/* * (C) Copyright 2009-2010 * Nokia Siemens Networks, michael.lawnick.ext@nsn.com * * Portions Copyright (C) 2010 - 2016 Cavium, Inc. * * This is a driver for the i2c adapter in Cavium Networks' OCTEON processors. * * This file is licensed under the terms of the GNU General Public * License version 2. This program is licensed "as is" without any * warranty of any kind, whether express or implied. */ #include #include #include #include #include #include #include #include #include #include #include #include #define DRV_NAME "i2c-octeon" /* Register offsets */ #define SW_TWSI 0x00 #define TWSI_INT 0x10 #define SW_TWSI_EXT 0x18 /* Controller command patterns */ #define SW_TWSI_V BIT_ULL(63) /* Valid bit */ #define SW_TWSI_EIA BIT_ULL(61) /* Extended internal address */ #define SW_TWSI_R BIT_ULL(56) /* Result or read bit */ #define SW_TWSI_SOVR BIT_ULL(55) /* Size override */ #define SW_TWSI_SIZE_SHIFT 52 #define SW_TWSI_ADDR_SHIFT 40 #define SW_TWSI_IA_SHIFT 32 /* Internal address */ /* Controller opcode word (bits 60:57) */ #define SW_TWSI_OP_SHIFT 57 #define SW_TWSI_OP_7 (0ULL << SW_TWSI_OP_SHIFT) #define SW_TWSI_OP_7_IA (1ULL << SW_TWSI_OP_SHIFT) #define SW_TWSI_OP_10 (2ULL << SW_TWSI_OP_SHIFT) #define SW_TWSI_OP_10_IA (3ULL << SW_TWSI_OP_SHIFT) #define SW_TWSI_OP_TWSI_CLK (4ULL << SW_TWSI_OP_SHIFT) #define SW_TWSI_OP_EOP (6ULL << SW_TWSI_OP_SHIFT) /* Extended opcode */ /* Controller extended opcode word (bits 34:32) */ #define SW_TWSI_EOP_SHIFT 32 #define SW_TWSI_EOP_TWSI_DATA (SW_TWSI_OP_EOP | 1ULL << SW_TWSI_EOP_SHIFT) #define SW_TWSI_EOP_TWSI_CTL (SW_TWSI_OP_EOP | 2ULL << SW_TWSI_EOP_SHIFT) #define SW_TWSI_EOP_TWSI_CLKCTL (SW_TWSI_OP_EOP | 3ULL << SW_TWSI_EOP_SHIFT) #define SW_TWSI_EOP_TWSI_STAT (SW_TWSI_OP_EOP | 3ULL << SW_TWSI_EOP_SHIFT) #define SW_TWSI_EOP_TWSI_RST (SW_TWSI_OP_EOP | 7ULL << SW_TWSI_EOP_SHIFT) /* Controller command and status bits */ #define TWSI_CTL_CE 0x80 /* High level controller enable */ #define TWSI_CTL_ENAB 0x40 /* Bus enable */ #define TWSI_CTL_STA 0x20 /* Master-mode start, HW clears when done */ #define TWSI_CTL_STP 0x10 /* Master-mode stop, HW clears when done */ #define TWSI_CTL_IFLG 0x08 /* HW event, SW writes 0 to ACK */ #define TWSI_CTL_AAK 0x04 /* Assert ACK */ /* Status values */ #define STAT_ERROR 0x00 #define STAT_START 0x08 #define STAT_REP_START 0x10 #define STAT_TXADDR_ACK 0x18 #define STAT_TXADDR_NAK 0x20 #define STAT_TXDATA_ACK 0x28 #define STAT_TXDATA_NAK 0x30 #define STAT_LOST_ARB_38 0x38 #define STAT_RXADDR_ACK 0x40 #define STAT_RXADDR_NAK 0x48 #define STAT_RXDATA_ACK 0x50 #define STAT_RXDATA_NAK 0x58 #define STAT_SLAVE_60 0x60 #define STAT_LOST_ARB_68 0x68 #define STAT_SLAVE_70 0x70 #define STAT_LOST_ARB_78 0x78 #define STAT_SLAVE_80 0x80 #define STAT_SLAVE_88 0x88 #define STAT_GENDATA_ACK 0x90 #define STAT_GENDATA_NAK 0x98 #define STAT_SLAVE_A0 0xA0 #define STAT_SLAVE_A8 0xA8 #define STAT_LOST_ARB_B0 0xB0 #define STAT_SLAVE_LOST 0xB8 #define STAT_SLAVE_NAK 0xC0 #define STAT_SLAVE_ACK 0xC8 #define STAT_AD2W_ACK 0xD0 #define STAT_AD2W_NAK 0xD8 #define STAT_IDLE 0xF8 /* TWSI_INT values */ #define TWSI_INT_ST_INT BIT_ULL(0) #define TWSI_INT_TS_INT BIT_ULL(1) #define TWSI_INT_CORE_INT BIT_ULL(2) #define TWSI_INT_ST_EN BIT_ULL(4) #define TWSI_INT_TS_EN BIT_ULL(5) #define TWSI_INT_CORE_EN BIT_ULL(6) #define TWSI_INT_SDA_OVR BIT_ULL(8) #define TWSI_INT_SCL_OVR BIT_ULL(9) #define TWSI_INT_SDA BIT_ULL(10) #define TWSI_INT_SCL BIT_ULL(11) #define I2C_OCTEON_EVENT_WAIT 80 /* microseconds */ struct octeon_i2c { wait_queue_head_t queue; struct i2c_adapter adap; int irq; int hlc_irq; /* For cn7890 only */ u32 twsi_freq; int sys_freq; void __iomem *twsi_base; struct device *dev; bool hlc_enabled; bool broken_irq_mode; bool