From: Douglas Anderson Date: Fri, 26 Jun 2020 22:19:50 +0000 (-0700) Subject: spi: spi-geni-qcom: Don't set the cs if it was already right X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=638d8488ae00d2e5dd5033804e82b458d3cf85b1;p=linux.git spi: spi-geni-qcom: Don't set the cs if it was already right Setting the chip select on the Qualcomm geni SPI controller isn't exactly cheap. Let's cache the current setting and avoid setting the chip select if it's already right. Using "flashrom" to read or write the EC firmware on a Chromebook shows roughly a 25% reduction in interrupts and a 15% speedup. Signed-off-by: Douglas Anderson Link: https://lore.kernel.org/r/20200626151946.1.I06134fd669bf91fd387dc6ecfe21d44c202bd412@changeid Signed-off-by: Mark Brown --- diff --git a/drivers/spi/spi-geni-qcom.c b/drivers/spi/spi-geni-qcom.c index 5b1dca1fff79a..e99a9d57449f5 100644 --- a/drivers/spi/spi-geni-qcom.c +++ b/drivers/spi/spi-geni-qcom.c @@ -79,6 +79,7 @@ struct spi_geni_master { unsigned int oversampling; spinlock_t lock; int irq; + bool cs_flag; }; static int get_spi_clk_cfg(unsigned int speed_hz, @@ -146,10 +147,15 @@ static void spi_geni_set_cs(struct spi_device *slv, bool set_flag) struct geni_se *se = &mas->se; unsigned long time_left; - pm_runtime_get_sync(mas->dev); if (!(slv->mode & SPI_CS_HIGH)) set_flag = !set_flag; + if (set_flag == mas->cs_flag) + return; + + mas->cs_flag = set_flag; + + pm_runtime_get_sync(mas->dev); spin_lock_irq(&mas->lock); reinit_completion(&mas->cs_done); if (set_flag)