[U-Boot] [PATCH v5 3/5] i2c: UniPhier: add driver for UniPhier FIFO-builtin i2c controller
Simon Glass
sjg at chromium.org
Tue Jan 13 02:42:52 CET 2015
Hi Masahiro,
On 8 January 2015 at 00:47, Masahiro Yamada <yamada.m at jp.panasonic.com> wrote:
> This commit adds on-chip I2C driver used on newer SoCs of Panasonic
> UniPhier platform.
>
> Signed-off-by: Masahiro Yamada <yamada.m at jp.panasonic.com>
> Reviewed-by: Simon Glass <sjg at chromium.org>
> Acked-by: Heiko Schocher <hs at denx.de>
Acked-by: Simon Glass <sjg at chromium.org>
A few nits below. If you prefer with the last two I can fix them when
applying. The first one you probably don't want to change.
> ---
>
> Changes in v5:
> - Drop unnecessary __packed
>
> Changes in v4:
> - Use a structure instead of macros for register access
>
> Changes in v3:
> - Fix a bug in that device busy is checked even if the stop
> condition is not issued.
>
> Changes in v2:
> - Fix a typo. s/freqency/frequency/
> - Rename the struct member for clarification. s/wait_us/timeout/
> - Add comments on all the registers
> - Skip stop condition if the next message is read
>
> drivers/i2c/Kconfig | 8 +
> drivers/i2c/Makefile | 1 +
> drivers/i2c/i2c-uniphier-f.c | 380 +++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 389 insertions(+)
> create mode 100644 drivers/i2c/i2c-uniphier-f.c
>
> diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig
> index 6a479ef..202ea5d 100644
> --- a/drivers/i2c/Kconfig
> +++ b/drivers/i2c/Kconfig
> @@ -12,3 +12,11 @@ config SYS_I2C_UNIPHIER
> help
> Support for Panasonic UniPhier I2C controller driver. This I2C
> controller is used on PH1-LD4, PH1-sLD8 or older UniPhier SoCs.
> +
> +config SYS_I2C_UNIPHIER_F
> + bool "UniPhier FIFO-builtin I2C driver"
> + depends on ARCH_UNIPHIER && DM_I2C
> + default y
> + help
> + Support for Panasonic UniPhier FIFO-builtin I2C controller driver.
> + This I2C controller is used on PH1-Pro4 or newer UniPhier SoCs.
> diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile
> index e2fcd24..0e4c9f4 100644
> --- a/drivers/i2c/Makefile
> +++ b/drivers/i2c/Makefile
> @@ -32,4 +32,5 @@ obj-$(CONFIG_SYS_I2C_SH) += sh_i2c.o
> obj-$(CONFIG_SYS_I2C_SOFT) += soft_i2c.o
> obj-$(CONFIG_SYS_I2C_TEGRA) += tegra_i2c.o
> obj-$(CONFIG_SYS_I2C_UNIPHIER) += i2c-uniphier.o
> +obj-$(CONFIG_SYS_I2C_UNIPHIER_F) += i2c-uniphier-f.o
> obj-$(CONFIG_SYS_I2C_ZYNQ) += zynq_i2c.o
> diff --git a/drivers/i2c/i2c-uniphier-f.c b/drivers/i2c/i2c-uniphier-f.c
> new file mode 100644
> index 0000000..7bd524c
> --- /dev/null
> +++ b/drivers/i2c/i2c-uniphier-f.c
> @@ -0,0 +1,380 @@
> +/*
> + * Copyright (C) 2014 Panasonic Corporation
> + * Author: Masahiro Yamada <yamada.m at jp.panasonic.com>
> + *
> + * SPDX-License-Identifier: GPL-2.0+
> + */
> +
> +#include <common.h>
> +#include <linux/types.h>
