[PATCHv5 3/3] i2c: altera: Add Altera I2C Controller driver
Wolfram Sang
wsa at the-dreams.de
Mon Jul 31 06:31:24 PDT 2017
Hi Thor,
thanks for the patches! A few comments and questions from me.
On Mon, Jul 17, 2017 at 11:35:14AM -0500, thor.thayer at linux.intel.com wrote:
> From: Thor Thayer <thor.thayer at linux.intel.com>
>
> Add driver support for the Altera I2C Controller. The I2C
> controller is soft IP for use in FPGAs.
>
> Signed-off-by: Thor Thayer <thor.thayer at linux.intel.com>
> ---
> v2 Remove altr, from fifo-size to agree with bindings.
> Change compatible string to "altr,softip-i2c"
> v3 Add version to compatible string "altr,softip-i2c-v1.0"
> v4 Add default 100kHz message. Cleanup IRQ error message.
> v5 Cleanup header usage - remove init.h.
> Fix 1 byte RX bug and add convenience function for transfer shared by RX and TX.
> Use readl_poll_timeout_atomic() function.
> Cache the I2C Interrupt Status Enable Register.
> Cleanup of irq_mask by combining into 1 function.
> Use i2c_8bit_addr_from_msg() for cleaner xfer_msg implementation.
> Restructure altr_i2c_xfer() without arrays and indexes.
> Remove redundant assignments.
> Remove function calls from inside if() statements.
> Convert of_property_read_u32() to device_property_read_u32().
> Call i2c_m_read() once in irq.
> ---
> drivers/i2c/busses/Kconfig | 10 +
> drivers/i2c/busses/Makefile | 1 +
> drivers/i2c/busses/i2c-altera.c | 510 ++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 521 insertions(+)
> create mode 100644 drivers/i2c/busses/i2c-altera.c
>
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index 1006b23..668147bf 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -328,6 +328,16 @@ config I2C_POWERMAC
>
> comment "I2C system bus drivers (mostly embedded / system-on-chip)"
>
> +config I2C_ALTERA
> + tristate "Altera Soft IP I2C"
> + depends on (ARCH_SOCFPGA || NIOS2) && OF
> + help
> + If you say yes to this option, support will be included for the
> + Altera Soft IP I2C interfaces on SoCFPGA and Nios2 architectures.
> +
> + This driver can also be built as a module. If so, the module
> + will be called i2c-altera.
> +
> config I2C_ASPEED
> tristate "Aspeed I2C Controller"
> depends on ARCH_ASPEED || COMPILE_TEST
> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> index 1b2fc81..1395dcb 100644
> --- a/drivers/i2c/busses/Makefile
> +++ b/drivers/i2c/busses/Makefile
> @@ -29,6 +29,7 @@ obj-$(CONFIG_I2C_HYDRA) += i2c-hydra.o
> obj-$(CONFIG_I2C_POWERMAC) += i2c-powermac.o
>
> # Embedded system I2C/SMBus host controller drivers
> +obj-$(CONFIG_I2C_ALTERA) += i2c-altera.o
> obj-$(CONFIG_I2C_ASPEED) += i2c-aspeed.o
> obj-$(CONFIG_I2C_AT91) += i2c-at91.o
> obj-$(CONFIG_I2C_AU1550) += i2c-au1550.o
> diff --git a/drivers/i2c/busses/i2c-altera.c b/drivers/i2c/busses/i2c-altera.c
> new file mode 100644
> index 0000000..e818901
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-altera.c
> @@ -0,0 +1,510 @@
> +/*
> + * Copyright Intel Corporation (C) 2017.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License along with
> + * this program. If not, see <http://www.gnu.org/licenses/>.
> + *
> + * Based on the i2c-axxia.c driver.
