Create a struct to hold the three timing parameters. This will make it easier to move these calculations into a separate function in a later patch.
Signed-off-by: Simon Glass sjg@chromium.org Reviewed-by: Heiko Schocher hs@denx.de ---
Changes in v3: None Changes in v2: None
drivers/i2c/designware_i2c.c | 82 ++++++++++++++++++++++++------------ 1 file changed, 55 insertions(+), 27 deletions(-)
diff --git a/drivers/i2c/designware_i2c.c b/drivers/i2c/designware_i2c.c index 6e5545cd0c..e50987a717 100644 --- a/drivers/i2c/designware_i2c.c +++ b/drivers/i2c/designware_i2c.c @@ -13,6 +13,23 @@ #include <asm/io.h> #include "designware_i2c.h"
+/** + * struct dw_i2c_speed_config - timings to use for a particular speed + * + * This holds calculated values to be written to the I2C controller. Each value + * is represented as a number of IC clock cycles. + * + * @scl_lcnt: Low count value for SCL + * @scl_hcnt: High count value for SCL + * @sda_hold: Data hold count + */ +struct dw_i2c_speed_config { + /* SCL high and low period count */ + uint scl_lcnt; + uint scl_hcnt; + uint sda_hold; +}; + #ifdef CONFIG_SYS_I2C_DW_ENABLE_STATUS_UNSUPPORTED static int dw_i2c_enable(struct i2c_regs *i2c_base, bool enable) { @@ -58,10 +75,10 @@ static unsigned int __dw_i2c_set_bus_speed(struct dw_i2c *priv, unsigned int bus_clk) { const struct dw_scl_sda_cfg *scl_sda_cfg = NULL; + struct dw_i2c_speed_config config; ulong bus_khz = bus_clk / 1000; enum i2c_speed_mode i2c_spd; unsigned int cntl; - unsigned int hcnt, lcnt; unsigned int ena;
if (priv) @@ -83,53 +100,64 @@ static unsigned int __dw_i2c_set_bus_speed(struct dw_i2c *priv,
cntl = (readl(&i2c_base->ic_con) & (~IC_CON_SPD_MSK));
+ config.scl_hcnt = 0; + config.scl_lcnt = 0; + config.sda_hold = 0; + if (scl_sda_cfg) { + config.sda_hold = scl_sda_cfg->sda_hold; + if (i2c_spd == IC_SPEED_MODE_STANDARD) { + config.scl_hcnt = scl_sda_cfg->ss_hcnt; + config.scl_lcnt = scl_sda_cfg->ss_lcnt; + } else { + config.scl_hcnt = scl_sda_cfg->fs_hcnt; + config.scl_lcnt = scl_sda_cfg->fs_lcnt; + } + } + switch (i2c_spd) { case IC_SPEED_MODE_HIGH: cntl |= IC_CON_SPD_SS; - if (scl_sda_cfg) { - hcnt = scl_sda_cfg->fs_hcnt; - lcnt = scl_sda_cfg->fs_lcnt; - } else { - hcnt = (bus_khz * MIN_HS_SCL_HIGHTIME) / NANO_TO_KILO; - lcnt = (bus_khz * MIN_HS_SCL_LOWTIME) / NANO_TO_KILO; + if (!scl_sda_cfg) { + config.scl_hcnt = (bus_khz * MIN_HS_SCL_HIGHTIME) / + NANO_TO_KILO; + config.scl_lcnt = (bus_khz * MIN_HS_SCL_LOWTIME) / + NANO_TO_KILO; } - writel(hcnt, &i2c_base->ic_hs_scl_hcnt); - writel(lcnt, &i2c_base->ic_hs_scl_lcnt); + writel(config.scl_hcnt, &i2c_base->ic_hs_scl_hcnt); + writel(config.scl_lcnt, &i2c_base->ic_hs_scl_lcnt); break;
case IC_SPEED_MODE_STANDARD: cntl |= IC_CON_SPD_SS; - if (scl_sda_cfg) { - hcnt = scl_sda_cfg->ss_hcnt; - lcnt = scl_sda_cfg->ss_lcnt; - } else { - hcnt = (bus_khz * MIN_SS_SCL_HIGHTIME) / NANO_TO_KILO; - lcnt = (bus_khz * MIN_SS_SCL_LOWTIME) / NANO_TO_KILO; + if (!scl_sda_cfg) { + config.scl_hcnt = (bus_khz * MIN_SS_SCL_HIGHTIME) / + NANO_TO_KILO; + config.scl_lcnt = (bus_khz * MIN_SS_SCL_LOWTIME) / + NANO_TO_KILO; } - writel(hcnt, &i2c_base->ic_ss_scl_hcnt); - writel(lcnt, &i2c_base->ic_ss_scl_lcnt); + writel(config.scl_hcnt, &i2c_base->ic_ss_scl_hcnt); + writel(config.scl_lcnt, &i2c_base->ic_ss_scl_lcnt); break;
case IC_SPEED_MODE_FAST: default: cntl |= IC_CON_SPD_FS; - if (scl_sda_cfg) { - hcnt = scl_sda_cfg->fs_hcnt; - lcnt = scl_sda_cfg->fs_lcnt; - } else { - hcnt = (bus_khz * MIN_FS_SCL_HIGHTIME) / NANO_TO_KILO; - lcnt = (bus_khz * MIN_FS_SCL_LOWTIME) / NANO_TO_KILO; + if (!scl_sda_cfg) { + config.scl_hcnt = (bus_khz * MIN_FS_SCL_HIGHTIME) / + NANO_TO_KILO; + config.scl_lcnt = (bus_khz * MIN_FS_SCL_LOWTIME) / + NANO_TO_KILO; } - writel(hcnt, &i2c_base->ic_fs_scl_hcnt); - writel(lcnt, &i2c_base->ic_fs_scl_lcnt); + writel(config.scl_hcnt, &i2c_base->ic_fs_scl_hcnt); + writel(config.scl_lcnt, &i2c_base->ic_fs_scl_lcnt); break; }
writel(cntl, &i2c_base->ic_con);
/* Configure SDA Hold Time if required */ - if (scl_sda_cfg) - writel(scl_sda_cfg->sda_hold, &i2c_base->ic_sda_hold); + if (config.sda_hold) + writel(config.sda_hold, &i2c_base->ic_sda_hold);
/* Restore back i2c now speed set */ if (ena == IC_ENABLE_0B)