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i2c: bcm2835: Make clock-stretch timeout configurable #4855

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Merged
merged 1 commit into from
Jan 31, 2022
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i2c: bcm2835: Make clock-stretch timeout configurable #4855

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10 changes: 7 additions & 3 deletions drivers/i2c/busses/i2c-bcm2835.c
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Original file line number Diff line number Diff line change
Expand Up @@ -55,6 +55,10 @@ static unsigned int debug;
module_param(debug, uint, 0644);
MODULE_PARM_DESC(debug, "1=err, 2=isr, 3=xfer");

static unsigned int clk_tout_ms = 35; /* SMBUs-recommended 35ms */
module_param(clk_tout_ms, uint, 0644);
MODULE_PARM_DESC(clk_tout_ms, "clock-stretch timeout (mS)");

#define BCM2835_DEBUG_MAX 512
struct bcm2835_debug {
struct i2c_msg *msg;
Expand Down Expand Up @@ -214,12 +218,12 @@ static int clk_bcm2835_i2c_set_rate(struct clk_hw *hw, unsigned long rate,
(redl << BCM2835_I2C_REDL_SHIFT));

/*
* Set the clock stretch timeout to the SMBUs-recommended 35ms.
* Set the clock stretch timeout.
*/
if (rate > 0xffff*1000/35)
if (rate > 0xffff*1000/clk_tout_ms)
clk_tout = 0xffff;
else
clk_tout = 35*rate/1000;
clk_tout = clk_tout_ms*rate/1000;

bcm2835_i2c_writel(div->i2c_dev, BCM2835_I2C_CLKT, clk_tout);

Expand Down