret = -ENXIO; goto err_clk; } i2c->regs = ioremap(res->start, resource_size(res)); if (i2c->regs == NULL) { dev_err(&pdev->dev, "cannot map IO\n"); ret = -ENXIO; goto err_ioarea; } dev_dbg(&pdev->dev, "registers %p (%p, %p)\n", i2c->regs, i2c->ioarea, res); /* setup info block for the i2c core */ i2c->adap.algo_data = i2c; i2c->adap.dev.parent = &pdev->dev; mfp_set_groupg(&pdev->dev); clk_get_rate(i2c->clk); ret = (i2c->clk.apbfreq)/(pdata->bus_freq * 5) - 1; writel(ret & 0xffff, i2c->regs + DIVIDER); /* find the IRQ for this unit (note, this relies on the init call to * ensure no current IRQs pending */ i2c->irq = ret = platform_get_irq(pdev, 0); if (ret <= 0) { dev_err(&pdev->dev, "cannot find IRQ\n"); goto err_iomap; } ret = request_irq(i2c->irq, nuc900_i2c_irq, IRQF_DISABLED | IRQF_SHARED, dev_name(&pdev->dev), i2c); if (ret != 0) { dev_err(&pdev->dev, "cannot claim IRQ %d\n", i2c->irq); goto err_iomap; } /* Note, previous versions of the driver used i2c_add_adapter() * to add the bus at any number. We now pass the bus number via * the platform data, so if unset it will now default to always * being bus 0. */ i2c->adap.nr = pdata->bus_num; ret = i2c_add_numbered_adapter(&i2c->adap); if (ret < 0) { dev_err(&pdev->dev, "failed to add bus to i2c core\n"); goto err_irq; } platform_set_drvdata(pdev, i2c); dev_info(&pdev->dev, "%s: NUC900 I2C adapter\n", dev_name(&i2c->adap.dev)); return 0; err_irq: free_irq(i2c->irq, i2c); err_iomap: iounmap(i2c->regs); err_ioarea: release_resource(i2c->ioarea); kfree(i2c->ioarea); err_clk: clk_disable(i2c->clk); clk_put(i2c->clk); err_noclk: kfree(i2c); return ret; } /* nuc900_i2c_remove * * called when device is removed from the bus */ static int __devexit nuc900_i2c_remove(struct platform_device *pdev) { struct nuc900_i2c *i2c = platform_get_drvdata(pdev); i2c_del_adapter(&i2c->adap); free_irq(i2c->irq, i2c); clk_disable(i2c->clk); clk_put(i2c->clk); iounmap(i2c->regs); release_resource(i2c->ioarea); kfree(i2c->ioarea); kfree(i2c); return 0; } static struct platform_driver nuc900_i2c_driver = { .probe = nuc900_i2c_probe, .remove = __devexit_p(nuc900_i2c_remove), .driver = { .owner = THIS_MODULE, .name = "nuc900-i2c0", }, }; static int __init i2c_adap_nuc900_init(void) { return platform_driver_register(&nuc900_i2c_driver); } static void __exit i2c_adap_nuc900_exit(void) { platform_driver_unregister(&nuc900_i2c_driver); } subsys_initcall(i2c_adap_nuc900_init); module_exit(i2c_adap_nuc900_exit); MODULE_DESCRIPTION("NUC900 I2C Bus driver"); MODULE_AUTHOR("Wan ZongShun, <mcuos.com-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:nuc900-i2c0");
