diff options
Diffstat (limited to 'drivers/w1')
| -rw-r--r-- | drivers/w1/masters/mxc_w1.c | 32 |
1 files changed, 15 insertions, 17 deletions
diff --git a/drivers/w1/masters/mxc_w1.c b/drivers/w1/masters/mxc_w1.c index a5df5e89d456..0d05abe34362 100644 --- a/drivers/w1/masters/mxc_w1.c +++ b/drivers/w1/masters/mxc_w1.c @@ -15,16 +15,13 @@ #include <linux/clk.h> #include <linux/delay.h> #include <linux/io.h> +#include <linux/jiffies.h> #include <linux/module.h> #include <linux/platform_device.h> #include "../w1.h" #include "../w1_int.h" -/* According to the mx27 Datasheet the reset procedure should take up to about - * 1350us. We set the timeout to 500*100us = 50ms for sure */ -#define MXC_W1_RESET_TIMEOUT 500 - /* * MXC W1 Register offsets */ @@ -49,24 +46,25 @@ struct mxc_w1_device { */ static u8 mxc_w1_ds2_reset_bus(void *data) { - u8 reg_val; - unsigned int timeout_cnt = 0; struct mxc_w1_device *dev = data; + unsigned long timeout; - writeb(MXC_W1_CONTROL_RPP, (dev->regs + MXC_W1_CONTROL)); + writeb(MXC_W1_CONTROL_RPP, dev->regs + MXC_W1_CONTROL); - while (1) { - reg_val = readb(dev->regs + MXC_W1_CONTROL); + /* Wait for reset sequence 511+512us, use 1500us for sure */ + timeout = jiffies + usecs_to_jiffies(1500); - if (!(reg_val & MXC_W1_CONTROL_RPP) || - timeout_cnt > MXC_W1_RESET_TIMEOUT) - break; - else - timeout_cnt++; + udelay(511 + 512); - udelay(100); - } - return !(reg_val & MXC_W1_CONTROL_PST); + do { + u8 ctrl = readb(dev->regs + MXC_W1_CONTROL); + + /* PST bit is valid after the RPP bit is self-cleared */ + if (!(ctrl & MXC_W1_CONTROL_RPP)) + return !(ctrl & MXC_W1_CONTROL_PST); + } while (time_is_after_jiffies(timeout)); + + return 1; } /* |