diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-tegra.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-tegra.c | 77 |
1 files changed, 61 insertions, 16 deletions
diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c index fb3b4f8f8152..3c94c4a81a55 100644 --- a/drivers/i2c/busses/i2c-tegra.c +++ b/drivers/i2c/busses/i2c-tegra.c @@ -26,6 +26,7 @@ #include <linux/delay.h> #include <linux/slab.h> #include <linux/i2c-tegra.h> +#include <linux/of_i2c.h> #include <asm/unaligned.h> @@ -269,14 +270,30 @@ static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev) /* Rounds down to not include partial word at the end of buf */ words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD; - if (words_to_transfer > tx_fifo_avail) - words_to_transfer = tx_fifo_avail; - i2c_writesl(i2c_dev, buf, I2C_TX_FIFO, words_to_transfer); - - buf += words_to_transfer * BYTES_PER_FIFO_WORD; - buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD; - tx_fifo_avail -= words_to_transfer; + /* It's very common to have < 4 bytes, so optimize that case. */ + if (words_to_transfer) { + if (words_to_transfer > tx_fifo_avail) + words_to_transfer = tx_fifo_avail; + + /* + * Update state before writing to FIFO. If this casues us + * to finish writing all bytes (AKA buf_remaining goes to 0) we + * have a potential for an interrupt (PACKET_XFER_COMPLETE is + * not maskable). We need to make sure that the isr sees + * buf_remaining as 0 and doesn't call us back re-entrantly. + */ + buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD; + tx_fifo_avail -= words_to_transfer; + i2c_dev->msg_buf_remaining = buf_remaining; + i2c_dev->msg_buf = buf + + words_to_transfer * BYTES_PER_FIFO_WORD; + barrier(); + + i2c_writesl(i2c_dev, buf, I2C_TX_FIFO, words_to_transfer); + + buf += words_to_transfer * BYTES_PER_FIFO_WORD; + } /* * If there is a partial word at the end of buf, handle it manually to @@ -286,14 +303,15 @@ static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev) if (tx_fifo_avail > 0 && buf_remaining > 0) { BUG_ON(buf_remaining > 3); memcpy(&val, buf, buf_remaining); + + /* Again update before writing to FIFO to make sure isr sees. */ + i2c_dev->msg_buf_remaining = 0; + i2c_dev->msg_buf = NULL; + barrier(); + i2c_writel(i2c_dev, val, I2C_TX_FIFO); - buf_remaining = 0; - tx_fifo_avail--; } - BUG_ON(tx_fifo_avail > 0 && buf_remaining > 0); - i2c_dev->msg_buf_remaining = buf_remaining; - i2c_dev->msg_buf = buf; return 0; } @@ -410,9 +428,10 @@ 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) && - !i2c_dev->msg_buf_remaining) + 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) @@ -530,7 +549,7 @@ static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], static u32 tegra_i2c_func(struct i2c_adapter *adap) { - return I2C_FUNC_I2C; + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; } static const struct i2c_algorithm tegra_i2c_algo = { @@ -546,6 +565,7 @@ static int tegra_i2c_probe(struct platform_device *pdev) struct resource *iomem; struct clk *clk; struct clk *i2c_clk; + const unsigned int *prop; void *base; int irq; int ret = 0; @@ -603,7 +623,17 @@ static int tegra_i2c_probe(struct platform_device *pdev) i2c_dev->irq = irq; i2c_dev->cont_id = pdev->id; i2c_dev->dev = &pdev->dev; - i2c_dev->bus_clk_rate = pdata ? pdata->bus_clk_rate : 100000; + + i2c_dev->bus_clk_rate = 100000; /* default clock rate */ + if (pdata) { + i2c_dev->bus_clk_rate = pdata->bus_clk_rate; + + } else if (i2c_dev->dev->of_node) { /* if there is a device tree node ... */ + prop = of_get_property(i2c_dev->dev->of_node, + "clock-frequency", NULL); + if (prop) + i2c_dev->bus_clk_rate = be32_to_cpup(prop); + } if (pdev->id == 3) i2c_dev->is_dvc = 1; @@ -633,6 +663,7 @@ static int tegra_i2c_probe(struct platform_device *pdev) i2c_dev->adapter.algo = &tegra_i2c_algo; i2c_dev->adapter.dev.parent = &pdev->dev; i2c_dev->adapter.nr = pdev->id; + i2c_dev->adapter.dev.of_node = pdev->dev.of_node; ret = i2c_add_numbered_adapter(&i2c_dev->adapter); if (ret) { @@ -640,6 +671,8 @@ static int tegra_i2c_probe(struct platform_device *pdev) goto err_free_irq; } + of_i2c_register_devices(&i2c_dev->adapter); + return 0; err_free_irq: free_irq(i2c_dev->irq, i2c_dev); @@ -704,6 +737,17 @@ static int tegra_i2c_resume(struct platform_device *pdev) } #endif +#if defined(CONFIG_OF) +/* Match table for of_platform binding */ +static const struct of_device_id tegra_i2c_of_match[] __devinitconst = { + { .compatible = "nvidia,tegra20-i2c", }, + {}, +}; +MODULE_DEVICE_TABLE(of, tegra_i2c_of_match); +#else +#define tegra_i2c_of_match NULL +#endif + static struct platform_driver tegra_i2c_driver = { .probe = tegra_i2c_probe, .remove = tegra_i2c_remove, @@ -714,6 +758,7 @@ static struct platform_driver tegra_i2c_driver = { .driver = { .name = "tegra-i2c", .owner = THIS_MODULE, + .of_match_table = tegra_i2c_of_match, }, }; |