// SPDX-License-Identifier: GPL-2.0-only /* * 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. * * History: * Apr 2002: Initial version [CS] * Jun 2002: Properly separated 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* I2C register field definitions */ #define IBMR_SDAS (1 << 0) #define IBMR_SCLS (1 << 1) #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 ICR_HS (1 << 16) /* High Speed mode */ #define ICR_A3700_FM (1 << 16) /* fast mode for armada-3700 */ #define ICR_A3700_HS (1 << 17) /* high speed mode for armada-3700 */ #define ICR_GPIOEN (1 << 19) /* enable GPIO mode for SCL in HS */ #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 */ #define ILCR_SLV_SHIFT 0 #define ILCR_SLV_MASK (0x1FF << ILCR_SLV_SHIFT) #define ILCR_FLV_SHIFT 9 #define ILCR_FLV_MASK (0x1FF << ILCR_FLV_SHIFT) #define ILCR_HLVL_SHIFT 18 #define ILCR_HLVL_MASK (0x1FF << ILCR_HLVL_SHIFT) #define ILCR_HLVH_SHIFT 27 #define ILCR_HLVH_MASK (0x1F << ILCR_HLVH_SHIFT) #define IWCR_CNT_SHIFT 0 #define IWCR_CNT_MASK (0x1F << IWCR_CNT_SHIFT) #define IWCR_HS_CNT1_SHIFT 5 #define IWCR_HS_CNT1_MASK (0x1F << IWCR_HS_CNT1_SHIFT) #define IWCR_HS_CNT2_SHIFT 10 #define IWCR_HS_CNT2_MASK (0x1F << IWCR_HS_CNT2_SHIFT) /* need a longer timeout if we're dealing with the fact we may well be * looking at a multi-master environment */ #define DEF_TIMEOUT 32 #define BUS_ERROR (-EREMOTEIO) #define XFER_NAKED (-ECONNREFUSED) #define I2C_RETRY (-2000) /* an error has occurred retry transmit */ /* ICR initialize bit values * * 15 FM 0 (100 kHz operation) * 14 UR 0 (No unit reset) * 13 SADIE 0 (Disables the unit from interrupting on slave addresses * matching its slave address) * 12 ALDIE 0 (Disables the unit from interrupt when it loses arbitration * in master mode) * 11 SSDIE 0 (Disables interrupts from a slave stop detected, in slave mode) * 10 BEIE 1 (Enable interrupts from detected bus errors, no ACK sent) * 9 IRFIE 1 (Enable interrupts from full buffer received) * 8 ITEIE 1 (Enables the I2C unit to interrupt when transmit buffer empty) * 7 GCD 1 (Disables i2c unit response to general call messages as a slave) * 6 IUE 0 (Disable unit until we change settings) * 5 SCLE 1 (Enables the i2c clock output for master mode (drives SCL) * 4 MA 0 (Only send stop with the ICR stop bit) * 3 TB 0 (We are not transmitting a byte initially) * 2 ACKNAK 0 (Send an ACK after the unit receives a byte) * 1 STOP 0 (Do not send a STOP) * 0 START 0 (Do not send a START) */ #define I2C_ICR_INIT (ICR_BEIE | ICR_IRFIE | ICR_ITEIE | ICR_GCD | ICR_SCLE) /* I2C status register init values * * 10 BED 1 (Clear bus error detected) * 9 SAD 1 (Clear slave address detected) * 7 IRF 1 (Clear IDBR Receive Full) * 6 ITE 1 (Clear IDBR Transmit Empty) * 5 ALD 1 (Clear Arbitration Loss Detected) * 4 SSD 1 (Clear Slave Stop Detected) */ #define I2C_ISR_INIT 0x7FF /* status register init */ struct pxa_reg_layout { u32 ibmr; u32 idbr; u32 icr; u32 isr; u32 isar; u32 ilcr; u32 iwcr; u32 fm; u32 hs; }; enum pxa_i2c_types { REGS_PXA2XX, REGS_PXA3XX, REGS_CE4100, REGS_PXA910, REGS_A3700, }; /* I2C register layout definitions */ static struct pxa_reg_layout pxa_reg_layout[] = { [REGS_PXA2XX] = { .ibmr = 0x00, .idbr = 0x08, .icr = 0x10, .isr = 0x18, .isar = 0x20, .fm = ICR_FM, .hs = ICR_HS, }, [REGS_PXA3XX] = { .ibmr = 0x00, .idbr = 0x04, .icr = 0x08, .isr = 0x0c, .isar = 0x10, .fm = ICR_FM, .hs = ICR_HS, }, [REGS_CE4100] = { .ibmr = 0x14, .idbr = 0x0c, .icr = 0x00, .isr = 0x04, /* no isar register */ .fm = ICR_FM, .hs = ICR_HS, }, [REGS_PXA910] = { .ibmr = 0x00, .idbr = 0x08, .icr = 0x10, .isr = 0x18, .isar = 0x20, .ilcr = 0x28, .iwcr = 0x30, .fm = ICR_FM, .hs = ICR_HS, }, [REGS_A3700] = { .ibmr = 0x00, .idbr = 0x04, .icr = 0x08, .isr = 0x0c, .isar = 0x10, .fm = ICR_A3700_FM, .hs = ICR_A3700_HS, }, }; static const struct of_device_id i2c_pxa_dt_ids[] = { { .compatible = "mrvl,pxa-i2c", .data = (void *)REGS_PXA2XX }, { .compatible = "mrvl,pwri2c", .data = (void *)REGS_PXA3XX }, { .compatible = "mrvl,mmp-twsi", .data = (void *)REGS_PXA910 }, { .compatible = "marvell,armada-3700-i2c", .data = (void *)REGS_A3700 }, {} }; MODULE_DEVICE_TABLE(of, i2c_pxa_dt_ids); static const struct platform_device_id i2c_pxa_id_table[] = { { "pxa2xx-i2c", REGS_PXA2XX }, { "pxa3xx-pwri2c", REGS_PXA3XX }, { "ce4100-i2c", REGS_CE4100 }, { "pxa910-i2c", REGS_PXA910 }, { "armada-3700-i2c", REGS_A3700 }, { }, }; MODULE_DEVICE_TABLE(platform, i2c_pxa_id_table); 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; unsigned int req_slave_addr; struct i2c_adapter adap; struct clk *clk; #ifdef CONFIG_I2C_PXA_SLAVE struct i2c_client *slave; #endif unsigned int irqlogidx; u32 isrlog[32]; u32 icrlog[32]; void __iomem *reg_base; void __iomem *reg_ibmr; void __iomem *reg_idbr; void __iomem *reg_icr; void __iomem *reg_isr; void __iomem *reg_isar; void __iomem *reg_ilcr; void __iomem *reg_iwcr; unsigned long iobase; unsigned long iosize; int irq; unsigned int use_pio :1; unsigned int fast_mode :1; unsigned int high_mode:1; unsigned char master_code; unsigned long rate; bool highmode_enter; u32 fm_mask; u32 hs_mask; }; #define _IBMR(i2c) ((i2c)->reg_ibmr) #define _IDBR(i2c) ((i2c)->reg_idbr) #define _ICR(i2c) ((i2c)->reg_icr) #define _ISR(i2c) ((i2c)->reg_isr) #define _ISAR(i2c) ((i2c)->reg_isar) #define _ILCR(i2c) ((i2c)->reg_ilcr) #define _IWCR(i2c) ((i2c)->reg_iwcr) /* * 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) pr_cont(" %s", str); bits++; } pr_cont("\n"); } 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); } 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); } #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__) static void i2c_pxa_scream_blue_murder(struct pxa_i2c *i2c, const char *why) { unsigned int i; struct device *dev = &i2c->adap.dev; dev_err(dev, "slave_0x%x error: %s\n", i2c->req_slave_addr >> 1, why); dev_err(dev, "msg_num: %d msg_idx: %d msg_ptr: %d\n", i2c->msg_num, i2c->msg_idx, i2c->msg_ptr); dev_err(dev, "IBMR: %08x IDBR: %08x ICR: %08x ISR: %08x\n", readl(_IBMR(i2c)), readl(_IDBR(i2c)), readl(_ICR(i2c)), readl(_ISR(i2c))); dev_err(dev, "log:"); for (i = 0; i < i2c->irqlogidx; i++) pr_cont(" [%03x:%05x]", i2c->isrlog[i], i2c->icrlog[i]); pr_cont("\n"); } #else /* ifdef DEBUG */ #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) #define i2c_pxa_scream_blue_murder(i2c, why) do { } while (0) #endif /* ifdef DEBUG / else */ static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret); 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)) & IBMR_SDAS) == 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; u32 isr; while (1) { isr = readl(_ISR(i2c)); if (!