Re: [PATCH] i2c: add sc18is600 driver

From: Sebastian Reichel
Date: Fri Apr 28 2017 - 07:31:29 EST

Hi,

ping? This is really useful on RPi, which has only has I2C
controllers with broken clock stretching support.

-- Sebastian

On Wed, Mar 29, 2017 at 04:03:39PM +0200, Sebastian Reichel wrote:
> This adds an I²C master driver for SPI -> I²C bus bridge chips.
> It currently supports NXP's SC18IS600 and SC18IS601, as well as
> Silicon Labs' CP2120. The driver was only tested on SC18IS600.
>
> Signed-off-By: Sebastian Reichel <sre@xxxxxxxxxx>
> ---
> .../devicetree/bindings/i2c/i2c-cp2120.txt | 1 +
> .../devicetree/bindings/i2c/i2c-sc18is600.txt | 62 +++
> drivers/i2c/busses/Kconfig | 10 +
> drivers/i2c/busses/Makefile | 1 +
> drivers/i2c/busses/i2c-sc18is600.c | 572 +++++++++++++++++++++
> 5 files changed, 646 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/i2c/i2c-cp2120.txt
> create mode 100644 Documentation/devicetree/bindings/i2c/i2c-sc18is600.txt
> create mode 100644 drivers/i2c/busses/i2c-sc18is600.c
>
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-cp2120.txt b/Documentation/devicetree/bindings/i2c/i2c-cp2120.txt
> new file mode 100644
> index 000000000000..95e06e74f288
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/i2c/i2c-cp2120.txt
> @@ -0,0 +1 @@
> +Please see binding for i2c-sc18is600
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-sc18is600.txt b/Documentation/devicetree/bindings/i2c/i2c-sc18is600.txt
> new file mode 100644
> index 000000000000..d0d9e680a5d6
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/i2c/i2c-sc18is600.txt
> @@ -0,0 +1,62 @@
> +NXP SC18IS600 and Silabs CP2120 - SPI to I2C bus bridge
> +
> +NXP SC18IS600 is a SPI slave chip, which implements an I²C host,
> +also known as SPI to I²C bus bridge. SC18IS601 is the same chip,
> +but has an external clock input instead of using a builtin
> +oscillator. CP2120 is a similar chip from Silabs, which implements
> +the same interface as NXP's SC18IS600.
> +
> +Required properties:
> + - compatible: Should contain one of
> + * "nxp,sc18is600"
> + * "nxp,sc18is601"
> + * "silabs,cp2120"
> + - reg: address of the chip on SPI bus
> + - interrupts: Interrupt specifier. Refer to interrupt bindings.
> + - #address-cells: Should be 1.
> + - #size-cells: Should be 0.
> +
> +Required properties for sc18is601:
> + - clkin: Clock specifier for CLKIN pin
> +
> +Optional properties:
> + - clock-frequency:
> + Desired I2C bus frequency in Hz, otherwise defaults to 100 KHz
> + - reset-gpios
> + GPIO specifier for reset pin, which is active low.
> + - vdd-supply
> + Regulator specifier for VDD supply (3.3V).
> + - Child nodes conforming to i2c bus binding
> +
> +Example:
> +
> +&spi_controller {
> + sc18is600: i2c@0 {
> + compatible = "nxp,sc18is600";
> + spi-max-frequency = <700000>; /* 700KHz */
> + spi-cpol;
> + spi-cpha;
> + reg = <0>;
> +
> + vdd-supply = <&regulator_v33>;
> +
> + interrupt-parent = <&socgpio>;
> + interrupts = <25 0x2>;
> +
> + reset-gpios = <&i2cgpio1 9 GPIO_ACTIVE_LOW>;
> +
> + clock-frequency = <100000>; /* 100KHz */
> +
> + #address-cells = <0x1>;
> + #size-cells = <0x0>;
> + };
> +};
> +
> +&sc18is600 {
> + i2c_device@42 {
> + compatible = "some,i2c-device";
> + reg = <0x42>;
> + };
> +
> + ...
