[PATCH v4 5/6] lib: utils/i2c: Add minimal SiFive I2C driver
Anup Patel
anup at brainfault.org
Thu Nov 11 21:06:50 PST 2021
On Wed, Nov 10, 2021 at 3:12 PM Nikita Shubin <nikita.shubin at maquefel.me> wrote:
>
> From: Nikita Shubin <n.shubin at yadro.com>
>
> Minimum SiFive I2C driver to read/send bytes over I2C bus.
>
> This allows querying information and perform operation of onboard PMIC,
> as well as power-off and reset.
>
> Tested-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
> Reviewed-by: Alexandre Ghiti <alexandre.ghiti at canonical.com>
> Tested-by: Alexandre Ghiti <alexandre.ghiti at canonical.com>
> Signed-off-by: Nikita Shubin <n.shubin at yadro.com>
Quite a few lines in this patch were crossing 80 characters so I
have updated these lines at time of merging this patch.
Applied this patch to the riscv/opensbi repo.
Thanks,
Anup
> ---
> lib/utils/i2c/fdt_i2c.c | 3 +
> lib/utils/i2c/fdt_i2c_sifive.c | 262 +++++++++++++++++++++++++++++++++
> lib/utils/i2c/objects.mk | 1 +
> 3 files changed, 266 insertions(+)
> create mode 100644 lib/utils/i2c/fdt_i2c_sifive.c
>
> diff --git a/lib/utils/i2c/fdt_i2c.c b/lib/utils/i2c/fdt_i2c.c
> index 3182f56..d4ec6a3 100644
> --- a/lib/utils/i2c/fdt_i2c.c
> +++ b/lib/utils/i2c/fdt_i2c.c
> @@ -18,7 +18,10 @@
>
> #include <sbi/sbi_console.h>
>
> +extern struct fdt_i2c_adapter fdt_i2c_adapter_sifive;
> +
> static struct fdt_i2c_adapter *i2c_adapter_drivers[] = {
> + &fdt_i2c_adapter_sifive
> };
>
> static int fdt_i2c_adapter_init(void *fdt, int nodeoff)
> diff --git a/lib/utils/i2c/fdt_i2c_sifive.c b/lib/utils/i2c/fdt_i2c_sifive.c
> new file mode 100644
> index 0000000..404eda4
> --- /dev/null
> +++ b/lib/utils/i2c/fdt_i2c_sifive.c
> @@ -0,0 +1,262 @@
> +/*
> + * SPDX-License-Identifier: BSD-2-Clause
> + *
> + * Copyright (c) 2021 YADRO
> + *
> + * Authors:
> + * Nikita Shubin <n.shubin at yadro.com>
> + */
> +
> +#include <sbi/riscv_io.h>
> +#include <sbi/sbi_error.h>
> +#include <sbi/sbi_timer.h>
> +#include <sbi_utils/fdt/fdt_helper.h>
> +#include <sbi_utils/i2c/fdt_i2c.h>
> +
> +#define SIFIVE_I2C_ADAPTER_MAX 2
> +
> +#define SIFIVE_I2C_PRELO 0x00
> +#define SIFIVE_I2C_PREHI 0x04
> +#define SIFIVE_I2C_CTR 0x08
> +#define SIFIVE_I2C_TXR 0x00c
> +#define SIFIVE_I2C_RXR SIFIVE_I2C_TXR
> +#define SIFIVE_I2C_CR 0x010
> +#define SIFIVE_I2C_SR SIFIVE_I2C_CR
> +
> +#define SIFIVE_I2C_CTR_IEN (1 << 6)
> +#define SIFIVE_I2C_CTR_EN (1 << 7)
> +
> +#define SIFIVE_I2C_CMD_IACK (1 << 0)
> +#define SIFIVE_I2C_CMD_ACK (1 << 3)
> +#define SIFIVE_I2C_CMD_WR (1 << 4)
> +#define SIFIVE_I2C_CMD_RD (1 << 5)
> +#define SIFIVE_I2C_CMD_STO (1 << 6)
> +#define SIFIVE_I2C_CMD_STA (1 << 7)
> +
> +#define SIFIVE_I2C_STATUS_IF (1 << 0)
> +#define SIFIVE_I2C_STATUS_TIP (1 << 1)
> +#define SIFIVE_I2C_STATUS_AL (1 << 5)
> +#define SIFIVE_I2C_STATUS_BUSY (1 << 6)
> +#define SIFIVE_I2C_STATUS_RXACK (1 << 7)
> +
> +#define SIFIVE_I2C_WRITE_BIT (0 << 0)
> +#define SIFIVE_I2C_READ_BIT (1 << 0)
> +
> +struct sifive_i2c_adapter {
> + unsigned long addr;
> + struct i2c_adapter adapter;
> +};
> +