> + */
> +#include <linux/clk.h>
> +#include <linux/clkdev.h>
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/iopoll.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/platform_device.h>
> +
> +#define ALTR_I2C_TFR_CMD 0x00 /* Transfer Command register */
> +#define ALTR_I2C_TFR_CMD_STA BIT(9) /* send START before byte */
> +#define ALTR_I2C_TFR_CMD_STO BIT(8) /* send STOP after byte */
> +#define ALTR_I2C_TFR_CMD_RW_D BIT(0) /* Direction of transfer */
> +#define ALTR_I2C_RX_DATA 0x04 /* RX data FIFO register */
> +#define ALTR_I2C_CTRL 0x08 /* Control register */
> +#define ALTR_I2C_CTRL_RXT_SHFT 4 /* RX FIFO Threshold */
> +#define ALTR_I2C_CTRL_TCT_SHFT 2 /* TFER CMD FIFO Threshold */
> +#define ALTR_I2C_CTRL_BSPEED BIT(1) /* Bus Speed (1=Fast) */
> +#define ALTR_I2C_CTRL_EN BIT(0) /* Enable Core (1=Enable) */
> +#define ALTR_I2C_ISER 0x0C /* Interrupt Status Enable register */
> +#define ALTR_I2C_ISER_RXOF_EN BIT(4) /* Enable RX OVERFLOW IRQ */
> +#define ALTR_I2C_ISER_ARB_EN BIT(3) /* Enable ARB LOST IRQ */
> +#define ALTR_I2C_ISER_NACK_EN BIT(2) /* Enable NACK DET IRQ */
> +#define ALTR_I2C_ISER_RXRDY_EN BIT(1) /* Enable RX Ready IRQ */
> +#define ALTR_I2C_ISER_TXRDY_EN BIT(0) /* Enable TX Ready IRQ */
> +#define ALTR_I2C_ISR 0x10 /* Interrupt Status register */
> +#define ALTR_I2C_ISR_RXOF BIT(4) /* RX OVERFLOW IRQ */
> +#define ALTR_I2C_ISR_ARB BIT(3) /* ARB LOST IRQ */
> +#define ALTR_I2C_ISR_NACK BIT(2) /* NACK DET IRQ */
> +#define ALTR_I2C_ISR_RXRDY BIT(1) /* RX Ready IRQ */
> +#define ALTR_I2C_ISR_TXRDY BIT(0) /* TX Ready IRQ */
> +#define ALTR_I2C_STATUS 0x14 /* Status register */
> +#define ALTR_I2C_STAT_CORE BIT(0) /* Core Status (0=idle) */
> +#define ALTR_I2C_TC_FIFO_LVL 0x18 /* Transfer FIFO LVL register */
> +#define ALTR_I2C_RX_FIFO_LVL 0x1C /* Receive FIFO LVL register */
> +#define ALTR_I2C_SCL_LOW 0x20 /* SCL low count register */
> +#define ALTR_I2C_SCL_HIGH 0x24 /* SCL high count register */
> +#define ALTR_I2C_SDA_HOLD 0x28 /* SDA hold count register */
> +
> +#define ALTR_I2C_ALL_IRQ (ALTR_I2C_ISR_RXOF | ALTR_I2C_ISR_ARB | \
> + ALTR_I2C_ISR_NACK | ALTR_I2C_ISR_RXRDY | \
> + ALTR_I2C_ISR_TXRDY)
> +
> +#define ALTR_I2C_THRESHOLD 0 /* IRQ Threshold at 1 element */
> +#define ALTR_I2C_DFLT_FIFO_SZ 4
> +#define ALTR_I2C_TIMEOUT 100000 /* 100ms */
> +#define ALTR_I2C_XFER_TIMEOUT (msecs_to_jiffies(250))
> +
> +/**
> + * altr_i2c_dev - I2C device context
> + * @base: pointer to register struct
> + * @msg: pointer to current message
> + * @msg_len: number of bytes transferred in msg
> + * @msg_err: error code for completed message
> + * @msg_complete: xfer completion object
> + * @dev: device reference
> + * @adapter: core i2c abstraction
> + * @i2c_clk: clock reference for i2c input clock
> + * @bus_clk_rate: current i2c bus clock rate
> + * @buf: ptr to msg buffer for easier use.
> + * @fifo_size: size of the FIFO passed in.
> + */
> +struct altr_i2c_dev {
> + void __iomem *base;
> + struct i2c_msg *msg;
> + size_t msg_len;
> + int msg_err;
> + struct completion msg_complete;
> + struct device *dev;
> + struct i2c_adapter adapter;
> + struct clk *i2c_clk;
> + u32 bus_clk_rate;
> + u8 *buf;
> + u32 fifo_size;
> + u32 isr_mask;
The last one is not described in the kernel docs.
