diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-pxa.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-pxa.c | 1168 |
1 files changed, 1168 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c new file mode 100644 index 0000000..7f80d51 --- /dev/null +++ b/drivers/i2c/busses/i2c-pxa.c @@ -0,0 +1,1168 @@ +/* + * i2c_adap_pxa.c + * + * I2C adapter for the PXA I2C bus access. + * + * Copyright (C) 2002 Intrinsyc Software Inc. + * Copyright (C) 2004-2005 Deep Blue Solutions Ltd. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * History: + * Apr 2002: Initial version [CS] + * Jun 2002: Properly seperated algo/adap [FB] + * Jan 2003: Fixed several bugs concerning interrupt handling [Kai-Uwe Bloem] + * Jan 2003: added limited signal handling [Kai-Uwe Bloem] + * Sep 2004: Major rework to ensure efficient bus handling [RMK] + * Dec 2004: Added support for PXA27x and slave device probing [Liam Girdwood] + * Feb 2005: Rework slave mode handling [RMK] + */ +#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/sched.h> +#include <linux/delay.h> +#include <linux/errno.h> +#include <linux/interrupt.h> +#include <linux/i2c-pxa.h> +#include <linux/platform_device.h> +#include <linux/err.h> +#include <linux/clk.h> + +#include <mach/hardware.h> +#include <asm/irq.h> +#include <asm/io.h> +#include <mach/i2c.h> + +/* + * I2C registers and bit definitions + */ +#define IBMR (0x00) +#define IDBR (0x08) +#define ICR (0x10) +#define ISR (0x18) +#define ISAR (0x20) + +#define ICR_START (1 << 0) /* start bit */ +#define ICR_STOP (1 << 1) /* stop bit */ +#define ICR_ACKNAK (1 << 2) /* send ACK(0) or NAK(1) */ +#define ICR_TB (1 << 3) /* transfer byte bit */ +#define ICR_MA (1 << 4) /* master abort */ +#define ICR_SCLE (1 << 5) /* master clock enable */ +#define ICR_IUE (1 << 6) /* unit enable */ +#define ICR_GCD (1 << 7) /* general call disable */ +#define ICR_ITEIE (1 << 8) /* enable tx interrupts */ +#define ICR_IRFIE (1 << 9) /* enable rx interrupts */ +#define ICR_BEIE (1 << 10) /* enable bus error ints */ +#define ICR_SSDIE (1 << 11) /* slave STOP detected int enable */ +#define ICR_ALDIE (1 << 12) /* enable arbitration interrupt */ +#define ICR_SADIE (1 << 13) /* slave address detected int enable */ +#define ICR_UR (1 << 14) /* unit reset */ +#define ICR_FM (1 << 15) /* fast mode */ + +#define ISR_RWM (1 << 0) /* read/write mode */ +#define ISR_ACKNAK (1 << 1) /* ack/nak status */ +#define ISR_UB (1 << 2) /* unit busy */ +#define ISR_IBB (1 << 3) /* bus busy */ +#define ISR_SSD (1 << 4) /* slave stop detected */ +#define ISR_ALD (1 << 5) /* arbitration loss detected */ +#define ISR_ITE (1 << 6) /* tx buffer empty */ +#define ISR_IRF (1 << 7) /* rx buffer full */ +#define ISR_GCAD (1 << 8) /* general call address detected */ +#define ISR_SAD (1 << 9) /* slave address detected */ +#define ISR_BED (1 << 10) /* bus error no ACK/NAK */ + +struct pxa_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 slave_addr; + + struct i2c_adapter adap; + struct clk *clk; +#ifdef CONFIG_I2C_PXA_SLAVE + struct i2c_slave_client *slave; +#endif + + unsigned int irqlogidx; + u32 isrlog[32]; + u32 icrlog[32]; + + void __iomem *reg_base; + unsigned int reg_shift; + + unsigned long iobase; + unsigned long iosize; + + int irq; + unsigned int use_pio :1; + unsigned int fast_mode :1; +}; + +#define _IBMR(i2c) ((i2c)->reg_base + (0x0 << (i2c)->reg_shift)) +#define _IDBR(i2c) ((i2c)->reg_base + (0x4 << (i2c)->reg_shift)) +#define _ICR(i2c) ((i2c)->reg_base + (0x8 << (i2c)->reg_shift)) +#define _ISR(i2c) ((i2c)->reg_base + (0xc << (i2c)->reg_shift)) +#define _ISAR(i2c) ((i2c)->reg_base + (0x10 << (i2c)->reg_shift)) + +/* + * I2C Slave mode address + */ +#define I2C_PXA_SLAVE_ADDR 0x1 + +#ifdef DEBUG + +struct bits { + u32 mask; + const char *set; + const char *unset; +}; +#define PXA_BIT(m, s, u) { .mask = m, .set = s, .unset = u } + +static inline void +decode_bits(const char *prefix, const struct bits *bits, int num, u32 val) +{ + printk("%s %08x: ", prefix, val); + while (num--) { + const char *str = val & bits->mask ? bits->set : bits->unset; + if (str) + printk("%s ", str); + bits++; + } +} + +static const struct bits isr_bits[] = { + PXA_BIT(ISR_RWM, "RX", "TX"), + PXA_BIT(ISR_ACKNAK, "NAK", "ACK"), + PXA_BIT(ISR_UB, "Bsy", "Rdy"), + PXA_BIT(ISR_IBB, "BusBsy", "BusRdy"), + PXA_BIT(ISR_SSD, "SlaveStop", NULL), + PXA_BIT(ISR_ALD, "ALD", NULL), + PXA_BIT(ISR_ITE, "TxEmpty", NULL), + PXA_BIT(ISR_IRF, "RxFull", NULL), + PXA_BIT(ISR_GCAD, "GenCall", NULL), + PXA_BIT(ISR_SAD, "SlaveAddr", NULL), + PXA_BIT(ISR_BED, "BusErr", NULL), +}; + +static void decode_ISR(unsigned int val) +{ + decode_bits(KERN_DEBUG "ISR", isr_bits, ARRAY_SIZE(isr_bits), val); + printk("\n"); +} + +static const struct bits icr_bits[] = { + PXA_BIT(ICR_START, "START", NULL), + PXA_BIT(ICR_STOP, "STOP", NULL), + PXA_BIT(ICR_ACKNAK, "ACKNAK", NULL), + PXA_BIT(ICR_TB, "TB", NULL), + PXA_BIT(ICR_MA, "MA", NULL), + PXA_BIT(ICR_SCLE, "SCLE", "scle"), + PXA_BIT(ICR_IUE, "IUE", "iue"), + PXA_BIT(ICR_GCD, "GCD", NULL), + PXA_BIT(ICR_ITEIE, "ITEIE", NULL), + PXA_BIT(ICR_IRFIE, "IRFIE", NULL), + PXA_BIT(ICR_BEIE, "BEIE", NULL), + PXA_BIT(ICR_SSDIE, "SSDIE", NULL), + PXA_BIT(ICR_ALDIE, "ALDIE", NULL), + PXA_BIT(ICR_SADIE, "SADIE", NULL), + PXA_BIT(ICR_UR, "UR", "ur"), +}; + +#ifdef CONFIG_I2C_PXA_SLAVE +static void decode_ICR(unsigned int val) +{ + decode_bits(KERN_DEBUG "ICR", icr_bits, ARRAY_SIZE(icr_bits), val); + printk("\n"); +} +#endif + +static unsigned int i2c_debug = DEBUG; + +static void i2c_pxa_show_state(struct pxa_i2c *i2c, int lno, const char *fname) +{ + dev_dbg(&i2c->adap.dev, "state:%s:%d: ISR=%08x, ICR=%08x, IBMR=%02x\n", fname, lno, + readl(_ISR(i2c)), readl(_ICR(i2c)), readl(_IBMR(i2c))); +} + +#define show_state(i2c) i2c_pxa_show_state(i2c, __LINE__, __func__) +#else +#define i2c_debug 0 + +#define show_state(i2c) do { } while (0) +#define decode_ISR(val) do { } while (0) +#define decode_ICR(val) do { } while (0) +#endif + +#define eedbg(lvl, x...) do { if ((lvl) < 1) { printk(KERN_DEBUG "" x); } } while(0) + +static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret); +static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id); + +static void i2c_pxa_scream_blue_murder(struct pxa_i2c *i2c, const char *why) +{ + unsigned int i; + printk("i2c: error: %s\n", why); + printk("i2c: msg_num: %d msg_idx: %d msg_ptr: %d\n", + i2c->msg_num, i2c->msg_idx, i2c->msg_ptr); + printk("i2c: ICR: %08x ISR: %08x\n" + "i2c: log: ", readl(_ICR(i2c)), readl(_ISR(i2c))); + for (i = 0; i < i2c->irqlogidx; i++) + printk("[%08x:%08x] ", i2c->isrlog[i], i2c->icrlog[i]); + printk("\n"); +} + +static inline int i2c_pxa_is_slavemode(struct pxa_i2c *i2c) +{ + return !