From 6d106139191e58b9f4ef126cfc1e3c26c0d6702e Mon Sep 17 00:00:00 2001 From: Arseny Solokha Date: Thu, 7 Dec 2017 17:20:00 +0700 Subject: i2c: mpc: get MPC8xxx I2C clock prescaler before using it in calculations Obtaining the actual I2C clock prescaler value in mpc_i2c_setup_8xxx() only happens when the clock parameter is set to something other than MPC_I2C_CLOCK_LEGACY. When the clock parameter is exactly MPC_I2C_CLOCK_LEGACY, the prescaler parameter is used in arithmetic division as provided by the caller, resulting in a division by zero for the majority of processors supported by the module. Avoid division by zero by obtaining the actual I2C clock prescaler in mpc_i2c_setup_8xxx() unconditionally regardless of the passed clock value. Signed-off-by: Arseny Solokha Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-mpc.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'drivers/i2c') diff --git a/drivers/i2c/busses/i2c-mpc.c b/drivers/i2c/busses/i2c-mpc.c index 950a9d74f54d..6ad87555f71e 100644 --- a/drivers/i2c/busses/i2c-mpc.c +++ b/drivers/i2c/busses/i2c-mpc.c @@ -382,18 +382,18 @@ static int mpc_i2c_get_fdr_8xxx(struct device_node *node, u32 clock, u32 divider; int i; - if (clock == MPC_I2C_CLOCK_LEGACY) { - /* see below - default fdr = 0x1031 -> div = 16 * 3072 */ - *real_clk = fsl_get_sys_freq() / prescaler / (16 * 3072); - return -EINVAL; - } - /* Determine proper divider value */ if (of_device_is_compatible(node, "fsl,mpc8544-i2c")) prescaler = mpc_i2c_get_sec_cfg_8xxx() ? 3 : 2; if (!prescaler) prescaler = mpc_i2c_get_prescaler_8xxx(); + if (clock == MPC_I2C_CLOCK_LEGACY) { + /* see below - default fdr = 0x1031 -> div = 16 * 3072 */ + *real_clk = fsl_get_sys_freq() / prescaler / (16 * 3072); + return -EINVAL; + } + divider = fsl_get_sys_freq() / clock / prescaler; pr_debug("I2C: src_clock=%d clock=%d divider=%d\n", -- cgit v1.2.3