> +#include <asm/io.h>
> +#include <asm/errno.h>
> +#include <dm/device.h>
> +#include <dm/root.h>
> +#include <i2c.h>
> +#include <fdtdec.h>
> +
> +DECLARE_GLOBAL_DATA_PTR;
> +
> +struct uniphier_fi2c_regs {
> + u32 cr; /* control register */
> +#define I2C_CR_MST (1 << 3) /* master mode */
> +#define I2C_CR_STA (1 << 2) /* start condition */
> +#define I2C_CR_STO (1 << 1) /* stop condition */
> +#define I2C_CR_NACK (1 << 0) /* not ACK */
> + u32 dttx; /* send FIFO (write-only) */
> +#define dtrx dttx /* receive FIFO (read-only) */
> +#define I2C_DTTX_CMD (1 << 8) /* send command (slave addr) */
> +#define I2C_DTTX_RD (1 << 0) /* read */
> + u32 __reserved; /* no register at offset 0x08 */
> + u32 slad; /* slave address */
> + u32 cyc; /* clock cycle control */
> + u32 lctl; /* clock low period control */
> + u32 ssut; /* restart/stop setup time control */
> + u32 dsut; /* data setup time control */
> + u32 intr; /* interrupt status */
> + u32 ie; /* interrupt enable */
> + u32 ic; /* interrupt clear */
> +#define I2C_INT_TE (1 << 9) /* TX FIFO empty */
> +#define I2C_INT_RB (1 << 4) /* received specified bytes */
> +#define I2C_INT_NA (1 << 2) /* no answer */
> +#define I2C_INT_AL (1 << 1) /* arbitration lost */
> + u32 sr; /* status register */
> +#define I2C_SR_DB (1 << 12) /* device busy */
> +#define I2C_SR_BB (1 << 8) /* bus busy */
> +#define I2C_SR_RFF (1 << 3) /* Rx FIFO full */
> +#define I2C_SR_RNE (1 << 2) /* Rx FIFO not empty */
> +#define I2C_SR_TNF (1 << 1) /* Tx FIFO not full */
> +#define I2C_SR_TFE (1 << 0) /* Tx FIFO empty */
> + u32 __reserved2; /* no register at offset 0x30 */
> + u32 rst; /* reset control */
> +#define I2C_RST_TBRST (1 << 2) /* clear Tx FIFO */
> +#define I2C_RST_RBRST (1 << 1) /* clear Rx FIFO */
> +#define I2C_RST_RST (1 << 0) /* forcible bus reset */
> + u32 bm; /* bus monitor */
> + u32 noise; /* noise filter control */
> + u32 tbc; /* Tx byte count setting */
> + u32 rbc; /* Rx byte count setting */
> + u32 tbcm; /* Tx byte count monitor */
> + u32 rbcm; /* Rx byte count monitor */
> + u32 brst; /* bus reset */
> +#define I2C_BRST_FOEN (1 << 1) /* normal operation */
> +#define I2C_BRST_RSCLO (1 << 0) /* release SCL low fixing */
> +};
> +
> +#define FIOCLK 50000000
> +
> +struct uniphier_fi2c_dev {
> + struct uniphier_fi2c_regs __iomem *regs; /* register base */
> + unsigned long fioclk; /* internal operation clock */
> + unsigned long timeout; /* time out (us) */
> +};
> +
> +static int poll_status(u32 __iomem *reg, u32 flag)
> +{
> + int wait = 1000000; /* 1 sec */
> +
> + while (readl(reg) & flag) {
> + if (wait-- < 0)
> + return -EREMOTEIO;
> + udelay(1);
> + }
> +
> + return 0;
> +}
> +
> +static int reset_bus(struct uniphier_fi2c_dev *dev)
Optional - you could pass struct uniphier_fi2c_regs to this function
and the next.
> +{
> + int ret;
> +
> + /* bus forcible reset */
> + writel(I2C_RST_RST, &dev->regs->rst);
> + ret = poll_status(&dev->regs->rst, I2C_RST_RST);
> + if (ret < 0)
> + debug("error: fail to reset I2C controller\n");
> +
> + return ret;
> +}
> +
> +static int check_device_busy(struct uniphier_fi2c_dev *dev)
> +{
> + int ret;
> +
> + ret = poll_status(&dev->regs->sr, I2C_SR_DB);
> + if (ret < 0) {
> + debug("error: device busy too long. reset...\n");
> + ret = reset_bus(dev);
> + }
> +
> + return ret;
> +}
> +
> +static int uniphier_fi2c_probe(struct udevice *dev)
> +{
> + fdt_addr_t addr;
> + fdt_size_t size;
> + struct uniphier_fi2c_dev *priv = dev_get_priv(dev);
> + int ret;
> +
> + addr = fdtdec_get_addr_size(gd->fdt_blob, dev->of_offset, "reg",
> + &size);
> +
> + priv->regs = map_sysmem(addr, size);
> +
> + if (!priv->regs)
> + return -ENOMEM;
> +
> + priv->fioclk = FIOCLK;
> +
> + /* bus forcible reset */
> + ret = reset_bus(priv);
> + if (ret < 0)
> + return ret;
> +
> + writel(I2C_BRST_FOEN | I2C_BRST_RSCLO, &priv->regs->brst);
> +
> + return 0;
> +}
> +
> +static int uniphier_fi2c_remove(struct udevice *dev)
> +{
> + struct uniphier_fi2c_dev *priv = dev_get_priv(dev);
> +
> + unmap_sysmem(priv->regs);
> +
> + return 0;
> +}
> +
> +static int uniphier_fi2c_child_pre_probe(struct udevice *dev)
> +{
> + struct dm_i2c_chip *i2c_chip = dev_get_parentdata(dev);
> +
> + if (dev->of_offset == -1)
> + return 0;
> + return i2c_chip_ofdata_to_platdata(gd->fdt_blob, dev->of_offset,
> + i2c_chip);
> +}
> +
> +static int wait_for_irq(struct uniphier_fi2c_dev *dev, u32 flags,
> + bool *stop)
> +{
> + u32 irq;
> + unsigned long wait = dev->timeout;
> + int ret = -EREMOTEIO;
> +
> + do {
> + udelay(1);
> + irq = readl(&dev->regs->intr);
> + } while (!(irq & flags) && wait--);
> +
> + if (wait < 0) {
> + debug("error: time out\n");
> + return ret;
> + }
> +
> + if (irq & I2C_INT_AL) {
> + debug("error: arbitration lost\n");
> + *stop = false;
> + return ret;
> + }
> +
> + if (irq & I2C_INT_NA) {
> + debug("error: no answer\n");
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +int issue_stop(struct uniphier_fi2c_dev *dev, int old_ret)
static?
> +{
> + int ret;
> +
> + debug("stop condition\n");
> + writel(I2C_CR_MST | I2C_CR_STO, &dev->regs->cr);
> +
> + ret = poll_status(&dev->regs->sr, I2C_SR_DB);
> + if (ret < 0)
> + debug("error: device busy after operation\n");
> +
> + return old_ret ? old_ret : ret;
> +}
> +
> +static int uniphier_fi2c_transmit(struct uniphier_fi2c_dev *dev, uint addr,
> + uint len, const u8 *buf, bool *stop)
> +{
> + int ret;
> + const u32 irq_flags = I2C_INT_TE | I2C_INT_NA | I2C_INT_AL;
> + struct uniphier_fi2c_regs __iomem *regs = dev->regs;
> +
> + debug("%s: addr = %x, len = %d\n", __func__, addr, len);
> +
> + writel(I2C_DTTX_CMD | addr << 1, ®s->dttx);
> +
> + writel(irq_flags, ®s->ie);
> + writel(irq_flags, ®s->ic);
> +
> + debug("start condition\n");
> + writel(I2C_CR_MST | I2C_CR_STA, ®s->cr);
> +
> + ret = wait_for_irq(dev, irq_flags, stop);
> + if (ret < 0)
> + goto error;
> +
> + while (len--) {
> + debug("sending %x\n", *buf);
> + writel(*buf++, ®s->dttx);
> +
> + writel(irq_flags, ®s->ic);
> +
> + ret = wait_for_irq(dev, irq_flags, stop);
> + if (ret < 0)
> + goto error;
> + }
> +
> +error:
> + writel(irq_flags, ®s->ic);
> +
> + if (*stop)
> + ret = issue_stop(dev, ret);
> +
> + return ret;
> +}
> +
> +static int uniphier_fi2c_receive(struct uniphier_fi2c_dev *dev, uint addr,
> + uint len, u8 *buf, bool *stop)
> +{
> + int ret = 0;
> + const u32 irq_flags = I2C_INT_RB | I2C_INT_NA | I2C_INT_AL;
> + struct uniphier_fi2c_regs __iomem *regs = dev->regs;
> +
> + debug("%s: addr = %x, len = %d\n", __func__, addr, len);
> +
> + /*
> + * In case 'len == 0', only the slave address should be sent
> + * for probing, which is covered by the transmit function.
> + */
> + if (len == 0)
> + return uniphier_fi2c_transmit(dev, addr, len, buf, stop);
> +
> + writel(I2C_DTTX_CMD | I2C_DTTX_RD | addr << 1, ®s->dttx);
> +
> + writel(0, ®s->rbc);
> + writel(irq_flags, ®s->ie);
> + writel(irq_flags, ®s->ic);
> +
> + debug("start condition\n");
> + writel(I2C_CR_MST | I2C_CR_STA | (len == 1 ? I2C_CR_NACK : 0),
> + ®s->cr);
> +
> + while (len--) {
> + ret = wait_for_irq(dev, irq_flags, stop);
> + if (ret < 0)
> + goto error;
> +
> + *buf++ = readl(®s->dtrx);
> + debug("received %x\n", *(buf - 1));
> +
> + if (len == 1)
> + writel(I2C_CR_MST | I2C_CR_NACK, ®s->cr);
> +
> + writel(irq_flags, ®s->ic);
> + }
> +
> +error:
> + writel(irq_flags, ®s->ic);
> +
> + if (*stop)
> + ret = issue_stop(dev, ret);
> +
> + return ret;
> +}
> +
> +static int uniphier_fi2c_xfer(struct udevice *bus, struct i2c_msg *msg,
> + int nmsgs)
> +{
> + int ret;
> + struct uniphier_fi2c_dev *dev = dev_get_priv(bus);
> + bool stop;
> +
extra blank line
> +
> + ret = check_device_busy(dev);
> + if (ret < 0)
> + return ret;
> +
> + for (; nmsgs > 0; nmsgs--, msg++) {
> + /* If next message is read, skip the stop condition */
> + stop = nmsgs > 1 && msg[1].flags & I2C_M_RD ? false : true;
> +
> + if (msg->flags & I2C_M_RD)
> + ret = uniphier_fi2c_receive(dev, msg->addr, msg->len,
> + msg->buf, &stop);
> + else
> + ret = uniphier_fi2c_transmit(dev, msg->addr, msg->len,
> + msg->buf, &stop);
> +
> + if (ret < 0)
> + break;
> + }
> +
> + return ret;
> +}
> +
> +static int uniphier_fi2c_set_bus_speed(struct udevice *bus, unsigned int speed)
> +{
> + int ret;
> + unsigned int clk_count;
> + struct uniphier_fi2c_dev *dev = dev_get_priv(bus);
> + struct uniphier_fi2c_regs __iomem *regs = dev->regs;
> +
> + /* max supported frequency is 400 kHz */
> + if (speed > 400000)
> + return -EINVAL;
> +
> + ret = check_device_busy(dev);
> + if (ret < 0)
> + return ret;
> +
> + /* make sure the bus is idle when changing the frequency */
> + writel(I2C_BRST_RSCLO, ®s->brst);
> +
> + clk_count = dev->fioclk / speed;
> +
> + writel(clk_count, ®s->cyc);
> + writel(clk_count / 2, ®s->lctl);
> + writel(clk_count / 2, ®s->ssut);
> + writel(clk_count / 16, ®s->dsut);
> +
> + writel(I2C_BRST_FOEN | I2C_BRST_RSCLO, ®s->brst);
> +
> + /*
> + * Theoretically, each byte can be transferred in
> + * 1000000 * 9 / speed usec.
> + * This time out value is long enough.
> + */
> + dev->timeout = 100000000L / speed;
> +
> + return 0;
> +}
> +
> +static const struct dm_i2c_ops uniphier_fi2c_ops = {
> + .xfer = uniphier_fi2c_xfer,
> + .set_bus_speed = uniphier_fi2c_set_bus_speed,
> +};
> +
> +static const struct udevice_id uniphier_fi2c_of_match[] = {
> + { .compatible = "panasonic,uniphier-fi2c" },
> + {},
> +};
> +
> +U_BOOT_DRIVER(uniphier_fi2c) = {
> + .name = "uniphier-fi2c",
> + .id = UCLASS_I2C,
> + .of_match = uniphier_fi2c_of_match,
> + .probe = uniphier_fi2c_probe,
> + .remove = uniphier_fi2c_remove,
> + .per_child_auto_alloc_size = sizeof(struct dm_i2c_chip),
> + .child_pre_probe = uniphier_fi2c_child_pre_probe,
> + .priv_auto_alloc_size = sizeof(struct uniphier_fi2c_dev),
> + .ops = &uniphier_fi2c_ops,
> +};
Regards,
Simon
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