> +};
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index 8adc0f1d7ad0..3e6386ff8de3 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -210,6 +210,16 @@ config I2C_NFORCE2_S4985
> This driver can also be built as a module. If so, the module
> will be called i2c-nforce2-s4985.
>
> +config I2C_SC18IS600
> + tristate "NXP SC18IS600"
> + depends on SPI && REGMAP
> + help
> + If you say yes to this option, support will be included for the
> + NXP SC18IS600 SPI to I2C-bus interface.
> +
> + This driver can also be built as a module. If so, the module
> + will be called i2c-sc18is600.
> +
> config I2C_SIS5595
> tristate "SiS 5595"
> depends on PCI
> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> index 30b60855fbcd..29971aebd238 100644
> --- a/drivers/i2c/busses/Makefile
> +++ b/drivers/i2c/busses/Makefile
> @@ -18,6 +18,7 @@ obj-$(CONFIG_I2C_ISMT) += i2c-ismt.o
> obj-$(CONFIG_I2C_NFORCE2) += i2c-nforce2.o
> obj-$(CONFIG_I2C_NFORCE2_S4985) += i2c-nforce2-s4985.o
> obj-$(CONFIG_I2C_PIIX4) += i2c-piix4.o
> +obj-$(CONFIG_I2C_SC18IS600) += i2c-sc18is600.o
> obj-$(CONFIG_I2C_SIS5595) += i2c-sis5595.o
> obj-$(CONFIG_I2C_SIS630) += i2c-sis630.o
> obj-$(CONFIG_I2C_SIS96X) += i2c-sis96x.o
> diff --git a/drivers/i2c/busses/i2c-sc18is600.c b/drivers/i2c/busses/i2c-sc18is600.c
> new file mode 100644
> index 000000000000..e4d4b3caf3a9
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-sc18is600.c
> @@ -0,0 +1,572 @@
> +/*
> + * NXP SC18IS600 SPI to I2C bus interface driver
> + *
> + * Copyright (C) 2017 Sebastian Reichel <sre@xxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that 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.
> + *
> + * Datasheets:
> + * - http://www.nxp.com/documents/data_sheet/SC18IS600.pdf
> + * - https://www.silabs.com/documents/public/data-sheets/CP2120.pdf
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/i2c.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/regmap.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/spi/spi.h>
> +
> +#define SC18IS600_I2C_PM_TIMEOUT 1000 /* ms */
> +#define SC18IS600_DEFAULT_FREQ 100000
> +
> +#define SC18IS600_CMD_WR 0x00 /* write */
> +#define SC18IS600_CMD_RD 0x01 /* read */
> +#define SC18IS600_CMD_WR_RD 0x02 /* read after write */
> +#define SC18IS600_CMD_WR_WR 0x03 /* write after write */
> +#define SC18IS600_CMD_RDBUF 0x06 /* read buffer */
> +#define CP2120_CMD_WRMULTI 0x09 /* write to multiple slaves */
> +#define SC18IS600_CMD_SPICON 0x18 /* spi endianess configuration */
> +#define SC18IS600_CMD_REG_WR 0x20 /* write register */
> +#define SC18IS600_CMD_REG_RD 0x21 /* read register */
> +#define SC18IS600_CMD_PWRDWN 0x30 /* power down */
> +#define CP2120_CMD_REVISION 0x40 /* read revision */
> +
> +#define SC18IS600_REG_IO_CONFIG 0x00
> +#define SC18IS600_REG_IO_STATE 0x01
> +#define SC18IS600_REG_I2C_CLOCK 0x02
> +#define SC18IS600_REG_I2C_TIMEOUT 0x03
