Hi John. i check the code which functions need read/write register. 3 functions (prepare_message, set_cs, transfer_one) are used at same function __spi_pump_messages at spi.c.
the __spi_pump_message is protected by spi_master->queue_lock this make sure spi device operation is serialized. the spi bus is protected by spi_master->bus_lock_spinlock. you can found it at spi_async function. it make sure only one spi device work on the same spi bus. so the 3 functions don't have lock problem. about the setup function. it maybe be called by user space to setup a new spi device. but it will not affect other spi device. because it just disable the new spi device by useing cs pin. so i think it is save to remove the lock protect. the most important is the lock on probe function must be wrong. because it only call spin_lock_irqsave. but not call spin_unlock_irqrestore. 2015-10-26 22:26 GMT+08:00 John Crispin <[email protected]>: > Hi Michael, > > while merging the series i stumbled across this patch. to me this looks > wrong. > > rather than removing the locking i think we should add more to > rt2880_spi_read and rt2880_spi_write. > > i'll merge the other 7 patches just now if they apply without 2/8 > > > John > > On 08/10/2015 16:16, Michael Lee wrote: > > Signed-off-by: Michael Lee <[email protected]> > > --- > > ...0050-SPI-ralink-add-Ralink-SoC-spi-driver.patch | 23 > +++++----------------- > > 1 file changed, 5 insertions(+), 18 deletions(-) > > > > diff --git > a/target/linux/ramips/patches-3.18/0050-SPI-ralink-add-Ralink-SoC-spi-driver.patch > b/target/linux/ramips/patches-3.18/0050-SPI-ralink-add-Ralink-SoC-spi-driver.patch > > index ca04a17..d6a462c 100644 > > --- > a/target/linux/ramips/patches-3.18/0050-SPI-ralink-add-Ralink-SoC-spi-driver.patch > > +++ > b/target/linux/ramips/patches-3.18/0050-SPI-ralink-add-Ralink-SoC-spi-driver.patch > > @@ -41,7 +41,7 @@ Acked-by: John Crispin <[email protected]> > > spi-s3c24xx-hw-$(CONFIG_SPI_S3C24XX_FIQ) += spi-s3c24xx-fiq.o > > --- /dev/null > > +++ b/drivers/spi/spi-rt2880.c > > -@@ -0,0 +1,493 @@ > > +@@ -0,0 +1,480 @@ > > +/* > > + * spi-rt2880.c -- Ralink RT288x/RT305x SPI controller driver > > + * > > @@ -174,7 +174,6 @@ Acked-by: John Crispin <[email protected]> > > + unsigned int sys_freq; > > + unsigned int speed; > > + struct clk *clk; > > -+ spinlock_t lock; > > +}; > > + > > +static inline struct rt2880_spi *spidev_to_rt2880_spi(struct > spi_device *spi) > > @@ -187,7 +186,8 @@ Acked-by: John Crispin <[email protected]> > > + return ioread32(rs->base + reg); > > +} > > + > > -+static inline void rt2880_spi_write(struct rt2880_spi *rs, u32 reg, > u32 val) > > ++static inline void rt2880_spi_write(struct rt2880_spi *rs, u32 reg, > > ++ const u32 val) > > +{ > > + iowrite32(val, rs->base + reg); > > +} > > @@ -195,27 +195,15 @@ Acked-by: John Crispin <[email protected]> > > +static inline void rt2880_spi_setbits(struct rt2880_spi *rs, u32 reg, > u32 mask) > > +{ > > + void __iomem *addr = rs->base + reg; > > -+ unsigned long flags; > > -+ u32 val; > > + > > -+ spin_lock_irqsave(&rs->lock, flags); > > -+ val = ioread32(addr); > > -+ val |= mask; > > -+ iowrite32(val, addr); > > -+ spin_unlock_irqrestore(&rs->lock, flags); > > ++ iowrite32((ioread32(addr) | mask), addr); > > +} > > + > > +static inline void rt2880_spi_clrbits(struct rt2880_spi *rs, u32 reg, > u32 mask) > > +{ > > + void __iomem *addr = rs->base + reg; > > -+ unsigned long flags; > > -+ u32 val; > > + > > -+ spin_lock_irqsave(&rs->lock, flags); > > -+ val = ioread32(addr); > > -+ val &= ~mask; > > -+ iowrite32(val, addr); > > -+ spin_unlock_irqrestore(&rs->lock, flags); > > ++ iowrite32((ioread32(addr) & ~mask), addr); > > +} > > + > > +static int rt2880_spi_baudrate_set(struct spi_device *spi, unsigned > int speed) > > @@ -488,7 +476,6 @@ Acked-by: John Crispin <[email protected]> > > + rs->master = master; > > + rs->sys_freq = clk_get_rate(rs->clk); > > + dev_dbg(&pdev->dev, "sys_freq: %u\n", rs->sys_freq); > > -+ spin_lock_irqsave(&rs->lock, flags); > > + > > + device_reset(&pdev->dev); > > + > > >
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