(readl(_ICR(i2c)) & ICR_SCLE); +} + +static void i2c_pxa_abort(struct pxa_i2c *i2c) +{ + int i = 250; + + if (i2c_pxa_is_slavemode(i2c)) { + dev_dbg(&i2c->adap.dev, "%s: called in slave mode\n", __func__); + return; + } + + while ((i > 0) && (readl(_IBMR(i2c)) & 0x1) == 0) { + unsigned long icr = readl(_ICR(i2c)); + + icr &= ~ICR_START; + icr |= ICR_ACKNAK | ICR_STOP | ICR_TB; + + writel(icr, _ICR(i2c)); + + show_state(i2c); + + mdelay(1); + i --; + } + + writel(readl(_ICR(i2c)) & ~(ICR_MA | ICR_START | ICR_STOP), + _ICR(i2c)); +} + +static int i2c_pxa_wait_bus_not_busy(struct pxa_i2c *i2c) +{ + int timeout = DEF_TIMEOUT; + + while (timeout-- && readl(_ISR(i2c)) & (ISR_IBB | ISR_UB)) { + if ((readl(_ISR(i2c)) & ISR_SAD) != 0) + timeout += 4; + + msleep(2); + show_state(i2c); + } + + if (timeout <= 0) + show_state(i2c); + + return timeout <= 0 ? I2C_RETRY : 0; +} + +static int i2c_pxa_wait_master(struct pxa_i2c *i2c) +{ + unsigned long timeout = jiffies + HZ*4; + + while (time_before(jiffies, timeout)) { + if (i2c_debug > 1) + dev_dbg(&i2c->adap.dev, "%s: %ld: ISR=%08x, ICR=%08x, IBMR=%02x\n", + __func__, (long)jiffies, readl(_ISR(i2c)), readl(_ICR(i2c)), readl(_IBMR(i2c))); + + if (readl(_ISR(i2c)) & ISR_SAD) { + if (i2c_debug > 0) + dev_dbg(&i2c->adap.dev, "%s: Slave detected\n", __func__); + goto out; + } + + /* wait for unit and bus being not busy, and we also do a + * quick check of the i2c lines themselves to ensure they've + * gone high... + */ + if ((readl(_ISR(i2c)) & (ISR_UB | ISR_IBB)) == 0 && readl(_IBMR(i2c)) == 3) { + if (i2c_debug > 0) + dev_dbg(&i2c->adap.dev, "%s: done\n", __func__); + return 1; + } + + msleep(1); + } + + if (i2c_debug > 0) + dev_dbg(&i2c->adap.dev, "%s: did not free\n", __func__); + out: + return 0; +} + +static int i2c_pxa_set_master(struct pxa_i2c *i2c) +{ + if (i2c_debug) + dev_dbg(&i2c->adap.dev, "setting to bus master\n"); + + if ((readl(_ISR(i2c)) & (ISR_UB | ISR_IBB)) != 0) { + dev_dbg(&i2c->adap.dev, "%s: unit is busy\n", __func__); + if (!i2c_pxa_wait_master(i2c)) { + dev_dbg(&i2c->adap.dev, "%s: error: unit busy\n", __func__); + return I2C_RETRY; + } + } + + writel(readl(_ICR(i2c)) | ICR_SCLE, _ICR(i2c)); + return 0; +} + +#ifdef CONFIG_I2C_PXA_SLAVE +static int i2c_pxa_wait_slave(struct pxa_i2c *i2c) +{ + unsigned long timeout = jiffies + HZ*1; + + /* wait for stop */ + + show_state(i2c); + + while (time_before(jiffies, timeout)) { + if (i2c_debug > 1) + dev_dbg(&i2c->adap.dev, "%s: %ld: ISR=%08x, ICR=%08x, IBMR=%02x\n", + __func__, (long)jiffies, readl(_ISR(i2c)), readl(_ICR(i2c)), readl(_IBMR(i2c))); + + if ((readl(_ISR(i2c)) & (ISR_UB|ISR_IBB)) == 0 || + (readl(_ISR(i2c)) & ISR_SAD) != 0 || + (readl(_ICR(i2c)) & ICR_SCLE) == 0) { + if (i2c_debug > 1) + dev_dbg(&i2c->adap.dev, "%s: done\n", __func__); + return 1; + } + + msleep(1); + } + + if (i2c_debug > 0) + dev_dbg(&i2c->adap.dev, "%s: did not free\n", __func__); + return 0; +} + +/* + * clear the hold on the bus, and take of anything else + * that has been configured + */ +static void i2c_pxa_set_slave(struct pxa_i2c *i2c, int errcode) +{ + show_state(i2c); + + if (errcode < 0) { + udelay(100); /* simple delay */ + } else { + /* we need to wait for the stop condition to end */ + + /* if we where in stop, then clear... */ + if (readl(_ICR(i2c)) & ICR_STOP) { + udelay(100); + writel(readl(_ICR(i2c)) & ~ICR_STOP, _ICR(i2c)); + } + + if (!i2c_pxa_wait_slave(i2c)) { + dev_err(&i2c->adap.dev, "%s: wait timedout\n", + __func__); + return; + } + } + + writel(readl(_ICR(i2c)) & ~(ICR_STOP|ICR_ACKNAK|ICR_MA), _ICR(i2c)); + writel(readl(_ICR(i2c)) & ~ICR_SCLE, _ICR(i2c)); + + if (i2c_debug) { + dev_dbg(&i2c->adap.dev, "ICR now %08x, ISR %08x\n", readl(_ICR(i2c)), readl(_ISR(i2c))); + decode_ICR(readl(_ICR(i2c))); + } +} +#else +#define i2c_pxa_set_slave(i2c, err) do { } while (0) +#endif + +static void i2c_pxa_reset(struct pxa_i2c *i2c) +{ + pr_debug("Resetting I2C Controller Unit\n"); + + /* abort any transfer currently under way */ + i2c_pxa_abort(i2c); + + /* reset according to 9.8 */ + writel(ICR_UR, _ICR(i2c)); + writel(I2C_ISR_INIT, _ISR(i2c)); + writel(readl(_ICR(i2c)) & ~ICR_UR, _ICR(i2c)); + + writel(i2c->slave_addr, _ISAR(i2c)); + + /* set control register values */ + writel(I2C_ICR_INIT | (i2c->fast_mode ? ICR_FM : 0), _ICR(i2c)); + +#ifdef CONFIG_I2C_PXA_SLAVE + dev_info(&i2c->adap.dev, "Enabling slave mode\n"); + writel(readl(_ICR(i2c)) | ICR_SADIE | ICR_ALDIE | ICR_SSDIE, _ICR(i2c)); +#endif + + i2c_pxa_set_slave(i2c, 0); + + /* enable unit */ + writel(readl(_ICR(i2c)) | ICR_IUE, _ICR(i2c)); + udelay(100); +} + + +#ifdef CONFIG_I2C_PXA_SLAVE +/* + * PXA I2C Slave mode + */ + +static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr) +{ + if (isr & ISR_BED) { + /* what should we do here? */ + } else { + int ret = 0; + + if (i2c->slave != NULL) + ret = i2c->slave->read(i2c->slave->data); + + writel(ret, _IDBR(i2c)); + writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c)); /* allow next byte */ + } +} + +static void i2c_pxa_slave_rxfull(struct pxa_i2c *i2c, u32 isr) +{ + unsigned int byte = readl(_IDBR(i2c)); + + if (i2c->slave != NULL) + i2c->slave->write(i2c->slave->data, byte); + + writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c)); +} + +static void i2c_pxa_slave_start(struct pxa_i2c *i2c, u32 isr) +{ + int timeout; + + if (i2c_debug > 0) + dev_dbg(&i2c->adap.dev, "SAD, mode is slave-%cx\n", + (isr & ISR_RWM) ? 'r' : 't'); + + if (i2c->slave != NULL) + i2c->slave->event(i2c->slave->data, + (isr & ISR_RWM) ? I2C_SLAVE_EVENT_START_READ : I2C_SLAVE_EVENT_START_WRITE); + + /* + * slave could interrupt in the middle of us generating a + * start condition... if this happens, we'd better back off + * and stop holding the poor thing up + */ + writel(readl(_ICR(i2c)) & ~(ICR_START|ICR_STOP), _ICR(i2c)); + writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c)); + + timeout = 0x10000; + + while (1) { + if ((readl(_IBMR(i2c)) & 2) == 2) + break; + + timeout--; + + if (timeout <= 0) { + dev_err(&i2c->adap.dev, "timeout waiting for SCL high\n"); + break; + } + } + + writel(readl(_ICR(i2c)) & ~ICR_SCLE, _ICR(i2c)); +} + +static void i2c_pxa_slave_stop(struct pxa_i2c *i2c) +{ + if (i2c_debug > 2) + dev_dbg(&i2c->adap.dev, "ISR: SSD (Slave Stop)\n"); + + if (i2c->slave != NULL) + i2c->slave->event(i2c->slave->data, I2C_SLAVE_EVENT_STOP); + + if (i2c_debug > 2) + dev_dbg(&i2c->adap.dev, "ISR: SSD (Slave Stop) acked\n"); + + /* + * If we have a master-mode message waiting, + * kick it off now that the slave has completed. + */ + if (i2c->msg) + i2c_pxa_master_complete(i2c, I2C_RETRY); +} +#else +static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr) +{ + if (isr & ISR_BED) { + /* what should we do here? */ + } else { + writel(0, _IDBR(i2c)); + writel(readl(_ICR(i2c)) | ICR_TB, _ICR(i2c)); + } +} + +static void i2c_pxa_slave_rxfull(struct pxa_i2c *i2c, u32 isr) +{ + writel(readl(_ICR(i2c)) | ICR_TB | ICR_ACKNAK, _ICR(i2c)); +} + +static void i2c_pxa_slave_start(struct pxa_i2c *i2c, u32 isr) +{ + int timeout; + + /* + * slave