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authorMichael Hennerich <michael.hennerich@analog.com>2009-05-18 08:14:41 -0400
committerBen Dooks <ben-linux@fluff.org>2009-06-13 10:39:25 +0100
commit9528d1c7a541b481a0e80301dc8d545848104023 (patch)
treed42eedf34ee8d79d4fe4acf3a48c260748443b34
parentf3ad116588151b3371ae4e092290e4f48e62b8bb (diff)
i2c: Blackfin TWI: make sure we don't end up with a CLKDIV=0
Make sure we don't end up with an invalid CLKDIV=0 in case someone specifies 20kHz SCL or less (5 * 1024 / 20 = 0x100). Signed-off-by: Michael Hennerich <michael.hennerich@analog.com> Signed-off-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Bryan Wu <cooloney@kernel.org> [ben-linux@fluff.org: shortened subject line] Signed-off-by: Ben Dooks <ben-linux@fluff.org>
-rw-r--r--drivers/i2c/busses/Kconfig2
-rw-r--r--drivers/i2c/busses/i2c-bfin-twi.c11
2 files changed, 9 insertions, 4 deletions
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index f1c6ca7e285..c8460fa9cfa 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -298,7 +298,7 @@ config I2C_BLACKFIN_TWI
config I2C_BLACKFIN_TWI_CLK_KHZ
int "Blackfin TWI I2C clock (kHz)"
depends on I2C_BLACKFIN_TWI
- range 10 400
+ range 21 400
default 50
help
The unit of the TWI clock is kHz.
diff --git a/drivers/i2c/busses/i2c-bfin-twi.c b/drivers/i2c/busses/i2c-bfin-twi.c
index fc548b3d002..77cafb6ba92 100644
--- a/drivers/i2c/busses/i2c-bfin-twi.c
+++ b/drivers/i2c/busses/i2c-bfin-twi.c
@@ -614,6 +614,7 @@ static int i2c_bfin_twi_probe(struct platform_device *pdev)
struct i2c_adapter *p_adap;
struct resource *res;
int rc;
+ unsigned int clkhilow;
iface = kzalloc(sizeof(struct bfin_twi_iface), GFP_KERNEL);
if (!iface) {
@@ -675,10 +676,14 @@ static int i2c_bfin_twi_probe(struct platform_device *pdev)
/* Set TWI internal clock as 10MHz */
write_CONTROL(iface, ((get_sclk() / 1024 / 1024 + 5) / 10) & 0x7F);
+ /*
+ * We will not end up with a CLKDIV=0 because no one will specify
+ * 20kHz SCL or less in Kconfig now. (5 * 1024 / 20 = 0x100)
+ */
+ clkhilow = 5 * 1024 / CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ;
+
/* Set Twi interface clock as specified */
- write_CLKDIV(iface, ((5*1024 / CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ)
- << 8) | ((5*1024 / CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ)
- & 0xFF));
+ write_CLKDIV(iface, (clkhilow << 8) | clkhilow);
/* Enable TWI */
write_CONTROL(iface, read_CONTROL(iface) | TWI_ENA);