From c41aa3ce938b684d853f1004072b6116a41bb1ce Mon Sep 17 00:00:00 2001 From: Max Schwarz Date: Wed, 11 Jun 2014 22:34:37 +0200 Subject: [PATCH 1/6] i2c: rk3x: add driver for Rockchip RK3xxx SoC I2C adapter Driver for the native I2C adapter found in Rockchip RK3xxx SoCs. Configuration is only possible through devicetree. The driver is interrupt driven and supports the I2C_M_IGNORE_NAK mangling bit. Signed-off-by: Max Schwarz Signed-off-by: Wolfram Sang --- .../devicetree/bindings/i2c/i2c-rk3x.txt | 42 + drivers/i2c/busses/Kconfig | 10 + drivers/i2c/busses/Makefile | 1 + drivers/i2c/busses/i2c-rk3x.c | 762 ++++++++++++++++++ 4 files changed, 815 insertions(+) create mode 100644 Documentation/devicetree/bindings/i2c/i2c-rk3x.txt create mode 100644 drivers/i2c/busses/i2c-rk3x.c diff --git a/Documentation/devicetree/bindings/i2c/i2c-rk3x.txt b/Documentation/devicetree/bindings/i2c/i2c-rk3x.txt new file mode 100644 index 000000000000..dde6c22ce91a --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-rk3x.txt @@ -0,0 +1,42 @@ +* Rockchip RK3xxx I2C controller + +This driver interfaces with the native I2C controller present in Rockchip +RK3xxx SoCs. + +Required properties : + + - reg : Offset and length of the register set for the device + - compatible : should be "rockchip,rk3066-i2c", "rockchip,rk3188-i2c" or + "rockchip,rk3288-i2c". + - interrupts : interrupt number + - clocks : parent clock + +Required on RK3066, RK3188 : + + - rockchip,grf : the phandle of the syscon node for the general register + file (GRF) + - on those SoCs an alias with the correct I2C bus ID (bit offset in the GRF) + is also required. + +Optional properties : + + - clock-frequency : SCL frequency to use (in Hz). If omitted, 100kHz is used. + +Example: + +aliases { + i2c0 = &i2c0; +} + +i2c0: i2c@2002d000 { + compatible = "rockchip,rk3188-i2c"; + reg = <0x2002d000 0x1000>; + interrupts = ; + #address-cells = <1>; + #size-cells = <0>; + + rockchip,grf = <&grf>; + + clock-names = "i2c"; + clocks = <&cru PCLK_I2C0>; +}; diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index 620d1004a1e7..759ee30dc63a 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -676,6 +676,16 @@ config I2C_RIIC This driver can also be built as a module. If so, the module will be called i2c-riic. +config I2C_RK3X + tristate "Rockchip RK3xxx I2C adapter" + depends on OF + help + Say Y here to include support for the I2C adapter in Rockchip RK3xxx + SoCs. + + This driver can also be built as a module. If so, the module will + be called i2c-rk3x. + config HAVE_S3C2410_I2C bool help diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index 298692cc6000..8ac83374cf7e 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -66,6 +66,7 @@ obj-$(CONFIG_I2C_PXA) += i2c-pxa.o obj-$(CONFIG_I2C_PXA_PCI) += i2c-pxa-pci.o obj-$(CONFIG_I2C_QUP) += i2c-qup.o obj-$(CONFIG_I2C_RIIC) += i2c-riic.o +obj-$(CONFIG_I2C_RK3X) += i2c-rk3x.o obj-$(CONFIG_I2C_S3C2410) += i2c-s3c2410.o obj-$(CONFIG_I2C_S6000) += i2c-s6000.o obj-$(CONFIG_I2C_SH7760) += i2c-sh7760.o diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c new file mode 100644 index 000000000000..9e3084c5e343 --- /dev/null +++ b/drivers/i2c/busses/i2c-rk3x.c @@ -0,0 +1,762 @@ +/* + * Driver for I2C adapter in Rockchip RK3xxx SoC + * + * Max Schwarz + * based on the patches by Rockchip Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + + +/* Register Map */ +#define REG_CON 0x00 /* control register */ +#define REG_CLKDIV 0x04 /* clock divisor register */ +#define REG_MRXADDR 0x08 /* slave address for REGISTER_TX */ +#define REG_MRXRADDR 0x0c /* slave register address for REGISTER_TX */ +#define REG_MTXCNT 0x10 /* number of bytes to be transmitted */ +#define REG_MRXCNT 0x14 /* number of bytes to be received */ +#define REG_IEN 0x18 /* interrupt enable */ +#define REG_IPD 0x1c /* interrupt pending */ +#define REG_FCNT 0x20 /* finished count */ + +/* Data buffer offsets */ +#define TXBUFFER_BASE 0x100 +#define RXBUFFER_BASE 0x200 + +/* REG_CON bits */ +#define REG_CON_EN BIT(0) +enum { + REG_CON_MOD_TX = 0, /* transmit data */ + REG_CON_MOD_REGISTER_TX, /* select register and restart */ + REG_CON_MOD_RX, /* receive data */ + REG_CON_MOD_REGISTER_RX, /* broken: transmits read addr AND writes + * register addr */ +}; +#define REG_CON_MOD(mod) ((mod) << 1) +#define REG_CON_MOD_MASK (BIT(1) | BIT(2)) +#define REG_CON_START BIT(3) +#define REG_CON_STOP BIT(4) +#define REG_CON_LASTACK BIT(5) /* 1: send NACK after last received byte */ +#define REG_CON_ACTACK BIT(6) /* 1: stop if NACK is received */ + +/* REG_MRXADDR bits */ +#define REG_MRXADDR_VALID(x) BIT(24 + (x)) /* [x*8+7:x*8] of MRX[R]ADDR valid */ + +/* REG_IEN/REG_IPD bits */ +#define REG_INT_BTF BIT(0) /* a byte was transmitted */ +#define REG_INT_BRF BIT(1) /* a byte was received */ +#define REG_INT_MBTF BIT(2) /* master data transmit finished */ +#define REG_INT_MBRF BIT(3) /* master data receive finished */ +#define REG_INT_START BIT(4) /* START condition generated */ +#define REG_INT_STOP BIT(5) /* STOP condition generated */ +#define REG_INT_NAKRCV BIT(6) /* NACK received */ +#define REG_INT_ALL 0x7f + +/* Constants */ +#define WAIT_TIMEOUT 200 /* ms */ +#define DEFAULT_SCL_RATE (100 * 1000) /* Hz */ + +enum rk3x_i2c_state { + STATE_IDLE, + STATE_START, + STATE_READ, + STATE_WRITE, + STATE_STOP +}; + +/** + * @grf_offset: offset inside the grf regmap for setting the i2c type + */ +struct rk3x_i2c_soc_data { + int grf_offset; +}; + +struct rk3x_i2c { + struct i2c_adapter adap; + struct device *dev; + struct rk3x_i2c_soc_data *soc_data; + + /* Hardware resources */ + void __iomem *regs; + struct clk *clk; + + /* Settings */ + unsigned int scl_frequency; + + /* Synchronization & notification */ + spinlock_t lock; + wait_queue_head_t wait; + bool busy; + + /* Current message */ + struct i2c_msg *msg; + u8 addr; + unsigned int mode; + bool is_last_msg; + + /* I2C state machine */ + enum rk3x_i2c_state state; + unsigned int processed; /* sent/received bytes */ + int error; +}; + +static inline void i2c_writel(struct rk3x_i2c *i2c, u32 value, + unsigned int offset) +{ + writel(value, i2c->regs + offset); +} + +static inline u32 i2c_readl(struct rk3x_i2c *i2c, unsigned int offset) +{ + return readl(i2c->regs + offset); +} + +/* Reset all interrupt pending bits */ +static inline void rk3x_i2c_clean_ipd(struct rk3x_i2c *i2c) +{ + i2c_writel(i2c, REG_INT_ALL, REG_IPD); +} + +/** + * Generate a START condition, which triggers a REG_INT_START interrupt. + */ +static void rk3x_i2c_start(struct rk3x_i2c *i2c) +{ + u32 val; + + rk3x_i2c_clean_ipd(i2c); + i2c_writel(i2c, REG_INT_START, REG_IEN); + + /* enable adapter with correct mode, send START condition */ + val = REG_CON_EN | REG_CON_MOD(i2c->mode) | REG_CON_START; + + /* if we want to react to NACK, set ACTACK bit */ + if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) + val |= REG_CON_ACTACK; + + i2c_writel(i2c, val, REG_CON); +} + +/** + * Generate a STOP condition, which triggers a REG_INT_STOP interrupt. + * + * @error: Error code to return in rk3x_i2c_xfer + */ +static void rk3x_i2c_stop(struct rk3x_i2c *i2c, int error) +{ + unsigned int ctrl; + + i2c->processed = 0; + i2c->msg = NULL; + i2c->error = error; + + if (i2c->is_last_msg) { + /* Enable stop interrupt */ + i2c_writel(i2c, REG_INT_STOP, REG_IEN); + + i2c->state = STATE_STOP; + + ctrl = i2c_readl(i2c, REG_CON); + ctrl |= REG_CON_STOP; + i2c_writel(i2c, ctrl, REG_CON); + } else { + /* Signal rk3x_i2c_xfer to start the next message. */ + i2c->busy = false; + i2c->state = STATE_IDLE; + + /* + * The HW is actually not capable of REPEATED START. But we can + * get the intended effect by resetting its internal state + * and issuing an ordinary START. + */ + i2c_writel(i2c, 0, REG_CON); + + /* signal that we are finished with the current msg */ + wake_up(&i2c->wait); + } +} + +/** + * Setup a read according to i2c->msg + */ +static void rk3x_i2c_prepare_read(struct rk3x_i2c *i2c) +{ + unsigned int len = i2c->msg->len - i2c->processed; + u32 con; + + con = i2c_readl(i2c, REG_CON); + + /* + * The hw can read up to 32 bytes at a time. If we need more than one + * chunk, send an ACK after the last byte of the current chunk. + */ + if (unlikely(len > 32)) { + len = 32; + con &= ~REG_CON_LASTACK; + } else { + con |= REG_CON_LASTACK; + } + + /* make sure we are in plain RX mode if we read a second chunk */ + if (i2c->processed != 0) { + con &= ~REG_CON_MOD_MASK; + con |= REG_CON_MOD(REG_CON_MOD_RX); + } + + i2c_writel(i2c, con, REG_CON); + i2c_writel(i2c, len, REG_MRXCNT); +} + +/** + * Fill the transmit buffer with data from i2c->msg + */ +static void rk3x_i2c_fill_transmit_buf(struct rk3x_i2c *i2c) +{ + unsigned int i, j; + u32 cnt = 0; + u32 val; + u8 byte; + + for (i = 0; i < 8; ++i) { + val = 0; + for (j = 0; j < 4; ++j) { + if (i2c->processed == i2c->msg->len) + break; + + if (i2c->processed == 0 && cnt == 0) + byte = (i2c->addr & 0x7f) << 1; + else + byte = i2c->msg->buf[i2c->processed++]; + + val |= byte << (j * 8); + cnt++; + } + + i2c_writel(i2c, val, TXBUFFER_BASE + 4 * i); + + if (i2c->processed == i2c->msg->len) + break; + } + + i2c_writel(i2c, cnt, REG_MTXCNT); +} + + +/* IRQ handlers for individual states */ + +static void rk3x_i2c_handle_start(struct rk3x_i2c *i2c, unsigned int ipd) +{ + if (!