could interrupt in the middle of us generating a + * start condition... if this happens, we'd better back off + * and stop holding the poor thing up + */ + writel(readl(_ICR(i2c)) & ~(ICR_START|ICR_STOP), _ICR(i2c)); + writel(readl(_ICR(i2c)) | ICR_TB | ICR_ACKNAK, _ICR(i2c)); + + timeout = 0x10000; + + while (1) { + if ((readl(_IBMR(i2c)) & 2) == 2) + break; + + timeout--; + + if (timeout <= 0) { + dev_err(&i2c->adap.dev, "timeout waiting for SCL high\n"); + break; + } + } + + writel(readl(_ICR(i2c)) & ~ICR_SCLE, _ICR(i2c)); +} + +static void i2c_pxa_slave_stop(struct pxa_i2c *i2c) +{ + if (i2c->msg) + i2c_pxa_master_complete(i2c, I2C_RETRY); +} +#endif + +/* + * PXA I2C Master mode + */ + +static inline unsigned int i2c_pxa_addr_byte(struct i2c_msg *msg) +{ + unsigned int addr = (msg->addr & 0x7f) << 1; + + if (msg->flags & I2C_M_RD) + addr |= 1; + + return addr; +} + +static inline void i2c_pxa_start_message(struct pxa_i2c *i2c) +{ + u32 icr; + + /* + * Step 1: target slave address into IDBR + */ + writel(i2c_pxa_addr_byte(i2c->msg), _IDBR(i2c)); + + /* + * Step 2: initiate the write. + */ + icr = readl(_ICR(i2c)) & ~(ICR_STOP | ICR_ALDIE); + writel(icr | ICR_START | ICR_TB, _ICR(i2c)); +} + +static inline void i2c_pxa_stop_message(struct pxa_i2c *i2c) +{ + u32 icr; + + /* + * Clear the STOP and ACK flags + */ + icr = readl(_ICR(i2c)); + icr &= ~(ICR_STOP | ICR_ACKNAK); + writel(icr, _ICR(i2c)); +} + +static int i2c_pxa_pio_set_master(struct pxa_i2c *i2c) +{ + /* make timeout the same as for interrupt based functions */ + long timeout = 2 * DEF_TIMEOUT; + + /* + * Wait for the bus to become free. + */ + while (timeout-- && readl(_ISR(i2c)) & (ISR_IBB | ISR_UB)) { + udelay(1000); + show_state(i2c); + } + + if (timeout <= 0) { + show_state(i2c); + dev_err(&i2c->adap.dev, + "i2c_pxa: timeout waiting for bus free\n"); + return I2C_RETRY; + } + + /* + * Set master mode. + */ + writel(readl(_ICR(i2c)) | ICR_SCLE, _ICR(i2c)); + + return 0; +} + +static int i2c_pxa_do_pio_xfer(struct pxa_i2c *i2c, + struct i2c_msg *msg, int num) +{ + unsigned long timeout = 500000; /* 5 seconds */ + int ret = 0; + + ret = i2c_pxa_pio_set_master(i2c); + if (ret) + goto out; + + i2c->msg = msg; + i2c->msg_num = num; + i2c->msg_idx = 0; + i2c->msg_ptr = 0; + i2c->irqlogidx = 0; + + i2c_pxa_start_message(i2c); + + while (i2c->msg_num > 0 && --timeout) { + i2c_pxa_handler(0, i2c); + udelay(10); + } + + i2c_pxa_stop_message(i2c); + + /* + * We place the return code in i2c->msg_idx. + */ + ret = i2c->msg_idx; + +out: + if (timeout == 0) + i2c_pxa_scream_blue_murder(i2c, "timeout"); + + return ret; +} + +/* + * We are protected by the adapter bus mutex. + */ +static int i2c_pxa_do_xfer(struct pxa_i2c *i2c, struct i2c_msg *msg, int num) +{ + long timeout; + int ret; + + /* + * Wait for the bus to become free. + */ + ret = i2c_pxa_wait_bus_not_busy(i2c); + if (ret) { + dev_err(&i2c->adap.dev, "i2c_pxa: timeout waiting for bus free\n"); + goto out; + } + + /* + * Set master mode. + */ + ret = i2c_pxa_set_master(i2c); + if (ret) { + dev_err(&i2c->adap.dev, "i2c_pxa_set_master: error %d\n", ret); + goto out; + } + + spin_lock_irq(&i2c->lock); + + i2c->msg = msg; + i2c->msg_num = num; + i2c->msg_idx = 0; + i2c->msg_ptr = 0; + i2c->irqlogidx = 0; + + i2c_pxa_start_message(i2c); + + spin_unlock_irq(&i2c->lock); + + /* + * The rest of the processing occurs in the interrupt handler. + */ + timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5); + i2c_pxa_stop_message(i2c); + + /* + * We place the return code in i2c->msg_idx. + */ + ret = i2c->msg_idx; + + if (timeout == 0) + i2c_pxa_scream_blue_murder(i2c, "timeout"); + + out: + return ret; +} + +static int i2c_pxa_pio_xfer(struct i2c_adapter *adap, + struct i2c_msg msgs[], int num) +{ + struct pxa_i2c *i2c = adap->algo_data; + int ret, i; + + /* If the I2C controller is disabled we need to reset it + (probably due to a suspend/resume destroying state). We do + this here as we can then avoid worrying about resuming the + controller before its users. */ + if (!(readl(_ICR(i2c)) & ICR_IUE)) + i2c_pxa_reset(i2c); + + for (i = adap->retries; i >= 0; i--) { + ret = i2c_pxa_do_pio_xfer(i2c, msgs, num); + if (ret != I2C_RETRY) + goto out; + + if (i2c_debug) + dev_dbg(&adap->dev, "Retrying transmission\n"); + udelay(100); + } + i2c_pxa_scream_blue_murder(i2c, "exhausted retries"); + ret = -EREMOTEIO; + out: + i2c_pxa_set_slave(i2c, ret); + return ret; +} + +/* + * i2c_pxa_master_complete - complete the message and wake up. + */ +static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret) +{ + i2c->msg_ptr = 0; + i2c->msg = NULL; + i2c->msg_idx ++; + i2c->msg_num = 0; + if (ret) + i2c->msg_idx = ret; + if (!i2c->use_pio) + wake_up(&i2c->wait); +} + +static void i2c_pxa_irq_txempty(struct pxa_i2c *i2c, u32 isr) +{ + u32 icr = readl(_ICR(i2c)) & ~(ICR_START|ICR_STOP|ICR_ACKNAK|ICR_TB); + + again: + /* + * If ISR_ALD is set, we lost arbitration. + */ + if (isr & ISR_ALD) { + /* + * Do we need to do anything here? The PXA docs + * are vague about what happens. + */ + i2c_pxa_scream_blue_murder(i2c, "ALD set"); + + /* + * We ignore this error. We seem to see spurious ALDs + * for seemingly no reason. If we handle them as I think + * they should, we end up causing an I2C error, which + * is painful for some systems. + */ + return; /* ignore */ + } + + if (isr & ISR_BED) { + int ret = BUS_ERROR; + + /* + * I2C bus error - either the device NAK'd us, or + * something more serious happened. If we were NAK'd + * on the initial address phase, we can retry. + */ + if (isr & ISR_ACKNAK) { + if (i2c->msg_ptr == 0 && i2c->msg_idx == 0) + ret = I2C_RETRY; + else + ret = XFER_NAKED; + } + i2c_pxa_master_complete(i2c, ret); + } else if (isr & ISR_RWM) { + /* + * Read mode. We have just sent the address byte, and + * now we must initiate the transfer. + */ + if (i2c->msg_ptr == i2c->msg->len - 1 && + i2c->msg_idx == i2c->msg_num - 1) + icr |= ICR_STOP | ICR_ACKNAK; + + icr |= ICR_ALDIE | ICR_TB; + } else if (i2c->msg_ptr < i2c->msg->len) { + /* + * Write mode. Write the next data byte. + */ + writel(i2c->msg->buf[i2c->msg_ptr++], _IDBR(i2c)); + + icr |= ICR_ALDIE | ICR_TB; + + /* + * If this is the last byte of the last message, send + * a STOP. + */ + if (i2c->msg_ptr == i2c->msg->len && + i2c->msg_idx == i2c->msg_num - 1) + icr |= ICR_STOP; + } else if (i2c->msg_idx < i2c->msg_num - 1) { + /* + * Next segment of the message. + */ + i2c->msg_ptr = 0; + i2c->msg_idx ++; + i2c->msg++; + + /* + * If we aren't doing a repeated start and address, + * go back and try to send the next byte. Note that + * we do not support switching the R/W direction here. + */ + if (i2c->msg->flags & I2C_M_NOSTART) + goto again; + + /* + * Write the next address. + */ + writel(i2c_pxa_addr_byte(i2c->msg), _IDBR(i2c)); + + /* + * And trigger a repeated start, and send the byte. + */ + icr &= ~ICR_ALDIE; + icr |= ICR_START | ICR_TB; + } else { + if (i2c->msg->len == 0) { + /* + * Device probes have a message length of zero + * and need the bus to be reset before it can + * be used again. + */ + i2c_pxa_reset(i2c); + } + i2c_pxa_master_complete(i2c, 0); + } + + i2c->icrlog[i2c->irqlogidx-1] = icr; + + writel(icr, _ICR(i2c)); + show_state(i2c); +} + +static void i2c_pxa_irq_rxfull(struct pxa_i2c *i2c, u32 isr) +{ + u32 icr = readl(_ICR(i2c)) & ~(ICR_START|ICR_STOP|ICR_ACKNAK|ICR_TB); + + /* + * Read the byte. + */ + i2c->msg->buf[i2c->msg_ptr++] = readl(_IDBR(i2c)); + + if (i2c->msg_ptr < i2c->msg->len) { + /* + * If this is the last byte of the last + * message, send a STOP. + */ + if (i2c->msg_ptr == i2c->msg->len - 1) + icr |= ICR_STOP | ICR_ACKNAK; + + icr |= ICR_ALDIE | ICR_TB; + } else { + i2c_pxa_master_complete(i2c, 0); + } + + i2c->icrlog[i2c->irqlogidx-1] = icr; + + writel(icr, _ICR(i2c)); +} + +static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id) +{ + struct pxa_i2c *i2c = dev_id; + u32 isr = readl(_ISR(i2c)); + + if (i2c_debug > 2 && 0) { + dev_dbg(&i2c->adap.dev, "%s: ISR=%08x, ICR=%08x, IBMR=%02x\n", + __func__, isr, readl(_ICR(i2c)), readl(_IBMR(i2c))); + decode_ISR(isr); + } + + if (i2c->irqlogidx < ARRAY_SIZE(i2c->isrlog)) + i2c->isrlog[i2c->irqlogidx++] = isr; + + show_state(i2c); + + /* + * Always clear all pending IRQs. + */ + writel(isr & (ISR_SSD|ISR_ALD|ISR_ITE|ISR_IRF|ISR_SAD|ISR_BED), _ISR(i2c)); + + if (isr & ISR_SAD) + i2c_pxa_slave_start(i2c, isr); + if (isr & ISR_SSD) + i2c_pxa_slave_stop(i2c); + + if (i2c_pxa_is_slavemode(i2c)) { + if (isr & ISR_ITE) + i2c_pxa_slave_txempty(i2c, isr); + if (isr & ISR_IRF) + i2c_pxa_slave_rxfull(i2c, isr); + } else if (i2c->msg) { + if (isr & ISR_ITE) + i2c_pxa_irq_txempty(i2c, isr); + if (isr & ISR_IRF) + i2c_pxa_irq_rxfull(i2c, isr); + } else { + i2c_pxa_scream_blue_murder(i2c, "spurious irq"); + } + + return IRQ_HANDLED; +} + + +static int i2c_pxa_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) +{ + struct pxa_i2c *i2c = adap->algo_data; + int ret, i; + + for (i = adap->retries; i >= 0; i--) { + ret = i2c_pxa_do_xfer(i2c, msgs, num); + if (ret != I2C_RETRY) + goto out; + + if (i2c_debug) + dev_dbg(&adap->dev, "Retrying transmission\n"); + udelay(100); + } + i2c_pxa_scream_blue_murder(i2c, "exhausted retries"); + ret = -EREMOTEIO; + out: + i2c_pxa_set_slave(i2c, ret); + return ret; +} + +static u32 i2c_pxa_functionality(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; +} + +static const struct i2c_algorithm i2c_pxa_algorithm = { + .master_xfer = i2c_pxa_xfer, + .functionality = i2c_pxa_functionality, +}; + +static const struct i2c_algorithm i2c_pxa_pio_algorithm = { + .master_xfer = i2c_pxa_pio_xfer, + .functionality = i2c_pxa_functionality, +}; + +#define res_len(r) ((r)->end - (r)->start + 1) +static int i2c_pxa_probe(struct platform_device *dev) +{ + struct pxa_i2c *i2c; + struct resource *res; + struct i2c_pxa_platform_data *plat = dev->dev.platform_data; + int ret; + int irq; + + res = platform_get_resource(dev, IORESOURCE_MEM, 0); + irq = platform_get_irq(dev, 0); + if (res == NULL || irq < 0) + return -ENODEV; + + if (!request_mem_region(res->start, res_len(res), res->name)) + return -ENOMEM; + + i2c = kzalloc(sizeof(struct pxa_i2c), GFP_KERNEL); + if (!i2c) { + ret = -ENOMEM; + goto emalloc; + } + + i2c->adap.owner = THIS_MODULE; + i2c->adap.retries = 5; + + spin_lock_init(&i2c->lock); + init_waitqueue_head(&i2c->wait); + + /* + * If "dev->id" is negative we consider it as zero. + * The reason to do so is to avoid sysfs names that only make + * sense when there are multiple adapters. + */ + i2c->adap.nr = dev->id != -1 ? dev->id : 0; + snprintf(i2c->adap.name, sizeof(i2c->adap.name), "pxa_i2c-i2c.