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Message-ID: <20241114064943-GYA998060@gentoo>
Date: Thu, 14 Nov 2024 14:49:43 +0800
From: Yixun Lan <dlan@...too.org>
To: Troy Mitchell <troymitchell988@...il.com>
Cc: Andi Shyti <andi.shyti@...nel.org>, Rob Herring <robh@...nel.org>,
Krzysztof Kozlowski <krzk+dt@...nel.org>,
Conor Dooley <conor+dt@...nel.org>, linux-riscv@...ts.infradead.org,
linux-i2c@...r.kernel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/2] i2c: spacemit: add support for SpacemiT K1 SoC
On 11:07 Tue 12 Nov , Troy Mitchell wrote:
> From: Troy Mitchell <troymitchell988@...il.com>
>
> This patch introduces basic I2C support for the SpacemiT K1 SoC,
> utilizing interrupts for transfers.
>
> The driver has been tested using i2c-tools on a Bananapi-F3 board,
> and basic I2C read/write operations have been confirmed to work.
>
> Signed-off-by: Troy Mitchell <TroyMitchell988@...il.com>
> ---
> drivers/i2c/busses/Kconfig | 19 ++
> drivers/i2c/busses/Makefile | 1 +
> drivers/i2c/busses/i2c-k1.c | 656 ++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 676 insertions(+)
>
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index 6b3ba7e5723a..91630f55667f 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -779,6 +779,25 @@ config I2C_JZ4780
>
> If you don't know what to do here, say N.
>
> +config I2C_K1
> + tristate "Spacemit K1 I2C adapter"
> + depends on ARCH_SPACEMIT || COMPILE_TEST
> + depends on OF
> + help
> + This option enables support for the I2C interface on the Spacemit K1
> + platform.
> +
> + If you enable this configuration, the kernel will include support for
> + the I2C adapter specific to the Spacemit K1 platform. This driver ca
> + be used to manage I2C bus transactions, which are necessary for
> + interfacing with I2C peripherals such as sensors, EEPROMs, and other
> + devices.
> +
> + This driver can also be compiled as a module. If you choose to build
> + it as a module, the resulting kernel module will be named `i2c-k1`.
> + Loading this module will enable the I2C functionality for the K1
> + platform dynamically, without requiring a rebuild of the kernel.
> +
> config I2C_KEBA
> tristate "KEBA I2C controller support"
> depends on HAS_IOMEM
> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> index ecc07c50f2a0..9744b0e58598 100644
> --- a/drivers/i2c/busses/Makefile
> +++ b/drivers/i2c/busses/Makefile
> @@ -76,6 +76,7 @@ obj-$(CONFIG_I2C_IMX) += i2c-imx.o
> obj-$(CONFIG_I2C_IMX_LPI2C) += i2c-imx-lpi2c.o
> obj-$(CONFIG_I2C_IOP3XX) += i2c-iop3xx.o
> obj-$(CONFIG_I2C_JZ4780) += i2c-jz4780.o
> +obj-$(CONFIG_I2C_K1) += i2c-k1.o
> obj-$(CONFIG_I2C_KEBA) += i2c-keba.o
> obj-$(CONFIG_I2C_KEMPLD) += i2c-kempld.o
> obj-$(CONFIG_I2C_LPC2K) += i2c-lpc2k.o
> diff --git a/drivers/i2c/busses/i2c-k1.c b/drivers/i2c/busses/i2c-k1.c
> new file mode 100644
> index 000000000000..12bb71625e0a
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-k1.c
> @@ -0,0 +1,656 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2024 Troy Mitchell <troymitchell988@...il.com>
> + */
> +
> + #include <linux/clk.h>
> + #include <linux/i2c.h>
> + #include <linux/iopoll.h>
