diff options
| -rw-r--r-- | drivers/i2c/busses/i2c-mpc.c | 426 |
1 files changed, 239 insertions, 187 deletions
diff --git a/drivers/i2c/busses/i2c-mpc.c b/drivers/i2c/busses/i2c-mpc.c index 3c8bcdfff7e7..0a80fafbe6c6 100644 --- a/drivers/i2c/busses/i2c-mpc.c +++ b/drivers/i2c/busses/i2c-mpc.c @@ -58,11 +58,35 @@ #define CSR_MIF 0x02 #define CSR_RXAK 0x01 +enum mpc_i2c_action { + MPC_I2C_ACTION_START = 1, + MPC_I2C_ACTION_RESTART, + MPC_I2C_ACTION_READ_BEGIN, + MPC_I2C_ACTION_READ_BYTE, + MPC_I2C_ACTION_WRITE, + MPC_I2C_ACTION_STOP, + + __MPC_I2C_ACTION_CNT +}; + +static const char * const action_str[] = { + "invalid", + "start", + "restart", + "read begin", + "read", + "write", + "stop", +}; + +static_assert(ARRAY_SIZE(action_str) == __MPC_I2C_ACTION_CNT); + struct mpc_i2c { struct device *dev; void __iomem *base; u32 interrupt; - wait_queue_head_t queue; + wait_queue_head_t waitq; + spinlock_t lock; struct i2c_adapter adap; int irq; u32 real_clk; @@ -70,6 +94,16 @@ struct mpc_i2c { u8 fdr, dfsrr; #endif struct clk *clk_per; + u32 cntl_bits; + enum mpc_i2c_action action; + struct i2c_msg *msgs; + int num_msgs; + int curr_msg; + u32 byte_posn; + u32 block; + int rc; + int expect_rxack; + }; struct mpc_i2c_divider { @@ -86,19 +120,6 @@ static inline void writeccr(struct mpc_i2c *i2c, u32 x) writeb(x, i2c->base + MPC_I2C_CR); } -static irqreturn_t mpc_i2c_isr(int irq, void *dev_id) -{ - struct mpc_i2c *i2c = dev_id; - if (readb(i2c->base + MPC_I2C_SR) & CSR_MIF) { - /* Read again to allow register to stabilise */ - i2c->interrupt = readb(i2c->base + MPC_I2C_SR); - writeb(0, i2c->base + MPC_I2C_SR); - wake_up(&i2c->queue); - return IRQ_HANDLED; - } - return IRQ_NONE; -} - /* Sometimes 9th clock pulse isn't generated, and slave doesn't release * the bus, because it wants to send ACK. * Following sequence of enabling/disabling and sending start/stop generates @@ -121,45 +142,6 @@ static void mpc_i2c_fixup(struct mpc_i2c *i2c) } } -static int i2c_wait(struct mpc_i2c *i2c, unsigned timeout, int writing) -{ - u32 cmd_err; - int result; - - result = wait_event_timeout(i2c->queue, - (i2c->interrupt & CSR_MIF), timeout); - - if (unlikely(!(i2c->interrupt & CSR_MIF))) { - dev_dbg(i2c->dev, "wait timeout\n"); - writeccr(i2c, 0); - result = -ETIMEDOUT; - } - - cmd_err = i2c->interrupt; - i2c->interrupt = 0; - - if (result < 0) - return result; - - if (!(cmd_err & CSR_MCF)) { - dev_dbg(i2c->dev, "unfinished\n"); - return -EIO; - } - - if (cmd_err & CSR_MAL) { - dev_dbg(i2c->dev, "MAL\n"); - return -EAGAIN; - } - - if (writing && (cmd_err & CSR_RXAK)) { - dev_dbg(i2c->dev, "No RXAK\n"); - /* generate stop */ - writeccr(i2c, CCR_MEN); - return -ENXIO; - } - return 0; -} - #if defined(CONFIG_PPC_MPC52xx) || defined(CONFIG_PPC_MPC512x) static const struct mpc_i2c_divider mpc_i2c_dividers_52xx[] = { {20, 0x20}, {22, 0x21}, {24, 0x22}, {26, 0x23}, @@ -434,168 +416,209 @@ static void mpc_i2c_setup_8xxx(struct device_node *node, } #endif /* CONFIG_FSL_SOC */ -static void mpc_i2c_start(struct mpc_i2c *i2c) +static void mpc_i2c_finish(struct mpc_i2c *i2c, int rc) { - /* Clear arbitration */ - writeb(0, i2c->base + MPC_I2C_SR); - /* Start with MEN */ - writeccr(i2c, CCR_MEN); + i2c->rc = rc; + i2c->block = 0; + i2c->cntl_bits = CCR_MEN; + writeccr(i2c, i2c->cntl_bits); + wake_up(&i2c->waitq); } -static void mpc_i2c_stop(struct mpc_i2c *i2c) +static void mpc_i2c_do_action(struct mpc_i2c *i2c) { - writeccr(i2c, CCR_MEN); -} + struct i2c_msg *msg = &i2c->msgs[i2c->curr_msg]; + int dir = 0; + int recv_len = 0; + u8 byte; + + dev_dbg(i2c->dev, "action = %s\n", action_str[i2c->action]); + + i2c->cntl_bits &= ~(CCR_RSTA | CCR_MTX | CCR_TXAK); + + if (msg->flags & I2C_M_RD) + dir = 1; + if (msg->flags & I2C_M_RECV_LEN) + recv_len = 1; + + switch (i2c->action) { + case MPC_I2C_ACTION_RESTART: + i2c->cntl_bits |= CCR_RSTA; + fallthrough; + + case MPC_I2C_ACTION_START: + i2c->cntl_bits |= CCR_MSTA | CCR_MTX; + writeccr(i2c, i2c->cntl_bits); + writeb((msg->addr << 1) | dir, i2c->base + MPC_I2C_DR); + i2c->expect_rxack = 1; + i2c->action = dir ? MPC_I2C_ACTION_READ_BEGIN : MPC_I2C_ACTION_WRITE; + break; + + case MPC_I2C_ACTION_READ_BEGIN: + if (msg->len) { + if (msg->len == 1 && !(msg->flags & I2C_M_RECV_LEN)) + i2c->cntl_bits |= CCR_TXAK; + + writeccr(i2c, i2c->cntl_bits); + /* Dummy read */ + readb(i2c->base + MPC_I2C_DR); + } + i2c->action = MPC_I2C_ACTION_READ_BYTE; + break; + + case MPC_I2C_ACTION_READ_BYTE: + if (i2c->byte_posn || !recv_len) { + /* Generate Tx ACK on next to last byte */ + if (i2c->byte_posn == msg->len - 2) + i2c->cntl_bits |= CCR_TXAK; + /* Do not generate stop on last byte */ + if (i2c->byte_posn == msg->len - 1) + i2c->cntl_bits |= CCR_MTX; -static int mpc_write(struct mpc_i2c *i2c, int target, - const u8 *data, int length, int restart) -{ - int i, result; - unsigned timeout = i2c->adap.timeout; - u32 flags = restart ? CCR_RSTA : 0; + writeccr(i2c, i2c->cntl_bits); + } - /* Start as master */ - writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_MTX | flags); - /* Write target byte */ - writeb((target << 1), i2c->base + MPC_I2C_DR); + byte = readb(i2c->base + MPC_I2C_DR); - result = i2c_wait(i2c, timeout, 1); - if (result < 0) - return result; + if (i2c->byte_posn == 0 && recv_len) { + if (byte == 0 || byte > I2C_SMBUS_BLOCK_MAX) { + mpc_i2c_finish(i2c, -EPROTO); + return; + } + msg->len += byte; + /* + * For block reads, generate Tx ACK here if data length + * is 1 byte (total length is 2 bytes). + */ + if (msg->len == 2) { + i2c->cntl_bits |= CCR_TXAK; + writeccr(i2c, i2c->cntl_bits); + } + } + + dev_dbg(i2c->dev, "%s %02x\n", action_str[i2c->action], byte); + msg->buf[i2c->byte_posn++] = byte; + break; - for (i = 0; i < length; i++) { - /* Write data byte */ - writeb(data[i], i2c->base + MPC_I2C_DR); + case MPC_I2C_ACTION_WRITE: + dev_dbg(i2c->dev, "%s %02x\n", action_str[i2c->action], + msg->buf[i2c->byte_posn]); + writeb(msg->buf[i2c->byte_posn++], i2c->base + MPC_I2C_DR); + i2c->expect_rxack = 1; + break; - result = i2c_wait(i2c, timeout, 1); - if (result < 0) - return result; + case MPC_I2C_ACTION_STOP: + mpc_i2c_finish(i2c, 0); + break; + + default: + WARN(1, "Unexpected action %d\n", i2c->action); + break; } - return 0; + if (msg->len == i2c->byte_posn) { + i2c->curr_msg++; + i2c->byte_posn = 0; + + if (i2c->curr_msg == i2c->num_msgs) { + i2c->action = MPC_I2C_ACTION_STOP; + /* + * We don't get another interrupt on read so + * finish the transfer now + */ + if (dir) + mpc_i2c_finish(i2c, 0); + } else { + i2c->action = MPC_I2C_ACTION_RESTART; + } + } } -static int mpc_read(struct mpc_i2c *i2c, int target, - u8 *data, int length, int restart, bool recv_len) +static void mpc_i2c_do_intr(struct mpc_i2c *i2c, u8 status) { - unsigned timeout = i2c->adap.timeout; - int i, result; - u32 flags = restart ? CCR_RSTA : 0; + spin_lock(&i2c->lock); - /* Switch to read - restart */ - writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_MTX | flags); - /* Write target address byte - this time with the read flag set */ - writeb((target << 1) | 1, i2c->base + MPC_I2C_DR); + if (!(status & CSR_MCF)) { + dev_dbg(i2c->dev, "unfinished\n"); + mpc_i2c_finish(i2c, -EIO); + goto out; + } - result = i2c_wait(i2c, timeout, 1); - if (result < 0) - return result; + if (status & CSR_MAL) { + dev_dbg(i2c->dev, "arbitration lost\n"); + mpc_i2c_finish(i2c, -EAGAIN); + goto out; + } - if (length) { - if (length == 1 && !recv_len) - writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_TXAK); - else - writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA); - /* Dummy read */ - readb(i2c->base + MPC_I2C_DR); + if (i2c->expect_rxack && (status & CSR_RXAK)) { + dev_dbg(i2c->dev, "no Rx ACK\n"); + mpc_i2c_finish(i2c, -ENXIO); + goto out; } + i2c->expect_rxack = 0; - for (i = 0; i < length; i++) { - u8 byte; - - result = i2c_wait(i2c, timeout, 0); - if (result < 0) - return result; - - /* - * For block reads, we have to know the total length (1st byte) - * before we can determine if we are done. - */ - if (i || !recv_len) { - /* Generate txack on next to last byte */ - if (i == length - 2) - writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA - | CCR_TXAK); - /* Do not generate stop on last byte */ - if (i == length - 1) - writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA - | CCR_MTX); - } + mpc_i2c_do_action(i2c); - byte = readb(i2c->base + MPC_I2C_DR); +out: + spin_unlock(&i2c->lock); +} - /* - * Adjust length if first received byte is length. - * The length is 1 length byte plus actually data length - */ - if (i == 0 && recv_len) { - if (byte == 0 || byte > I2C_SMBUS_BLOCK_MAX) - return -EPROTO; - length += byte; - /* - * For block reads, generate txack here if data length - * is 1 byte (total length is 2 bytes). - */ - if (length == 2) - writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA - | CCR_TXAK); - } - data[i] = byte; +static irqreturn_t mpc_i2c_isr(int irq, void *dev_id) +{ + struct mpc_i2c *i2c = dev_id; + u8 status; + + status = readb(i2c->base + MPC_I2C_SR); + if (status & CSR_MIF) { + writeb(0, i2c->base + MPC_I2C_SR); + mpc_i2c_do_intr(i2c, status); + return IRQ_HANDLED; } + return IRQ_NONE; +} - return length; +static int mpc_i2c_wait_for_completion(struct mpc_i2c *i2c) +{ + long time_left; + + time_left = wait_event_timeout(i2c->waitq, !i2c->block, i2c->adap.timeout); + if (!time_left) + return -ETIMEDOUT; + if (time_left < 0) + return time_left; + + return 0; } -static