/* * Driver for I2C adapter in Rockchip RK3xxx SoC * * Max Schwarz * based on the patches by Rockchip Inc. * * 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. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* Register Map */ #define REG_CON 0x00 /* control register */ #define REG_CLKDIV 0x04 /* clock divisor register */ #define REG_MRXADDR 0x08 /* slave address for REGISTER_TX */ #define REG_MRXRADDR 0x0c /* slave register address for REGISTER_TX */ #define REG_MTXCNT 0x10 /* number of bytes to be transmitted */ #define REG_MRXCNT 0x14 /* number of bytes to be received */ #define REG_IEN 0x18 /* interrupt enable */ #define REG_IPD 0x1c /* interrupt pending */ #define REG_FCNT 0x20 /* finished count */ /* Data buffer offsets */ #define TXBUFFER_BASE 0x100 #define RXBUFFER_BASE 0x200 /* REG_CON bits */ #define REG_CON_EN BIT(0) enum { REG_CON_MOD_TX = 0, /* transmit data */ REG_CON_MOD_REGISTER_TX, /* select register and restart */ REG_CON_MOD_RX, /* receive data */ REG_CON_MOD_REGISTER_RX, /* broken: transmits read addr AND writes * register addr */ }; #define REG_CON_MOD(mod) ((mod) << 1) #define REG_CON_MOD_MASK (BIT(1) | BIT(2)) #define REG_CON_START BIT(3) #define REG_CON_STOP BIT(4) #define REG_CON_LASTACK BIT(5) /* 1: send NACK after last received byte */ #define REG_CON_ACTACK BIT(6) /* 1: stop if NACK is received */ /* REG_MRXADDR bits */ #define REG_MRXADDR_VALID(x) BIT(24 + (x)) /* [x*8+7:x*8] of MRX[R]ADDR valid */ /* REG_IEN/REG_IPD bits */ #define REG_INT_BTF BIT(0) /* a byte was transmitted */ #define REG_INT_BRF BIT(1) /* a byte was received */ #define REG_INT_MBTF BIT(2) /* master data transmit finished */ #define REG_INT_MBRF BIT(3) /* master data receive finished */ #define REG_INT_START BIT(4) /* START condition generated */ #define REG_INT_STOP BIT(5) /* STOP condition generated */ #define REG_INT_NAKRCV BIT(6) /* NACK received */ #define REG_INT_ALL 0x7f /* Constants */ #define WAIT_TIMEOUT 200 /* ms */ #define DEFAULT_SCL_RATE (100 * 1000) /* Hz */ enum rk3x_i2c_state { STATE_IDLE, STATE_START, STATE_READ, STATE_WRITE, STATE_STOP }; /** * @grf_offset: offset inside the grf regmap for setting the i2c type */ struct rk3x_i2c_soc_data { int grf_offset; }; struct rk3x_i2c { struct i2c_adapter adap; struct device *dev; struct rk3x_i2c_soc_data *soc_data; /* Hardware resources */ void __iomem *regs; struct clk *clk; /* Settings */ unsigned int scl_frequency; /* Synchronization & notification */ spinlock_t lock; wait_queue_head_t wait; bool busy; /* Current message */ struct i2c_msg *msg; u8 addr; unsigned int mode; bool is_last_msg; /* I2C state machine */ enum rk3x_i2c_state state; unsigned int processed; /* sent/received bytes */ int error; }; static inline void i2c_writel(struct rk3x_i2c *i2c, u32 value, unsigned int offset) { writel(value, i2c->regs + offset); } static inline u32 i2c_readl(struct rk3x_i2c *i2c, unsigned int offset) { return readl(i2c->regs + offset); } /* Reset all interrupt pending bits */ static inline void rk3x_i2c_clean_ipd(struct rk3x_i2c *i2c) { i2c_writel(i2c, REG_INT_ALL, REG_IPD); } /** * Generate a START condition, which triggers a REG_INT_START interrupt. */ static void rk3x_i2c_start(struct rk3x_i2c *i2c) { u32 val; rk3x_i2c_clean_ipd(i2c); i2c_writel(i2c, REG_INT_START, REG_IEN); /* enable adapter with correct mode, send START condition */ val = REG_CON_EN | REG_CON_MOD(i2c->mode) | REG_CON_START; /* if we want to react to NACK, set ACTACK bit */ if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) val |= REG_CON_ACTACK; i2c_writel(i2c, val, REG_CON); } /** * Generate a STOP condition, which triggers a REG_INT_STOP interrupt. * * @error: Error code to return in rk3x_i2c_xfer */ static void rk3x_i2c_stop(struct rk3x_i2c *i2c, int error) { unsigned int ctrl; i2c->processed = 0; i2c->msg = NULL; i2c->error = error; if (i2c->is_last_msg) { /* Enable stop interrupt */ i2c_writel(i2c, REG_INT_STOP, REG_IEN); i2c->state = STATE_STOP; ctrl = i2c_readl(i2c, REG_CON); ctrl |= REG_CON_STOP; i2c_writel(i2c, ctrl, REG_CON); } else { /* Signal rk3x_i2c_xfer to start the next message. */ i2c->busy = false; i2c->state = STATE_IDLE; /* * The HW is actually not capable of REPEATED START. But we can * get the intended effect by resetting its internal state * and issuing an ordinary START. */ i2c_writel(i2c, 0, REG_CON); /* signal that we are finished with the current msg */ wake_up(&i2c->wait); } } /** * Setup a read according to i2c->msg */ static void rk3x_i2c_prepare_read(struct rk3x_i2c *i2c) { unsigned int len = i2c->msg->len - i2c->processed; u32 con; con = i2c_readl(i2c, REG_CON); /* * The hw can read up to 32 bytes at a time. If we need more than one * chunk, send an ACK after the last byte of the current chunk. */ if (unlikely(len > 32)) { len = 32; con &= ~REG_CON_LASTACK; } else { con |= REG_CON_LASTACK; } /* make sure we are in plain RX mode if we read a second chunk */ if (i2c->processed != 0) { con &= ~REG_CON_MOD_MASK; con |= REG_CON_MOD(REG_CON_MOD_RX); } i2c_writel(i2c, con, REG_CON); i2c_writel(i2c, len, REG_MRXCNT); } /** * Fill the transmit buffer with data from i2c->msg */ static void rk3x_i2c_fill_transmit_buf(struct rk3x_i2c *i2c) { unsigned int i, j; u32 cnt = 0; u32 val; u8 byte; for (i = 0; i < 8; ++i) { val = 0; for (j = 0; j < 4; ++j) { if (i2c->processed == i2c->msg->len) break; if (i2c->processed == 0 && cnt == 0) byte = (i2c->addr & 0x7f) << 1; else byte = i2c->msg->buf[i2c->processed++]; val |= byte << (j * 8); cnt++; } i2c_writel(i2c, val, TXBUFFER_BASE + 4 * i); if (i2c->processed == i2c->msg->len) break; } i2c_writel(i2c, cnt, REG_MTXCNT); } /* IRQ handlers for individual states */ static void rk3x_i2c_handle_start(struct rk3x_i2c *i2c, unsigned int ipd) { if (!(ipd & REG_INT_START)) { rk3x_i2c_stop(i2c, -EIO); dev_warn(i2c->dev, "unexpected irq in START: 0x%x\n", ipd); rk3x_i2c_clean_ipd(i2c); return; } /* ack interrupt */ i2c_writel(i2c, REG_INT_START, REG_IPD); /* disable start bit */ i2c_writel(i2c, i2c_readl(i2c, REG_CON) & ~REG_CON_START, REG_CON); /* enable appropriate interrupts and transition */ if (i2c->mode == REG_CON_MOD_TX) { i2c_writel(i2c, REG_INT_MBTF | REG_INT_NAKRCV, REG_IEN); i2c->state = STATE_WRITE; rk3x_i2c_fill_transmit_buf(i2c); } else { /* in any other case, we are going to be reading. */ i2c_writel(i2c, REG_INT_MBRF | REG_INT_NAKRCV, REG_IEN); i2c->state = STATE_READ; rk3x_i2c_prepare_read(i2c); } } static void rk3x_i2c_handle_write(struct rk3x_i2c *i2c, unsigned int ipd) { if (!