> + #include <linux/module.h>
> + #include <linux/of_address.h>
> + #include <linux/platform_device.h>
> +
> +/* spacemit i2c registers */
> +#define ICR 0x0 /* Control Register */
> +#define ISR 0x4 /* Status Register */
> +#define ISAR 0x8 /* Slave Address Register */
> +#define IDBR 0xc /* Data Buffer Register */
> +#define ILCR 0x10 /* Load Count Register */
> +#define IWCR 0x14 /* Wait Count Register */
> +#define IRST_CYC 0x18 /* Bus reset cycle counter */
> +#define IBMR 0x1c /* Bus monitor register */
> +#define IWFIFO 0x20 /* Write FIFO Register */
> +#define IWFIFO_WPTR 0x24 /* Write FIFO Write Pointer Register */
> +#define IWFIFO_RPTR 0x28 /* Write FIFO Read Pointer Register */
> +#define IRFIFO 0x2c /* Read FIFO Register */
> +#define IRFIFO_WPTR 0x30 /* Read FIFO Write Pointer Register */
> +#define IRFIFO_RPTR 0x34 /* Read FIFO Read Pointer Register */
> +
> +/* register ICR fields */
> +#define CR_START BIT(0) /* start bit */
> +#define CR_STOP BIT(1) /* stop bit */
> +#define CR_ACKNAK BIT(2) /* send ACK(0) or NAK(1) */
> +#define CR_TB BIT(3) /* transfer byte bit */
> +#define CR_TXBEGIN BIT(4) /* transaction begin */
> +#define CR_FIFOEN BIT(5) /* enable FIFO mode */
> +#define CR_GPIOEN BIT(6) /* enable GPIO mode for SCL in HS */
> +#define CR_DMAEN BIT(7) /* enable DMA for TX and RX FIFOs */
> +#define CR_MODE_FAST BIT(8) /* bus mode (master operation) */
> +#define CR_MODE_HIGH BIT(9) /* bus mode (master operation) */
> +#define CR_UR BIT(10) /* unit reset */
> +#define CR_RSTREQ BIT(11) /* i2c bus reset request */
> +#define CR_MA BIT(12) /* master abort */
> +#define CR_SCLE BIT(13) /* master clock enable */
> +#define CR_IUE BIT(14) /* unit enable */
> +#define CR_HS_STRETCH BIT(16) /* I2C hs stretch */
> +#define CR_ALDIE BIT(18) /* enable arbitration interrupt */
> +#define CR_DTEIE BIT(19) /* enable tx interrupts */
> +#define CR_DRFIE BIT(20) /* enable rx interrupts */
> +#define CR_GCD BIT(21) /* general call disable */
> +#define CR_BEIE BIT(22) /* enable bus error ints */
> +#define CR_SADIE BIT(23) /* slave address detected int enable */
> +#define CR_SSDIE BIT(24) /* slave STOP detected int enable */
> +#define CR_MSDIE BIT(25) /* master STOP detected int enable */
> +#define CR_MSDE BIT(26) /* master STOP detected enable */
> +#define CR_TXDONEIE BIT(27) /* transaction done int enable */
> +#define CR_TXEIE BIT(28) /* transmit FIFO empty int enable */
> +#define CR_RXHFIE BIT(29) /* receive FIFO half-full int enable */
> +#define CR_RXFIE BIT(30) /* receive FIFO full int enable */
> +#define CR_RXOVIE BIT(31) /* receive FIFO overrun int enable */
> +
> +/* register ISR fields */
> +#define SR_RWM BIT(13) /* read/write mode */
> +#define SR_ACKNAK BIT(14) /* ACK/NACK status */
> +#define SR_UB BIT(15) /* unit busy */
> +#define SR_IBB BIT(16) /* i2c bus busy */
> +#define SR_EBB BIT(17) /* early bus busy */
> +#define SR_ALD BIT(18) /* arbitration loss detected */
> +#define SR_ITE BIT(19) /* tx buffer empty */
> +#define SR_IRF BIT(20) /* rx buffer full */
> +#define SR_GCAD BIT(21) /* general call address detected */
> +#define SR_BED BIT(22) /* bus error no ACK/NAK */
> +#define SR_SAD BIT(23) /* slave address detected */
> +#define SR_SSD BIT(24) /* slave stop detected */
> +#define SR_MSD BIT(26) /* master stop detected */
> +#define SR_TXDONE BIT(27) /* transaction done */
> +#define SR_TXE BIT(28) /* tx FIFO empty */
> +#define SR_RXHF BIT(29) /* rx FIFO half-full */
> +#define SR_RXF BIT(30) /* rx FIFO full */
> +#define SR_RXOV BIT(31) /* RX FIFO overrun */
> +
> +/* register ILCR fields */
> +#define LCR_SLV 0x000001FF /* SLV: bit[8:0] */
> +#define LCR_FLV 0x0003FE00 /* FLV: bit[17:9] */
> +#define LCR_HLVH 0x07FC0000 /* HLVH: bit[26:18] */
> +#define LCR_HLVL 0xF8000000 /* HLVL: bit[31:27] */
> +
> +/* register IWCR fields */
> +#define WCR_COUNT 0x0000001F /* COUNT: bit[4:0] */
> +#define WCR_COUNT1 0x000003E0 /* HS_COUNT1: bit[9:5] */
> +#define WCR_COUNT2 0x00007C00 /* HS_COUNT2: bit[14:10] */
> +
> +/* register IBMR fields */
> +#define BMR_SDA BIT(0) /* SDA line level */
> +#define BMR_SCL BIT(1) /* SCL line level */
> +
> +/* register IWFIFO fields */
> +#define WFIFO_DATA_MSK 0x000000FF /* data: bit[7:0] */
> +#define WFIFO_CTRL_MSK 0x000003E0 /* control: bit[11:8] */
> +#define WFIFO_CTRL_START BIT(8) /* start bit */
> +#define WFIFO_CTRL_STOP BIT(9) /* stop bit */
> +#define WFIFO_CTRL_ACKNAK BIT(10) /* send ACK(0) or NAK(1) */
> +#define WFIFO_CTRL_TB BIT(11) /* transfer byte bit */
> +
> +/* status register init value */
> +#define I2C_INT_STATUS_MASK 0xfffc0000 /* SR bits[31:18] */
> +#define I2C_INT_CTRL_MASK (CR_ALDIE | CR_DTEIE | CR_DRFIE | \
> + CR_BEIE | CR_TXDONEIE | CR_TXEIE | \
> + CR_RXHFIE | CR_RXFIE | CR_RXOVIE | \
> + CR_MSDIE)
> +
> +/* i2c bus recover timeout: us */
> +#define I2C_BUS_RECOVER_TIMEOUT (100000)
> +
> +#define I2C_FAST_MODE_FREQ (400000)
> +
> +enum spacemit_i2c_state {
> + STATE_IDLE,
> + STATE_START,
> + STATE_READ,
> + STATE_WRITE,
> +};
> +
> +enum spacemit_i2c_dir {
> + DIR_WRITE,
> + DIR_READ
> +};
> +
> +/* i2c-spacemit driver's main struct */
> +struct spacemit_i2c_dev {
> + struct device *dev;
> + struct i2c_adapter adapt;
> +
> + /* hardware resources */
> + void __iomem *base;
> + int irq;
> +
> + struct i2c_msg *msgs;
> + int msg_num;
> + struct i2c_msg *cur_msg;
> +
> + /* index of the current message being processed */
> + int msg_idx;
> + u8 *msg_buf;
> + /* the number of unprocessed bytes remaining in each message */
> + size_t unprocessed;
> +
> + enum spacemit_i2c_state state;
> + enum spacemit_i2c_dir dir;
> + struct completion complete;
> + u32 status;
> + u32 err;
> +};
> +
> +static void spacemit_i2c_enable(struct spacemit_i2c_dev *i2c)
> +{
> + u32 val;
> +
> + val = readl(i2c->base + ICR);
> + writel(val | CR_IUE, i2c->base + ICR);
> +}
> +
> +static void spacemit_i2c_disable(struct spacemit_i2c_dev *i2c)
> +{
> + u32 val;
> +
> + val = readl(i2c->base + ICR);
> + val &= ~CR_IUE;
> + writel(val, i2c->base + ICR);
> +}
> +
> +static void spacemit_i2c_reset(struct spacemit_i2c_dev *i2c)
> +{
> + writel(CR_UR, i2c->base + ICR);
> + udelay(5);
> + writel(0, i2c->base + ICR);
> +}
> +
> +static int spacemit_i2c_handle_err(struct spacemit_i2c_dev *i2c);
> +
> +static void spacemit_i2c_bus_reset(struct spacemit_i2c_dev *i2c)
> +{
> + u32 status;
> +
> + /* if bus is locked, reset unit. 0: locked */
> + status = readl(i2c->base + IBMR);
> + if ((status & BMR_SDA) && (status & BMR_SCL))
> + return;
> +
> + spacemit_i2c_reset(i2c);
> + usleep_range(10, 20);
> +
> + /* check scl status again */
> + status = readl(i2c->base + IBMR);
> + if (!(status & BMR_SCL))
> + dev_warn_ratelimited(i2c->dev, "unit reset failed\n");
> +}
> +
> +static int spacemit_i2c_recover_bus_busy(struct spacemit_i2c_dev *i2c)
> +{
> + int ret = 0;
> + u32 val;
> +
> + val = readl(i2c->base + ISR);
> + if (likely(!(val & (SR_UB | SR_IBB))))
> + return 0;
> +
> + ret = readl_poll_timeout(i2c->base + ISR, val, !(val & (SR_UB | SR_IBB)),
> + 1500, I2C_BUS_RECOVER_TIMEOUT);
> + if (unlikely(ret)) {
> + spacemit_i2c_reset(i2c);
> + ret = -EAGAIN;
> + }
> +
> + return ret;
> +}
> +
> +static void spacemit_i2c_check_bus_release(struct spacemit_i2c_dev *i2c)
> +{
> + /* in case bus is not released after transfer completes */
> + if (unlikely(readl(i2c->base + ISR) & SR_EBB)) {
> + spacemit_i2c_bus_reset(i2c);
> + usleep_range(90, 150);
> + }
> +}
> +
> +static void spacemit_i2c_init(struct spacemit_i2c_dev *i2c)
> +{
> + u32 val = 0;
> +
> + /*
> + * Unmask interrupt bits for all xfer mode:
> + * bus error, arbitration loss detected.
> + * For transaction complete signal, we use master stop
> + * interrupt, so we don't need to unmask CR_TXDONEIE.
> + */
> + val |= CR_BEIE | CR_ALDIE;
> +
> + /*
> + * Unmask interrupt bits for interrupt xfer mode:
> + * DBR rx full.
> + * For tx empty interrupt CR_DTEIE, we only
> + * need to enable when trigger byte transfer to start
> + * data sending.
> + */
> + val |= CR_DRFIE;
> +
> + /* set speed bits: default fast mode */
> + val |= CR_MODE_FAST;
> +
> + /* disable response to general call */
> + val |= CR_GCD;
> +
> + /* enable SCL clock output */
> + val |= CR_SCLE;
> +
> + /* enable master stop detected */
> + val |= CR_MSDE | CR_MSDIE;
> +
> + writel(val, i2c->base + ICR);
> +}
> +
> +static inline void
> +spacemit_i2c_clear_int_status(struct spacemit_i2c_dev *i2c, u32 mask)
> +{
> + writel(mask & I2C_INT_STATUS_MASK, i2c->base + ISR);
> +}
> +
> +static void spacemit_i2c_start(struct spacemit_i2c_dev *i2c)
> +{
> + u32 slave_addr_rw, val;
> +
> + i2c->dir = i2c->cur_msg->flags & I2C_M_RD;
> + i2c->state = STATE_START;
> +
> + if (i2c->cur_msg->flags & I2C_M_RD)
> + slave_addr_rw = ((i2c->cur_msg->addr & 0x7f) << 1) | 1;
> + else
> + slave_addr_rw = (i2c->cur_msg->addr & 0x7f) << 1;
> +
> + writel(slave_addr_rw, i2c->base + IDBR);
> +
> + val = readl(i2c->base + ICR);
> +
> + /* send start pulse */
> + val &= ~CR_STOP;
> + val |= CR_START | CR_TB | CR_DTEIE;
> + writel(val, i2c->base + ICR);
> +}
> +
> +static void spacemit_i2c_stop(struct spacemit_i2c_dev *i2c)
> +{
> + u32 val;
> +
> + val = readl(i2c->base + ICR);
> +
> + val |= CR_STOP | CR_ALDIE | CR_TB;
> +
> + if (i2c->dir == DIR_READ)
> + val |= CR_ACKNAK;
> +
> + writel(val, i2c->base + ICR);
> +}
> +
> +static int spacemit_i2c_xfer_msg(struct spacemit_i2c_dev *i2c)
> +{
> + unsigned long time_left;
> +
> + for (i2c->msg_idx = 0; i2c->msg_idx < i2c->msg_num; i2c->msg_idx++) {
> + i2c->cur_msg = i2c->msgs + i2c->msg_idx;
> + i2c->msg_buf = i2c->cur_msg->buf;
> + i2c->err = 0;
> + i2c->status = 0;
> + i2c->unprocessed = i2c->cur_msg->len;
> +
> + reinit_completion(&i2c->complete);
> +
> + spacemit_i2c_start(i2c);
> +
> + time_left = wait_for_completion_timeout(&i2c->complete,
> + i2c->adapt.timeout);
> + if (unlikely(time_left == 0)) {
> + dev_alert(i2c->dev, "msg completion timeout\n");
> + spacemit_i2c_bus_reset(i2c);
> + spacemit_i2c_reset(i2c);
> + return -ETIMEDOUT;
> + }
> +
> + if (unlikely(i2c->err))
> + return spacemit_i2c_handle_err(i2c);
> + }
> +
> + return 0;
> +}
> +
> +static int spacemit_i2c_is_last_msg(struct spacemit_i2c_dev *i2c)
> +{
> + if (i2c->dir == DIR_READ) {
> + if (i2c->unprocessed == 1 && i2c->msg_idx == i2c->msg_num - 1)
> + return 1;
> + } else if (i2c->dir == DIR_WRITE) {
> + if (!i2c->unprocessed && i2c->msg_idx == i2c->msg_num - 1)
> + return 1;
> + }
> +
> + return 0;
> +}
> +
> +static void spacemit_i2c_handle_write(struct spacemit_i2c_dev *i2c)
> +{
> + /* if transfer completes, ISR will handle it */
> + if (i2c->status & SR_MSD)
> + return;
> +
> + if (i2c->unprocessed) {
> + writel(*i2c->msg_buf++, i2c->base + IDBR);
> + i2c->unprocessed--;
> + return;
> + }
> +
> + /* STATE_IDLE avoids trigger next byte */
> + i2c->state = STATE_IDLE;
> + complete(&i2c->complete);
> +}
> +
> +static void spacemit_i2c_handle_read(struct spacemit_i2c_dev *i2c)
> +{
> + if (i2c->unprocessed) {
> + *i2c->msg_buf++ = readl(i2c->base + IDBR);
> + i2c->unprocessed--;
> + }
> +
> + /* if transfer completes, ISR will handle it */
> + if (i2c->status & (SR_MSD | SR_ACKNAK))
> + return;
> +
> + /* it has to append stop bit in icr that read last byte */
> + if (i2c->unprocessed)
> + return;
> +
> + /* STATE_IDLE avoids trigger next byte */
> + i2c->state = STATE_IDLE;
> + complete(&i2c->complete);
> +}
> +
> +static void spacemit_i2c_handle_start(struct spacemit_i2c_dev *i2c)
> +{
> + if (i2c->dir == DIR_READ) {
> + i2c->state = STATE_READ;
> + return;
> + }
> +
> + if (i2c->dir == DIR_WRITE) {
> + i2c->state = STATE_WRITE;
> + spacemit_i2c_handle_write(i2c);
> + }
> +}
> +
> +static int spacemit_i2c_handle_err(struct spacemit_i2c_dev *i2c)
> +{
> + if (!i2c->err)
> + return 0;
> +
> + dev_dbg(i2c->dev, "i2c error status: 0x%08x\n", i2c->status);
> +
> + if (i2c->err & (SR_BED | SR_ALD))
> + spacemit_i2c_reset(i2c);
> +
> + if (i2c->err & (SR_RXOV | SR_ALD))
> + return -EAGAIN;
> +
> + return (i2c->status & SR_ACKNAK) ? -ENXIO : -EIO;
> +}
> +
> +static void spacemit_i2c_err_check(struct spacemit_i2c_dev *i2c)
> +{
> + u32 val;
> + /*
> + * send transaction complete signal:
> + * error happens, detect master stop
> + */
> + if (likely(i2c->err || (i2c->status & SR_MSD))) {
> + /*
> + * Here the transaction is already done, we don't need any
> + * other interrupt signals from now, in case any interrupt
> + * happens before spacemit_i2c_xfer to disable irq and i2c unit,
> + * we mask all the interrupt signals and clear the interrupt
> + * status.
> + */
> + val = readl(i2c->base + ICR);
> + val &= ~I2C_INT_CTRL_MASK;
> + writel(val, i2c->base + ICR);
> +
> + spacemit_i2c_clear_int_status(i2c, I2C_INT_STATUS_MASK);
> +
> + i2c->state = STATE_IDLE;
> + complete(&i2c->complete);
> + }
> +}
> +
> +static irqreturn_t spacemit_i2c_irq_handler(int irq, void *devid)
> +{
> + struct spacemit_i2c_dev *i2c = devid;
> + u32 status, val;
> +
> + status = readl(i2c->base + ISR);
> + if (!status)
> + return IRQ_HANDLED;
> +
> + i2c->status = status;
> +
> + i2c->err = status & (SR_BED | SR_RXOV | SR_ALD);
> +
> + spacemit_i2c_clear_int_status(i2c, status);
> +
> + if (unlikely(i2c->err))
> + goto err_out;
> +
> + val = readl(i2c->base + ICR);
> +
> + val &= ~(CR_TB | CR_ACKNAK | CR_STOP | CR_START);
> + writel(val, i2c->base + ICR);
> +
> + switch (i2c->state) {
> + case STATE_START:
> + spacemit_i2c_handle_start(i2c);
> + break;
> + case STATE_READ:
> + spacemit_i2c_handle_read(i2c);
> + break;
> + case STATE_WRITE:
> + spacemit_i2c_handle_write(i2c);
> + break;
> + default:
> + break;
> + }
> +
> + if (i2c->state != STATE_IDLE) {
> + if (spacemit_i2c_is_last_msg(i2c)) {
> + /* trigger next byte with stop */
> + spacemit_i2c_stop(i2c);
> + } else {
> + /* trigger next byte */
> + val |= CR_ALDIE | CR_TB;
> + writel(val, i2c->base + ICR);
> + }
> + }
> +
> +err_out:
> + spacemit_i2c_err_check(i2c);
> + return IRQ_HANDLED;
> +}
> +
> +static void spacemit_i2c_calc_timeout(struct spacemit_i2c_dev *i2c)
> +{
> + unsigned long timeout;
> + int idx = 0, cnt = 0, freq;
> +
> + while (idx < i2c->msg_num) {
> + cnt += (i2c->msgs + idx)->len + 1;
> + idx++;
> + }
> +
> + freq = I2C_FAST_MODE_FREQ;
so this will set frequency to fast mode (400K), this contradict with PATCH[1/2] which
says default clock-frequency is 100000, either you need to change the code? or
update the dt-binding?
> + /*
> + * multiply by 9 because each byte in I2C transmission requires
> + * 9 clock cycles: 8 bits of data plus 1 ACK/NACK bit.
> + */
> + timeout = cnt * 9 * USEC_PER_SEC / freq;
> +
> + i2c->adapt.timeout = usecs_to_jiffies(timeout + USEC_PER_SEC / 2) / i2c->msg_num;
> +}
> +
> +static inline int spacemit_i2c_xfer_core(struct spacemit_i2c_dev *i2c)
drop inline? IMO, it isn't worth here for long function
> +{
> + int ret = 0;
no need to initilize to 0
> +
> + spacemit_i2c_reset(i2c);
> +
> + spacemit_i2c_calc_timeout(i2c);
> +
> + spacemit_i2c_init(i2c);
> +
> + spacemit_i2c_enable(i2c);
> + enable_irq(i2c->irq);
> +
> + /* i2c wait for bus busy */
> + ret = spacemit_i2c_recover_bus_busy(i2c);
> + if (unlikely(ret))
> + return ret;
> +
> + ret = spacemit_i2c_xfer_msg(i2c);
> + if (unlikely(ret < 0)) {
> + dev_dbg(i2c->dev, "i2c transfer error\n");
> + /* timeout error should not be overridden, and the transfer
> + * error will be confirmed by err handle function latter,
> + * the reset should be invalid argument error.
> + */
> + if (ret != -ETIMEDOUT)
> + ret = -EINVAL;
> + }
> +
> + return ret;
> +}
> +
> +static int
> +spacemit_i2c_xfer(struct i2c_adapter *adapt, struct i2c_msg msgs[], int num)
no need to wrap the line, it makes the code a little bit weird..
