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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>
This commit is contained in:
Chew, Chiau Ee 2014-03-11 19:33:45 +08:00 committed by Wolfram Sang
parent 4fda99627d
commit 8efd1e9ee3
1 changed files with 28 additions and 0 deletions
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28
drivers/i2c/busses/i2c-designware-pcidrv.c
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@ -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);