i2c: at91: add support for digital filtering

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>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Reviewed-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

diff --git a/drivers/i2c/busses/i2c-at91-core.c b/drivers/i2c/busses/i2c-at91-core.c
index caf1846..e96360f 100644 (file)
--- 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 a3fcc35..df80557 100644 (file)
--- 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);
 }
 
 /*
@@ -793,6 +799,9 @@ 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-digital-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 (file)
--- 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);