(isr & (ISR_IBB | ISR_UB))) return 0; if (isr & ISR_SAD) timeout += 4; if (!timeout--) break; msleep(2); show_state(i2c); } show_state(i2c); return I2C_RETRY; } 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)) == (IBMR_SCLS | IBMR_SDAS)) { 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)); if (i2c->reg_isar && IS_ENABLED(CONFIG_I2C_PXA_SLAVE)) writel(i2c->slave_addr, _ISAR(i2c)); /* set control register values */ writel(I2C_ICR_INIT | (i2c->fast_mode ? i2c->fm_mask : 0), _ICR(i2c)); writel(readl(_ICR(i2c)) | (i2c->high_mode ? i2c->hs_mask : 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 { u8 byte = 0; if (i2c->slave != NULL) i2c_slave_event(i2c->slave, I2C_SLAVE_READ_PROCESSED, &byte); writel(byte, _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) { u8 byte = readl(_IDBR(i2c)); if (i2c->slave != NULL) i2c_slave_event(i2c->slave, I2C_SLAVE_WRITE_RECEIVED, &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) { if (isr & ISR_RWM) { u8 byte = 0; i2c_slave_event(i2c->slave, I2C_SLAVE_READ_REQUESTED, &byte); writel(byte, _IDBR(i2c)); } else { i2c_slave_event(i2c->slave, I2C_SLAVE_WRITE_REQUESTED, NULL); } } /* * 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)) & IBMR_SCLS) == IBMR_SCLS) 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, I2C_SLAVE_STOP, NULL); 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); } static int i2c_pxa_slave_reg(struct i2c_client *slave) { struct pxa_i2c *i2c = slave->adapter->algo_data; if (i2c->slave) return -EBUSY; if (!i2c->reg_isar) return -EAFNOSUPPORT; i2c->slave = slave; i2c->slave_addr = slave->addr; writel(i2c->slave_addr, _ISAR(i2c)); return 0; } static int i2c_pxa_slave_unreg(struct i2c_client *slave) { struct pxa_i2c *i2c = slave->adapter->algo_data; WARN_ON(!i2c->slave); i2c->slave_addr = I2C_PXA_SLAVE_ADDR; writel(i2c->slave_addr, _ISAR(i2c)); i2c->slave = NULL; return 0; } #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)) & IBMR_SCLS) == IBMR_SCLS) 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 void i2c_pxa_start_message(struct pxa_i2c *i2c) { u32 icr; /* * Step 1: target slave address into IDBR */ i2c->req_slave_addr = i2c_8bit_addr_from_msg(i2c->msg); writel(i2c->req_slave_addr, _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)); } /* * PXA I2C send master code * 1. Load master code to IDBR and send it. * Note for HS mode, set ICR [GPIOEN]. * 2. Wait until win arbitration. */ static int i2c_pxa_send_mastercode(struct pxa_i2c *i2c) { u32 icr; long timeout; spin_lock_irq(&i2c->lock); i2c->highmode_enter = true; writel(i2c->master_code, _IDBR(i2c)); icr = readl(_ICR(i2c)) & ~(ICR_STOP | ICR_ALDIE); icr |= ICR_GPIOEN | ICR_START | ICR_TB | ICR_ITEIE; writel(icr, _ICR(i2c)); spin_unlock_irq(&i2c->lock); timeout = wait_event_timeout(i2c->wait, i2c->highmode_enter == false, HZ * 1); i2c->highmode_enter = false; return (timeout == 0) ? I2C_RETRY : 0; } /* * 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) && (!((i2c->msg->flags & I2C_M_IGNORE_NAK) && (isr & ISR_ACKNAK)))) { 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 or last byte * of any message with I2C_M_STOP (e.g. SCCB), send a STOP. */ if ((i2c->msg_ptr == i2c->msg->len) && ((i2c->msg->flags & I2C_M_STOP) || (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. */ i2c->req_slave_addr = i2c_8bit_addr_from_msg(i2c->msg); writel(i2c->req_slave_addr, _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)); } #define VALID_INT_SOURCE (ISR_SSD | ISR_ALD | ISR_ITE | ISR_IRF | \ ISR_SAD | ISR_BED) static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id) { struct pxa_i2c *i2c = dev_id; u32 isr = readl(_ISR(i2c)); if (!