(ipd & REG_INT_MBTF)) { rk3x_i2c_stop(i2c, -EIO); dev_err(i2c->dev, "unexpected irq in WRITE: 0x%x\n", ipd); rk3x_i2c_clean_ipd(i2c); return; } /* ack interrupt */ i2c_writel(i2c, REG_INT_MBTF, REG_IPD); /* are we finished? */ if (i2c->processed == i2c->msg->len) rk3x_i2c_stop(i2c, i2c->error); else rk3x_i2c_fill_transmit_buf(i2c); } static void rk3x_i2c_handle_read(struct rk3x_i2c *i2c, unsigned int ipd) { unsigned int i; unsigned int len = i2c->msg->len - i2c->processed; u32 uninitialized_var(val); u8 byte; /* we only care for MBRF here. */ if (!(ipd & REG_INT_MBRF)) return; /* ack interrupt */ i2c_writel(i2c, REG_INT_MBRF, REG_IPD); /* Can only handle a maximum of 32 bytes at a time */ if (len > 32) len = 32; /* read the data from receive buffer */ for (i = 0; i < len; ++i) { if (i % 4 == 0) val = i2c_readl(i2c, RXBUFFER_BASE + (i / 4) * 4); byte = (val >> ((i % 4) * 8)) & 0xff; i2c->msg->buf[i2c->processed++] = byte; } /* are we finished? */ if (i2c->processed == i2c->msg->len) rk3x_i2c_stop(i2c, i2c->error); else rk3x_i2c_prepare_read(i2c); } static void rk3x_i2c_handle_stop(struct rk3x_i2c *i2c, unsigned int ipd) { unsigned int con; if (!(ipd & REG_INT_STOP)) { rk3x_i2c_stop(i2c, -EIO); dev_err(i2c->dev, "unexpected irq in STOP: 0x%x\n", ipd); rk3x_i2c_clean_ipd(i2c); return; } /* ack interrupt */ i2c_writel(i2c, REG_INT_STOP, REG_IPD); /* disable STOP bit */ con = i2c_readl(i2c, REG_CON); con &= ~REG_CON_STOP; i2c_writel(i2c, con, REG_CON); i2c->busy = false; i2c->state = STATE_IDLE; /* signal rk3x_i2c_xfer that we are finished */ wake_up(&i2c->wait); } static irqreturn_t rk3x_i2c_irq(int irqno, void *dev_id) { struct rk3x_i2c *i2c = dev_id; unsigned int ipd; spin_lock(&i2c->lock); ipd = i2c_readl(i2c, REG_IPD); if (i2c->state == STATE_IDLE) { dev_warn(i2c->dev, "irq in STATE_IDLE, ipd = 0x%x\n", ipd); rk3x_i2c_clean_ipd(i2c); goto out; } dev_dbg(i2c->dev, "IRQ: state %d, ipd: %x\n", i2c->state, ipd); /* Clean interrupt bits we don't care about */ ipd &= ~(REG_INT_BRF | REG_INT_BTF); if (ipd & REG_INT_NAKRCV) { /* * We got a NACK in the last operation. Depending on whether * IGNORE_NAK is set, we have to stop the operation and report * an error. */ i2c_writel(i2c, REG_INT_NAKRCV, REG_IPD); ipd &= ~REG_INT_NAKRCV; if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) rk3x_i2c_stop(i2c, -ENXIO); } /* is there anything left to handle? */ if (unlikely((ipd & REG_INT_ALL) == 0)) goto out; switch (i2c->state) { case STATE_START: rk3x_i2c_handle_start(i2c, ipd); break; case STATE_WRITE: rk3x_i2c_handle_write(i2c, ipd); break; case STATE_READ: rk3x_i2c_handle_read(i2c, ipd); break; case STATE_STOP: rk3x_i2c_handle_stop(i2c, ipd); break; case STATE_IDLE: break; } out: spin_unlock(&i2c->lock); return IRQ_HANDLED; } static void rk3x_i2c_set_scl_rate(struct rk3x_i2c *i2c, unsigned long scl_rate) { unsigned long i2c_rate = clk_get_rate(i2c->clk); unsigned int div; /* set DIV = DIVH = DIVL * SCL rate = (clk rate) / (8 * (DIVH + 1 + DIVL + 1)) * = (clk rate) / (16 * (DIV + 1)) */ div = DIV_ROUND_UP(i2c_rate, scl_rate * 16) - 1; i2c_writel(i2c, (div << 16) | (div & 0xffff), REG_CLKDIV); } /** * Setup I2C registers for an I2C operation specified by msgs, num. * * Must be called with i2c->lock held. * * @msgs: I2C msgs to process * @num: Number of msgs * * returns: Number of I2C msgs processed or negative in case of error */ static int rk3x_i2c_setup(struct rk3x_i2c *i2c, struct i2c_msg *msgs, int num) { u32 addr = (msgs[0].addr & 0x7f) << 1; int ret = 0; /* * The I2C adapter can issue a small (len < 4) write packet before * reading. This speeds up SMBus-style register reads. * The MRXADDR/MRXRADDR hold the slave address and the slave register * address in this case. */ if (num >= 2 && msgs[0].len < 4 && !