broken_irq_check; void (*int_enable)(struct octeon_i2c *); void (*int_disable)(struct octeon_i2c *); void (*hlc_int_enable)(struct octeon_i2c *); void (*hlc_int_disable)(struct octeon_i2c *); atomic_t int_enable_cnt; atomic_t hlc_int_enable_cnt; }; static void octeon_i2c_writeq_flush(u64 val, void __iomem *addr) { __raw_writeq(val, addr); __raw_readq(addr); /* wait for write to land */ } /** * octeon_i2c_reg_write - write an I2C core register * @i2c: The struct octeon_i2c * @eop_reg: Register selector * @data: Value to be written * * The I2C core registers are accessed indirectly via the SW_TWSI CSR. */ static void octeon_i2c_reg_write(struct octeon_i2c *i2c, u64 eop_reg, u8 data) { u64 tmp; __raw_writeq(SW_TWSI_V | eop_reg | data, i2c->twsi_base + SW_TWSI); do { tmp = __raw_readq(i2c->twsi_base + SW_TWSI); } while ((tmp & SW_TWSI_V) != 0); } #define octeon_i2c_ctl_write(i2c, val) \ octeon_i2c_reg_write(i2c, SW_TWSI_EOP_TWSI_CTL, val) #define octeon_i2c_data_write(i2c, val) \ octeon_i2c_reg_write(i2c, SW_TWSI_EOP_TWSI_DATA, val) /** * octeon_i2c_reg_read - read lower bits of an I2C core register * @i2c: The struct octeon_i2c * @eop_reg: Register selector * * Returns the data. * * The I2C core registers are accessed indirectly via the SW_TWSI CSR. */ static u8 octeon_i2c_reg_read(struct octeon_i2c *i2c, u64 eop_reg) { u64 tmp; __raw_writeq(SW_TWSI_V | eop_reg | SW_TWSI_R, i2c->twsi_base + SW_TWSI); do { tmp = __raw_readq(i2c->twsi_base + SW_TWSI); } while ((tmp & SW_TWSI_V) != 0); return tmp & 0xFF; } #define octeon_i2c_ctl_read(i2c) \ octeon_i2c_reg_read(i2c, SW_TWSI_EOP_TWSI_CTL) #define octeon_i2c_data_read(i2c) \ octeon_i2c_reg_read(i2c, SW_TWSI_EOP_TWSI_DATA) #define octeon_i2c_stat_read(i2c) \ octeon_i2c_reg_read(i2c, SW_TWSI_EOP_TWSI_STAT) /** * octeon_i2c_read_int - read the TWSI_INT register * @i2c: The struct octeon_i2c * * Returns the value of the register. */ static u64 octeon_i2c_read_int(struct octeon_i2c *i2c) { return __raw_readq(i2c->twsi_base + TWSI_INT); } /** * octeon_i2c_write_int - write the TWSI_INT register * @i2c: The struct octeon_i2c * @data: Value to be written */ static void octeon_i2c_write_int(struct octeon_i2c *i2c, u64 data) { octeon_i2c_writeq_flush(data, i2c->twsi_base + TWSI_INT); } /** * octeon_i2c_int_enable - enable the CORE interrupt * @i2c: The struct octeon_i2c * * The interrupt will be asserted when there is non-STAT_IDLE state in * the SW_TWSI_EOP_TWSI_STAT register. */ static void octeon_i2c_int_enable(struct octeon_i2c *i2c) { octeon_i2c_write_int(i2c, TWSI_INT_CORE_EN); } /* disable the CORE interrupt */ static void octeon_i2c_int_disable(struct octeon_i2c *i2c) { /* clear TS/ST/IFLG events */ octeon_i2c_write_int(i2c, 0); } /** * octeon_i2c_int_enable78 - enable the CORE interrupt * @i2c: The struct octeon_i2c * * The interrupt will be asserted when there is non-STAT_IDLE state in the * SW_TWSI_EOP_TWSI_STAT register. */ static void octeon_i2c_int_enable78(struct octeon_i2c *i2c) { atomic_inc_return(&i2c->int_enable_cnt); enable_irq(i2c->irq); } static void __octeon_i2c_irq_disable(atomic_t *cnt, int irq) { int count; /* * The interrupt can be disabled in two places, but we only * want to make the disable_irq_nosync() call once, so keep * track with the atomic variable. */ count = atomic_dec_if_positive(cnt); if (count >= 0) disable_irq_nosync(irq); } /* disable the CORE interrupt */ static void octeon_i2c_int_disable78(struct octeon_i2c *i2c) { __octeon_i2c_irq_disable(&i2c->int_enable_cnt, i2c->irq); } /** * octeon_i2c_hlc_int_enable78 - enable the ST interrupt * @i2c: The struct octeon_i2c * * The interrupt will be asserted when there is non-STAT_IDLE state in * the SW_TWSI_EOP_TWSI_STAT register. */ static void octeon_i2c_hlc_int_enable78(struct octeon_i2c *i2c) { atomic_inc_return(&i2c->hlc_int_enable_cnt); enable_irq(i2c->hlc_irq); } /* disable the ST interrupt */ static void octeon_i2c_hlc_int_disable78(struct octeon_i2c *i2c) { __octeon_i2c_irq_disable(&i2c->hlc_int_enable_cnt, i2c->hlc_irq); } /* * Cleanup low-level state & enable high-level controller. */ static void octeon_i2c_hlc_enable(struct octeon_i2c *i2c) { int try = 0; u64 val; if (i2c->hlc_enabled) return; i2c->hlc_enabled = true; while (1) { val = octeon_i2c_ctl_read(i2c); if (!