(ipd & REG_INT_START)) { + rk3x_i2c_stop(i2c, -EIO); + dev_warn(i2c->dev, "unexpected irq in START: 0x%x\n", ipd); + rk3x_i2c_clean_ipd(i2c); + return; + } + + /* ack interrupt */ + i2c_writel(i2c, REG_INT_START, REG_IPD); + + /* disable start bit */ + i2c_writel(i2c, i2c_readl(i2c, REG_CON) & ~REG_CON_START, REG_CON); + + /* enable appropriate interrupts and transition */ + if (i2c->mode == REG_CON_MOD_TX) { + i2c_writel(i2c, REG_INT_MBTF | REG_INT_NAKRCV, REG_IEN); + i2c->state = STATE_WRITE; + rk3x_i2c_fill_transmit_buf(i2c); + } else { + /* in any other case, we are going to be reading. */ + i2c_writel(i2c, REG_INT_MBRF | REG_INT_NAKRCV, REG_IEN); + i2c->state = STATE_READ; + rk3x_i2c_prepare_read(i2c); + } +} + +static void rk3x_i2c_handle_write(struct rk3x_i2c *i2c, unsigned int ipd) +{ + if (!(ipd & REG_INT_MBTF)) { + rk3x_i2c_stop(i2c, -EIO); + dev_err(i2c->dev, "unexpected irq in WRITE: 0x%x\n", ipd); + rk3x_i2c_clean_ipd(i2c); + return; + } + + /* ack interrupt */ + i2c_writel(i2c, REG_INT_MBTF, REG_IPD); + + /* are we finished? */ + if (i2c->processed == i2c->msg->len) + rk3x_i2c_stop(i2c, i2c->error); + else + rk3x_i2c_fill_transmit_buf(i2c); +} + +static void rk3x_i2c_handle_read(struct rk3x_i2c *i2c, unsigned int ipd) +{ + unsigned int i; + unsigned int len = i2c->msg->len - i2c->processed; + u32 uninitialized_var(val); + u8 byte; + + /* we only care for MBRF here. */ + if (!(ipd & REG_INT_MBRF)) + return; + + /* ack interrupt */ + i2c_writel(i2c, REG_INT_MBRF, REG_IPD); + + /* read the data from receive buffer */ + for (i = 0; i < len; ++i) { + if (i % 4 == 0) + val = i2c_readl(i2c, RXBUFFER_BASE + (i / 4) * 4); + + byte = (val >> ((i % 4) * 8)) & 0xff; + i2c->msg->buf[i2c->processed++] = byte; + } + + /* are we finished? */ + if (i2c->processed == i2c->msg->len) + rk3x_i2c_stop(i2c, i2c->error); + else + rk3x_i2c_prepare_read(i2c); +} + +static void rk3x_i2c_handle_stop(struct rk3x_i2c *i2c, unsigned int ipd) +{ + unsigned int con; + + if (!(ipd & REG_INT_STOP)) { + rk3x_i2c_stop(i2c, -EIO); + dev_err(i2c->dev, "unexpected irq in STOP: 0x%x\n", ipd); + rk3x_i2c_clean_ipd(i2c); + return; + } + + /* ack interrupt */ + i2c_writel(i2c, REG_INT_STOP, REG_IPD); + + /* disable STOP bit */ + con = i2c_readl(i2c, REG_CON); + con &= ~REG_CON_STOP; + i2c_writel(i2c, con, REG_CON); + + i2c->busy = false; + i2c->state = STATE_IDLE; + + /* signal rk3x_i2c_xfer that we are finished */ + wake_up(&i2c->wait); +} + +static irqreturn_t rk3x_i2c_irq(int irqno, void *dev_id) +{ + struct rk3x_i2c *i2c = dev_id; + unsigned int ipd; + + spin_lock(&i2c->lock); + + ipd = i2c_readl(i2c, REG_IPD); + if (i2c->state == STATE_IDLE) { + dev_warn(i2c->dev, "irq in STATE_IDLE, ipd = 0x%x\n", ipd); + rk3x_i2c_clean_ipd(i2c); + goto out; + } + + dev_dbg(i2c->dev, "IRQ: state %d, ipd: %x\n", i2c->state, ipd); + + /* Clean interrupt bits we don't care about */ + ipd &= ~(REG_INT_BRF | REG_INT_BTF); + + if (ipd & REG_INT_NAKRCV) { + /* + * We got a NACK in the last operation. Depending on whether + * IGNORE_NAK is set, we have to stop the operation and report + * an error. + */ + i2c_writel(i2c, REG_INT_NAKRCV, REG_IPD); + + ipd &= ~REG_INT_NAKRCV; + + if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) + rk3x_i2c_stop(i2c, -ENXIO); + } + + /* is there anything left to handle? */ + if (unlikely(ipd == 0)) + goto out; + + switch (i2c->state) { + case STATE_START: + rk3x_i2c_handle_start(i2c, ipd); + break; + case STATE_WRITE: + rk3x_i2c_handle_write(i2c, ipd); + break; + case STATE_READ: + rk3x_i2c_handle_read(i2c, ipd); + break; + case STATE_STOP: + rk3x_i2c_handle_stop(i2c, ipd); + break; + case STATE_IDLE: + break; + } + +out: + spin_unlock(&i2c->lock); + return IRQ_HANDLED; +} + +static void rk3x_i2c_set_scl_rate(struct rk3x_i2c *i2c, unsigned long scl_rate) +{ + unsigned long i2c_rate = clk_get_rate(i2c->clk); + unsigned int div; + + /* SCL rate = (clk rate) / (8 * DIV) */ + div = DIV_ROUND_UP(i2c_rate, scl_rate * 8); + + /* The lower and upper half of the CLKDIV reg describe the length of + * SCL low & high periods. */ + div = DIV_ROUND_UP(div, 2); + + i2c_writel(i2c, (div << 16) | (div & 0xffff), REG_CLKDIV); +} + +/** + * Setup I2C registers for an I2C operation specified by msgs, num. + * + * Must be called with i2c->lock held. + * + * @msgs: I2C msgs to process + * @num: Number of msgs + * + * returns: Number of I2C msgs processed or negative in case of error + */ +static int rk3x_i2c_setup(struct rk3x_i2c *i2c, struct i2c_msg *msgs, int num) +{ + u32 addr = (msgs[0].addr & 0x7f) << 1; + int ret = 0; + + /* + * The I2C adapter can issue a small (len < 4) write packet before + * reading. This speeds up SMBus-style register reads. + * The MRXADDR/MRXRADDR hold the slave address and the slave register + * address in this case. + */ + + if (num >= 2 && msgs[0].len < 4 && + !(msgs[0].flags & I2C_M_RD) && (msgs[1].flags & I2C_M_RD)) { + u32 reg_addr = 0; + int i; + + dev_dbg(i2c->dev, "Combined write/read from addr 0x%x\n", + addr >> 1); + + /* Fill MRXRADDR with the register address(es) */ + for (i = 0; i < msgs[0].len; ++i) { + reg_addr |= msgs[0].buf[i] << (i * 8); + reg_addr |= REG_MRXADDR_VALID(i); + } + + /* msgs[0] is handled by hw. */ + i2c->msg = &msgs[1]; + + i2c->mode = REG_CON_MOD_REGISTER_TX; + + i2c_writel(i2c, addr | REG_MRXADDR_VALID(0), REG_MRXADDR); + i2c_writel(i2c, reg_addr, REG_MRXRADDR); + + ret = 2; + } else { + /* + * We'll have to do it the boring way and process the msgs + * one-by-one. + */ + + if (msgs[0].flags & I2C_M_RD) { + addr |= 1; /* set read bit */ + + /* + * We have to transmit the slave addr first. Use + * MOD_REGISTER_TX for that purpose. + */ + i2c->mode = REG_CON_MOD_REGISTER_TX; + i2c_writel(i2c, addr | REG_MRXADDR_VALID(0), + REG_MRXADDR); + i2c_writel(i2c, 0, REG_MRXRADDR); + } else { + i2c->mode = REG_CON_MOD_TX; + } + + i2c->msg = &msgs[0]; + + ret = 1; + } + + i2c->addr = msgs[0].addr; + i2c->busy = true; + i2c->state = STATE_START; + i2c->processed = 