diff options
| author | Eugen Hristev <eugen.hristev@microchip.com> | 2019-09-11 08:24:31 +0000 |
|---|---|---|
| committer | Wolfram Sang <wsa@the-dreams.de> | 2019-10-24 20:25:09 +0200 |
| commit | 2be357af5fdd9fc74d28d929a9e29d2fcee75e4a (patch) | |
| tree | 37ce4c43b9d8f5da196f7e387f78f7110256a228 /drivers/i2c/busses/i2c-at91-master.c | |
| parent | 2989b45923b96981a3f50be7f64afdf9221c3b17 (diff) | |
i2c: at91: add support for advanced digital filtering
Add new platform data support for advanced digital filtering for i2c.
The sama5d2 and sam9x60 support this feature.
This digital filter allows the user to configure the maximum
width of the spikes that can be filtered.
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Reviewed-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'drivers/i2c/busses/i2c-at91-master.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-at91-master.c | 30 |
1 files changed, 27 insertions, 3 deletions
diff --git a/drivers/i2c/busses/i2c-at91-master.c b/drivers/i2c/busses/i2c-at91-master.c index df80557eabfe..273bd8bda32d 100644 --- a/drivers/i2c/busses/i2c-at91-master.c +++ b/drivers/i2c/busses/i2c-at91-master.c @@ -43,6 +43,12 @@ void at91_init_twi_bus_master(struct at91_twi_dev *dev) /* enable digital filter */ if (pdata->has_dig_filtr && dev->enable_dig_filt) at91_twi_write(dev, AT91_TWI_FILTR, AT91_TWI_FILTR_FILT); + + /* enable advanced digital filter */ + if (pdata->has_adv_dig_filtr && dev->enable_dig_filt) + at91_twi_write(dev, AT91_TWI_FILTR, AT91_TWI_FILTR_FILT | + (AT91_TWI_FILTR_THRES(dev->filter_width) & + AT91_TWI_FILTR_THRES_MASK)); } /* @@ -51,7 +57,7 @@ void at91_init_twi_bus_master(struct at91_twi_dev *dev) */ static void at91_calc_twi_clock(struct at91_twi_dev *dev) { - int ckdiv, cdiv, div, hold = 0; + int ckdiv, cdiv, div, hold = 0, filter_width = 0; struct at91_twi_pdata *pdata = dev->pdata; int offset = pdata->clk_offset; int max_ckdiv = pdata->clk_max_div; @@ -90,11 +96,29 @@ static void at91_calc_twi_clock(struct at91_twi_dev *dev) } } + if (pdata->has_adv_dig_filtr) { + /* + * filter width = 0 to AT91_TWI_FILTR_THRES_MAX + * peripheral clocks + */ + filter_width = DIV_ROUND_UP(t->digital_filter_width_ns + * (clk_get_rate(dev->clk) / 1000), 1000000); + if (filter_width > AT91_TWI_FILTR_THRES_MAX) { + dev_warn(dev->dev, + "Filter threshold set to its maximum value (%d instead of %d)\n", + AT91_TWI_FILTR_THRES_MAX, filter_width); + filter_width = AT91_TWI_FILTR_THRES_MAX; + } + } + dev->twi_cwgr_reg = (ckdiv << 16) | (cdiv << 8) | cdiv | AT91_TWI_CWGR_HOLD(hold); - dev_dbg(dev->dev, "cdiv %d ckdiv %d hold %d (%d ns)\n", - cdiv, ckdiv, hold, t->sda_hold_ns); + dev->filter_width = filter_width; + + dev_dbg(dev->dev, "cdiv %d ckdiv %d hold %d (%d ns), filter_width %d (%d ns)\n", + cdiv, ckdiv, hold, t->sda_hold_ns, filter_width, + t->digital_filter_width_ns); } static void at91_twi_dma_cleanup(struct at91_twi_dev *dev) |