(val & (TWSI_CTL_STA | TWSI_CTL_STP))) break; /* clear IFLG event */ if (val & TWSI_CTL_IFLG) octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB); if (try++ > 100) { pr_err("%s: giving up\n", __func__); break; } /* spin until any start/stop has finished */ udelay(10); } octeon_i2c_ctl_write(i2c, TWSI_CTL_CE | TWSI_CTL_AAK | TWSI_CTL_ENAB); } static void octeon_i2c_hlc_disable(struct octeon_i2c *i2c) { if (!i2c->hlc_enabled) return; i2c->hlc_enabled = false; octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB); } /* interrupt service routine */ static irqreturn_t octeon_i2c_isr(int irq, void *dev_id) { struct octeon_i2c *i2c = dev_id; i2c->int_disable(i2c); wake_up(&i2c->queue); return IRQ_HANDLED; } /* HLC interrupt service routine */ static irqreturn_t octeon_i2c_hlc_isr78(int irq, void *dev_id) { struct octeon_i2c *i2c = dev_id; i2c->hlc_int_disable(i2c); wake_up(&i2c->queue); return IRQ_HANDLED; } static bool octeon_i2c_test_iflg(struct octeon_i2c *i2c) { return (octeon_i2c_ctl_read(i2c) & TWSI_CTL_IFLG); } static bool octeon_i2c_test_ready(struct octeon_i2c *i2c, bool *first) { if (octeon_i2c_test_iflg(i2c)) return true; if (*first) { *first = false; return false; } /* * IRQ has signaled an event but IFLG hasn't changed. * Sleep and retry once. */ usleep_range(I2C_OCTEON_EVENT_WAIT, 2 * I2C_OCTEON_EVENT_WAIT); return octeon_i2c_test_iflg(i2c); } /** * octeon_i2c_wait - wait for the IFLG to be set * @i2c: The struct octeon_i2c * * Returns 0 on success, otherwise a negative errno. */ static int octeon_i2c_wait(struct octeon_i2c *i2c) { long time_left; bool first = 1; /* * Some chip revisions don't assert the irq in the interrupt * controller. So we must poll for the IFLG change. */ if (i2c->broken_irq_mode) { u64 end = get_jiffies_64() + i2c->adap.timeout; while (!octeon_i2c_test_iflg(i2c) && time_before64(get_jiffies_64(), end)) usleep_range(I2C_OCTEON_EVENT_WAIT / 2, I2C_OCTEON_EVENT_WAIT); return octeon_i2c_test_iflg(i2c) ? 0 : -ETIMEDOUT; } i2c->int_enable(i2c); time_left = wait_event_timeout(i2c->queue, octeon_i2c_test_ready(i2c, &first), i2c->adap.timeout); i2c->int_disable(i2c); if (i2c->broken_irq_check && !time_left && octeon_i2c_test_iflg(i2c)) { dev_err(i2c->dev, "broken irq connection detected, switching to polling mode.\n"); i2c->broken_irq_mode = true; return 0; } if (!time_left) return -ETIMEDOUT; return 0; } static int octeon_i2c_check_status(struct octeon_i2c *i2c, int final_read) { u8 stat = octeon_i2c_stat_read(i2c); switch (stat) { /* Everything is fine */ case STAT_IDLE: case STAT_AD2W_ACK: case STAT_RXADDR_ACK: case STAT_TXADDR_ACK: case STAT_TXDATA_ACK: return 0; /* ACK allowed on pre-terminal bytes only */ case STAT_RXDATA_ACK: if (!final_read) return 0; return -EIO; /* NAK allowed on terminal byte only */ case STAT_RXDATA_NAK: if (final_read) return 0; return -EIO; /* Arbitration lost */ case STAT_LOST_ARB_38: case STAT_LOST_ARB_68: case STAT_LOST_ARB_78: case STAT_LOST_ARB_B0: return -EAGAIN; /* Being addressed as slave, should back off & listen */ case STAT_SLAVE_60: case STAT_SLAVE_70: case STAT_GENDATA_ACK: case STAT_GENDATA_NAK: return -EOPNOTSUPP; /* Core busy as slave */ case