%u", + i2c->adap.nr); + + i2c->clk = clk_get(&dev->dev, "I2CCLK"); + if (IS_ERR(i2c->clk)) { + ret = PTR_ERR(i2c->clk); + goto eclk; + } + + i2c->reg_base = ioremap(res->start, res_len(res)); + if (!i2c->reg_base) { + ret = -EIO; + goto eremap; + } + i2c->reg_shift = (cpu_is_pxa3xx() && (dev->id == 1)) ? 0 : 1; + + i2c->iobase = res->start; + i2c->iosize = res_len(res); + + i2c->irq = irq; + + i2c->slave_addr = I2C_PXA_SLAVE_ADDR; + +#ifdef CONFIG_I2C_PXA_SLAVE + if (plat) { + i2c->slave_addr = plat->slave_addr; + i2c->slave = plat->slave; + } +#endif + + clk_enable(i2c->clk); + + if (plat) { + i2c->adap.class = plat->class; + i2c->use_pio = plat->use_pio; + i2c->fast_mode = plat->fast_mode; + } + + if (i2c->use_pio) { + i2c->adap.algo = &i2c_pxa_pio_algorithm; + } else { + i2c->adap.algo = &i2c_pxa_algorithm; + ret = request_irq(irq, i2c_pxa_handler, IRQF_DISABLED, + i2c->adap.name, i2c); + if (ret) + goto ereqirq; + } + + i2c_pxa_reset(i2c); + + i2c->adap.algo_data = i2c; + i2c->adap.dev.parent = &dev->dev; + + ret = i2c_add_numbered_adapter(&i2c->adap); + if (ret < 0) { + printk(KERN_INFO "I2C: Failed to add bus\n"); + goto eadapt; + } + + platform_set_drvdata(dev, i2c); + +#ifdef CONFIG_I2C_PXA_SLAVE + printk(KERN_INFO "I2C: %s: PXA I2C adapter, slave address %d\n", + i2c->adap.dev.bus_id, i2c->slave_addr); +#else + printk(KERN_INFO "I2C: %s: PXA I2C adapter\n", + i2c->adap.dev.bus_id); +#endif + return 0; + +eadapt: + if (!i2c->use_pio) + free_irq(irq, i2c); +ereqirq: + clk_disable(i2c->clk); + iounmap(i2c->reg_base); +eremap: + clk_put(i2c->clk); +eclk: + kfree(i2c); +emalloc: + release_mem_region(res->start, res_len(res)); + return ret; +} + +static int __exit i2c_pxa_remove(struct platform_device *dev) +{ + struct pxa_i2c *i2c = platform_get_drvdata(dev); + + platform_set_drvdata(dev, NULL); + + i2c_del_adapter(&i2c->adap); + if (!i2c->use_pio) + free_irq(i2c->irq, i2c); + + clk_disable(i2c->clk); + clk_put(i2c->clk); + + iounmap(i2c->reg_base); + release_mem_region(i2c->iobase, i2c->iosize); + kfree(i2c); + + return 0; +} + +#ifdef CONFIG_PM +static int i2c_pxa_suspend_late(struct platform_device *dev, pm_message_t state) +{ + struct pxa_i2c *i2c = platform_get_drvdata(dev); + clk_disable(i2c->clk); + return 0; +} + +static int i2c_pxa_resume_early(struct platform_device *dev) +{ + struct pxa_i2c *i2c = platform_get_drvdata(dev); + + clk_enable(i2c->clk); + i2c_pxa_reset(i2c); + + return 0; +} +#else +#define i2c_pxa_suspend_late NULL +#define i2c_pxa_resume_early NULL +#endif + +static struct platform_driver i2c_pxa_driver = { + .probe = i2c_pxa_probe, + .remove = __exit_p(i2c_pxa_remove), + .suspend_late = i2c_pxa_suspend_late, + .resume_early = i2c_pxa_resume_early, + .driver = { + .name = "pxa2xx-i2c", + .owner = THIS_MODULE, + }, +}; + +static int __init i2c_adap_pxa_init(void) +{ + return platform_driver_register(&i2c_pxa_driver); +} + +static void __exit i2c_adap_pxa_exit(void) +{ + platform_driver_unregister(&i2c_pxa_driver); +} + +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:pxa2xx-i2c"); + +subsys_initcall(i2c_adap_pxa_init); +module_exit(i2c_adap_pxa_exit); |
