[PATCH v2 16/21] spi: add spi controller support for MediaTek MT7620 SoC
Weijie Gao
weijie.gao at mediatek.com
Mon Nov 9 03:10:33 CET 2020
On Mon, 2020-11-02 at 11:30 +0530, Jagan Teki wrote:
> On Fri, Oct 30, 2020 at 3:05 PM Weijie Gao <weijie.gao at mediatek.com> wrote:
> >
> > This patch adds spi controller support for MediaTek MT7620 SoC.
> >
> > The SPI controller supports two chip selects. These two chip selects are
> > implemented as two separate register groups, but they share the same bus
> > (DI/DO/CLK), only CS pins are dedicated for each register group.
> > Appearently these two register groups cannot operates simulataneously so
> > they are implemented as one controller.
> >
> > Signed-off-by: Weijie Gao <weijie.gao at mediatek.com>
> > ---
> > v2 changes: none
> > ---
> > drivers/spi/Kconfig | 7 +
> > drivers/spi/Makefile | 1 +
> > drivers/spi/mt7620_spi.c | 277 +++++++++++++++++++++++++++++++++++++++
> > 3 files changed, 285 insertions(+)
> > create mode 100644 drivers/spi/mt7620_spi.c
> >
> > diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
> > index f7a9852565..ec50d843ef 100644
> > --- a/drivers/spi/Kconfig
> > +++ b/drivers/spi/Kconfig
> > @@ -202,6 +202,13 @@ config MSCC_BB_SPI
> > Enable MSCC bitbang SPI driver. This driver can be used on
> > MSCC SOCs.
> >
> > +config MT7620_SPI
> > + bool "MediaTek MT7620 SPI driver"
> > + depends on SOC_MT7620
> > + help
> > + Enable the MT7620 SPI driver. This driver can be used to access
> > + generic SPI devices on MediaTek MT7620 SoC.
> > +
> > config MT7621_SPI
> > bool "MediaTek MT7621 SPI driver"
> > depends on SOC_MT7628
> > diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
> > index d9b5bd9b79..bfd142d153 100644
> > --- a/drivers/spi/Makefile
> > +++ b/drivers/spi/Makefile
> > @@ -36,6 +36,7 @@ obj-$(CONFIG_MESON_SPIFC) += meson_spifc.o
> > obj-$(CONFIG_MPC8XX_SPI) += mpc8xx_spi.o
> > obj-$(CONFIG_MPC8XXX_SPI) += mpc8xxx_spi.o
> > obj-$(CONFIG_MTK_SNFI_SPI) += mtk_snfi_spi.o
> > +obj-$(CONFIG_MT7620_SPI) += mt7620_spi.o
> > obj-$(CONFIG_MT7621_SPI) += mt7621_spi.o
> > obj-$(CONFIG_MSCC_BB_SPI) += mscc_bb_spi.o
> > obj-$(CONFIG_MVEBU_A3700_SPI) += mvebu_a3700_spi.o
> > diff --git a/drivers/spi/mt7620_spi.c b/drivers/spi/mt7620_spi.c
> > new file mode 100644
> > index 0000000000..c0b3d1d8eb
> > --- /dev/null
> > +++ b/drivers/spi/mt7620_spi.c
> > @@ -0,0 +1,277 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (C) 2020 MediaTek Inc.
> > + *
> > + * Author: Weijie Gao <weijie.gao at mediatek.com>
> > + *
> > + * Generic SPI driver for MediaTek MT7620 SoC
> > + */
> > +
> > +#include <clk.h>
> > +#include <dm.h>
> > +#include <spi.h>
> > +#include <linux/bitops.h>
> > +#include <linux/iopoll.h>
> > +#include <linux/io.h>
> > +#include <linux/log2.h>
> > +
> > +#define MT7620_SPI_NUM_CS 2
> > +#define MT7620_SPI_MASTER1_OFF 0x00
> > +#define MT7620_SPI_MASTER2_OFF 0x40
> > +
> > +/* SPI_STAT */
> > +#define SPI_BUSY BIT(0)
> > +
> > +/* SPI_CFG */
> > +#define MSB_FIRST BIT(8)
> > +#define SPI_CLK_POL BIT(6)
> > +#define RX_CLK_EDGE BIT(5)
> > +#define TX_CLK_EDGE BIT(4)
> > +#define SPI_CLK_S 0
> > +#define SPI_CLK_M GENMASK(2, 0)
> > +
> > +/* SPI_CTL */
> > +#define START_WR BIT(2)
> > +#define START_RD BIT(1)
> > +#define SPI_HIGH BIT(0)
> > +
> > +#define SPI_ARB 0xf0
> > +#define ARB_EN BIT(31)
> > +
> > +struct mt7620_spi_master_regs {
> > + u32 stat;
> > + u32 reserved0[3];
> > + u32 cfg;
> > + u32 ctl;
> > + u32 reserved1[2];
> > + u32 data;
> > +};
> > +
> > +struct mt7620_spi {
> > + void __iomem *regs;
> > + struct mt7620_spi_master_regs *m[MT7620_SPI_NUM_CS];
> > + unsigned int sys_freq;
> > + u32 wait_us;
> > + uint mode;
> > + uint speed;
> > +};
> > +
> > +static void mt7620_spi_master_setup(struct mt7620_spi *ms, int cs)
> > +{
> > + u32 rate, prescale, freq, tmo, cfg;
> > +
> > + /* Calculate the clock divsior */
> > + rate = DIV_ROUND_UP(ms->sys_freq, ms->speed);
> > + rate = roundup_pow_of_two(rate);
> > +
> > + prescale = ilog2(rate / 2);
> > + if (prescale > 6)
> > + prescale = 6;
> > +
> > + /* Calculate the real clock, and usecs for one byte transaction */
> > + freq = ms->sys_freq >> (prescale + 1);
> > + tmo = DIV_ROUND_UP(8 * 1000000, freq);
> > +
> > + /* 10 times tolerance plus 100us */
> > + ms->wait_us = 10 * tmo + 100;
>
> Replace the above magic numbers with meaningful macros.
ok.