> +};
> +
> +static void i2c_int_enable(struct altr_i2c_dev *idev, u32 mask, bool enable)
> +{
> + u32 int_en = readl(idev->base + ALTR_I2C_ISER);
> +
> + if (enable)
> + idev->isr_mask = int_en | mask;
> + else
> + idev->isr_mask = int_en & ~mask;
> +
> + writel(idev->isr_mask, idev->base + ALTR_I2C_ISER);
> +}
> +
> +static void i2c_int_clear(struct altr_i2c_dev *idev, u32 mask)
> +{
> + u32 int_en = readl(idev->base + ALTR_I2C_ISR);
> +
> + writel(int_en | mask, idev->base + ALTR_I2C_ISR);
> +}
Those two functions would also suit an altr_ prefix.
> +
> +static void altr_i2c_core_disable(struct altr_i2c_dev *idev)
> +{
> + u32 tmp = readl(idev->base + ALTR_I2C_CTRL);
> +
> + writel(tmp & ~ALTR_I2C_CTRL_EN, idev->base + ALTR_I2C_CTRL);
> +}
> +
> +static void altr_i2c_core_enable(struct altr_i2c_dev *idev)
> +{
> + u32 tmp = readl(idev->base + ALTR_I2C_CTRL);
> +
> + writel(tmp | ALTR_I2C_CTRL_EN, idev->base + ALTR_I2C_CTRL);
> +}
> +
> +static void altr_i2c_reset(struct altr_i2c_dev *idev)
> +{
> + altr_i2c_core_disable(idev);
> + altr_i2c_core_enable(idev);
> +}
> +
> +static void altr_i2c_recover(struct altr_i2c_dev *idev)
> +{
> + altr_i2c_reset(idev);
> + /* Clock start bit + 8 bits + stop bit out */
Really 8? It should be 9 (ACK bit).
> + writel(ALTR_I2C_TFR_CMD_STA | ALTR_I2C_TFR_CMD_STO,
> + idev->base + ALTR_I2C_TFR_CMD);
> + altr_i2c_reset(idev);
Why the second reset?
> +
> + i2c_recover_bus(&idev->adapter);
This will return an error since you don't have a struct
i2c_bus_recovery_info defined. This whole recovery looks fishy, maybe it
should be dropped now and added incrementally?
> +}
> +
> +static inline void altr_i2c_stop(struct altr_i2c_dev *idev)
> +{
> + writel(ALTR_I2C_TFR_CMD_STO, idev->base + ALTR_I2C_TFR_CMD);
> +}
> +
> +static void altr_i2c_init(struct altr_i2c_dev *idev)
> +{
> + u32 divisor = clk_get_rate(idev->i2c_clk) / idev->bus_clk_rate;
> + u32 clk_mhz = clk_get_rate(idev->i2c_clk) / 1000000;
> + u32 tmp = (ALTR_I2C_THRESHOLD << ALTR_I2C_CTRL_RXT_SHFT) |
> + (ALTR_I2C_THRESHOLD << ALTR_I2C_CTRL_TCT_SHFT);
> + u32 t_high, t_low;
> +
> + if (idev->bus_clk_rate <= 100000) {
> + tmp &= ~ALTR_I2C_CTRL_BSPEED;
> + /* Standard mode SCL 50/50 */
> + t_high = divisor * 1 / 2;
> + t_low = divisor * 1 / 2;
> + } else {
> + tmp |= ALTR_I2C_CTRL_BSPEED;
> + /* Fast mode SCL 33/66 */
> + t_high = divisor * 1 / 3;
> + t_low = divisor * 2 / 3;
> + }
> + writel(tmp, idev->base + ALTR_I2C_CTRL);
> +
> + dev_dbg(idev->dev, "rate=%uHz per_clk=%uMHz -> ratio=1:%u\n",
> + idev->bus_clk_rate, clk_mhz, divisor);
> +
> + /* Reset controller */
> + altr_i2c_reset(idev);
> +
> + /* SCL High Time */
> + writel(t_high, idev->base + ALTR_I2C_SCL_HIGH);
> + /* SCL Low Time */
> + writel(t_low, idev->base + ALTR_I2C_SCL_LOW);
> + /* SDA Hold Time, 300ns */
> + writel(div_u64(300 * clk_mhz, 1000), idev->base + ALTR_I2C_SDA_HOLD);
> +
> + /* Mask all master interrupt bits */
> + i2c_int_enable(idev, ALTR_I2C_ALL_IRQ, false);
> +}
> +
> +static int i2c_m_rd(const struct i2c_msg *msg)
> +{
> + return (msg->flags & I2C_M_RD) != 0;
> +}
I'll leave it to you, but I'd think an extra function doesn't really
improve readability here.