(msgs[0].flags & I2C_M_RD) && (msgs[1].flags & I2C_M_RD)) { u32 reg_addr = 0; int i; dev_dbg(i2c->dev, "Combined write/read from addr 0x%x\n", addr >> 1); /* Fill MRXRADDR with the register address(es) */ for (i = 0; i < msgs[0].len; ++i) { reg_addr |= msgs[0].buf[i] << (i * 8); reg_addr |= REG_MRXADDR_VALID(i); } /* msgs[0] is handled by hw. */ i2c->msg = &msgs[1]; i2c->mode = REG_CON_MOD_REGISTER_TX; i2c_writel(i2c, addr | REG_MRXADDR_VALID(0), REG_MRXADDR); i2c_writel(i2c, reg_addr, REG_MRXRADDR); ret = 2; } else { /* * We'll have to do it the boring way and process the msgs * one-by-one. */ if (msgs[0].flags & I2C_M_RD) { addr |= 1; /* set read bit */ /* * We have to transmit the slave addr first. Use * MOD_REGISTER_TX for that purpose. */ i2c->mode = REG_CON_MOD_REGISTER_TX; i2c_writel(i2c, addr | REG_MRXADDR_VALID(0), REG_MRXADDR); i2c_writel(i2c, 0, REG_MRXRADDR); } else { i2c->mode = REG_CON_MOD_TX; } i2c->msg = &msgs[0]; ret = 1; } i2c->addr = msgs[0].addr; i2c->busy = true; i2c->state = STATE_START; i2c->processed = 0; i2c->error = 0; rk3x_i2c_clean_ipd(i2c); return ret; } static int rk3x_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) { struct rk3x_i2c *i2c = (struct rk3x_i2c *)adap->algo_data; unsigned long timeout, flags; int ret = 0; int i; spin_lock_irqsave(&i2c->lock, flags); clk_enable(i2c->clk); /* The clock rate might have changed, so setup the divider again */ rk3x_i2c_set_scl_rate(i2c, i2c->scl_frequency); i2c->is_last_msg = false; /* * Process msgs. We can handle more than one message at once (see * rk3x_i2c_setup()). */ for (i = 0; i < num; i += ret) { ret = rk3x_i2c_setup(i2c, msgs + i, num - i); if (ret < 0) { dev_err(i2c->dev, "rk3x_i2c_setup() failed\n"); break; } if (i + ret >= num) i2c->is_last_msg = true; spin_unlock_irqrestore(&i2c->lock, flags); rk3x_i2c_start(i2c); timeout = wait_event_timeout(i2c->wait, !i2c->busy, msecs_to_jiffies(WAIT_TIMEOUT)); spin_lock_irqsave(&i2c->lock, flags); if (timeout == 0) { dev_err(i2c->dev, "timeout, ipd: 0x%02x, state: %d\n", i2c_readl(i2c, REG_IPD), i2c->state); /* Force a STOP condition without interrupt */ i2c_writel(i2c, 0, REG_IEN); i2c_writel(i2c, REG_CON_EN | REG_CON_STOP, REG_CON); i2c->state = STATE_IDLE; ret = -ETIMEDOUT; break; } if (i2c->error) { ret = i2c->error; break; } } clk_disable(i2c->clk); spin_unlock_irqrestore(&i2c->lock, flags); return ret; } static u32 rk3x_i2c_func(struct i2c_adapter *adap) { return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING; } static const struct i2c_algorithm rk3x_i2c_algorithm = { .master_xfer = rk3x_i2c_xfer, .functionality = rk3x_i2c_func, }; static struct rk3x_i2c_soc_data soc_data[3] = { { .grf_offset = 0x154 }, /* rk3066 */ { .grf_offset = 0x0a4 }, /* rk3188 */ { .grf_offset = -1 }, /* no I2C switching needed */ }; static const struct of_device_id rk3x_i2c_match[] = { { .compatible = "rockchip,rk3066-i2c", .data = (void *)&soc_data[0] }, { .compatible = "rockchip,rk3188-i2c", .data = (void *)&soc_data[1] }, { .compatible = "rockchip,rk3288-i2c", .data = (void *)&soc_data[2] }, {}, }; static int rk3x_i2c_probe(struct platform_device *pdev) { struct device_node *np = pdev->dev.of_node; const struct of_device_id *match; struct rk3x_i2c *i2c; struct resource *mem; int ret = 0; int bus_nr; u32 value; int irq; i2c = devm_kzalloc(&pdev->dev, sizeof(struct rk3x_i2c), GFP_KERNEL); if (!i2c) return -ENOMEM; match = of_match_node(rk3x_i2c_match, np); i2c->soc_data = (struct rk3x_i2c_soc_data *)match->data; if (of_property_read_u32(pdev->dev.of_node, "clock-frequency", &i2c->scl_frequency)) { dev_info(&pdev->dev, "using default SCL frequency: %d\n", DEFAULT_SCL_RATE); i2c->scl_frequency = DEFAULT_SCL_RATE; } if (i2c->scl_frequency == 0 || i2c->scl_frequency > 400 * 1000) { dev_warn(&pdev->dev, "invalid SCL frequency specified.\n"); dev_warn(&pdev->dev, "using default SCL frequency: %d\n", DEFAULT_SCL_RATE); i2c->scl_frequency = DEFAULT_SCL_RATE; } strlcpy(i2c->adap.name, "rk3x-i2c", sizeof(i2c->adap.name)); i2c->adap.owner = THIS_MODULE; i2c->adap.algo = &rk3x_i2c_algorithm; i2c->adap.retries = 3; i2c->adap.dev.of_node = np; i2c->adap.algo_data = i2c; i2c->adap.dev.parent = &pdev->dev; i2c->dev = &pdev->dev; spin_lock_init(&i2c->lock); init_waitqueue_head(&i2c->wait); i2c->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(i2c->clk)) { dev_err(&pdev->dev, "cannot get clock\n"); return PTR_ERR(i2c->clk); } mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); i2c->regs = devm_ioremap_resource(&pdev->dev, mem); if (IS_ERR(i2c->regs)) return PTR_ERR(i2c->regs); /* Try to set the I2C adapter number from dt */ bus_nr = of_alias_get_id(np, "i2c"); /* * Switch to new interface if the SoC also offers the old one. * The control bit is located in the GRF register space. */ if (i2c->soc_data->grf_offset >= 0) { struct regmap *grf; grf = syscon_regmap_lookup_by_phandle(np, "rockchip,grf"); if (IS_ERR(grf)) { dev_err(&pdev->dev, "rk3x-i2c needs 'rockchip,grf' property\n"); return PTR_ERR(grf); } if (bus_nr < 0) { dev_err(&pdev->dev, "rk3x-i2c needs i2cX alias"); return -EINVAL; } /* 27+i: write mask, 11+i: value */ value = BIT(27 + bus_nr) | BIT(11 + bus_nr); ret = regmap_write(grf, i2c->soc_data->grf_offset, value); if (ret != 0) { dev_err(i2c->dev, "Could not write to GRF: %d\n", ret); return ret; } } /* IRQ setup */ irq = platform_get_irq(pdev, 0); if (irq < 0) { dev_err(&pdev->dev, "cannot find rk3x IRQ\n"); return irq; } ret = devm_request_irq(&pdev->dev, irq, rk3x_i2c_irq, 0, dev_name(&pdev->dev), i2c); if (ret < 0) { dev_err(&pdev->dev, "cannot request IRQ\n"); return ret; } platform_set_drvdata(pdev, i2c); ret = clk_prepare(i2c->clk); if (ret < 0) { dev_err(&pdev->dev, "Could not prepare clock\n"); return ret; } ret = i2c_add_adapter(&i2c->adap); if (ret < 0) { dev_err(&pdev->dev, "Could not register adapter\n"); goto err_clk; } dev_info(&pdev->dev, "Initialized RK3xxx I2C bus at %p\n", i2c->regs); return 0; err_clk: clk_unprepare(i2c->clk); return ret; } static int rk3x_i2c_remove(struct platform_device *pdev) { struct rk3x_i2c *i2c = platform_get_drvdata(pdev); i2c_del_adapter(&i2c->adap); clk_unprepare(i2c->clk); return 0; } static struct platform_driver rk3x_i2c_driver = { .probe = rk3x_i2c_probe, .remove = rk3x_i2c_remove, .driver = { .owner = THIS_MODULE, .name = "rk3x-i2c", .of_match_table = rk3x_i2c_match, }, }; module_platform_driver(rk3x_i2c_driver); MODULE_DESCRIPTION("Rockchip RK3xxx I2C Bus driver"); MODULE_AUTHOR("Max Schwarz "); MODULE_LICENSE("GPL v2");