(isr & VALID_INT_SOURCE)) return IRQ_NONE; 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 & VALID_INT_SOURCE, _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 && (!i2c->highmode_enter)) { if (isr & ISR_ITE) i2c_pxa_irq_txempty(i2c, isr); if (isr & ISR_IRF) i2c_pxa_irq_rxfull(i2c, isr); } else if ((isr & ISR_ITE) && i2c->highmode_enter) { i2c->highmode_enter = false; wake_up(&i2c->wait); } else { i2c_pxa_scream_blue_murder(i2c, "spurious irq"); } return IRQ_HANDLED; } /* * 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; } if (i2c->high_mode) { ret = i2c_pxa_send_mastercode(i2c); if (ret) { dev_err(&i2c->adap.dev, "i2c_pxa_send_mastercode timeout\n"); 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 && i2c->msg_num) { i2c_pxa_scream_blue_murder(i2c, "timeout"); ret = I2C_RETRY; } out: return ret; } static int i2c_pxa_internal_xfer(struct pxa_i2c *i2c, struct i2c_msg *msgs, int num, int (*xfer)(struct pxa_i2c *, struct i2c_msg *, int num)) { int ret, i; for (i = i2c->adap.retries; i >= 0; i--) { ret = xfer(i2c, msgs, num); if (ret != I2C_RETRY) goto out; if (i2c_debug) dev_dbg(&i2c->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 int i2c_pxa_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) { struct pxa_i2c *i2c = adap->algo_data; return i2c_pxa_internal_xfer(i2c, msgs, num, i2c_pxa_do_xfer); } static u32 i2c_pxa_functionality(struct i2c_adapter *adap) { return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING | I2C_FUNC_NOSTART; } static const struct i2c_algorithm i2c_pxa_algorithm = { .master_xfer = i2c_pxa_xfer, .functionality = i2c_pxa_functionality, #ifdef CONFIG_I2C_PXA_SLAVE .reg_slave = i2c_pxa_slave_reg, .unreg_slave = i2c_pxa_slave_unreg, #endif }; /* Non-interrupt mode support */ 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"); ret = I2C_RETRY; } 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; /* 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); return i2c_pxa_internal_xfer(i2c, msgs, num, i2c_pxa_do_pio_xfer); } static const struct i2c_algorithm i2c_pxa_pio_algorithm = { .master_xfer = i2c_pxa_pio_xfer, .functionality = i2c_pxa_functionality, #ifdef CONFIG_I2C_PXA_SLAVE .reg_slave = i2c_pxa_slave_reg, .unreg_slave = i2c_pxa_slave_unreg, #endif }; static int i2c_pxa_probe_dt(struct platform_device *pdev, struct pxa_i2c *i2c, enum pxa_i2c_types *i2c_types) { struct device_node *np = pdev->dev.of_node; const struct of_device_id *of_id = of_match_device(i2c_pxa_dt_ids, &pdev->dev); if (!of_id) return 1; /* For device tree we always use the dynamic or alias-assigned ID */ i2c->adap.nr = -1; if (of_get_property(np, "mrvl,i2c-polling", NULL)) i2c->use_pio = 1; if (of_get_property(np, "mrvl,i2c-fast-mode", NULL)) i2c->fast_mode = 1; *i2c_types = (enum pxa_i2c_types)(of_id->data); return 0; } static int i2c_pxa_probe_pdata(struct platform_device *pdev, struct pxa_i2c *i2c, enum pxa_i2c_types *i2c_types) { struct i2c_pxa_platform_data *plat = dev_get_platdata(&pdev->dev); const struct platform_device_id *id = platform_get_device_id(pdev); *i2c_types = id->driver_data; if (plat) { i2c->use_pio = plat->use_pio; i2c->fast_mode = plat->fast_mode; i2c->high_mode = plat->high_mode; i2c->master_code = plat->master_code; if (!i2c->master_code) i2c->master_code = 0xe; i2c->rate = plat->rate; } return 0; } static int i2c_pxa_probe(struct platform_device *dev) { struct i2c_pxa_platform_data *plat = dev_get_platdata(&dev->dev); enum pxa_i2c_types i2c_type; struct pxa_i2c *i2c; struct resource *res = NULL; int ret, irq; i2c = devm_kzalloc(&dev->dev, sizeof(struct pxa_i2c), GFP_KERNEL); if (!i2c) return -ENOMEM; res = platform_get_resource(dev, IORESOURCE_MEM, 0); i2c->reg_base = devm_ioremap_resource(&dev->dev, res); if (IS_ERR(i2c->reg_base)) return PTR_ERR(i2c->reg_base); irq = platform_get_irq(dev, 0); if (irq < 0) return irq; /* Default adapter num to device id; i2c_pxa_probe_dt can override. */ i2c->adap.nr = dev->id; ret = i2c_pxa_probe_dt(dev, i2c, &i2c_type); if (ret > 0) ret = i2c_pxa_probe_pdata(dev, i2c, &i2c_type); if (ret < 0) return ret; i2c->adap.owner = THIS_MODULE; i2c->adap.retries = 5; spin_lock_init(&i2c->lock); init_waitqueue_head(&i2c->wait); strlcpy(i2c->adap.name, "pxa_i2c-i2c", sizeof(i2c->adap.name)); i2c->clk = devm_clk_get(&dev->dev, NULL); if (IS_ERR(i2c->clk)) { dev_err(&dev->dev, "failed to get the clk: %ld\n", PTR_ERR(i2c->clk)); return PTR_ERR(i2c->clk); } i2c->reg_ibmr = i2c->reg_base + pxa_reg_layout[i2c_type].ibmr; i2c->reg_idbr = i2c->reg_base + pxa_reg_layout[i2c_type].idbr; i2c->reg_icr = i2c->reg_base + pxa_reg_layout[i2c_type].icr; i2c->reg_isr = i2c->reg_base + pxa_reg_layout[i2c_type].isr; i2c->fm_mask = pxa_reg_layout[i2c_type].fm; i2c->hs_mask = pxa_reg_layout[i2c_type].hs; if (i2c_type != REGS_CE4100) i2c->reg_isar = i2c->reg_base + pxa_reg_layout[i2c_type].isar; if (i2c_type == REGS_PXA910) { i2c->reg_ilcr = i2c->reg_base + pxa_reg_layout[i2c_type].ilcr; i2c->reg_iwcr = i2c->reg_base + pxa_reg_layout[i2c_type].iwcr; } i2c->iobase = res->start; i2c->iosize = resource_size(res); i2c->irq = irq; i2c->slave_addr = I2C_PXA_SLAVE_ADDR; i2c->highmode_enter = false; if (plat) { i2c->adap.class = plat->class; } if (i2c->high_mode) { if (i2c->rate) { clk_set_rate(i2c->clk, i2c->rate); pr_info("i2c: <%s> set rate to %ld\n", i2c->adap.name, clk_get_rate(i2c->clk)); } else pr_warn("i2c: <%s> clock rate not set\n", i2c->adap.name); } clk_prepare_enable(i2c->clk); if (i2c->use_pio) { i2c->adap.algo = &i2c_pxa_pio_algorithm; } else { i2c->adap.algo = &i2c_pxa_algorithm; ret = devm_request_irq(&dev->dev, irq, i2c_pxa_handler, IRQF_SHARED | IRQF_NO_SUSPEND, dev_name(&dev->dev), i2c); if (ret) { dev_err(&dev->dev, "failed to request irq: %d\n", ret); goto ereqirq; } } i2c_pxa_reset(i2c); i2c->adap.algo_data = i2c; i2c->adap.dev.parent = &dev->dev; #ifdef CONFIG_OF i2c->adap.dev.of_node = dev->dev.of_node; #endif ret = i2c_add_numbered_adapter(&i2c->adap); if (ret < 0) goto ereqirq; platform_set_drvdata(dev, i2c); #ifdef CONFIG_I2C_PXA_SLAVE dev_info(&i2c->adap.dev, " PXA I2C adapter, slave address %d\n", i2c->slave_addr); #else dev_info(&i2c->adap.dev, " PXA I2C adapter\n"); #endif return 0; ereqirq: clk_disable_unprepare(i2c->clk); return ret; } static int i2c_pxa_remove(struct platform_device *dev) { struct pxa_i2c *i2c = platform_get_drvdata(dev); i2c_del_adapter(&i2c->adap); clk_disable_unprepare(i2c->clk); return 0; } #ifdef CONFIG_PM static int i2c_pxa_suspend_noirq(struct device *dev) { struct pxa_i2c *i2c = dev_get_drvdata(dev); clk_disable(i2c->clk); return 0; } static int i2c_pxa_resume_noirq(struct device *dev) { struct pxa_i2c *i2c = dev_get_drvdata(dev); clk_enable(i2c->clk); i2c_pxa_reset(i2c); return 0; } static const struct dev_pm_ops i2c_pxa_dev_pm_ops = { .suspend_noirq = i2c_pxa_suspend_noirq, .resume_noirq = i2c_pxa_resume_noirq, }; #define I2C_PXA_DEV_PM_OPS (&i2c_pxa_dev_pm_ops) #else #define I2C_PXA_DEV_PM_OPS NULL #endif static struct platform_driver i2c_pxa_driver = { .probe = i2c_pxa_probe, .remove = i2c_pxa_remove, .driver = { .name = "pxa2xx-i2c", .pm = I2C_PXA_DEV_PM_OPS, .of_match_table = i2c_pxa_dt_ids, }, .id_table = i2c_pxa_id_table, }; 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);