[PATCH v3 5/9] i2c: at91: add support for digital filtering

Eugen.Hristev
2019-07-09T13:20:17Z

Add new platform data support for digital filtering for i2c.
The sama5d4, sama5d2 and sam9x60 support this feature.

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
---
drivers/i2c/busses/i2c-at91-core.c | 9 +++++++++
drivers/i2c/busses/i2c-at91-master.c | 9 +++++++++
drivers/i2c/busses/i2c-at91.h | 5 +++++
3 files changed, 23 insertions(+)

diff --git a/drivers/i2c/busses/i2c-at91-core.c b/drivers/i2c/busses/i2c-at91-core.c
index a663a7a..62610af 100644
--- a/drivers/i2c/busses/i2c-at91-core.c
+++ b/drivers/i2c/busses/i2c-at91-core.c
@@ -68,6 +68,7 @@ static struct at91_twi_pdata at91rm9200_config = {
.has_unre_flag = true,
.has_alt_cmd = false,
.has_hold_field = false,
+ .has_dig_filtr = false,
};

static struct at91_twi_pdata at91sam9261_config = {
@@ -76,6 +77,7 @@ static struct at91_twi_pdata at91sam9261_config = {
.has_unre_flag = false,
.has_alt_cmd = false,
.has_hold_field = false,
+ .has_dig_filtr = false,
};

static struct at91_twi_pdata at91sam9260_config = {
@@ -84,6 +86,7 @@ static struct at91_twi_pdata at91sam9260_config = {
.has_unre_flag = false,
.has_alt_cmd = false,
.has_hold_field = false,
+ .has_dig_filtr = false,
};

static struct at91_twi_pdata at91sam9g20_config = {
@@ -92,6 +95,7 @@ static struct at91_twi_pdata at91sam9g20_config = {
.has_unre_flag = false,
.has_alt_cmd = false,
.has_hold_field = false,
+ .has_dig_filtr = false,
};

static struct at91_twi_pdata at91sam9g10_config = {
@@ -100,6 +104,7 @@ static struct at91_twi_pdata at91sam9g10_config = {
.has_unre_flag = false,
.has_alt_cmd = false,
.has_hold_field = false,
+ .has_dig_filtr = false,
};

static const struct platform_device_id at91_twi_devtypes[] = {
@@ -130,6 +135,7 @@ static struct at91_twi_pdata at91sam9x5_config = {
.has_unre_flag = false,
.has_alt_cmd = false,
.has_hold_field = false,
+ .has_dig_filtr = false,
};

static struct at91_twi_pdata sama5d4_config = {
@@ -138,6 +144,7 @@ static struct at91_twi_pdata sama5d4_config = {
.has_unre_flag = false,
.has_alt_cmd = false,
.has_hold_field = true,
+ .has_dig_filtr = true,
};

static struct at91_twi_pdata sama5d2_config = {
@@ -146,6 +153,7 @@ static struct at91_twi_pdata sama5d2_config = {
.has_unre_flag = true,
.has_alt_cmd = true,
.has_hold_field = true,
+ .has_dig_filtr = true,
};

static struct at91_twi_pdata sam9x60_config = {
@@ -154,6 +162,7 @@ static struct at91_twi_pdata sam9x60_config = {
.has_unre_flag = true,
.has_alt_cmd = true,
.has_hold_field = true,
+ .has_dig_filtr = true,
};

static const struct of_device_id atmel_twi_dt_ids[] = {
diff --git a/drivers/i2c/busses/i2c-at91-master.c b/drivers/i2c/busses/i2c-at91-master.c
index e87232f..099161a 100644
--- a/drivers/i2c/busses/i2c-at91-master.c
+++ b/drivers/i2c/busses/i2c-at91-master.c
@@ -31,12 +31,18 @@

void at91_init_twi_bus_master(struct at91_twi_dev *dev)
{
+ struct at91_twi_pdata *pdata = dev->pdata;
+
/* FIFO should be enabled immediately after the software reset */
if (dev->fifo_size)
at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_FIFOEN);
at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_MSEN);
at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_SVDIS);
at91_twi_write(dev, AT91_TWI_CWGR, dev->twi_cwgr_reg);
+
+ /* enable digital filter */
+ if (pdata->has_dig_filtr && dev->enable_dig_filt)
+ at91_twi_write(dev, AT91_TWI_FILTR, AT91_TWI_FILTR_FILT);
}

/*
@@ -792,6 +798,9 @@ int at91_twi_probe_master(struct platform_device *pdev,
dev_info(dev->dev, "Using FIFO (%u data)\n", dev->fifo_size);
}

+ dev->enable_dig_filt = of_property_read_bool(pdev->dev.of_node,
+ "i2c-dig-filter");
+
at91_calc_twi_clock(dev);

dev->adapter.algo = &at91_twi_algorithm;
diff --git a/drivers/i2c/busses/i2c-at91.h b/drivers/i2c/busses/i2c-at91.h
index 499b506..c75447e 100644
--- a/drivers/i2c/busses/i2c-at91.h
+++ b/drivers/i2c/busses/i2c-at91.h
@@ -84,6 +84,9 @@
#define AT91_TWI_ACR_DATAL(len) ((len) & 0xff)
#define AT91_TWI_ACR_DIR BIT(8)

+#define AT91_TWI_FILTR 0x0044
+#define AT91_TWI_FILTR_FILT BIT(0)
+
#define AT91_TWI_FMR 0x0050 /* FIFO Mode Register */
#define AT91_TWI_FMR_TXRDYM(mode) (((mode) & 0x3) << 0)
#define AT91_TWI_FMR_TXRDYM_MASK (0x3 << 0)
@@ -108,6 +111,7 @@ struct at91_twi_pdata {
bool has_unre_flag;
bool has_alt_cmd;
bool has_hold_field;
+ bool has_dig_filtr;
struct at_dma_slave dma_slave;
};

@@ -145,6 +149,7 @@ struct at91_twi_dev {
unsigned smr;
struct i2c_client *slave;
#endif
+ bool enable_dig_filt;
};

unsigned at91_twi_read(struct at91_twi_dev *dev, unsigned reg);
--
2.7.4