diff options
Diffstat (limited to 'drivers/i2c/meson_i2c.c')
| -rw-r--r-- | drivers/i2c/meson_i2c.c | 263 |
1 files changed, 263 insertions, 0 deletions
diff --git a/drivers/i2c/meson_i2c.c b/drivers/i2c/meson_i2c.c new file mode 100644 index 00000000000..2434d9ed538 --- /dev/null +++ b/drivers/i2c/meson_i2c.c @@ -0,0 +1,263 @@ +/* + * (C) Copyright 2017 - Beniamino Galvani <b.galvani@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 + +/* 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; +}; + +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; +} + +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); + + 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; + } + + 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), + .ops = &meson_i2c_ops, +}; |