diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-designware-platdrv.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-designware-platdrv.c | 54 |
1 files changed, 35 insertions, 19 deletions
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c index 0b42a12171f3..6ce431323125 100644 --- a/drivers/i2c/busses/i2c-designware-platdrv.c +++ b/drivers/i2c/busses/i2c-designware-platdrv.c @@ -150,6 +150,29 @@ static int i2c_dw_plat_prepare_clk(struct dw_i2c_dev *i_dev, bool prepare) return 0; } +static void dw_i2c_set_fifo_size(struct dw_i2c_dev *dev, int id) +{ + u32 param, tx_fifo_depth, rx_fifo_depth; + + /* + * Try to detect the FIFO depth if not set by interface driver, + * the depth could be from 2 to 256 from HW spec. + */ + param = i2c_dw_read_comp_param(dev); + tx_fifo_depth = ((param >> 16) & 0xff) + 1; + rx_fifo_depth = ((param >> 8) & 0xff) + 1; + if (!dev->tx_fifo_depth) { + dev->tx_fifo_depth = tx_fifo_depth; + dev->rx_fifo_depth = rx_fifo_depth; + dev->adapter.nr = id; + } else if (tx_fifo_depth >= 2) { + dev->tx_fifo_depth = min_t(u32, dev->tx_fifo_depth, + tx_fifo_depth); + dev->rx_fifo_depth = min_t(u32, dev->rx_fifo_depth, + rx_fifo_depth); + } +} + static int dw_i2c_plat_probe(struct platform_device *pdev) { struct dw_i2c_platform_data *pdata = dev_get_platdata(&pdev->dev); @@ -176,9 +199,6 @@ static int dw_i2c_plat_probe(struct platform_device *pdev) dev->irq = irq; platform_set_drvdata(pdev, dev); - /* fast mode by default because of legacy reasons */ - dev->clk_freq = 400000; - if (pdata) { dev->clk_freq = pdata->i2c_scl_freq; } else { @@ -193,8 +213,16 @@ static int dw_i2c_plat_probe(struct platform_device *pdev) } acpi_speed = i2c_acpi_find_bus_speed(&pdev->dev); - if (acpi_speed) - dev->clk_freq = acpi_speed; + /* + * Find bus speed from the "clock-frequency" device property, ACPI + * or by using fast mode if neither is set. + */ + if (acpi_speed && dev->clk_freq) + dev->clk_freq = min(dev->clk_freq, acpi_speed); + else if (acpi_speed || dev->clk_freq) + dev->clk_freq = max(dev->clk_freq, acpi_speed); + else + dev->clk_freq = 400000; if (has_acpi_companion(&pdev->dev)) dw_i2c_acpi_configure(pdev); @@ -214,13 +242,7 @@ static int dw_i2c_plat_probe(struct platform_device *pdev) if (r) return r; - dev->functionality = - I2C_FUNC_I2C | - I2C_FUNC_10BIT_ADDR | - I2C_FUNC_SMBUS_BYTE | - I2C_FUNC_SMBUS_BYTE_DATA | - I2C_FUNC_SMBUS_WORD_DATA | - I2C_FUNC_SMBUS_I2C_BLOCK; + dev->functionality = I2C_FUNC_10BIT_ADDR | DW_IC_DEFAULT_FUNCTIONALITY; dev->master_cfg = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE | DW_IC_CON_RESTART_EN; @@ -246,13 +268,7 @@ static int dw_i2c_plat_probe(struct platform_device *pdev) 1000000); } - if (!dev->tx_fifo_depth) { - u32 param1 = i2c_dw_read_comp_param(dev); - - dev->tx_fifo_depth = ((param1 >> 16) & 0xff) + 1; - dev->rx_fifo_depth = ((param1 >> 8) & 0xff) + 1; - dev->adapter.nr = pdev->id; - } + dw_i2c_set_fifo_size(dev, pdev->id); adap = &dev->adapter; adap->owner = THIS_MODULE; |