0; + i2c->error = 0; + + rk3x_i2c_clean_ipd(i2c); + + return ret; +} + +static int rk3x_i2c_xfer(struct i2c_adapter *adap, + struct i2c_msg *msgs, int num) +{ + struct rk3x_i2c *i2c = (struct rk3x_i2c *)adap->algo_data; + unsigned long timeout, flags; + int ret = 0; + int i; + + spin_lock_irqsave(&i2c->lock, flags); + + clk_enable(i2c->clk); + + /* The clock rate might have changed, so setup the divider again */ + rk3x_i2c_set_scl_rate(i2c, i2c->scl_frequency); + + i2c->is_last_msg = false; + + /* + * Process msgs. We can handle more than one message at once (see + * rk3x_i2c_setup()). + */ + for (i = 0; i < num; i += ret) { + ret = rk3x_i2c_setup(i2c, msgs + i, num - i); + + if (ret < 0) { + dev_err(i2c->dev, "rk3x_i2c_setup() failed\n"); + break; + } + + if (i + ret >= num) + i2c->is_last_msg = true; + + spin_unlock_irqrestore(&i2c->lock, flags); + + rk3x_i2c_start(i2c); + + timeout = wait_event_timeout(i2c->wait, !i2c->busy, + msecs_to_jiffies(WAIT_TIMEOUT)); + + spin_lock_irqsave(&i2c->lock, flags); + + if (timeout == 0) { + dev_err(i2c->dev, "timeout, ipd: 0x%02x, state: %d\n", + i2c_readl(i2c, REG_IPD), i2c->state); + + /* Force a STOP condition without interrupt */ + i2c_writel(i2c, 0, REG_IEN); + i2c_writel(i2c, REG_CON_EN | REG_CON_STOP, REG_CON); + + i2c->state = STATE_IDLE; + + ret = -ETIMEDOUT; + break; + } + + if (i2c->error) { + ret = i2c->error; + break; + } + } + + clk_disable(i2c->clk); + spin_unlock_irqrestore(&i2c->lock, flags); + + return ret; +} + +static u32 rk3x_i2c_func(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING; +} + +static const struct i2c_algorithm rk3x_i2c_algorithm = { + .master_xfer = rk3x_i2c_xfer, + .functionality = rk3x_i2c_func, +}; + +static struct rk3x_i2c_soc_data soc_data[3] = { + { .grf_offset = 0x154 }, /* rk3066 */ + { .grf_offset = 0x0a4 }, /* rk3188 */ + { .grf_offset = -1 }, /* no I2C switching needed */ +}; + +static const struct of_device_id rk3x_i2c_match[] = { + { .compatible = "rockchip,rk3066-i2c", .data = (void *)&soc_data[0] }, + { .compatible = "rockchip,rk3188-i2c", .data = (void *)&soc_data[1] }, + { .compatible = "rockchip,rk3288-i2c", .data = (void *)&soc_data[2] }, +}; + +static int rk3x_i2c_probe(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + const struct of_device_id *match; + struct rk3x_i2c *i2c; + struct resource *mem; + int ret = 0; + int bus_nr; + u32 value; + int irq; + + i2c = devm_kzalloc(&pdev->dev, sizeof(struct rk3x_i2c), GFP_KERNEL); + if (!i2c) + return -ENOMEM; + + match = of_match_node(rk3x_i2c_match, np); + i2c->soc_data = (struct rk3x_i2c_soc_data *)match->data; + + if (of_property_read_u32(pdev->dev.of_node, "clock-frequency", + &i2c->scl_frequency)) { + dev_info(&pdev->dev, "using default SCL frequency: %d\n", + DEFAULT_SCL_RATE); + i2c->scl_frequency = DEFAULT_SCL_RATE; + } + + if (i2c->scl_frequency == 0 || i2c->scl_frequency > 400 * 1000) { + dev_warn(&pdev->dev, "invalid SCL frequency specified.