>
> > +
> > + /* set SPI_CFG */
> > + cfg = prescale << SPI_CLK_S;
> > +
> > + switch (ms->mode & (SPI_CPOL | SPI_CPHA)) {
> > + case SPI_MODE_0:
> > + cfg |= TX_CLK_EDGE;
> > + break;
> > + case SPI_MODE_1:
> > + cfg |= RX_CLK_EDGE;
> > + break;
> > + case SPI_MODE_2:
> > + cfg |= SPI_CLK_POL | RX_CLK_EDGE;
> > + break;
> > + case SPI_MODE_3:
> > + cfg |= SPI_CLK_POL | TX_CLK_EDGE;
> > + break;
> > + }
> > +
> > + if (!(ms->mode & SPI_LSB_FIRST))
> > + cfg |= MSB_FIRST;
> > +
> > + writel(cfg, &ms->m[cs]->cfg);
> > +
> > + writel(SPI_HIGH, &ms->m[cs]->ctl);
> > +}
> > +
> > +static void mt7620_spi_set_cs(struct mt7620_spi *ms, int cs, int enable)
> > +{
> > + if (enable)
> > + mt7620_spi_master_setup(ms, cs);
> > +
> > + if (ms->mode & SPI_CS_HIGH)
> > + enable = !enable;
> > +
> > + if (enable)
> > + clrbits_32(&ms->m[cs]->ctl, SPI_HIGH);
> > + else
> > + setbits_32(&ms->m[cs]->ctl, SPI_HIGH);
> > +}
> > +
> > +static int mt7620_spi_set_mode(struct udevice *bus, uint mode)
> > +{
> > + struct mt7620_spi *ms = dev_get_priv(bus);
> > +
> > + ms->mode = mode;
> > +
> > + /* Mode 0 is buggy. Force to use mode 3 */
> > + if ((mode & SPI_MODE_3) == SPI_MODE_0)
> > + ms->mode |= SPI_MODE_3;
> > +
> > + return 0;
> > +}
> > +
> > +static int mt7620_spi_set_speed(struct udevice *bus, uint speed)
> > +{
> > + struct mt7620_spi *ms = dev_get_priv(bus);
> > +
> > + ms->speed = speed;
> > +
> > + return 0;
> > +}
> > +
> > +static inline int mt7620_spi_busy_poll(struct mt7620_spi *ms, int cs)
> > +{
> > + u32 val;
> > +
> > + return readl_poll_timeout(&ms->m[cs]->stat, val, !(val & SPI_BUSY),
> > + ms->wait_us);
> > +}
> > +
> > +static int mt7620_spi_read(struct mt7620_spi *ms, int cs, u8 *buf, size_t len)
> > +{
> > + int ret;
> > +
> > + while (len) {
> > + setbits_32(&ms->m[cs]->ctl, START_RD);
> > +
> > + ret = mt7620_spi_busy_poll(ms, cs);
> > + if (ret) {
> > + pr_err("SPI read transaction timeout\n");
> > + return ret;
> > + }
> > +
> > + *buf++ = (u8)readl(&ms->m[cs]->data);
> > +
> > + len--;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int mt7620_spi_write(struct mt7620_spi *ms, int cs, const u8 *buf,
> > + size_t len)
> > +{
> > + int ret;
> > +
> > + while (len) {
> > + writel(*buf++, &ms->m[cs]->data);
> > + setbits_32(&ms->m[cs]->ctl, START_WR);
> > +
> > + ret = mt7620_spi_busy_poll(ms, cs);
> > + if (ret) {
> > + pr_err("SPI write transaction timeout\n");
> > + return ret;
> > + }
> > +
> > + len--;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int mt7620_spi_xfer(struct udevice *dev, unsigned int bitlen,
> > + const void *dout, void *din, unsigned long flags)
> > +{
> > + struct udevice *bus = dev->parent;
> > + struct mt7620_spi *ms = dev_get_priv(bus);
> > + int total_size = bitlen >> 3;
> > + int cs, ret = 0;
> > +
> > + /*
> > + * This driver only supports half-duplex, so complain and bail out
> > + * upon full-duplex messages
> > + */
> > + if (dout && din) {
> > + pr_err("Only half-duplex SPI transfer supported\n");
> > + return -EIO;
> > + }
> > +
> > + cs = spi_chip_select(dev);
> > + if (cs < 0 || cs >= MT7620_SPI_NUM_CS) {
> > + pr_err("Invalid chip select %d\n", cs);
> > + return -EINVAL;
> > + }
> > +
> > + if (flags & SPI_XFER_BEGIN)
> > + mt7620_spi_set_cs(ms, cs, 1);
>
> use boolean type for last argument.
ok.
>
> > +
> > + if (din)
> > + ret = mt7620_spi_read(ms, cs, din, total_size);
> > + else if (dout)
> > + ret = mt7620_spi_write(ms, cs, dout, total_size);
> > +
> > + if (flags & SPI_XFER_END)
> > + mt7620_spi_set_cs(ms, cs, 0);
>
> same as above.
More information about the U-Boot
mailing list