diff options
| author | Chew, Chiau Ee <chiau.ee.chew@intel.com> | 2014-03-11 12:33:45 +0100 |
|---|---|---|
| committer | Wolfram Sang <wsa@the-dreams.de> | 2014-03-12 08:14:04 +0100 |
| commit | 8efd1e9ee3bd55e20cb36e56ca53096cf2b3a930 (patch) | |
| tree | db5abf2de8a390ddf456e2ac7f899f65c93bf7e8 /drivers/i2c | |
| parent | i2c: st: Fix return in case of arbitration lost (diff) | |
| download | linux-8efd1e9ee3bd55e20cb36e56ca53096cf2b3a930.tar.xz linux-8efd1e9ee3bd55e20cb36e56ca53096cf2b3a930.zip | |
i2c: designware-pci: set ideal HCNT, LCNT and SDA hold time value
On Intel BayTrail, there was case whereby the resulting fast mode
bus speed becomes slower (~20% slower compared to expected speed)
if using the HCNT/LCNT calculated in the core layer. Thus, this
patch is added to allow pci glue layer to pass in optimal
HCNT/LCNT/SDA hold time values to core layer since the core
layer supports cofigurable HCNT/LCNT/SDA hold time values now.
Signed-off-by: Chew, Chiau Ee <chiau.ee.chew@intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/busses/i2c-designware-pcidrv.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-designware-pcidrv.c b/drivers/i2c/busses/i2c-designware-pcidrv.c index 094509bcc089..91d468f8cd39 100644 --- a/drivers/i2c/busses/i2c-designware-pcidrv.c +++ b/drivers/i2c/busses/i2c-designware-pcidrv.c @@ -58,6 +58,14 @@ enum dw_pci_ctl_id_t { baytrail, }; +struct dw_scl_sda_cfg { + u32 ss_hcnt; + u32 fs_hcnt; + u32 ss_lcnt; + u32 fs_lcnt; + u32 sda_hold; +}; + struct dw_pci_controller { u32 bus_num; u32 bus_cfg; @@ -65,6 +73,7 @@ struct dw_pci_controller { u32 rx_fifo_depth; u32 clk_khz; u32 functionality; + struct dw_scl_sda_cfg *scl_sda_cfg; }; #define INTEL_MID_STD_CFG (DW_IC_CON_MASTER | \ @@ -77,6 +86,15 @@ struct dw_pci_controller { I2C_FUNC_SMBUS_WORD_DATA | \ I2C_FUNC_SMBUS_I2C_BLOCK) +/* BayTrail HCNT/LCNT/SDA hold time */ +static struct dw_scl_sda_cfg byt_config = { + .ss_hcnt = 0x200, + .fs_hcnt = 0x55, + .ss_lcnt = 0x200, + .fs_lcnt = 0x99, + .sda_hold = 0x6, +}; + static struct dw_pci_controller dw_pci_controllers[] = { [moorestown_0] = { .bus_num = 0, @@ -148,6 +166,7 @@ static struct dw_pci_controller dw_pci_controllers[] = { .rx_fifo_depth = 32, .clk_khz = 100000, .functionality = I2C_FUNC_10BIT_ADDR, + .scl_sda_cfg = &byt_config, }, }; static struct i2c_algorithm i2c_dw_algo = { @@ -187,6 +206,7 @@ static int i2c_dw_pci_probe(struct pci_dev *pdev, struct i2c_adapter *adap; int r; struct dw_pci_controller *controller; + struct dw_scl_sda_cfg *cfg; if (id->driver_data >= ARRAY_SIZE(dw_pci_controllers)) { dev_err(&pdev->dev, "%s: invalid driver data %ld\n", __func__, @@ -224,6 +244,14 @@ static int i2c_dw_pci_probe(struct pci_dev *pdev, DW_DEFAULT_FUNCTIONALITY; dev->master_cfg = controller->bus_cfg; + if (controller->scl_sda_cfg) { + cfg = controller->scl_sda_cfg; + dev->ss_hcnt = cfg->ss_hcnt; + dev->fs_hcnt = cfg->fs_hcnt; + dev->ss_lcnt = cfg->ss_lcnt; + dev->fs_lcnt = cfg->fs_lcnt; + dev->sda_hold_time = cfg->sda_hold; + } pci_set_drvdata(pdev, dev); |