> +
> +/**
> + * altr_i2c_transfer - On the last byte to be transmitted, send
> + * a Stop bit on the last byte.
> + */
> +static void altr_i2c_transfer(struct altr_i2c_dev *idev, u32 data)
> +{
> + /* On the last byte to be transmitted, send STOP */
> + if (idev->msg_len == 1)
> + data |= ALTR_I2C_TFR_CMD_STO;
> + if (idev->msg_len > 0)
> + writel(data, idev->base + ALTR_I2C_TFR_CMD);
> +}
> +
> +/**
> + * altr_i2c_empty_rx_fifo - Fetch data from RX FIFO until end of
> + * transfer. Send a Stop bit on the last byte.
> + */
> +static void altr_i2c_empty_rx_fifo(struct altr_i2c_dev *idev)
> +{
> + size_t rx_fifo_avail = readl(idev->base + ALTR_I2C_RX_FIFO_LVL);
> + int bytes_to_transfer = min(rx_fifo_avail, idev->msg_len);
> +
> + while (bytes_to_transfer-- > 0) {
> + *idev->buf++ = readl(idev->base + ALTR_I2C_RX_DATA);
> + idev->msg_len--;
> + altr_i2c_transfer(idev, 0);
> + }
> +}
> +
> +/**
> + * altr_i2c_fill_tx_fifo - Fill TX FIFO from current message buffer.
> + * @return: Number of bytes left to transfer.
> + */
> +static int altr_i2c_fill_tx_fifo(struct altr_i2c_dev *idev)
> +{
> + size_t tx_fifo_avail = idev->fifo_size - readl(idev->base +
> + ALTR_I2C_TC_FIFO_LVL);
> + int bytes_to_transfer = min(tx_fifo_avail, idev->msg_len);
> + int ret = idev->msg_len - bytes_to_transfer;
> +
> + while (bytes_to_transfer-- > 0) {
> + altr_i2c_transfer(idev, *idev->buf++);
> + idev->msg_len--;
> + }
> +
> + return ret;
> +}
> +
> +static irqreturn_t altr_i2c_isr(int irq, void *_dev)
> +{
> + int ret, read;
> + struct altr_i2c_dev *idev = _dev;
> + /* Read IRQ status but only interested in Enabled IRQs. */
> + u32 status = readl(idev->base + ALTR_I2C_ISR) & idev->isr_mask;
> +
> + if (!idev->msg) {
> + dev_warn(idev->dev, "unexpected interrupt\n");
> + goto out;
Won't you get an interrupt storm if you don't use any i2c_int_clear()?
> + }
> + read = i2c_m_rd(idev->msg);
> +
> + /* handle Lost Arbitration */
> + if (unlikely(status & ALTR_I2C_ISR_ARB)) {
> + dev_err(idev->dev, "%s: arbitration lost\n", __func__);
Drop the message, it is not an error, but a to be expected bus condition
in multi-master setups.
> + i2c_int_clear(idev, ALTR_I2C_ISR_ARB);
> + idev->msg_err = -EAGAIN;
> + goto complete;
> + }
> +
> + if (unlikely(status & ALTR_I2C_ISR_NACK)) {
> + dev_dbg(idev->dev, "%s: could not get ACK\n", __func__);
> + idev->msg_err = -ENXIO;
> + i2c_int_clear(idev, ALTR_I2C_ISR_NACK);
> + altr_i2c_stop(idev);
> + goto complete;
> + }
> +
> + /* handle RX FIFO Overflow */
> + if (read && unlikely(status & ALTR_I2C_ISR_RXOF)) {
> + altr_i2c_empty_rx_fifo(idev);
> + i2c_int_clear(idev, ALTR_I2C_ISR_RXRDY);
> + altr_i2c_stop(idev);
> + dev_err(idev->dev, "%s: RX FIFO Overflow\n", __func__);
> + goto complete;
> + }
> +
> + /* RX FIFO needs service? */
> + if (read && (status & ALTR_I2C_ISR_RXRDY)) {
> + altr_i2c_empty_rx_fifo(idev);
> + i2c_int_clear(idev, ALTR_I2C_ISR_RXRDY);
> + if (!idev->msg_len)
> + goto complete;
> +
> + goto out;
> + }
> +
> + /* TX FIFO needs service? */
> + if (!read && (status & ALTR_I2C_ISR_TXRDY)) {
> + i2c_int_clear(idev, ALTR_I2C_ISR_TXRDY);
> + if (!altr_i2c_fill_tx_fifo(idev))
> + goto complete;
> +
> + goto out;
A bit too much goto in here for my taste. What about using a boolean
'complete' variable which gets set or cleared and have an 'if
(complete)' at the end of this routine?
> + }
> +
> +complete:
> + /* Wait for the Core to finish */
> + ret = readl_poll_timeout_atomic(idev->base + ALTR_I2C_STATUS, status,
> + ((status & ALTR_I2C_STAT_CORE) == 0),
> + 1, ALTR_I2C_TIMEOUT);
Why do you need this polling in an interrupt?
> + if (ret)
> + dev_err(idev->dev, "%s: message timeout\n", __func__);
> + i2c_int_enable(idev, ALTR_I2C_ALL_IRQ, false);
> + i2c_int_clear(idev, ALTR_I2C_ALL_IRQ);
> + complete(&idev->msg_complete);
> + dev_dbg(idev->dev, "%s: Message Complete\n", __func__);
> +
> +out:
> + return IRQ_HANDLED;
> +}
> +
> +static int altr_i2c_xfer_msg(struct altr_i2c_dev *idev, struct i2c_msg *msg)
> +{
> + u32 imask = ALTR_I2C_ISR_RXOF | ALTR_I2C_ISR_ARB | ALTR_I2C_ISR_NACK;
> + unsigned long time_left;
> + u32 value;
> + u8 addr = i2c_8bit_addr_from_msg(msg);
> +
> + idev->msg = msg;
> + idev->msg_len = msg->len;
> + idev->buf = msg->buf;
> + idev->msg_err = 0;
> + reinit_completion(&idev->msg_complete);
> + altr_i2c_core_enable(idev);
> +
> + /* Make sure RX FIFO is empty */
> + do {
> + readl(idev->base + ALTR_I2C_RX_DATA);
> + } while (readl(idev->base + ALTR_I2C_RX_FIFO_LVL));
> +
> + writel(ALTR_I2C_TFR_CMD_STA | addr, idev->base + ALTR_I2C_TFR_CMD);
> +
> + if (i2c_m_rd(msg)) {
> + imask |= ALTR_I2C_ISER_RXOF_EN | ALTR_I2C_ISER_RXRDY_EN;
> + i2c_int_enable(idev, imask, true);
> + /* write the first byte to start the RX */
> + altr_i2c_transfer(idev, 0);
> + } else {
> + imask |= ALTR_I2C_ISR_TXRDY;
> + i2c_int_enable(idev, imask, true);
> + altr_i2c_fill_tx_fifo(idev);
> + }
> +
> + time_left = wait_for_completion_timeout(&idev->msg_complete,
> + ALTR_I2C_XFER_TIMEOUT);
> + i2c_int_enable(idev, imask, false);
> +
> + value = readl(idev->base + ALTR_I2C_STATUS) & ALTR_I2C_STAT_CORE;
> + if (value)
> + dev_err(idev->dev, "%s: Core Status not IDLE...\n", __func__);
__func__ with dev_* is 99,9% superfluous.
> +
> + if (time_left == 0) {
> + idev->msg_err = -ETIMEDOUT;
> + dev_err(idev->dev, "%s: Transaction timed out.\n", __func__);
No error message here. This can happen when an EEPROM is currently
erasing.
> + altr_i2c_recover(idev);
And no need to reset the bus! Only if SDA is stuck low.
> + }
> +
> + if (unlikely(idev->msg_err) && idev->msg_err != -ENXIO)
> + altr_i2c_init(idev);
Why do you need to reinit on NACK?
> +
> + altr_i2c_core_disable(idev);
> +
> + return idev->msg_err;
> +}
> +
> +static int
> +altr_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
> +{
> + struct altr_i2c_dev *idev = i2c_get_adapdata(adap);
> + int i, ret;
> +
> + for (i = 0; i < num; i++) {
> + ret = altr_i2c_xfer_msg(idev, msgs++);
> + if (ret)
> + return ret;
> + }
> + return num;
> +}
> +
> +static u32 altr_i2c_func(struct i2c_adapter *adap)
> +{
> + return I2C_FUNC_I2C;
> +}
No emulated SMBUS?
