diff options
| author | Christian Ruppert <christian.ruppert@abilis.com> | 2013-06-26 10:55:06 +0200 |
|---|---|---|
| committer | Wolfram Sang <wsa@the-dreams.de> | 2013-06-26 16:02:06 +0200 |
| commit | 9803f868944e879c4623c0d910e81f1ae89ccfb4 (patch) | |
| tree | 1dc609539e707c857b7a3e38104a6b0063847a41 /drivers | |
| parent | 4c730a06c19bb83d2fa4308ee4cbb23abc84c9ca (diff) | |
| download | lwn-9803f868944e879c4623c0d910e81f1ae89ccfb4.tar.gz lwn-9803f868944e879c4623c0d910e81f1ae89ccfb4.zip | |
i2c-designware: make SDA hold time configurable
This patch makes the SDA hold time configurable through device tree.
Signed-off-by: Christian Ruppert <christian.ruppert@abilis.com>
Signed-off-by: Pierrick Hascoet <pierrick.hascoet@abilis.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com> for arch/arc bits
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/i2c/busses/i2c-designware-core.c | 13 | ||||
| -rw-r--r-- | drivers/i2c/busses/i2c-designware-core.h | 1 | ||||
| -rw-r--r-- | drivers/i2c/busses/i2c-designware-platdrv.c | 10 |
3 files changed, 24 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c index 3de549436992..ad46616de29e 100644 --- a/drivers/i2c/busses/i2c-designware-core.c +++ b/drivers/i2c/busses/i2c-designware-core.c @@ -67,9 +67,12 @@ #define DW_IC_STATUS 0x70 #define DW_IC_TXFLR 0x74 #define DW_IC_RXFLR 0x78 +#define DW_IC_SDA_HOLD 0x7c #define DW_IC_TX_ABRT_SOURCE 0x80 #define DW_IC_ENABLE_STATUS 0x9c #define DW_IC_COMP_PARAM_1 0xf4 +#define DW_IC_COMP_VERSION 0xf8 +#define DW_IC_SDA_HOLD_MIN_VERS 0x3131312A #define DW_IC_COMP_TYPE 0xfc #define DW_IC_COMP_TYPE_VALUE 0x44570140 @@ -332,6 +335,16 @@ int i2c_dw_init(struct dw_i2c_dev *dev) dw_writel(dev, lcnt, DW_IC_FS_SCL_LCNT); dev_dbg(dev->dev, "Fast-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt); + /* Configure SDA Hold Time if required */ + if (dev->sda_hold_time) { + reg = dw_readl(dev, DW_IC_COMP_VERSION); + if (reg >= DW_IC_SDA_HOLD_MIN_VERS) + dw_writel(dev, dev->sda_hold_time, DW_IC_SDA_HOLD); + else + dev_warn(dev->dev, + "Hardware too old to adjust SDA hold time."); + } + /* Configure Tx/Rx FIFO threshold levels */ dw_writel(dev, dev->tx_fifo_depth - 1, DW_IC_TX_TL); dw_writel(dev, 0, DW_IC_RX_TL); diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h index e761ad18dd61..912aa2262866 100644 --- a/drivers/i2c/busses/i2c-designware-core.h +++ b/drivers/i2c/busses/i2c-designware-core.h @@ -90,6 +90,7 @@ struct dw_i2c_dev { unsigned int tx_fifo_depth; unsigned int rx_fifo_depth; int rx_outstanding; + u32 sda_hold_time; }; #define ACCESS_SWAP 0x00000001 diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c index ee46c92d7e3c..def79b5fd4c8 100644 --- a/drivers/i2c/busses/i2c-designware-platdrv.c +++ b/drivers/i2c/busses/i2c-designware-platdrv.c @@ -34,6 +34,7 @@ #include <linux/sched.h> #include <linux/err.h> #include <linux/interrupt.h> +#include <linux/of.h> #include <linux/of_i2c.h> #include <linux/platform_device.h> #include <linux/pm.h> @@ -115,6 +116,15 @@ static int dw_i2c_probe(struct platform_device *pdev) return PTR_ERR(dev->clk); clk_prepare_enable(dev->clk); + if (pdev->dev.of_node) { + u32 ht = 0; + u32 ic_clk = dev->get_clk_rate_khz(dev); + + of_property_read_u32(pdev->dev.of_node, + "i2c-sda-hold-time-ns", &ht); + dev->sda_hold_time = ((u64)ic_clk * ht + 500000) / 1000000; + } + dev->functionality = I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR | |