Hi Benjamin,
On 29 October 2017 at 03:09, Beniamino Galvani <b.galv...@gmail.com> wrote:
>
> Add a driver for the I2C controller available on Amlogic Meson SoCs.
>
> Signed-off-by: Beniamino Galvani <b.galv...@gmail.com>
> ---
> arch/arm/include/asm/arch-meson/i2c.h | 11 ++
> drivers/i2c/Kconfig | 6 +
> drivers/i2c/Makefile | 1 +
> drivers/i2c/meson_i2c.c | 263
> ++++++++++++++++++++++++++++++++++
> 4 files changed, 281 insertions(+)
> create mode 100644 arch/arm/include/asm/arch-meson/i2c.h
> create mode 100644 drivers/i2c/meson_i2c.c
Reviewed-by: Simon Glass <s...@chromium.org>
But please look at the comments below.
>
> diff --git a/arch/arm/include/asm/arch-meson/i2c.h
> b/arch/arm/include/asm/arch-meson/i2c.h
> new file mode 100644
> index 0000000000..783bc3786f
> --- /dev/null
> +++ b/arch/arm/include/asm/arch-meson/i2c.h
> @@ -0,0 +1,11 @@
> +/*
> + * Copyright 2017 - Beniamino Galvani <b.galv...@gmail.com>
> + *
> + * SPDX-License-Identifier: GPL-2.0+
> + */
> +#ifndef _MESON_I2C_H_
> +#define _MESON_I2C_H_
> +
> +#define MESON_I2C_CLK_RATE 167000000
> +
> +#endif
> diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig
> index c296985d9b..1989f8eb57 100644
> --- a/drivers/i2c/Kconfig
> +++ b/drivers/i2c/Kconfig
> @@ -137,6 +137,12 @@ config SYS_I2C_IMX_LPI2C
> help
> Add support for the NXP i.MX LPI2C driver.
>
> +config SYS_I2C_MESON
> + bool "Amlogic Meson I2C driver"
> + depends on DM_I2C && ARCH_MESON
> + help
> + Add support for the Amlogic Meson I2C driver.
Any more details on this? What features does that hardware and your
driver support?
> +
> config SYS_I2C_MXC
> bool "NXP i.MX I2C driver"
> depends on MX6
> diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile
> index 3a8c61b485..733cd3e92f 100644
> --- a/drivers/i2c/Makefile
> +++ b/drivers/i2c/Makefile
> @@ -25,6 +25,7 @@ obj-$(CONFIG_SYS_I2C_INTEL) += intel_i2c.o
> obj-$(CONFIG_SYS_I2C_IMX_LPI2C) += imx_lpi2c.o
> obj-$(CONFIG_SYS_I2C_KONA) += kona_i2c.o
> obj-$(CONFIG_SYS_I2C_LPC32XX) += lpc32xx_i2c.o
> +obj-$(CONFIG_SYS_I2C_MESON) += meson_i2c.o
> obj-$(CONFIG_SYS_I2C_MVTWSI) += mvtwsi.o
> obj-$(CONFIG_SYS_I2C_MXC) += mxc_i2c.o
> obj-$(CONFIG_SYS_I2C_MXS) += mxs_i2c.o
> diff --git a/drivers/i2c/meson_i2c.c b/drivers/i2c/meson_i2c.c
> new file mode 100644
> index 0000000000..2434d9ed53
> --- /dev/null
> +++ b/drivers/i2c/meson_i2c.c
> @@ -0,0 +1,263 @@
> +/*
> + * (C) Copyright 2017 - Beniamino Galvani <b.galv...@gmail.com>
> + *
> + * SPDX-License-Identifier: GPL-2.0+
> + */
> +#include <common.h>
> +#include <asm/arch/i2c.h>
> +#include <asm/io.h>
> +#include <dm.h>
> +#include <i2c.h>
> +
> +#define I2C_TIMEOUT_MS 500
Wow that is a long time. Does it really take that long to fail>
> +
> +/* Control register fields */
> +#define REG_CTRL_START BIT(0)
> +#define REG_CTRL_ACK_IGNORE BIT(1)
> +#define REG_CTRL_STATUS BIT(2)
> +#define REG_CTRL_ERROR BIT(3)
> +#define REG_CTRL_CLKDIV_SHIFT 12
> +#define REG_CTRL_CLKDIV_MASK GENMASK(21, 12)
> +#define REG_CTRL_CLKDIVEXT_SHIFT 28
> +#define REG_CTRL_CLKDIVEXT_MASK GENMASK(29, 28)
> +
> +enum {
> + TOKEN_END = 0,
> + TOKEN_START,
> + TOKEN_SLAVE_ADDR_WRITE,
> + TOKEN_SLAVE_ADDR_READ,
> + TOKEN_DATA,
> + TOKEN_DATA_LAST,
> + TOKEN_STOP,
> +};
> +
> +struct i2c_regs {
> + u32 ctrl;
> + u32 slave_addr;
> + u32 tok_list0;
> + u32 tok_list1;
> + u32 tok_wdata0;
> + u32 tok_wdata1;
> + u32 tok_rdata0;
> + u32 tok_rdata1;
> +};
> +
> +struct meson_i2c {
> + struct i2c_regs *regs;
> + struct i2c_msg *msg;
> + bool last;
> + uint count;
> + uint pos;
> + u32 tokens[2];
> + uint num_tokens;
> +};
This struct could use some comments
> +
> +static void meson_i2c_reset_tokens(struct meson_i2c *i2c)
> +{
> + i2c->tokens[0] = 0;
> + i2c->tokens[1] = 0;
> + i2c->num_tokens = 0;
> +}
> +
> +static void meson_i2c_add_token(struct meson_i2c *i2c, int token)
> +{
> + if (i2c->num_tokens < 8)
> + i2c->tokens[0] |= (token & 0xf) << (i2c->num_tokens * 4);
> + else
> + i2c->tokens[1] |= (token & 0xf) << ((i2c->num_tokens % 8) *
> 4);
> +
> + i2c->num_tokens++;
> +}
> +
> +static void meson_i2c_get_data(struct meson_i2c *i2c, u8 *buf, int len)
> +{
> + u32 rdata0, rdata1;
> + int i;
> +
> + rdata0 = readl(&i2c->regs->tok_rdata0);
> + rdata1 = readl(&i2c->regs->tok_rdata1);
> +
> + debug("meson i2c: read data %08x %08x len %d\n", rdata0, rdata1, len);
> +
> + for (i = 0; i < min(4, len); i++)
> + *buf++ = (rdata0 >> i * 8) & 0xff;
> +
> + for (i = 4; i < min(8, len); i++)
> + *buf++ = (rdata1 >> (i - 4) * 8) & 0xff;
I don't really understand this function. If len is >= 8, what happens?
I think you should add a comment to this function describing what it
does and what the args mean.
> +}
> +
> +static void meson_i2c_put_data(struct meson_i2c *i2c, u8 *buf, int len)
> +{
> + u32 wdata0 = 0, wdata1 = 0;
> + int i;
> +
> + for (i = 0; i < min(4, len); i++)
> + wdata0 |= *buf++ << (i * 8);
> +
> + for (i = 4; i < min(8, len); i++)
> + wdata1 |= *buf++ << ((i - 4) * 8);
Same with this function.
> +
> + writel(wdata0, &i2c->regs->tok_wdata0);
> + writel(wdata1, &i2c->regs->tok_wdata1);
> +
> + debug("meson i2c: write data %08x %08x len %d\n", wdata0, wdata1,
> len);
> +}
> +
> +static void meson_i2c_prepare_xfer(struct meson_i2c *i2c)
> +{
> + bool write = !(i2c->msg->flags & I2C_M_RD);
> + int i;
> +
> + i2c->count = min(i2c->msg->len - i2c->pos, 8u);
> +
> + for (i = 0; i + 1 < i2c->count; i++)
> + meson_i2c_add_token(i2c, TOKEN_DATA);
> +
> + if (i2c->count) {
> + if (write || i2c->pos + i2c->count < i2c->msg->len)
> + meson_i2c_add_token(i2c, TOKEN_DATA);
> + else
> + meson_i2c_add_token(i2c, TOKEN_DATA_LAST);
> + }
> +
> + if (write)
> + meson_i2c_put_data(i2c, i2c->msg->buf + i2c->pos, i2c->count);
> +
> + if (i2c->last && i2c->pos + i2c->count >= i2c->msg->len)
> + meson_i2c_add_token(i2c, TOKEN_STOP);
> +
> + writel(i2c->tokens[0], &i2c->regs->tok_list0);
> + writel(i2c->tokens[1], &i2c->regs->tok_list1);
> +}
> +
> +static void meson_i2c_do_start(struct meson_i2c *i2c, struct i2c_msg *msg)
> +{
> + int token;
> +
> + token = (msg->flags & I2C_M_RD) ? TOKEN_SLAVE_ADDR_READ :
> + TOKEN_SLAVE_ADDR_WRITE;
> +
> + writel(msg->addr << 1, &i2c->regs->slave_addr);
> + meson_i2c_add_token(i2c, TOKEN_START);
> + meson_i2c_add_token(i2c, token);
> +}
> +
> +static int meson_i2c_xfer_msg(struct meson_i2c *i2c, struct i2c_msg *msg,
> + int last)
> +{
> + ulong start;
> +
> + debug("meson i2c: %s addr %u len %u\n",
> + (msg->flags & I2C_M_RD) ? "read" : "write",
> + msg->addr, msg->len);
> +
> + i2c->msg = msg;
> + i2c->last = last;
> + i2c->pos = 0;
> + i2c->count = 0;
> +
> + meson_i2c_reset_tokens(i2c);
> + meson_i2c_do_start(i2c, msg);
> +
> + do {
> + meson_i2c_prepare_xfer(i2c);
> +
> + /* start the transfer */
> + setbits_le32(&i2c->regs->ctrl, REG_CTRL_START);
> + start = get_timer(0);
> + while (readl(&i2c->regs->ctrl) & REG_CTRL_STATUS) {
> + if (get_timer(start) > I2C_TIMEOUT_MS) {
> + clrbits_le32(&i2c->regs->ctrl,
> REG_CTRL_START);
> + debug("meson i2c: timeout\n");
> + return -ETIMEDOUT;
> + }
> + udelay(1);
> + }
> + meson_i2c_reset_tokens(i2c);
> + clrbits_le32(&i2c->regs->ctrl, REG_CTRL_START);
> +
> + if (readl(&i2c->regs->ctrl) & REG_CTRL_ERROR) {
> + debug("meson i2c: error\n");
> + return -ENXIO;
> + }
> +
> + if ((msg->flags & I2C_M_RD) && i2c->count) {
> + meson_i2c_get_data(i2c, i2c->msg->buf + i2c->pos,
> + i2c->count);
> + }
> + i2c->pos += i2c->count;
> + } while (i2c->pos < msg->len);
> +
> + return 0;
> +}
> +
> +static int meson_i2c_xfer(struct udevice *bus, struct i2c_msg *msg,
> + int nmsgs)
> +{
> + struct meson_i2c *i2c = dev_get_priv(bus);
> + int i, ret = 0;
> +
> + for (i = 0; i < nmsgs; i++) {
> + ret = meson_i2c_xfer_msg(i2c, msg + i, i == nmsgs - 1);
> + if (ret)
> + return -EREMOTEIO;
Why not return ret? We don't normally change the error on the way through.
> + }
> +
> + return 0;
> +}
> +
> +static int meson_i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
> +{
> + struct meson_i2c *i2c = dev_get_priv(bus);
> + unsigned int clk_rate = MESON_I2C_CLK_RATE;
> + unsigned int div;
> +
> + div = DIV_ROUND_UP(clk_rate, speed * 4);
> +
> + /* clock divider has 12 bits */
> + if (div >= (1 << 12)) {
> + debug("meson i2c: requested bus frequency too low\n");
> + div = (1 << 12) - 1;
> + }
> +
> + clrsetbits_le32(&i2c->regs->ctrl, REG_CTRL_CLKDIV_MASK,
> + (div & GENMASK(9, 0)) << REG_CTRL_CLKDIV_SHIFT);
> +
> + clrsetbits_le32(&i2c->regs->ctrl, REG_CTRL_CLKDIVEXT_MASK,
> + (div >> 10) << REG_CTRL_CLKDIVEXT_SHIFT);
> +
> + debug("meson i2c: set clk %u, src %u, div %u\n", speed, clk_rate,
> div);
> +
> + return 0;
> +}
> +
> +static int meson_i2c_probe(struct udevice *bus)
> +{
> + struct meson_i2c *i2c = dev_get_priv(bus);
> +
> + i2c->regs = dev_read_addr_ptr(bus);
> + clrbits_le32(&i2c->regs->ctrl, REG_CTRL_START);
> +
> + return 0;
> +}
> +
> +static const struct dm_i2c_ops meson_i2c_ops = {
> + .xfer = meson_i2c_xfer,
> + .set_bus_speed = meson_i2c_set_bus_speed,
> +};
> +
> +static const struct udevice_id meson_i2c_ids[] = {
> + { .compatible = "amlogic,meson6-i2c" },
> + { .compatible = "amlogic,meson-gx-i2c" },
> + { .compatible = "amlogic,meson-gxbb-i2c" },
> + { }
> +};
> +
> +U_BOOT_DRIVER(i2c_meson) = {
> + .name = "i2c_meson",
> + .id = UCLASS_I2C,
> + .of_match = meson_i2c_ids,
> + .probe = meson_i2c_probe,
> + .priv_auto_alloc_size = sizeof(struct meson_i2c),
I think meson_i2c_priv might be a better name since it indicates that
it is driver-private data. But if you prefer the shorter name, that's
fine with me.
> + .ops = &meson_i2c_ops,
> +};
> --
> 2.13.6
>
Regards,
Simon
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