\n"); + dev_warn(&pdev->dev, "using default SCL frequency: %d\n", + DEFAULT_SCL_RATE); + i2c->scl_frequency = DEFAULT_SCL_RATE; + } + + strlcpy(i2c->adap.name, "rk3x-i2c", sizeof(i2c->adap.name)); + i2c->adap.owner = THIS_MODULE; + i2c->adap.algo = &rk3x_i2c_algorithm; + i2c->adap.retries = 3; + i2c->adap.dev.of_node = np; + i2c->adap.algo_data = i2c; + i2c->adap.dev.parent = &pdev->dev; + + i2c->dev = &pdev->dev; + + spin_lock_init(&i2c->lock); + init_waitqueue_head(&i2c->wait); + + i2c->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(i2c->clk)) { + dev_err(&pdev->dev, "cannot get clock\n"); + return PTR_ERR(i2c->clk); + } + + mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); + i2c->regs = devm_ioremap_resource(&pdev->dev, mem); + if (IS_ERR(i2c->regs)) + return PTR_ERR(i2c->regs); + + /* Try to set the I2C adapter number from dt */ + bus_nr = of_alias_get_id(np, "i2c"); + + /* + * Switch to new interface if the SoC also offers the old one. + * The control bit is located in the GRF register space. + */ + if (i2c->soc_data->grf_offset >= 0) { + struct regmap *grf; + + grf = syscon_regmap_lookup_by_phandle(np, "rockchip,grf"); + if (IS_ERR(grf)) { + dev_err(&pdev->dev, + "rk3x-i2c needs 'rockchip,grf' property\n"); + return PTR_ERR(grf); + } + + if (bus_nr < 0) { + dev_err(&pdev->dev, "rk3x-i2c needs i2cX alias"); + return -EINVAL; + } + + /* 27+i: write mask, 11+i: value */ + value = BIT(27 + bus_nr) | BIT(11 + bus_nr); + + ret = regmap_write(grf, i2c->soc_data->grf_offset, value); + if (ret != 0) { + dev_err(i2c->dev, "Could not write to GRF: %d\n", ret); + return ret; + } + } + + /* IRQ setup */ + irq = platform_get_irq(pdev, 0); + if (irq < 0) { + dev_err(&pdev->dev, "cannot find rk3x IRQ\n"); + return irq; + } + + ret = devm_request_irq(&pdev->dev, irq, rk3x_i2c_irq, + 0, dev_name(&pdev->dev), i2c); + if (ret < 0) { + dev_err(&pdev->dev, "cannot request IRQ\n"); + return ret; + } + + platform_set_drvdata(pdev, i2c); + + ret = clk_prepare(i2c->clk); + if (ret < 0) { + dev_err(&pdev->dev, "Could not prepare clock\n"); + return ret; + } + + ret = i2c_add_adapter(&i2c->adap); + if (ret < 0) { + dev_err(&pdev->dev, "Could not register adapter\n"); + goto err_clk; + } + + dev_info(&pdev->dev, "Initialized RK3xxx I2C bus at %p\n", i2c->regs); + + return 0; + +err_clk: + clk_unprepare(i2c->clk); + return ret; +} + +static int rk3x_i2c_remove(struct platform_device *pdev) +{ + struct rk3x_i2c *i2c = platform_get_drvdata(pdev); + + i2c_del_adapter(&i2c->adap); + clk_unprepare(i2c->clk); + + return 0; +} + +static struct platform_driver rk3x_i2c_driver = { + .probe = rk3x_i2c_probe, + .remove = rk3x_i2c_remove, + .driver = { + .owner = THIS_MODULE, + .name = "rk3x-i2c", + .of_match_table = rk3x_i2c_match, + }, +}; + +module_platform_driver(rk3x_i2c_driver); + +MODULE_DESCRIPTION("Rockchip RK3xxx I2C Bus driver"); +MODULE_AUTHOR("Max Schwarz "); +MODULE_LICENSE("GPL v2"); From bb336ba0aaa5bef253d60bdeb08537ddecc7f42f Mon Sep 17 00:00:00 2001 From: Boris BREZILLON Date: Wed, 11 Jun 2014 11:17:29 +0200 Subject: [PATCH 2/6] i2c: sunxi: add P2WI DT bindings documentation P2WI (Push/Pull 2 Wire Interface) is an SMBus like