> +
> +static const struct i2c_algorithm altr_i2c_algo = {
> + .master_xfer = altr_i2c_xfer,
> + .functionality = altr_i2c_func,
> +};
> +
> +static int altr_i2c_probe(struct platform_device *pdev)
> +{
> + struct altr_i2c_dev *idev = NULL;
> + struct resource *res;
> + int irq, ret;
> + u32 val;
> +
> + idev = devm_kzalloc(&pdev->dev, sizeof(*idev), GFP_KERNEL);
> + if (!idev)
> + return -ENOMEM;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + idev->base = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(idev->base))
> + return PTR_ERR(idev->base);
> +
> + irq = platform_get_irq(pdev, 0);
> + if (irq < 0) {
> + dev_err(&pdev->dev, "missing interrupt resource\n");
> + return irq;
> + }
> +
> + idev->i2c_clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(idev->i2c_clk)) {
> + dev_err(&pdev->dev, "missing clock\n");
> + return PTR_ERR(idev->i2c_clk);
> + }
> +
> + idev->dev = &pdev->dev;
> + init_completion(&idev->msg_complete);
> +
> + val = device_property_read_u32(idev->dev, "fifo-size",
> + &idev->fifo_size);
> + if (val) {
> + dev_err(&pdev->dev, "FIFO size set to default of %d\n",
> + ALTR_I2C_DFLT_FIFO_SZ);
> + idev->fifo_size = ALTR_I2C_DFLT_FIFO_SZ;
> + }
> +
> + val = device_property_read_u32(idev->dev, "clock-frequency",
> + &idev->bus_clk_rate);
> + if (val) {
> + dev_err(&pdev->dev, "Default to 100kHz\n");
> + idev->bus_clk_rate = 100000; /* default clock rate */
> + }
> +
> + if (idev->bus_clk_rate > 400000) {
> + dev_err(&pdev->dev, "invalid clock-frequency %d\n",
> + idev->bus_clk_rate);
> + return -EINVAL;
> + }
> +
> + ret = devm_request_irq(&pdev->dev, irq, altr_i2c_isr, 0,
> + pdev->name, idev);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to claim IRQ %d\n", irq);
> + return ret;
> + }
> +
> + ret = clk_prepare_enable(idev->i2c_clk);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to enable clock\n");
> + return ret;
> + }
> +
> + altr_i2c_init(idev);
> +
> + i2c_set_adapdata(&idev->adapter, idev);
> + strlcpy(idev->adapter.name, pdev->name, sizeof(idev->adapter.name));
> + idev->adapter.owner = THIS_MODULE;
> + idev->adapter.algo = &altr_i2c_algo;
> + idev->adapter.dev.parent = &pdev->dev;
> + idev->adapter.dev.of_node = pdev->dev.of_node;
> +
> + platform_set_drvdata(pdev, idev);
> +
> + ret = i2c_add_adapter(&idev->adapter);
> + if (ret) {
> + clk_disable_unprepare(idev->i2c_clk);
> + return ret;
> + }
> + dev_info(&pdev->dev, "Altera SoftIP I2C Probe Complete\n");
> +
> + return 0;
> +}
> +
> +static int altr_i2c_remove(struct platform_device *pdev)
> +{
> + struct altr_i2c_dev *idev = platform_get_drvdata(pdev);
> +
> + clk_disable_unprepare(idev->i2c_clk);
> + i2c_del_adapter(&idev->adapter);
> +
> + return 0;
> +}
> +
> +/* Match table for of_platform binding */
> +static const struct of_device_id altr_i2c_of_match[] = {
> + { .compatible = "altr,softip-i2c-v1.0" },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, altr_i2c_of_match);
> +
> +static struct platform_driver altr_i2c_driver = {
> + .probe = altr_i2c_probe,
> + .remove = altr_i2c_remove,
> + .driver = {
> + .name = "altera-i2c",
> + .of_match_table = altr_i2c_of_match,
> + },
> +};
> +
> +module_platform_driver(altr_i2c_driver);
> +
> +MODULE_DESCRIPTION("Altera Soft IP I2C bus driver");
> +MODULE_AUTHOR("Thor Thayer <thor.thayer at linux.intel.com>");
> +MODULE_LICENSE("GPL v2");
> --
> 2.7.4
>
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