diff options
author | Alok Chauhan <alokc@nvidia.com> | 2011-05-05 10:32:20 +0530 |
---|---|---|
committer | Dan Willemsen <dwillemsen@nvidia.com> | 2011-11-30 21:41:52 -0800 |
commit | 579ecde73f6dbc5d79985eb5f10bc58b6e96367e (patch) | |
tree | 8408232c4b78afd96725356ff49a885b12f94a3d /drivers/i2c | |
parent | 4268cd392fdb3bf94a33fadaaf06e7bb19c5cb94 (diff) |
i2c: tegra: Making proper synchronization between isr and caller
Following are the changes:
- Added a mechanism to handle synchronization between caller thread
and isr so that isr should not get called when clock is disable or
controller is in reset state.
- Handling tx fifo overflow error.
- Added delay before resetting the controller which is required if
there is any error in previous transaction so proper stop signal
will be generated.
Original-Change-Id: I7ac121e056193cd4601f032cdabab59e7e0946ea
Reviewed-on: http://git-master/r/30457
Reviewed-by: Laxman Dewangan <ldewangan@nvidia.com>
Reviewed-by: Alok Chauhan <alokc@nvidia.com>
Tested-by: Alok Chauhan <alokc@nvidia.com>
Tested-by: Laxman Dewangan <ldewangan@nvidia.com>
Reviewed-by: Danielle Sun <dsun@nvidia.com>
Tested-by: Danielle Sun <dsun@nvidia.com>
Reviewed-by: Bo Yan <byan@nvidia.com>
Reviewed-by: Scott Williams <scwilliams@nvidia.com>
Rebase-Id: R0e7b428de2b0b1567a23bcac3c53aa5cc9d8d4a9
Diffstat (limited to 'drivers/i2c')
-rw-r--r-- | drivers/i2c/busses/i2c-tegra.c | 65 |
1 files changed, 54 insertions, 11 deletions
diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c index 420397626155..58cf7030860f 100644 --- a/drivers/i2c/busses/i2c-tegra.c +++ b/drivers/i2c/busses/i2c-tegra.c @@ -32,6 +32,7 @@ #include <linux/slab.h> #include <linux/i2c-tegra.h> #include <linux/of_i2c.h> +#include <linux/spinlock.h> #include <asm/unaligned.h> @@ -145,10 +146,12 @@ struct tegra_i2c_dev { struct clk *clk; struct resource *iomem; struct rt_mutex dev_lock; + spinlock_t clk_lock; void __iomem *base; int cont_id; int irq; bool irq_disabled; + bool controller_enabled; int is_dvc; bool is_slave; struct completion msg_complete; @@ -391,6 +394,10 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev) if (!i2c_dev->is_clkon_always) clk_enable(i2c_dev->clk); + /* Interrupt generated before sending stop signal so + * wait for some time so that stop signal can be send proerly */ + udelay(100); + tegra_periph_reset_assert(i2c_dev->clk); udelay(2); tegra_periph_reset_deassert(i2c_dev->clk); @@ -437,8 +444,16 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev) static irqreturn_t tegra_i2c_isr(int irq, void *dev_id) { u32 status; - const u32 status_err = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST; + const u32 status_err = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST | I2C_INT_TX_FIFO_OVERFLOW; struct tegra_i2c_dev *i2c_dev = dev_id; + unsigned long flags; + + spin_lock_irqsave(&i2c_dev->clk_lock, flags); + if (!i2c_dev->controller_enabled) { + dev_warn(i2c_dev->dev, "Controller not enabled\n"); + spin_unlock_irqrestore(&i2c_dev->clk_lock, flags); + return IRQ_NONE; + } status = i2c_readl(i2c_dev, I2C_INT_STATUS); @@ -452,7 +467,6 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id) i2c_dev->irq_disabled = 1; } - complete(&i2c_dev->msg_complete); goto err; } @@ -474,7 +488,13 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id) i2c_readl(i2c_dev, I2C_PACKET_TRANSFER_STATUS)); } - complete(&i2c_dev->msg_complete); + if (status & I2C_INT_TX_FIFO_OVERFLOW) { + i2c_dev->msg_err |= I2C_INT_TX_FIFO_OVERFLOW; + dev_warn(i2c_dev->dev, "Tx fifo overflow during " + " communicate to add 0x%x\n", i2c_dev->msg_add); + dev_warn(i2c_dev->dev, "Packet status 0x%08x\n", + i2c_readl(i2c_dev, I2C_PACKET_TRANSFER_STATUS)); + } goto err; } @@ -490,7 +510,6 