| Message ID | 1394537625-27205-1-git-send-email-chiau.ee.chew@intel.com |
|---|---|
| State | Accepted |
| Headers | show |
> Subject: [PATCHv2 RESEND] i2c: designware-pci: set ideal HCNT, LCNT and SDA > hold time value > > From: Chew, Chiau Ee <chiau.ee.chew@intel.com> > > 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> > --- > v2 changelog: > * Add 'dw_' prefix to struct scl_sda_cfg > * Add Baytrail HCNT/LCNT/SDA hold time values directly in the > struct instead of using macro definition > * Replace tab before "=" with space in struct > > drivers/i2c/busses/i2c-designware-pcidrv.c | 28 > ++++++++++++++++++++++++++++ > 1 files changed, 28 insertions(+), 0 deletions(-) > I have misplaced the changelog in the previous v2 patch which would cause the removal of signed-off-by line. I'm resending this to fix that problem. Sorry for any confusion and inconvenience caused. -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Mar 11, 2014 at 07:33:45PM +0800, Chew Chiau Ee wrote: > From: Chew, Chiau Ee <chiau.ee.chew@intel.com> > > 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> -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Mar 11, 2014 at 07:33:45PM +0800, Chew Chiau Ee wrote: > From: Chew, Chiau Ee <chiau.ee.chew@intel.com> > > 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> Applied to for-next, thanks!
diff --git a/drivers/i2c/busses/i2c-designware-pcidrv.c b/drivers/i2c/busses/i2c-designware-pcidrv.c index 094509bc..91d468f 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);