@@ -27,7 +27,8 @@
#define FSI_ENGID_I2C 0x7
-#define I2C_DEFAULT_CLK_DIV 6
+#define I2C_DEFAULT_CLK_DIV 7
+#define I2C_DEFAULT_CLK_RATE 400000
/* i2c registers */
#define I2C_FSI_FIFO 0x00
@@ -150,6 +151,7 @@ struct fsi_i2c_master {
u8 fifo_size;
struct list_head ports;
struct mutex lock;
+ u32 clock_div;
};
struct fsi_i2c_port {
@@ -194,7 +196,7 @@ static int fsi_i2c_dev_init(struct fsi_i2c_master *i2c)
if (rc)
return rc;
- mode |= FIELD_PREP(I2C_MODE_CLKDIV, I2C_DEFAULT_CLK_DIV);
+ mode |= FIELD_PREP(I2C_MODE_CLKDIV, i2c->clock_div);
rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode);
if (rc)
return rc;
@@ -680,6 +682,7 @@ static int fsi_i2c_probe(struct device *dev)
struct fsi_i2c_port *port;
struct device_node *np;
u32 port_no, ports, stat;
+ u32 lbus;
int rc;
i2c = devm_kzalloc(dev, sizeof(*i2c), GFP_KERNEL);
@@ -689,6 +692,20 @@ static int fsi_i2c_probe(struct device *dev)
mutex_init(&i2c->lock);
i2c->fsi = to_fsi_dev(dev);
INIT_LIST_HEAD(&i2c->ports);
+ i2c->clock_div = I2C_DEFAULT_CLK_DIV;
+
+ lbus = fsi_device_local_bus_frequency(i2c->fsi);
+ if (lbus) {
+ u32 clock = I2C_DEFAULT_CLK_RATE;
+
+ if (!device_property_read_u32(dev, "clock-frequency", &clock)) {
+ if (!clock)
+ clock = I2C_DEFAULT_CLK_RATE;
+ }
+
+ // i2c clock rate = local bus clock / (4 * (i2c clock div + 1))
+ i2c->clock_div = (((lbus + (clock - 1)) / clock) / 4) - 1;
+ }
rc = fsi_i2c_dev_init(i2c);
if (rc)
Use the new FSI device local bus clock to calculate the proper i2c clock divder and look up an optional clock-frequency property from device tree. Change the default clock divider to 7 now that the default local bus clock divider has been reduced as well. Signed-off-by: Eddie James <eajames@linux.ibm.com> --- drivers/i2c/busses/i2c-fsi.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-)