> -----Original Message----- > From: Valentin Longchamp [mailto:valentin.longch...@keymile.com] > Sent: 15 August 2012 21:02 > To: u-boot@lists.denx.de > Cc: Valentin Longchamp; Holger Brunck; Prafulla Wadaskar > Subject: [PATCH v2] kw_spi: fix clock prescaler computation > > The computation was not correct with low clock values: setting a 1MHz > clock would result in an overlap that would then configure a 25Mhz > clock. > > This patch implements a correct computation method according to the > kirkwood functionnal spec. table 600 (Serial Memory Interface > Configuration Register). > > Signed-off-by: Valentin Longchamp <valentin.longch...@keymile.com> > cc: Holger Brunck <holger.bru...@keymile.com> > cc: Prafulla Wadaskar <prafu...@marvell.com> > --- > changes for v2: > - table nb in commit message > > > arch/arm/include/asm/arch-kirkwood/spi.h | 1 + > drivers/spi/kirkwood_spi.c | 5 +++-- > 2 files changed, 4 insertions(+), 2 deletions(-) > > diff --git a/arch/arm/include/asm/arch-kirkwood/spi.h > b/arch/arm/include/asm/arch-kirkwood/spi.h > index 1d5043f..5a38dc5 100644 > --- a/arch/arm/include/asm/arch-kirkwood/spi.h > +++ b/arch/arm/include/asm/arch-kirkwood/spi.h > @@ -38,6 +38,7 @@ struct kwspi_registers { > }; > > #define KWSPI_CLKPRESCL_MASK 0x1f > +#define KWSPI_CLKPRESCL_MIN 0x12 > #define KWSPI_CSN_ACT 1 /* Activates serial memory interface > */ > #define KWSPI_SMEMRDY (1 << 1) /* SerMem Data xfer ready */ > #define KWSPI_IRQUNMASK 1 /* unmask SPI interrupt */ > diff --git a/drivers/spi/kirkwood_spi.c b/drivers/spi/kirkwood_spi.c > index ee14669..9b3f6a4 100644 > --- a/drivers/spi/kirkwood_spi.c > +++ b/drivers/spi/kirkwood_spi.c > @@ -57,8 +57,9 @@ struct spi_slave *spi_setup_slave(unsigned int bus, > unsigned int cs, > writel(~KWSPI_CSN_ACT | KWSPI_SMEMRDY, &spireg->ctrl); > > /* calculate spi clock prescaller using max_hz */ > - data = ((CONFIG_SYS_TCLK / 2) / max_hz) & KWSPI_CLKPRESCL_MASK; > - data |= 0x10; > + data = ((CONFIG_SYS_TCLK / 2) / max_hz) + 0x10; > + data = data < KWSPI_CLKPRESCL_MIN ? KWSPI_CLKPRESCL_MIN : data; > + data = data > KWSPI_CLKPRESCL_MASK ? KWSPI_CLKPRESCL_MASK : data; > > /* program spi clock prescaller using max_hz */ > writel(KWSPI_ADRLEN_3BYTE | data, &spireg->cfg); > --
Acked-by: Prafulla Wadaskar <prafu...@marvell.com> Will pull this soon. Regards... Prafulla . . . _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