> +#define SC18IS600_REG_I2C_STAT 0x04
> +#define SC18IS600_REG_I2C_ADDR 0x05
> +#define SC18IS600_REG_I2C_BUFFER 0x06 /* only cp2120 */
> +#define SC18IS600_REG_IO_CONFIG2 0x07 /* only cp2120 */
> +#define SC18IS600_REG_EDGEINT 0x08 /* only cp2120 */
> +#define SC18IS600_REG_I2C_TIMEOUT2 0x09 /* only cp2120 */
> +
> +#define SC18IS600_STAT_OK 0xF0
> +#define SC18IS600_STAT_NAK_ADDR 0xF1
> +#define SC18IS600_STAT_NAK_DATA 0xF2
> +#define SC18IS600_STAT_BUSY 0xF3
> +#define SC18IS600_STAT_TIMEOUT 0xF8
> +#define SC18IS600_STAT_SIZE 0xF9
> +#define SC18IS600_STAT_TIMEOUT2 0xFA /* only cp2120 */
> +#define SC18IS600_STAT_BLOCKED 0xFB /* only cp2120 */
> +
> +#define CMD_BUFFER_SIZE 5
> +
> +enum chiptype {
> + SPI2I2C_SC18IS600,
> + SPI2I2C_SC18IS601,
> + SPI2I2C_CP2120,
> +};
> +
> +struct chipdesc {
> + u8 type;
> + u32 max_spi_speed;
> + u32 buffer_size;
> + u32 clock_base;
> + u32 timeout_base;
> + const struct regmap_config *regmap_cfg;
> +};
> +
> +static bool sc18is600_writeable_reg(struct device *dev, unsigned int reg)
> +{
> + switch (reg) {
> + case SC18IS600_REG_I2C_STAT:
> + case SC18IS600_REG_I2C_BUFFER:
> + return false;
> + default:
> + return true;
> + }
> +}
> +
> +static const struct regmap_config sc18is600_regmap_config = {
> + .reg_bits = 8,
> + .val_bits = 8,
> +
> + .max_register = 0x05,
> + .writeable_reg = sc18is600_writeable_reg,
> +};
> +
> +static const struct regmap_config cp2120_regmap_config = {
> + .reg_bits = 8,
> + .val_bits = 8,
> +
> + .max_register = 0x09,
> + .writeable_reg = sc18is600_writeable_reg,
> +};
> +
> +/*
> + * Note: The sc18is600's datasheet promises 1.2MHz SPI support, but my chip did
> + * not behave correctly at that speed. It received the bytes correctly, but
> + * just sent them back instead of interpreting them correctly. At 800 KHz I
> + * still got a few errors (about 1%) and at 700 KHz everything works smoothly.
> + */
> +static const struct chipdesc chip_sc18is600 = {
> + .type = SPI2I2C_SC18IS600,
> + .max_spi_speed = 700000,
> + .buffer_size = 96,
> + .clock_base = 1843200,
> + .buffer_size = 96,
> + .clock_base = 1843200,
> + .timeout_base = 1125, /* 112.5 Hz */
> + .regmap_cfg = &sc18is600_regmap_config,
> +};
> +
> +static const struct chipdesc chip_sc18is601 = {
> + .type = SPI2I2C_SC18IS601,
> + .max_spi_speed = 3000000,
> + .buffer_size = 96,
> + .clock_base = 0,
> + .timeout_base = 1125, /* 112.5 Hz */
> + .regmap_cfg = &sc18is600_regmap_config,
> +};
> +
> +static const struct chipdesc chip_cp2120 = {
> + .type = SPI2I2C_CP2120,
> + .max_spi_speed = 1000000,
> + .buffer_size = 255,
> + .clock_base = 2000000,
> + .timeout_base = 1280, /* 128 Hz */
> + .regmap_cfg = &cp2120_regmap_config,
> +};
> +
> +struct sc18is600dev {
> + struct i2c_adapter adapter;
> + struct completion completion;
> + struct spi_device *spi;
> + struct regmap *regmap;
> + const struct chipdesc *chip;
> + struct gpio_desc *reset;
> + struct regulator *vdd;
> + struct clk *clk;
> + u32 clock_base;
> + u32 i2c_clock_frequency;
> + int state;
> +};
> +
> +static irqreturn_t sc18is600_irq_handler(int this_irq, void *data)
> +{
> + struct sc18is600dev *dev = data;
> + int err;
> +
> + err = regmap_read(dev->regmap, SC18IS600_REG_I2C_STAT, &dev->state);
> + if (err)
> + return IRQ_NONE;
> +
> + dev_vdbg(&dev->spi->dev, "irq received, stat=%08x", dev->state);
> +
> + /* no irq is generated for busy state, so ignore this irq */
> + if (dev->state == SC18IS600_STAT_BUSY)
> + return IRQ_NONE;
> +
> + complete(&dev->completion);
> + return IRQ_HANDLED;
> +}
> +
> +static int reg_read(void *context, unsigned int reg, unsigned int *val)
> +{
> + struct device *dev = context;
> + struct spi_device *spi = to_spi_device(dev);
> + u8 txbuffer[2] = { SC18IS600_CMD_REG_RD, reg & 0xff };
> + u8 rxbuffer[1];
> + int err;
> +
> + err = spi_write_then_read(spi, txbuffer, sizeof(txbuffer),
> + rxbuffer, sizeof(rxbuffer));
> + if (err)
> + return err;
> +
> + *val = rxbuffer[0];
> +
> + return 0;
> +}
> +
> +static int reg_write(void *context, unsigned int reg, unsigned int val)
> +{
> + struct device *dev = context;
> + struct spi_device *spi = to_spi_device(dev);
> + u8 txbuffer[3] = { SC18IS600_CMD_REG_WR, reg & 0xff, val & 0xff };
> +
> + return spi_write(spi, txbuffer, sizeof(txbuffer));
> +}
> +
> +static struct regmap_bus regmap_sc18is600_bus = {
> + .reg_write = reg_write,
> + .reg_read = reg_read,
> + .reg_format_endian_default = REGMAP_ENDIAN_BIG,
> + .val_format_endian_default = REGMAP_ENDIAN_BIG,
> +};
> +
> +static void sc18is600_setup_clock_frequency(struct sc18is600dev *dev)
> +{
> + int reg = DIV_ROUND_UP(dev->clock_base, dev->i2c_clock_frequency);
> +
> + if (reg < 5)
> + reg = 5;
> + if (reg > 255)
> + reg = 255;
> +
> + dev_dbg(&dev->spi->dev, "i2c clock frequency: %08x", reg);
> + regmap_write(dev->regmap, SC18IS600_REG_I2C_CLOCK, reg);
> +}
> +
> +static void sc18is600_setup_timeout(struct sc18is600dev *dev,
> + bool enable, int timeout_ms)
> +{
> + int timeout = DIV_ROUND_UP(timeout_ms * dev->chip->timeout_base, 10000);
> + u8 reg;
> +
> + if (timeout <= 0)
> + timeout = 1;
> + if (timeout > 255)
> + timeout = 255;
> +
> + reg = (timeout & 0x7F) << 1;
> + reg |= (!!enable);
> +
> + dev_dbg(&dev->spi->dev, "i2c timeout: %08x", reg);
> + regmap_write(dev->regmap, SC18IS600_REG_I2C_TIMEOUT, reg);
> +}
> +
> +static void sc18is600_reset(struct sc18is600dev *dev)
> +{
> + if (dev->reset) {
> + gpiod_set_value_cansleep(dev->reset, 1);
> + usleep_range(50, 100);
> + gpiod_set_value_cansleep(dev->reset, 0);
> + usleep_range(50, 100);
> + }
> +
> + sc18is600_setup_clock_frequency(dev);
> + sc18is600_setup_timeout(dev, true, 500);
> +}
> +
> +static int sc18is600_read(struct sc18is600dev *dev, struct i2c_msg *msg)
> +{
> + u8 header[] = { SC18IS600_CMD_RD, msg->len, msg->addr << 1 };
> + struct spi_transfer xfer[1] = { 0 };
> +
> + xfer[0].tx_buf = header;
> + xfer[0].len = sizeof(header);
> +
> + dev_dbg(&dev->spi->dev, "r(addr=%x, len=%d)", msg->addr, msg->len);
> + return spi_sync_transfer(dev->spi, xfer, 1);
> +}
> +
> +static int sc18is600_write(struct sc18is600dev *dev, struct i2c_msg *msg)
> +{
> + u8 header[] = { SC18IS600_CMD_WR, msg->len, msg->addr << 1 };
> + struct spi_transfer xfer[2] = { 0 };
> +
> + xfer[0].tx_buf = header;
> + xfer[0].len = sizeof(header);
> +
> + xfer[1].tx_buf = msg->buf;
> + xfer[1].len = msg->len;
> +
> + dev_dbg(&dev->spi->dev, "w(addr=%x, len=%d)", msg->addr, msg->len);
> + return spi_sync_transfer(dev->spi, xfer, 2);
> +}
> +
> +static int sc18is600_read_after_write(struct sc18is600dev *dev,
> + struct i2c_msg *msg1,
> + struct i2c_msg *msg2)
> +{
> + u8 header1[] =
> + { SC18IS600_CMD_WR_RD, msg1->len, msg2->len, msg1->addr << 1 };
> + u8 header2[] = { msg2->addr << 1 };
> + struct spi_transfer xfer[3] = { 0 };
> +
> + xfer[0].tx_buf = header1;
> + xfer[0].len = sizeof(header1);
> +
> + xfer[1].tx_buf = msg1->buf;
> + xfer[1].len = msg1->len;
> +
> + xfer[2].tx_buf = header2;
> + xfer[2].len = sizeof(header2);
> +
> + dev_dbg(&dev->spi->dev, "w(addr=%x, len=%d) + r(addr=%x, len=%d)",
> + msg1->addr, msg1->len, msg2->addr, msg2->len);
> + return spi_sync_transfer(dev->spi, xfer, 3);
> +}
> +
> +static int sc18is600_write_after_write(struct sc18is600dev *dev,
> + struct i2c_msg *msg1,
> + struct i2c_msg *msg2)
> +{
> + u8 header1[] =
> + { SC18IS600_CMD_WR_WR, msg1->len, msg2->len, msg1->addr << 1 };
> + u8 header2[] = { msg2->addr << 1 };
> + struct spi_transfer xfer[4] = { 0 };
> +
> + xfer[0].tx_buf = header1;
> + xfer[0].len = sizeof(header1);
> +
> + xfer[1].tx_buf = msg1->buf;
> + xfer[1].len = msg1->len;
> +
> + xfer[2].tx_buf = header2;
> + xfer[2].len = sizeof(header2);
> +
> + xfer[3].tx_buf = msg2->buf;
> + xfer[3].len = msg2->len;
> +
> + dev_dbg(&dev->spi->dev, "w(addr=%x, len=%d) + w(addr=%x, len=%d)",
> + msg1->addr, msg1->len, msg2->addr, msg2->len);
> + return spi_sync_transfer(dev->spi, xfer, 4);
> +}
> +
> +static int sc18is600_read_buffer(struct sc18is600dev *dev, struct i2c_msg *msg)
> +{
> + static const u8 read_buffer_cmd = SC18IS600_REG_I2C_BUFFER;
> +
> + return spi_write_then_read(dev->spi, &read_buffer_cmd, 1,
> + msg->buf, msg->len);
> +}
> +
> +static int sc18is600_xfer(struct i2c_adapter *adapter,
> + struct i2c_msg *msgs, int num)
> +{
> + struct sc18is600dev *dev = adapter->algo_data;
> + int read_operations = 0;
> + int i, err;
> +
> + for (i = 0; i < num; i++) {
> + if (msgs[i].len > dev->chip->buffer_size)
> + return -EOPNOTSUPP;
> +
> + /* chip only support standard read & write */
> + if (msgs[i].flags & ~I2C_M_RD)
> + return -EOPNOTSUPP;
> +
> + if (msgs[i].flags & I2C_M_RD)
> + read_operations++;
> + }
> +
> + reinit_completion(&dev->completion);