> +static unsigned int sifive_i2c_adapter_count;
> +static struct sifive_i2c_adapter sifive_i2c_adapter_array[SIFIVE_I2C_ADAPTER_MAX];
> +
> +extern struct fdt_i2c_adapter fdt_i2c_adapter_sifive;
> +
> +static inline void sifive_i2c_setreg(struct sifive_i2c_adapter *adap,
> + uint8_t reg, uint8_t value)
> +{
> + writel(value, (volatile void *)adap->addr + reg);
> +}
> +
> +static inline uint8_t sifive_i2c_getreg(struct sifive_i2c_adapter *adap,
> + uint8_t reg)
> +{
> + return readl((volatile void *)adap->addr + reg);
> +}
> +
> +static int sifive_i2c_adapter_rxack(struct sifive_i2c_adapter *adap)
> +{
> + uint8_t val = sifive_i2c_getreg(adap, SIFIVE_I2C_SR);
> +
> + if (val & SIFIVE_I2C_STATUS_RXACK)
> + return SBI_EIO;
> +
> + return 0;
> +}
> +
> +static int sifive_i2c_adapter_poll(struct sifive_i2c_adapter *adap, uint32_t mask)
> +{
> + unsigned int timeout = 1; // [msec]
> + int count = 0;
> + uint8_t val;
> +
> + sbi_timer_udelay(80); // worst case if bus speed is 100 kHz
> +
> + do {
> + val = sifive_i2c_getreg(adap, SIFIVE_I2C_SR);
> + if (!(val & mask))
> + return 0;
> +
> + sbi_timer_udelay(1);
> + count += 1;
> + if (count == (timeout * 1000))
> + return SBI_ETIMEDOUT;
> + } while (1);
> +}
> +
> +#define sifive_i2c_adapter_poll_tip(adap) sifive_i2c_adapter_poll(adap, SIFIVE_I2C_STATUS_TIP)
> +#define sifive_i2c_adapter_poll_busy(adap) sifive_i2c_adapter_poll(adap, SIFIVE_I2C_STATUS_BUSY)
> +
> +static int sifive_i2c_adapter_start(struct sifive_i2c_adapter *adap, uint8_t addr, uint8_t bit)
> +{
> + uint8_t val = (addr << 1) | bit;
> +
> + sifive_i2c_setreg(adap, SIFIVE_I2C_TXR, val);
> + val = SIFIVE_I2C_CMD_STA | SIFIVE_I2C_CMD_WR | SIFIVE_I2C_CMD_IACK;
> + sifive_i2c_setreg(adap, SIFIVE_I2C_CR, val);
> +
> + return sifive_i2c_adapter_poll_tip(adap);
> +}
> +
> +static int sifive_i2c_adapter_write(struct i2c_adapter *ia, uint8_t addr,
> + uint8_t reg, uint8_t *buffer, int len)
> +{
> + struct sifive_i2c_adapter *adap =
> + container_of(ia, struct sifive_i2c_adapter, adapter);
> + int rc = sifive_i2c_adapter_start(adap, addr, SIFIVE_I2C_WRITE_BIT);
> +
> + if (rc)
> + return rc;
> +
> + rc = sifive_i2c_adapter_rxack(adap);
> + if (rc)
> + return rc;
> +
> + /* set register address */
> + sifive_i2c_setreg(adap, SIFIVE_I2C_TXR, reg);
> + sifive_i2c_setreg(adap, SIFIVE_I2C_CR, SIFIVE_I2C_CMD_WR | SIFIVE_I2C_CMD_IACK);
> + rc = sifive_i2c_adapter_poll_tip(adap);
> + if (rc)
> + return rc;
> +
> + rc = sifive_i2c_adapter_rxack(adap);
> + if (rc)
> + return rc;
> +
> + /* set value */
> + while (len) {
> + sifive_i2c_setreg(adap, SIFIVE_I2C_TXR, *buffer);
> + sifive_i2c_setreg(adap, SIFIVE_I2C_CR, SIFIVE_I2C_CMD_WR | SIFIVE_I2C_CMD_IACK);
> +
> + rc = sifive_i2c_adapter_poll_tip(adap);
> + if (rc)
> + return rc;
> +
> + rc = sifive_i2c_adapter_rxack(adap);
> + if (rc)
> + return rc;
> +
> + buffer++;
> + len--;
> + }
> +
> + sifive_i2c_setreg(adap, SIFIVE_I2C_CR, SIFIVE_I2C_CMD_STO | SIFIVE_I2C_CMD_IACK);
> +
> + /* poll BUSY instead of ACK*/
> + rc = sifive_i2c_adapter_poll_busy(adap);
> + if (rc)