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id) i2c_dev->irq_disabled = 1; } - complete(&i2c_dev->msg_complete); goto err; } @@ -508,16 +527,17 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id) tegra_i2c_mask_irq(i2c_dev, I2C_INT_TX_FIFO_DATA_REQ); } - if (status & I2C_INT_PACKET_XFER_COMPLETE) { - BUG_ON(i2c_dev->msg_buf_remaining); - complete(&i2c_dev->msg_complete); - } - i2c_writel(i2c_dev, status, I2C_INT_STATUS); if (i2c_dev->is_dvc) dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS); + if (status & I2C_INT_PACKET_XFER_COMPLETE) { + BUG_ON(i2c_dev->msg_buf_remaining); + complete(&i2c_dev->msg_complete); + } + + spin_unlock_irqrestore(&i2c_dev->clk_lock, flags); return IRQ_HANDLED; err: @@ -544,13 +564,15 @@ err: /* An error occurred, mask all interrupts */ tegra_i2c_mask_irq(i2c_dev, I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST | I2C_INT_PACKET_XFER_COMPLETE | I2C_INT_TX_FIFO_DATA_REQ | - I2C_INT_RX_FIFO_DATA_REQ); + I2C_INT_RX_FIFO_DATA_REQ | I2C_INT_TX_FIFO_OVERFLOW); i2c_writel(i2c_dev, status, I2C_INT_STATUS); if (i2c_dev->is_dvc) dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS); + complete(&i2c_dev->msg_complete); + spin_unlock_irqrestore(&i2c_dev->clk_lock, flags); return IRQ_HANDLED; } @@ -560,6 +582,7 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_bus *i2c_bus, struct tegra_i2c_dev *i2c_dev = i2c_bus->dev; u32 int_mask; int ret; + unsigned long flags; tegra_i2c_flush_fifos(i2c_dev); @@ -598,7 +621,7 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_bus *i2c_bus, if (!(msg->flags & I2C_M_RD)) tegra_i2c_fill_tx_fifo(i2c_dev); - int_mask = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST; + int_mask = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST | I2C_INT_TX_FIFO_OVERFLOW; if (msg->flags & I2C_M_RD) int_mask |= I2C_INT_RX_FIFO_DATA_REQ; else if (i2c_dev->msg_buf_remaining) @@ -616,7 +639,10 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_bus *i2c_bus, "i2c transfer timed out, addr 0x%04x, data 0x%02x\n", msg->addr, msg->buf[0]); + spin_lock_irqsave(&i2c_dev->clk_lock, flags); + i2c_dev->controller_enabled = false; tegra_i2c_init(i2c_dev); + spin_unlock_irqrestore(&i2c_dev->clk_lock, flags); return -ETIMEDOUT; } @@ -626,7 +652,11 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_bus *i2c_bus, if (likely(i2c_dev->msg_err == I2C_ERR_NONE)) return 0; + spin_lock_irqsave(&i2c_dev->clk_lock, flags); + i2c_dev->controller_enabled = false; tegra_i2c_init(i2c_dev); + spin_unlock_irqrestore(&i2c_dev->clk_lock, flags); + if (i2c_dev->msg_err == I2C_ERR_NO_ACK) { if (msg->flags & I2C_M_IGNORE_NAK) return 0; @@ -646,6 +676,7 @@ static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], struct tegra_i2c_dev *i2c_dev = i2c_bus->dev; int i; int ret = 0; + unsigned long flags; if (i2c_dev->is_suspended) return -EBUSY; @@ -671,12 +702,22 @@ static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], if (!i2c_dev->is_clkon_always) clk_enable(i2c_dev->clk); + + spin_lock_irqsave(&i2c_dev->clk_lock, flags); + i2c_dev->controller_enabled = true; + spin_unlock_irqrestore(&i2c_dev->clk_lock, flags); + for (i = 0; i < num; i++) { int stop = (i == (num - 1)) ? 1 : 0; ret = tegra_i2c_xfer_msg(i2c_bus, &msgs[i], stop); if (ret) break; } + + spin_lock_irqsave(&i2c_dev->clk_lock, flags); + i2c_dev->controller_enabled = false; + spin_unlock_irqrestore(&i2c_dev->clk_lock, flags); + if (!i2c_dev->is_clkon_always) clk_disable(i2c_dev->clk); @@ -786,7 +827,9 @@ static int tegra_i2c_probe(struct platform_device *pdev) i2c_dev->msgs = NULL; i2c_dev->msgs_num = 0; + i2c_dev->controller_enabled = false; rt_mutex_init(&i2c_dev->dev_lock); + spin_lock_init(&i2c_dev->clk_lock); i2c_dev->slave_addr = plat->slave_addr; i2c_dev->is_dvc = plat->is_dvc; |