diff options
Diffstat (limited to 'drivers/spi/spi-mem.c')
| -rw-r--r-- | drivers/spi/spi-mem.c | 27 |
1 files changed, 22 insertions, 5 deletions
diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c index 5db0639d3b01..d3b7e857b377 100644 --- a/drivers/spi/spi-mem.c +++ b/drivers/spi/spi-mem.c @@ -586,14 +586,26 @@ EXPORT_SYMBOL_GPL(spi_mem_adjust_op_freq); * accurate, all these combinations should be rated (eg. with a time estimate) * and the best pick should be taken based on these calculations. * - * Returns a ns estimate for the time this op would take. + * Returns a ns estimate for the time this op would take, except if no + * frequency limit has been set, in this case we return the number of + * cycles nevertheless to allow callers to distinguish which operation + * would be the fastest at iso-frequency. */ -u64 spi_mem_calc_op_duration(struct spi_mem_op *op) +u64 spi_mem_calc_op_duration(struct spi_mem *mem, struct spi_mem_op *op) { u64 ncycles = 0; - u32 ns_per_cycles; + u64 ps_per_cycles, duration; + + spi_mem_adjust_op_freq(mem, op); + + if (op->max_freq) { + ps_per_cycles = 1000000000000ULL; + do_div(ps_per_cycles, op->max_freq); + } else { + /* In this case, the unit is no longer a time unit */ + ps_per_cycles = 1; + } - ns_per_cycles = 1000000000 / op->max_freq; ncycles += ((op->cmd.nbytes * 8) / op->cmd.buswidth) / (op->cmd.dtr ? 2 : 1); ncycles += ((op->addr.nbytes * 8) / op->addr.buswidth) / (op->addr.dtr ? 2 : 1); @@ -603,7 +615,12 @@ u64 spi_mem_calc_op_duration(struct spi_mem_op *op) ncycles += ((op->data.nbytes * 8) / op->data.buswidth) / (op->data.dtr ? 2 : 1); - return ncycles * ns_per_cycles; + /* Derive the duration in ps */ + duration = ncycles * ps_per_cycles; + /* Convert into ns */ + do_div(duration, 1000); + + return duration; } EXPORT_SYMBOL_GPL(spi_mem_calc_op_duration); |