> +
> + if (num == 1 && read_operations == 1)
> + err = sc18is600_read(dev, &msgs[0]);
> + else if (num == 1)
> + err = sc18is600_write(dev, &msgs[0]);
> + else if (num == 2 && read_operations == 1)
> + err = sc18is600_read_after_write(dev, &msgs[0], &msgs[1]);
> + else if (num == 2)
> + err = sc18is600_write_after_write(dev, &msgs[0], &msgs[1]);
> + else
> + return -EOPNOTSUPP;
> +
> + if (err) {
> + dev_err(&dev->spi->dev, "spi transfer failed: %d", err);
> + return err;
> + }
> +
> + err = wait_for_completion_timeout(&dev->completion, adapter->timeout);
> + if (!err) {
> + dev_warn(&dev->spi->dev,
> + "timeout waiting for irq, poll status register");
> + dev->state = SC18IS600_STAT_BUSY;
> + regmap_read(dev->regmap, SC18IS600_REG_I2C_STAT, &dev->state);
> + }
> +
> + switch (dev->state) {
> + case SC18IS600_STAT_OK:
> + break;
> + case SC18IS600_STAT_NAK_ADDR:
> + return -EIO;
> + case SC18IS600_STAT_NAK_DATA:
> + return -EREMOTEIO;
> + case SC18IS600_STAT_SIZE:
> + return -EINVAL;
> + case SC18IS600_STAT_TIMEOUT:
> + return -ETIMEDOUT;
> + case SC18IS600_STAT_TIMEOUT2:
> + return -ETIMEDOUT;
> + case SC18IS600_STAT_BLOCKED:
> + return -ETIMEDOUT;
> + default:
> + case SC18IS600_STAT_BUSY:
> + dev_err(&dev->spi->dev, "device hangup detected, reset!");
> + sc18is600_reset(dev);
> + return -EAGAIN;
> + }
> +
> + if (!read_operations)
> + return 0;
> +
> + err = sc18is600_read_buffer(dev, &msgs[num-1]);
> + if (err)
> + return err;
> +
> + return num;
> +}
> +
> +static u32 sc18is600_func(struct i2c_adapter *adap)
> +{
> + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
> +}
> +
> +static const struct i2c_algorithm sc18is600_algorithm = {
> + .master_xfer = sc18is600_xfer,
> + .functionality = sc18is600_func,
> +};
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id sc18is600_of_match[] = {
> + { .compatible = "nxp,sc18is600", .data = &chip_sc18is600 },
> + { .compatible = "nxp,sc18is601", .data = &chip_sc18is601 },
> + { .compatible = "silabs,cp2120", .data = &chip_cp2120 },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, sc18is600_of_match);
> +#endif
> +
> +static int sc18is600_probe(struct spi_device *spi)
> +{
> + const struct of_device_id *of_id;
> + struct sc18is600dev *dev;
> + int err;
> +
> + of_id = of_match_device(sc18is600_of_match, &spi->dev);
> + if (!of_id)
> + return -ENODEV;
> +
> + dev = devm_kzalloc(&spi->dev, sizeof(*dev), GFP_KERNEL);
> + if (dev == NULL)
> + return -ENOMEM;
> + spi_set_drvdata(spi, dev);
> +
> + init_completion(&dev->completion);
> +
> + dev->spi = spi;
> + dev->adapter.owner = THIS_MODULE;
> + dev->adapter.class = I2C_CLASS_DEPRECATED;
> + dev->adapter.algo = &sc18is600_algorithm;
> + dev->adapter.algo_data = dev;
> + dev->adapter.dev.parent = &spi->dev;
> + dev->chip = of_id->data;
> +
> + snprintf(dev->adapter.name, sizeof(dev->adapter.name),
> + "SC18IS600 at SPI %02d device %02d",
