This allows to set the TWI bite rate based on a programmable clock source.
The lan966x supports this feature.
Signed-off-by: Horatiu Vultur <horatiu.vultur@xxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-at91-core.c | 16 ++++++++++++++++
drivers/i2c/busses/i2c-at91-master.c | 23 +++++++++++++++++++++--
drivers/i2c/busses/i2c-at91.h | 1 +
3 files changed, 38 insertions(+), 2 deletions(-)
diff --git a/drivers/i2c/busses/i2c-at91-core.c b/drivers/i2c/busses/i2c-at91-core.c
index 2df9df585131..d98b437e5775 100644
--- a/drivers/i2c/busses/i2c-at91-core.c
+++ b/drivers/i2c/busses/i2c-at91-core.c
@@ -146,6 +146,19 @@ static struct at91_twi_pdata sam9x60_config = {
.has_clear_cmd = true,
};
+static struct at91_twi_pdata lan966x_config = {
+ .clk_max_div = 7,
+ .clk_offset = 0,
+ .clk_brsrcclk = true,
+ .has_unre_flag = true,
+ .has_alt_cmd = true,
+ .has_hold_field = true,
+ .has_dig_filtr = true,
+ .has_adv_dig_filtr = true,
+ .has_ana_filtr = true,
+ .has_clear_cmd = true,
+};
+
static const struct of_device_id atmel_twi_dt_ids[] = {
{
.compatible = "atmel,at91rm9200-i2c",
@@ -174,6 +187,9 @@ static const struct of_device_id atmel_twi_dt_ids[] = {
}, {
.compatible = "microchip,sam9x60-i2c",
.data = &sam9x60_config,
+ }, {
+ .compatible = "microchip,lan966x-i2c",
+ .data = &lan966x_config,
}, {
/* sentinel */
}
diff --git a/drivers/i2c/busses/i2c-at91-master.c b/drivers/i2c/busses/i2c-at91-master.c
index b0eae94909f4..f504af30adbe 100644
--- a/drivers/i2c/busses/i2c-at91-master.c
+++ b/drivers/i2c/busses/i2c-at91-master.c
@@ -120,8 +120,27 @@ static void at91_calc_twi_clock(struct at91_twi_dev *dev)
}
}
- dev->twi_cwgr_reg = (ckdiv << 16) | (cdiv << 8) | cdiv
- | AT91_TWI_CWGR_HOLD(hold);
+ if (pdata->clk_brsrcclk) {
+ u8 chdiv, cldiv, gck_pr;
+
+ gck_pr = 1000000000 / clk_get_rate(dev->clk);
+
+ /* thigh = bus_freq_hz in ns * 0.4
+ * tlow = bus_freq_hz in ns * 0.6
+ * chdiv = (thigh / GCK_PR)/2 ^ CKDIV
+ * cldiv = (tlow / GCK_PR)/2 ^ CKDIV
+ * where ckdiv = 0;
+ */
+ cldiv = (1000000000 / t->bus_freq_hz * 6 / 10) / gck_pr;
+ chdiv = (1000000000 / t->bus_freq_hz * 4 / 10) / gck_pr;
+
+ dev->twi_cwgr_reg = (chdiv << 8) | cldiv
+ | AT91_TWI_CWGR_HOLD(hold)
+ | pdata->clk_brsrcclk << 20;
+ } else {
+ dev->twi_cwgr_reg = (ckdiv << 16) | (cdiv << 8) | cdiv
+ | AT91_TWI_CWGR_HOLD(hold);
+ }
dev->filter_width = filter_width;
diff --git a/drivers/i2c/busses/i2c-at91.h b/drivers/i2c/busses/i2c-at91.h
index 942e9c3973bb..f7328fbe8eb8 100644
--- a/drivers/i2c/busses/i2c-at91.h
+++ b/drivers/i2c/busses/i2c-at91.h
@@ -115,6 +115,7 @@
struct at91_twi_pdata {
unsigned clk_max_div;
unsigned clk_offset;
+ bool clk_brsrcclk;
bool has_unre_flag;
bool has_alt_cmd;
bool has_hold_field;
--
2.33.0