current policy increase to 100characters, the old 80-column is not enforced
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=bdc48fa11e46f867ea4d75fa59ee87a7f48be144
> +{
> + struct spacemit_i2c_dev *i2c = i2c_get_adapdata(adapt);
> + int ret;
> +
> + i2c->msgs = msgs;
> + i2c->msg_num = num;
> +
> + ret = spacemit_i2c_xfer_core(i2c);
> + if (likely(!ret))
> + spacemit_i2c_check_bus_release(i2c);
> +
> + disable_irq(i2c->irq);
> +
> + spacemit_i2c_disable(i2c);
> +
> + if (unlikely((ret == -ETIMEDOUT || ret == -EAGAIN)))
> + dev_alert(i2c->dev, "i2c transfer failed, ret %d err 0x%x\n", ret, i2c->err);
> +
> + return ret < 0 ? ret : num;
> +}
> +
> +static u32 spacemit_i2c_func(struct i2c_adapter *adap)
> +{
> + return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
> +}
> +
> +static const struct i2c_algorithm spacemit_i2c_algo = {
> + .xfer = spacemit_i2c_xfer,
> + .functionality = spacemit_i2c_func,
> +};
> +
> +static int spacemit_i2c_probe(struct platform_device *pdev)
> +{
> + struct spacemit_i2c_dev *i2c;
> + struct device_node *of_node = pdev->dev.of_node;
> + struct clk *clk;
> + int ret = 0;
> +
> + i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
> + if (!i2c)
> + return -ENOMEM;
> +
> + i2c->dev = &pdev->dev;
> +
> + i2c->base = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(i2c->base))
> + return dev_err_probe(&pdev->dev, PTR_ERR(i2c->base), "failed to do ioremap");
> +
> + i2c->irq = platform_get_irq(pdev, 0);
> + if (i2c->irq < 0)
> + return dev_err_probe(&pdev->dev, i2c->irq, "failed to get irq resource");
> +
> + ret = devm_request_irq(i2c->dev, i2c->irq, spacemit_i2c_irq_handler,
> + IRQF_NO_SUSPEND | IRQF_ONESHOT, dev_name(i2c->dev), i2c);
> + if (ret)
> + return dev_err_probe(&pdev->dev, ret, "failed to request irq");
> +
> + disable_irq(i2c->irq);
> +
> + clk = devm_clk_get_enabled(&pdev->dev, NULL);
> + if (IS_ERR(clk))
> + return dev_err_probe(&pdev->dev, PTR_ERR(clk), "failed to enable clock");
> +
I'd suggest also to handle pin request here, since pinctrl driver is merged
https://lore.kernel.org/all/CACRpkdYnaJsKKfcdhHeMGTTp86M+wNODzZx2e=OYbxQ4Jc4Rjw@mail.gmail.com/
> + i2c_set_adapdata(&i2c->adapt, i2c);
> + i2c->adapt.owner = THIS_MODULE;
> + i2c->adapt.algo = &spacemit_i2c_algo;
> + i2c->adapt.dev.parent = i2c->dev;
> + i2c->adapt.nr = pdev->id;
> +
> + i2c->adapt.dev.of_node = of_node;
> + i2c->adapt.algo_data = i2c;
> +
> + strscpy(i2c->adapt.name, "spacemit-i2c-adapter", sizeof(i2c->adapt.name));
> +
> + init_completion(&i2c->complete);
> +
> + ret = i2c_add_numbered_adapter(&i2c->adapt);
> + if (ret)
> + return dev_err_probe(&pdev->dev, ret, "failed to add i2c adapter");
> +
> + platform_set_drvdata(pdev, i2c);
> +
> + return 0;
> +}
> +
> +static void spacemit_i2c_remove(struct platform_device *pdev)
> +{
> + struct spacemit_i2c_dev *i2c = platform_get_drvdata(pdev);
> +
> + i2c_del_adapter(&i2c->adapt);
> +}
> +
> +static const struct of_device_id spacemit_i2c_of_match[] = {
> + { .compatible = "spacemit,k1-i2c", },
> + { /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, spacemit_i2c_of_match);
> +
> +static struct platform_driver spacemit_i2c_driver = {
> + .probe = spacemit_i2c_probe,
> + .remove = spacemit_i2c_remove,
> + .driver = {
> + .name = "i2c-k1",
> + .of_match_table = spacemit_i2c_of_match,
> + },
> +};
> +module_platform_driver(spacemit_i2c_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("I2C bus driver for SpacemiT K1 SoC");
>
> --
> 2.34.1
>
--
Yixun Lan (dlan)
Gentoo Linux Developer
GPG Key ID AABEFD55
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