int mpc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) +static int mpc_i2c_execute_msg(struct mpc_i2c *i2c) { - struct i2c_msg *pmsg; - int i; - int ret = 0; - unsigned long orig_jiffies = jiffies; - struct mpc_i2c *i2c = i2c_get_adapdata(adap); + unsigned long orig_jiffies; + unsigned long flags; + int ret; - mpc_i2c_start(i2c); + spin_lock_irqsave(&i2c->lock, flags); - /* Allow bus up to 1s to become not busy */ - while (readb(i2c->base + MPC_I2C_SR) & CSR_MBB) { - if (signal_pending(current)) { - dev_dbg(i2c->dev, "Interrupted\n"); - writeccr(i2c, 0); - return -EINTR; - } - if (time_after(jiffies, orig_jiffies + HZ)) { - u8 status = readb(i2c->base + MPC_I2C_SR); + i2c->curr_msg = 0; + i2c->rc = 0; + i2c->byte_posn = 0; + i2c->block = 1; + i2c->action = MPC_I2C_ACTION_START; - dev_dbg(i2c->dev, "timeout\n"); - if ((status & (CSR_MCF | CSR_MBB | CSR_RXAK)) != 0) { - writeb(status & ~CSR_MAL, - i2c->base + MPC_I2C_SR); - i2c_recover_bus(&i2c->adap); - } - return -EIO; - } - schedule(); - } + i2c->cntl_bits = CCR_MEN | CCR_MIEN; + writeb(0, i2c->base + MPC_I2C_SR); + writeccr(i2c, i2c->cntl_bits); + + mpc_i2c_do_action(i2c); + + spin_unlock_irqrestore(&i2c->lock, flags); + + ret = mpc_i2c_wait_for_completion(i2c); + if (ret) + i2c->rc = ret; + + if (i2c->rc == -EIO || i2c->rc == -EAGAIN || i2c->rc == -ETIMEDOUT) + i2c_recover_bus(&i2c->adap); - for (i = 0; ret >= 0 && i < num; i++) { - pmsg = &msgs[i]; - dev_dbg(i2c->dev, - "Doing %s %d bytes to 0x%02x - %d of %d messages\n", - pmsg->flags & I2C_M_RD ? "read" : "write", - pmsg->len, pmsg->addr, i + 1, num); - if (pmsg->flags & I2C_M_RD) { - bool recv_len = pmsg->flags & I2C_M_RECV_LEN; - - ret = mpc_read(i2c, pmsg->addr, pmsg->buf, pmsg->len, i, - recv_len); - if (recv_len && ret > 0) - pmsg->len = ret; - } else { - ret = - mpc_write(i2c, pmsg->addr, pmsg->buf, pmsg->len, i); - } - } - mpc_i2c_stop(i2c); /* Initiate STOP */ orig_jiffies = jiffies; /* Wait until STOP is seen, allow up to 1 s */ while (readb(i2c->base + MPC_I2C_SR) & CSR_MBB) { @@ -612,7 +635,35 @@ static int mpc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) } cond_resched(); } - return (ret < 0) ? ret : num; + + return i2c->rc; +} + +static int mpc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) +{ + int rc, ret = num; + struct mpc_i2c *i2c = i2c_get_adapdata(adap); + int i; + + dev_dbg(i2c->dev, "num = %d\n", num); + for (i = 0; i < num; i++) + dev_dbg(i2c->dev, " addr = %02x, flags = %02x, len = %d, %*ph\n", + msgs[i].addr, msgs[i].flags, msgs[i].len, + msgs[i].flags & I2C_M_RD ? 0 : msgs[i].len, + msgs[i].buf); + + WARN_ON(i2c->msgs != NULL); + i2c->msgs = msgs; + i2c->num_msgs = num; + + rc = mpc_i2c_execute_msg(i2c); + if (rc < 0) + ret = rc; + + i2c->num_msgs = 0; + i2c->msgs = NULL; + + return ret; } static u32 mpc_functionality(struct i2c_adapter *adap) @@ -667,7 +718,8 @@ static int fsl_i2c_probe(struct platform_device *op) i2c->dev = &op->dev; /* for debug and error output */ - init_waitqueue_head(&i2c->queue); + init_waitqueue_head(&i2c->waitq); + spin_lock_init(&i2c->lock); i2c->base = devm_platform_ioremap_resource(op, 0); if (IS_ERR(i2c->base)) { |