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Commit 9528d1c7 authored by Michael Hennerich's avatar Michael Hennerich Committed by Ben Dooks
Browse files

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: default avatarMichael Hennerich <michael.hennerich@analog.com>
Signed-off-by: default avatarMike Frysinger <vapier@gentoo.org>
Signed-off-by: default avatarBryan Wu <cooloney@kernel.org>
[ben-linux@fluff.org: shortened subject line]
Signed-off-by: default avatarBen Dooks <ben-linux@fluff.org>
parent f3ad1165

drivers/i2c/busses/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -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.

drivers/i2c/busses/i2c-bfin-twi.c

+8 −3
Original line number Diff line number Diff line
@@ -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);