> + return rc;
> +
> + sifive_i2c_setreg(adap, SIFIVE_I2C_CR, SIFIVE_I2C_CMD_IACK);
> +
> + return 0;
> +}
> +
> +static int sifive_i2c_adapter_read(struct i2c_adapter *ia, uint8_t addr,
> + uint8_t reg, uint8_t *buffer, int len)
> +{
> + struct sifive_i2c_adapter *adap =
> + container_of(ia, struct sifive_i2c_adapter, adapter);
> + int rc;
> +
> + rc = sifive_i2c_adapter_start(adap, addr, SIFIVE_I2C_WRITE_BIT);
> + if (rc)
> + return rc;
> +
> + rc = sifive_i2c_adapter_rxack(adap);
> + if (rc)
> + return rc;
> +
> + sifive_i2c_setreg(adap, SIFIVE_I2C_TXR, reg);
> + sifive_i2c_setreg(adap, SIFIVE_I2C_CR, SIFIVE_I2C_CMD_WR | SIFIVE_I2C_CMD_IACK);
> +
> + rc = sifive_i2c_adapter_poll_tip(adap);
> + if (rc)
> + return rc;
> +
> + rc = sifive_i2c_adapter_rxack(adap);
> + if (rc)
> + return rc;
> +
> + /* setting addr with high 0 bit */
> + rc = sifive_i2c_adapter_start(adap, addr, SIFIVE_I2C_READ_BIT);
> + if (rc)
> + return rc;
> +
> + rc = sifive_i2c_adapter_rxack(adap);
> + if (rc)
> + return rc;
> +
> + while (len) {
> + if (len == 1)
> + sifive_i2c_setreg(adap, SIFIVE_I2C_CR, SIFIVE_I2C_CMD_ACK | SIFIVE_I2C_CMD_RD | SIFIVE_I2C_CMD_IACK);
> + else
> + sifive_i2c_setreg(adap, SIFIVE_I2C_CR, SIFIVE_I2C_CMD_RD | SIFIVE_I2C_CMD_IACK);
> +
> + rc = sifive_i2c_adapter_poll_tip(adap);
> + if (rc)
> + return rc;
> +
> + *buffer = sifive_i2c_getreg(adap, SIFIVE_I2C_RXR);
> + buffer++;
> + len--;
> + }
> +
> + sifive_i2c_setreg(adap, SIFIVE_I2C_CR, SIFIVE_I2C_CMD_STO | SIFIVE_I2C_CMD_IACK);
> + rc = sifive_i2c_adapter_poll_busy(adap);
> + if (rc)
> + return rc;
> +
> + sifive_i2c_setreg(adap, SIFIVE_I2C_CR, SIFIVE_I2C_CMD_IACK);
> +
> + return 0;
> +}
> +
> +static int sifive_i2c_init(void *fdt, int nodeoff,
> + const struct fdt_match *match)
> +{
> + int rc;
> + struct sifive_i2c_adapter *adapter;
> + uint64_t addr;
> +
> + if (sifive_i2c_adapter_count >= SIFIVE_I2C_ADAPTER_MAX)
> + return SBI_ENOSPC;
> +
> + adapter = &sifive_i2c_adapter_array[sifive_i2c_adapter_count];
> +
> + rc = fdt_get_node_addr_size(fdt, nodeoff, 0, &addr, NULL);
> + if (rc)
> + return rc;
> +
> + adapter->addr = addr;
> + adapter->adapter.driver = &fdt_i2c_adapter_sifive;
> + adapter->adapter.id = nodeoff;
> + adapter->adapter.write = sifive_i2c_adapter_write;
> + adapter->adapter.read = sifive_i2c_adapter_read;
> + rc = i2c_adapter_add(&adapter->adapter);
> + if (rc)
> + return rc;
> +
> + sifive_i2c_adapter_count++;
> + return 0;
> +}
> +
> +static const struct fdt_match sifive_i2c_match[] = {
> + { .compatible = "sifive,i2c0" },
> + { },
> +};
> +
> +struct fdt_i2c_adapter fdt_i2c_adapter_sifive = {
> + .match_table = sifive_i2c_match,
> + .init = sifive_i2c_init,
> +};
> diff --git a/lib/utils/i2c/objects.mk b/lib/utils/i2c/objects.mk
> index 06baa65..d52ab18 100644
> --- a/lib/utils/i2c/objects.mk
> +++ b/lib/utils/i2c/objects.mk
> @@ -9,3 +9,4 @@
>
> libsbiutils-objs-y += i2c/i2c.o
> libsbiutils-objs-y += i2c/fdt_i2c.o
> +libsbiutils-objs-y += i2c/fdt_i2c_sifive.o
> --
> 2.31.1
>
>
> --
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