Hi Jagan, On 2/26/2021 7:42 PM, Jagan Teki wrote: > On Fri, Feb 19, 2021 at 7:26 AM <tkuw584...@gmail.com> wrote: >> >> From: Takahiro Kuwano <takahiro.kuw...@infineon.com> >> >> Some of Spansion/Cypress chips support volatile version of configuration >> registers and it is recommended to update volatile registers in the field >> application due to a risk of the non-volatile registers corruption by >> power interrupt. This patch adds a function to set Quad Enable bit in CFR1 >> volatile. >> >> Signed-off-by: Takahiro Kuwano <takahiro.kuw...@infineon.com> >> --- >> Changes in v5: >> - Fix register address calculation, 'base | offset' -> 'base + offset' >> >> drivers/mtd/spi/spi-nor-core.c | 53 ++++++++++++++++++++++++++++++++++ >> include/linux/mtd/spi-nor.h | 1 + >> 2 files changed, 54 insertions(+) >> >> diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c >> index 2803536ed5..87c9fce408 100644 >> --- a/drivers/mtd/spi/spi-nor-core.c >> +++ b/drivers/mtd/spi/spi-nor-core.c >> @@ -1576,6 +1576,59 @@ static int spansion_read_cr_quad_enable(struct >> spi_nor *nor) >> return 0; >> } >> >> +/** >> + * spansion_quad_enable_volatile() - enable Quad I/O mode in volatile >> register. >> + * @nor: pointer to a 'struct spi_nor' >> + * @addr_base: base address of register (can be >0 in multi-die parts) >> + * @dummy: number of dummy cycles for register read >> + * >> + * It is recommended to update volatile registers in the field application >> due >> + * to a risk of the non-volatile registers corruption by power interrupt. >> This >> + * function sets Quad Enable bit in CFR1 volatile. >> + * >> + * Return: 0 on success, -errno otherwise. >> + */ >> +static int spansion_quad_enable_volatile(struct spi_nor *nor, u32 addr_base, >> + u8 dummy) >> +{ >> + u32 addr = addr_base + SPINOR_REG_ADDR_CFR1V; >> + >> + u8 cr; >> + int ret; >> + >> + /* Check current Quad Enable bit value. */ >> + ret = spansion_read_any_reg(nor, addr, dummy, &cr); > > What if we can use the exiting quad_enable hook by identifying > volatile QE at the function beginning instead of having a separate > call? > Do you mean something like this?
static int spansion_read_cr_quad_enable(struct spi_nor *nor) { u8 sr_cr[2]; int ret; if (JEDEC_MFR(nor->info) == SNOR_MFR_CYPRESS) { u32 base; for (base = 0; base < nor->mtd.size; base += SZ_128M) { u32 addr = base + SPINOR_REG_ADDR_CFR1V; /* Check current Quad Enable bit value. */ ret = spansion_read_any_reg(nor, addr, 0, &sr_cr[1]); [...] ret = spansion_write_any_reg(nor, addr, sr_cr[1]); [...] /* Read back and check it. */ ret = spansion_read_any_reg(nor, addr, 0, &sr_cr[1]); [...] } return 0; } /* Check current Quad Enable bit value. */ ret = read_cr(nor); if (ret < 0) { dev_dbg(nor->dev, "error while reading configuration register\n"); return -EINVAL; } [...] } Or defining a new flag like 'SNOR_F_HAS_VOLATILE_QE'? > Jagan. > Best Regards, Takahiro