STAT_SLAVE_80: case STAT_SLAVE_88: case STAT_SLAVE_A0: case STAT_SLAVE_A8: case STAT_SLAVE_LOST: case STAT_SLAVE_NAK: case STAT_SLAVE_ACK: return -EOPNOTSUPP; case STAT_TXDATA_NAK: return -EIO; case STAT_TXADDR_NAK: case STAT_RXADDR_NAK: case STAT_AD2W_NAK: return -ENXIO; default: dev_err(i2c->dev, "unhandled state: %d\n", stat); return -EIO; } } static bool octeon_i2c_hlc_test_valid(struct octeon_i2c *i2c) { return (__raw_readq(i2c->twsi_base + SW_TWSI) & SW_TWSI_V) == 0; } static bool octeon_i2c_hlc_test_ready(struct octeon_i2c *i2c, bool *first) { /* check if valid bit is cleared */ if (octeon_i2c_hlc_test_valid(i2c)) return true; if (*first) { *first = false; return false; } /* * IRQ has signaled an event but valid bit isn't cleared. * Sleep and retry once. */ usleep_range(I2C_OCTEON_EVENT_WAIT, 2 * I2C_OCTEON_EVENT_WAIT); return octeon_i2c_hlc_test_valid(i2c); } static void octeon_i2c_hlc_int_enable(struct octeon_i2c *i2c) { octeon_i2c_write_int(i2c, TWSI_INT_ST_EN); } static void octeon_i2c_hlc_int_clear(struct octeon_i2c *i2c) { /* clear ST/TS events, listen for neither */ octeon_i2c_write_int(i2c, TWSI_INT_ST_INT | TWSI_INT_TS_INT); } /** * octeon_i2c_hlc_wait - wait for an HLC operation to complete * @i2c: The struct octeon_i2c * * Returns 0 on success, otherwise -ETIMEDOUT. */ static int octeon_i2c_hlc_wait(struct octeon_i2c *i2c) { bool first = 1; int time_left; /* * Some cn38xx boards don't assert the irq in the interrupt * controller. So we must poll for the valid bit change. */ if (i2c->broken_irq_mode) { u64 end = get_jiffies_64() + i2c->adap.timeout; while (!octeon_i2c_hlc_test_valid(i2c) && time_before64(get_jiffies_64(), end)) usleep_range(I2C_OCTEON_EVENT_WAIT / 2, I2C_OCTEON_EVENT_WAIT); return octeon_i2c_hlc_test_valid(i2c) ? 0 : -ETIMEDOUT; } i2c->hlc_int_enable(i2c); time_left = wait_event_timeout(i2c->queue, octeon_i2c_hlc_test_ready(i2c, &first), i2c->adap.timeout); i2c->hlc_int_disable(i2c); if (!time_left) octeon_i2c_hlc_int_clear(i2c); if (i2c->broken_irq_check && !time_left && octeon_i2c_hlc_test_valid(i2c)) { dev_err(i2c->dev, "broken irq connection detected, switching to polling mode.\n"); i2c->broken_irq_mode = true; return 0; } if (!time_left) return -ETIMEDOUT; return 0; } /* high-level-controller pure read of up to 8 bytes */ static int octeon_i2c_hlc_read(struct octeon_i2c *i2c, struct i2c_msg *msgs) { int i, j, ret = 0; u64 cmd; octeon_i2c_hlc_enable(i2c); octeon_i2c_hlc_int_clear(i2c); cmd = SW_TWSI_V | SW_TWSI_R | SW_TWSI_SOVR; /* SIZE */ cmd |= (u64)(msgs[0].len - 1) << SW_TWSI_SIZE_SHIFT; /* A */ cmd |= (u64)(msgs[0].addr & 0x7full) << SW_TWSI_ADDR_SHIFT; if (msgs[0].flags & I2C_M_TEN) cmd |= SW_TWSI_OP_10; else cmd |= SW_TWSI_OP_7; octeon_i2c_writeq_flush(cmd, i2c->twsi_base + SW_TWSI); ret = octeon_i2c_hlc_wait(i2c); if (ret) goto err; cmd = __raw_readq(i2c->twsi_base + SW_TWSI); if ((cmd & SW_TWSI_R) == 0) return -EAGAIN; for (i = 0, j = msgs[0].len - 1; i < msgs[0].len && i < 4; i++, j--) msgs[0].buf[j] = (cmd >> (8 * i)) & 0xff; if (msgs[0].len > 4) { cmd = __raw_readq(i2c->twsi_base + SW_TWSI_EXT); for (i = 0; i < msgs[0].len - 4 && i < 4; i++, j--) msgs[0].buf[j] = (cmd >> (8 * i)) & 0xff; } err: return ret; } /* high-level-controller pure write of up to 8 bytes */ static int octeon_i2c_hlc_write(struct octeon_i2c *i2c, struct i2c_msg *msgs) { int i, j, ret = 0; u64 cmd; octeon_i2c_hlc_enable(i2c); octeon_i2c_hlc_int_clear(i2c); cmd = SW_TWSI_V | SW_TWSI_SOVR; /* SIZE */ cmd |= (u64)(msgs[0].len - 1) << SW_TWSI_SIZE_SHIFT; /* A */ cmd |= (u64)(msgs[0].addr & 0x7full) << SW_TWSI_ADDR_SHIFT; if (msgs[0].flags & I2C_M_TEN) cmd |= SW_TWSI_OP_10; else cmd |= SW_TWSI_OP_7; for (i = 0, j = msgs[0].len - 1; i < msgs[0].len && i < 4; i++, j--) cmd |= (u64)msgs[0].buf[j] << (8 * i); if (msgs[0].len > 4) { u64 ext = 0; for (i = 0; i < msgs[0].len - 4 && i < 4; i++, j--) ext |= (u64)msgs[0].buf[j] << (8 * i); octeon_i2c_writeq_flush(ext, i2c->twsi_base + SW_TWSI_EXT); } octeon_i2c_writeq_flush(cmd, i2c->twsi_base + SW_TWSI); ret = octeon_i2c_hlc_wait(i2c); if (ret) goto err; cmd = __raw_readq(i2c->twsi_base + SW_TWSI); if ((cmd & SW_TWSI_R) == 0) return -EAGAIN; ret = octeon_i2c_check_status(i2c, false); err: return ret; } /* high-level-controller composite write+read, msg0=addr, msg1=data */ static int octeon_i2c_hlc_comp_read(struct octeon_i2c *i2c, struct i2c_msg *msgs) { int i, j, ret = 0; u64 cmd; octeon_i2c_hlc_enable(i2c); cmd = SW_TWSI_V | SW_TWSI_R | SW_TWSI_SOVR; /* SIZE */ cmd |= (u64)(msgs[1].len - 1) << SW_TWSI_SIZE_SHIFT; /* A */ cmd |= (u64)(msgs[0].addr & 0x7full) << SW_TWSI_ADDR_SHIFT; if (msgs[0].flags & I2C_M_TEN) cmd |= SW_TWSI_OP_10_IA; else cmd |= SW_TWSI_OP_7_IA; if (msgs[0].len == 2) { u64 ext = 0; cmd |= SW_TWSI_EIA; ext = (u64)msgs[0].buf[0] << SW_TWSI_IA_SHIFT; cmd |= (u64)msgs[0].buf[1] << SW_TWSI_IA_SHIFT; octeon_i2c_writeq_flush(ext, i2c->twsi_base + SW_TWSI_EXT); } else { cmd |= (u64)msgs[0].buf[0] << SW_TWSI_IA_SHIFT; } octeon_i2c_hlc_int_clear(i2c); octeon_i2c_writeq_flush(cmd, i2c->twsi_base + SW_TWSI); ret = octeon_i2c_hlc_wait(i2c); if (ret) goto err; cmd = __raw_readq(i2c->twsi_base + SW_TWSI); if ((cmd & SW_TWSI_R) == 0) return -EAGAIN; for (i = 0, j = msgs[1].len - 1; i < msgs[1].len && i < 4; i++, j--) msgs[1].buf[j] = (cmd >> (8 * i)) & 0xff; if (msgs[1].len > 4) { cmd = __raw_readq(i2c->twsi_base + SW_TWSI_EXT); for (i = 0; i < msgs[1].len - 4 && i < 4; i++, j--) msgs[1].buf[j] = (cmd >> (8 * i)) & 0xff; } err: return ret; } /* high-level-controller composite write+write, m[0]len<=2, m[1]len<=8 */ static int octeon_i2c_hlc_comp_write(struct octeon_i2c *i2c, struct i2c_msg *msgs) { bool set_ext = false; int i, j, ret = 0; u64 cmd, ext = 0; octeon_i2c_hlc_enable(i2c); cmd = SW_TWSI_V | SW_TWSI_SOVR; /* SIZE */ cmd |= (u64)(msgs[1].len - 1) << SW_TWSI_SIZE_SHIFT; /* A */ cmd |= (u64)(msgs[0].addr & 0x7full) << SW_TWSI_ADDR_SHIFT; if (msgs[0].flags & I2C_M_TEN) cmd |= SW_TWSI_OP_10_IA; else cmd |= SW_TWSI_OP_7_IA; if (msgs[0].len == 2) { cmd |= SW_TWSI_EIA; ext |= (u64)msgs[0].buf[0] << SW_TWSI_IA_SHIFT; set_ext = true; cmd |= (u64)msgs[0].buf[1] << SW_TWSI_IA_SHIFT; } else { cmd |= (u64)msgs[0].buf[0] << SW_TWSI_IA_SHIFT; } for (i = 0, j = msgs[1].len - 1; i < msgs[1].len && i < 4; i++, j--) cmd |= (u64)msgs[1].buf[j] << (8 * i); if (msgs[1].len > 4) { for (i = 0; i < msgs[1].len - 4 && i < 4; i++, j--) ext |= (u64)msgs[1].buf[j] << (8 * i); set_ext = true; } if (set_ext) octeon_i2c_writeq_flush(ext, i2c->twsi_base + SW_TWSI_EXT); octeon_i2c_hlc_int_clear(i2c); octeon_i2c_writeq_flush(cmd, i2c->twsi_base + SW_TWSI); ret = octeon_i2c_hlc_wait(i2c); if (ret) goto err; cmd = __raw_readq(i2c->twsi_base + SW_TWSI); if ((cmd & SW_TWSI_R) == 0) return -EAGAIN; ret = octeon_i2c_check_status(i2c, false); err: return ret; } /* calculate and set clock divisors */ static void octeon_i2c_set_clock(struct octeon_i2c *i2c) { int tclk, thp_base, inc, thp_idx, mdiv_idx, ndiv_idx, foscl, diff; int thp = 0x18, mdiv = 2, ndiv = 0, delta_hz = 1000000; for (ndiv_idx = 0; ndiv_idx < 8 && delta_hz != 0; ndiv_idx++) { /* * An mdiv value of less than 2 seems to not work well * with ds1337 RTCs, so we constrain it to larger values. */ for (mdiv_idx = 15; mdiv_idx >= 2 && delta_hz != 0; mdiv_idx--) { /* * For given ndiv and mdiv values check the * two closest thp values. */ tclk = i2c->twsi_freq * (mdiv_idx + 1) * 10; tclk *= (1 << ndiv_idx); thp_base = (i2c->sys_freq / (tclk * 2)) - 1; for (inc = 0; inc <= 1; inc++) { thp_idx = thp_base + inc; if (thp_idx < 5 || thp_idx > 0xff) continue; foscl = i2c->sys_freq / (2 * (thp_idx + 1)); foscl = foscl / (1 << ndiv_idx); foscl = foscl / (mdiv_idx + 1) / 10; diff = abs(foscl - i2c->twsi_freq); if (diff < delta_hz) { delta_hz = diff; thp = thp_idx; mdiv = mdiv_idx; ndiv = ndiv_idx; } } } } octeon_i2c_reg_write(i2c, SW_TWSI_OP_TWSI_CLK, thp); octeon_i2c_reg_write(i2c, SW_TWSI_EOP_TWSI_CLKCTL, (mdiv << 3) | ndiv); } static int octeon_i2c_init_lowlevel(struct octeon_i2c *i2c) { u8 status = 0; int tries; /* reset controller */ octeon_i2c_reg_write(i2c, SW_TWSI_EOP_TWSI_RST, 0); for (tries = 10; tries && status != STAT_IDLE; tries--) { udelay(1); status = octeon_i2c_stat_read(i2c); if (status == STAT_IDLE) break; } if (status != STAT_IDLE) { dev_err(i2c->dev, "%s: TWSI_RST failed! (0x%x)\n", __func__, status); return -EIO; } /* toggle twice to force both teardowns */ octeon_i2c_hlc_enable(i2c); octeon_i2c_hlc_disable(i2c); return 0; } static int octeon_i2c_recovery(struct octeon_i2c *i2c) { int ret; ret = i2c_recover_bus(&i2c->adap); if (ret) /* recover failed, try hardware re-init */ ret = octeon_i2c_init_lowlevel(i2c); return ret; } /** * octeon_i2c_start - send START to the bus * @i2c: The struct octeon_i2c * * Returns 0 on success, otherwise a negative errno. */ static int octeon_i2c_start(struct octeon_i2c *i2c) { int ret; u8 stat; octeon_i2c_hlc_disable(i2c); octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB | TWSI_CTL_STA); ret = octeon_i2c_wait(i2c); if (ret) goto error; stat = octeon_i2c_stat_read(i2c); if (stat == STAT_START || stat == STAT_REP_START) /* START successful, bail out */ return 0; error: /* START failed, try to recover */ ret = octeon_i2c_recovery(i2c); return (ret) ? ret : -EAGAIN; } /* send STOP to the bus */ static void octeon_i2c_stop(struct octeon_i2c *i2c) { octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB | TWSI_CTL_STP); } /** * octeon_i2c_write - send data to the bus via low-level controller * @i2c: The struct octeon_i2c * @target: Target address * @data: Pointer to the data to be sent * @length: Length of the data * * The address is sent over the bus, then the data. * * Returns 0 on success, otherwise a negative errno. */ static int octeon_i2c_write(struct octeon_i2c *i2c, int target, const u8 *data, int length) { int i, result; octeon_i2c_data_write(i2c, target << 1); octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB); result = octeon_i2c_wait(i2c); if (result) return result; for (i = 0; i < length; i++) { result = octeon_i2c_check_status(i2c, false); if (result) return result; octeon_i2c_data_write(i2c, data[i]); octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB); result = octeon_i2c_wait(i2c); if (result) return result; } return 0; } /** * octeon_i2c_read - receive data from the bus via low-level controller * @i2c: The struct octeon_i2c * @target: Target address * @data: Pointer to the location to store the data * @rlength: Length of the data * @recv_len: flag for length byte * * The address is sent over the bus, then the data is read. * * Returns 0 on success, otherwise a negative errno. */ static int octeon_i2c_read(struct octeon_i2c *i2c, int target, u8 *data, u16 *rlength, bool recv_len) { int i, result, length = *rlength; bool final_read = false; octeon_i2c_data_write(i2c, (target << 1) | 1); octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB); result = octeon_i2c_wait(i2c); if (result) return result; /* address OK ? */ result = octeon_i2c_check_status(i2c, false); if (result) return result; for (i = 0; i < length; i++) { /* * For the last byte to receive TWSI_CTL_AAK must not be set. * * A special case is I2C_M_RECV_LEN where we don't know the * additional length yet. If recv_len is set we assume we're * not reading the final byte and therefore need to set * TWSI_CTL_AAK. */ if ((i + 1 == length) && !