Some AT91 hardware has no slave mode included or only limited features
(i.e. no fifos).

Signed-off-by: Juergen Fitschen <m...@jue.yt>
---
 drivers/i2c/busses/i2c-at91-core.c | 14 ++++++++++++--
 drivers/i2c/busses/i2c-at91.h      |  5 +++++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-at91-core.c 
b/drivers/i2c/busses/i2c-at91-core.c
index 3d7287c..9bf1e9d 100644
--- a/drivers/i2c/busses/i2c-at91-core.c
+++ b/drivers/i2c/busses/i2c-at91-core.c
@@ -69,6 +69,7 @@ void at91_init_twi_bus(struct at91_twi_dev *dev)
 static struct at91_twi_pdata at91rm9200_config = {
        .clk_max_div = 5,
        .clk_offset = 3,
+       .slave_mode_features = 0,
        .has_unre_flag = true,
        .has_alt_cmd = false,
        .has_hold_field = false,
@@ -77,6 +78,7 @@ static struct at91_twi_pdata at91rm9200_config = {
 static struct at91_twi_pdata at91sam9261_config = {
        .clk_max_div = 5,
        .clk_offset = 4,
+       .slave_mode_features = AT91_TWI_SM_AVAILABLE,
        .has_unre_flag = false,
        .has_alt_cmd = false,
        .has_hold_field = false,
@@ -85,6 +87,7 @@ static struct at91_twi_pdata at91sam9261_config = {
 static struct at91_twi_pdata at91sam9260_config = {
        .clk_max_div = 7,
        .clk_offset = 4,
+       .slave_mode_features = AT91_TWI_SM_AVAILABLE,
        .has_unre_flag = false,
        .has_alt_cmd = false,
        .has_hold_field = false,
@@ -93,6 +96,7 @@ static struct at91_twi_pdata at91sam9260_config = {
 static struct at91_twi_pdata at91sam9g20_config = {
        .clk_max_div = 7,
        .clk_offset = 4,
+       .slave_mode_features = AT91_TWI_SM_AVAILABLE,
        .has_unre_flag = false,
        .has_alt_cmd = false,
        .has_hold_field = false,
@@ -101,6 +105,7 @@ static struct at91_twi_pdata at91sam9g20_config = {
 static struct at91_twi_pdata at91sam9g10_config = {
        .clk_max_div = 7,
        .clk_offset = 4,
+       .slave_mode_features = AT91_TWI_SM_AVAILABLE,
        .has_unre_flag = false,
        .has_alt_cmd = false,
        .has_hold_field = false,
@@ -131,6 +136,7 @@ static const struct platform_device_id at91_twi_devtypes[] 
= {
 static struct at91_twi_pdata at91sam9x5_config = {
        .clk_max_div = 7,
        .clk_offset = 4,
+       .slave_mode_features = AT91_TWI_SM_AVAILABLE,
        .has_unre_flag = false,
        .has_alt_cmd = false,
        .has_hold_field = false,
@@ -139,6 +145,7 @@ static struct at91_twi_pdata at91sam9x5_config = {
 static struct at91_twi_pdata sama5d4_config = {
        .clk_max_div = 7,
        .clk_offset = 4,
+       .slave_mode_features = AT91_TWI_SM_AVAILABLE,
        .has_unre_flag = false,
        .has_alt_cmd = false,
        .has_hold_field = true,
@@ -147,6 +154,7 @@ static struct at91_twi_pdata sama5d4_config = {
 static struct at91_twi_pdata sama5d2_config = {
        .clk_max_div = 7,
        .clk_offset = 4,
+       .slave_mode_features = AT91_TWI_SM_AVAILABLE | AT91_TWI_SM_HAS_FIFO | 
AT91_TWI_SM_CAN_NACK,
        .has_unre_flag = true,
        .has_alt_cmd = true,
        .has_hold_field = true,
@@ -219,6 +227,10 @@ static int at91_twi_probe(struct platform_device *pdev)
        if (!dev->pdata)
                return -ENODEV;
 
+       dev->slave_detected = i2c_detect_slave_mode(&pdev->dev);
+       if (dev->slave_detected && dev->pdata->slave_mode_features == 0)
+               return -EPFNOSUPPORT;
+
        dev->base = devm_ioremap_resource(&pdev->dev, mem);
        if (IS_ERR(dev->base))
                return PTR_ERR(dev->base);
@@ -245,8 +257,6 @@ static int at91_twi_probe(struct platform_device *pdev)
        dev->adapter.timeout = AT91_I2C_TIMEOUT;
        dev->adapter.dev.of_node = pdev->dev.of_node;
 
-       dev->slave_detected = i2c_detect_slave_mode(&pdev->dev);
-
        if (dev->slave_detected)
                rc = at91_twi_probe_slave(pdev, phy_addr, dev);
        else
diff --git a/drivers/i2c/busses/i2c-at91.h b/drivers/i2c/busses/i2c-at91.h
index bb502c1..4a4fa67 100644
--- a/drivers/i2c/busses/i2c-at91.h
+++ b/drivers/i2c/busses/i2c-at91.h
@@ -107,9 +107,14 @@
 
 #define        AT91_TWI_VER            0x00fc  /* Version Register */
 
+#define        AT91_TWI_SM_AVAILABLE   BIT(0)  /* Slave mode supported */
+#define        AT91_TWI_SM_CAN_NACK    BIT(1)  /* Can send NACKs in slave mode 
*/
+#define        AT91_TWI_SM_HAS_FIFO    BIT(2)  /* Has FIFO for slave mode */
+
 struct at91_twi_pdata {
        unsigned clk_max_div;
        unsigned clk_offset;
+       unsigned slave_mode_features;
        bool has_unre_flag;
        bool has_alt_cmd;
        bool has_hold_field;
-- 
2.7.4

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