> + spi->master->bus_num, spi->chip_select);
> +
> + spi->bits_per_word = 8;
> + spi->mode = SPI_MODE_3;
> + spi->max_speed_hz = dev->chip->max_spi_speed;
> +
> + err = spi_setup(spi);
> + if (err)
> + return err;
> +
> + dev->reset = devm_gpiod_get_optional(&spi->dev, "reset", GPIOD_OUT_LOW);
> + if (IS_ERR(dev->reset)) {
> + err = PTR_ERR(dev->reset);
> + dev_err(&spi->dev, "Failed to reset gpio, err: %d\n", err);
> + return err;
> + }
> +
> + err = devm_request_threaded_irq(&spi->dev, spi->irq, NULL,
> + sc18is600_irq_handler,
> + IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
> + "sc18is600", dev);
> + if (err) {
> + dev_err(&spi->dev, "Failed to request irq, err: %d\n", err);
> + return err;
> + }
> +
> + dev->regmap = devm_regmap_init(&dev->spi->dev,
> + &regmap_sc18is600_bus, &dev->spi->dev,
> + dev->chip->regmap_cfg);
> + if (IS_ERR(dev->regmap)) {
> + err = PTR_ERR(dev->regmap);
> + dev_err(&spi->dev, "Failed to init regmap, err: %d\n", err);
> + return err;
> + }
> +
> + err = device_property_read_u32(&spi->dev, "clock-frequency",
> + &dev->i2c_clock_frequency);
> + if (err) {
> + dev->i2c_clock_frequency = SC18IS600_DEFAULT_FREQ;
> + dev_dbg(&spi->dev, "using default frequency %u\n",
> + dev->i2c_clock_frequency);
> + }
> +
> + dev->vdd = devm_regulator_get(&spi->dev, "vdd");
> + if (IS_ERR(dev->vdd)) {
> + err = PTR_ERR(dev->vdd);
> + dev_err(&spi->dev, "could not acquire vdd: %d\n", err);
> + return err;
> + }
> +
> + if (!dev->chip->clock_base) {
> + dev->clk = devm_clk_get(&spi->dev, "clkin");
> + if (IS_ERR(dev->clk)) {
> + err = PTR_ERR(dev->clk);
> + dev_err(&spi->dev, "could not acquire vdd: %d\n", err);
> + return err;
> + }
> +
> + clk_prepare_enable(dev->clk);
> +
> + dev->clock_base = clk_get_rate(dev->clk) / 4;
> + } else {
> + dev->clock_base = dev->chip->clock_base;
> + }
> +
> + err = regulator_enable(dev->vdd);
> + if (err) {
> + dev_err(&spi->dev, "could not enable vdd: %d\n", err);
> + return err;
> + }
> +
> + sc18is600_reset(dev);
> +
> + err = i2c_add_adapter(&dev->adapter);
> + if (err)
> + goto out_disable_regulator;
> +
> + return 0;
> +
> +out_disable_regulator:
> + regulator_disable(dev->vdd);
> + return err;
> +}
> +
> +static int sc18is600_remove(struct spi_device *spi)
> +{
> + struct sc18is600dev *dev = spi_get_drvdata(spi);
> +
> + i2c_del_adapter(&dev->adapter);
> +
> + regulator_disable(dev->vdd);
> +
> + return 0;
> +}
> +
> +static struct spi_driver sc18is600_driver = {
> + .probe = sc18is600_probe,
> + .remove = sc18is600_remove,
> + .driver = {
> + .name = "i2c-sc18is600",
> + .of_match_table = of_match_ptr(sc18is600_of_match),
> + },
> +};
> +module_spi_driver(sc18is600_driver);
> +
> +MODULE_AUTHOR("Sebastian Reichel <sre@xxxxxxxxxx>");
> +MODULE_DESCRIPTION("NXP SC18IS600 I2C bus adapter");
> +MODULE_LICENSE("GPL");
> --
> 2.11.0
>

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