(recv_len && i == 0)) final_read = true; /* clear iflg to allow next event */ if (final_read) octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB); else octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB | TWSI_CTL_AAK); result = octeon_i2c_wait(i2c); if (result) return result; data[i] = octeon_i2c_data_read(i2c); if (recv_len && i == 0) { if (data[i] > I2C_SMBUS_BLOCK_MAX + 1) return -EPROTO; length += data[i]; } result = octeon_i2c_check_status(i2c, final_read); if (result) return result; } *rlength = length; return 0; } /** * octeon_i2c_xfer - The driver's master_xfer function * @adap: Pointer to the i2c_adapter structure * @msgs: Pointer to the messages to be processed * @num: Length of the MSGS array * * Returns the number of messages processed, or a negative errno on failure. */ static int octeon_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) { struct octeon_i2c *i2c = i2c_get_adapdata(adap); int i, ret = 0; if (num == 1) { if (msgs[0].len > 0 && msgs[0].len <= 8) { if (msgs[0].flags & I2C_M_RD) ret = octeon_i2c_hlc_read(i2c, msgs); else ret = octeon_i2c_hlc_write(i2c, msgs); goto out; } } else if (num == 2) { if ((msgs[0].flags & I2C_M_RD) == 0 && (msgs[1].flags & I2C_M_RECV_LEN) == 0 && msgs[0].len > 0 && msgs[0].len <= 2 && msgs[1].len > 0 && msgs[1].len <= 8 && msgs[0].addr == msgs[1].addr) { if (msgs[1].flags & I2C_M_RD) ret = octeon_i2c_hlc_comp_read(i2c, msgs); else ret = octeon_i2c_hlc_comp_write(i2c, msgs); goto out; } } for (i = 0; ret == 0 && i < num; i++) { struct i2c_msg *pmsg = &msgs[i]; /* zero-length messages are not supported */ if (!pmsg->len) { ret = -EOPNOTSUPP; break; } ret = octeon_i2c_start(i2c); if (ret) return ret; if (pmsg->flags & I2C_M_RD) ret = octeon_i2c_read(i2c, pmsg->addr, pmsg->buf, &pmsg->len, pmsg->flags & I2C_M_RECV_LEN); else ret = octeon_i2c_write(i2c, pmsg->addr, pmsg->buf, pmsg->len); } octeon_i2c_stop(i2c); out: return (ret != 0) ? ret : num; } static int octeon_i2c_get_scl(struct i2c_adapter *adap) { struct octeon_i2c *i2c = i2c_get_adapdata(adap); u64 state; state = octeon_i2c_read_int(i2c); return state & TWSI_INT_SCL; } static void octeon_i2c_set_scl(struct i2c_adapter *adap, int val) { struct octeon_i2c *i2c = i2c_get_adapdata(adap); octeon_i2c_write_int(i2c, TWSI_INT_SCL_OVR); } static int octeon_i2c_get_sda(struct i2c_adapter *adap) { struct octeon_i2c *i2c = i2c_get_adapdata(adap); u64 state; state = octeon_i2c_read_int(i2c); return state & TWSI_INT_SDA; } static void octeon_i2c_prepare_recovery(struct i2c_adapter *adap) { struct octeon_i2c *i2c = i2c_get_adapdata(adap); /* * The stop resets the state machine, does not _transmit_ STOP unless * engine was active. */ octeon_i2c_stop(i2c); octeon_i2c_hlc_disable(i2c); octeon_i2c_write_int(i2c, 0); } static void octeon_i2c_unprepare_recovery(struct i2c_adapter *adap) { struct octeon_i2c *i2c = i2c_get_adapdata(adap); octeon_i2c_write_int(i2c, 0); } static struct i2c_bus_recovery_info octeon_i2c_recovery_info = { .recover_bus = i2c_generic_scl_recovery, .get_scl = octeon_i2c_get_scl, .set_scl = octeon_i2c_set_scl, .get_sda = octeon_i2c_get_sda, .prepare_recovery = octeon_i2c_prepare_recovery, .unprepare_recovery = octeon_i2c_unprepare_recovery, }; static u32 octeon_i2c_functionality(struct i2c_adapter *adap) { return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK) | I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_SMBUS_BLOCK_PROC_CALL; } static const struct i2c_algorithm octeon_i2c_algo = { .master_xfer = octeon_i2c_xfer, .functionality = octeon_i2c_functionality, }; static struct i2c_adapter octeon_i2c_ops = { .owner = THIS_MODULE, .name = "OCTEON adapter", .algo = &octeon_i2c_algo, }; static int octeon_i2c_probe(struct platform_device *pdev) { struct device_node *node = pdev->dev.of_node; int irq, result = 0, hlc_irq = 0; struct resource *res_mem; struct octeon_i2c *i2c; bool cn78xx_style; cn78xx_style = of_device_is_compatible(node, "cavium,octeon-7890-twsi"); if (cn78xx_style) { hlc_irq = platform_get_irq(pdev, 0); if (hlc_irq < 0) return hlc_irq; irq = platform_get_irq(pdev, 2); if (irq < 0) return irq; } else { /* All adaptors have an irq. */ irq = platform_get_irq(pdev, 0); if (irq < 0) return irq; } i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL); if (!i2c) { result = -ENOMEM; goto out; } i2c->dev = &pdev->dev; res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); i2c->twsi_base = devm_ioremap_resource(&pdev->dev, res_mem); if (IS_ERR(i2c->twsi_base)) { result = PTR_ERR(i2c->twsi_base); goto out; } /* * "clock-rate" is a legacy binding, the official binding is * "clock-frequency". Try the official one first and then * fall back if it doesn't exist. */ if (of_property_read_u32(node, "clock-frequency", &i2c->twsi_freq) && of_property_read_u32(node, "clock-rate", &i2c->twsi_freq)) { dev_err(i2c->dev, "no I2C 'clock-rate' or 'clock-frequency' property\n"); result = -ENXIO; goto out; } i2c->sys_freq = octeon_get_io_clock_rate(); init_waitqueue_head(&i2c->queue); i2c->irq = irq; if (cn78xx_style) { i2c->hlc_irq = hlc_irq; i2c->int_enable = octeon_i2c_int_enable78; i2c->int_disable = octeon_i2c_int_disable78; i2c->hlc_int_enable = octeon_i2c_hlc_int_enable78; i2c->hlc_int_disable = octeon_i2c_hlc_int_disable78; irq_set_status_flags(i2c->irq, IRQ_NOAUTOEN); irq_set_status_flags(i2c->hlc_irq, IRQ_NOAUTOEN); result = devm_request_irq(&pdev->dev, i2c->hlc_irq, octeon_i2c_hlc_isr78, 0, DRV_NAME, i2c); if (result < 0) { dev_err(i2c->dev, "failed to attach interrupt\n"); goto out; } } else { i2c->int_enable = octeon_i2c_int_enable; i2c->int_disable = octeon_i2c_int_disable; i2c->hlc_int_enable = octeon_i2c_hlc_int_enable; i2c->hlc_int_disable = octeon_i2c_int_disable; } result = devm_request_irq(&pdev->dev, i2c->irq, octeon_i2c_isr, 0, DRV_NAME, i2c); if (result < 0) { dev_err(i2c->dev, "failed to attach interrupt\n"); goto out; } if (OCTEON_IS_MODEL(OCTEON_CN38XX)) i2c->broken_irq_check = true; result = octeon_i2c_init_lowlevel(i2c); if (result) { dev_err(i2c->dev, "init low level failed\n"); goto out; } octeon_i2c_set_clock(i2c); i2c->adap = octeon_i2c_ops; i2c->adap.timeout = msecs_to_jiffies(2); i2c->adap.retries = 5; i2c->adap.bus_recovery_info = &octeon_i2c_recovery_info; i2c->adap.dev.parent = &pdev->dev; i2c->adap.dev.of_node = node; i2c_set_adapdata(&i2c->adap, i2c); platform_set_drvdata(pdev, i2c); result = i2c_add_adapter(&i2c->adap); if (result < 0) { dev_err(i2c->dev, "failed to add adapter\n"); goto out; } dev_info(i2c->dev, "probed\n"); return 0; out: return result; }; static int octeon_i2c_remove(struct platform_device *pdev) { struct octeon_i2c *i2c = platform_get_drvdata(pdev); i2c_del_adapter(&i2c->adap); return 0; }; static const struct of_device_id octeon_i2c_match[] = { { .compatible = "cavium,octeon-3860-twsi", }, { .compatible = "cavium,octeon-7890-twsi", }, {}, }; MODULE_DEVICE_TABLE(of, octeon_i2c_match); static struct platform_driver octeon_i2c_driver = { .probe = octeon_i2c_probe, .remove = octeon_i2c_remove, .driver = { .name = DRV_NAME, .of_match_table = octeon_i2c_match, }, }; module_platform_driver(octeon_i2c_driver); MODULE_AUTHOR("Michael Lawnick "); MODULE_DESCRIPTION("I2C-Bus adapter for Cavium OCTEON processors"); MODULE_LICENSE("GPL");