bus used to communicate with some PMICs (like the AXP221). Document P2WI DT bindings which are pretty much the same as the one defined for the marvell's mv64xxx controller. Signed-off-by: Boris BREZILLON Signed-off-by: Wolfram Sang --- .../bindings/i2c/i2c-sunxi-p2wi.txt | 41 +++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 Documentation/devicetree/bindings/i2c/i2c-sunxi-p2wi.txt diff --git a/Documentation/devicetree/bindings/i2c/i2c-sunxi-p2wi.txt b/Documentation/devicetree/bindings/i2c/i2c-sunxi-p2wi.txt new file mode 100644 index 000000000000..6b765485af7d --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-sunxi-p2wi.txt @@ -0,0 +1,41 @@ + +* Allwinner P2WI (Push/Pull 2 Wire Interface) controller + +Required properties : + + - reg : Offset and length of the register set for the device. + - compatible : Should one of the following: + - "allwinner,sun6i-a31-p2wi" + - interrupts : The interrupt line connected to the P2WI peripheral. + - clocks : The gate clk connected to the P2WI peripheral. + - resets : The reset line connected to the P2WI peripheral. + +Optional properties : + + - clock-frequency : Desired P2WI bus clock frequency in Hz. If not set the +default frequency is 100kHz + +A P2WI may contain one child node encoding a P2WI slave device. + +Slave device properties: + Required properties: + - reg : the I2C slave address used during the initialization + process to switch from I2C to P2WI mode + +Example: + + p2wi@01f03400 { + compatible = "allwinner,sun6i-a31-p2wi"; + reg = <0x01f03400 0x400>; + interrupts = <0 39 4>; + clocks = <&apb0_gates 3>; + clock-frequency = <6000000>; + resets = <&apb0_rst 3>; + + axp221: pmic@68 { + compatible = "x-powers,axp221"; + reg = <0x68>; + + /* ... */ + }; + }; From 3e833490fae55633f6adc03a5e6172d47c01f3e4 Mon Sep 17 00:00:00 2001 From: Boris BREZILLON Date: Wed, 11 Jun 2014 11:17:30 +0200 Subject: [PATCH 3/6] i2c: sunxi: add P2WI (Push/Pull 2 Wire Interface) controller support The P2WI controller looks like an SMBus controller which only supports byte data transfers. But, it differs from standard SMBus protocol on several aspects: - it supports only one slave device, and thus drop the address field - it adds a parity bit every 8bits of data - only one read access is required to read a byte (instead of a write followed by a read access in standard SMBus protocol) - there's no Ack bit after each byte transfer This means this bus cannot be used to interface with standard SMBus devices (the only known device to support this interface is the AXP221 PMIC). However the P2WI protocol is close enough to SMBus to be integrated in the I2C subsystem (see this thread [1] for detailed reasons that led to integrating this driver in the I2C subsystem). [1] http://www.spinics.net/lists/linux-i2c/msg15066.html Signed-off-by: Boris BREZILLON Acked-by: Maxime Ripard Acked-by: Arnd Bergmann Signed-off-by: Wolfram Sang --- drivers/i2c/busses/Kconfig | 13 ++ drivers/i2c/busses/Makefile | 1 + drivers/i2c/busses/i2c-sun6i-p2wi.c | 345 ++++++++++++++++++++++++++++ 3 files changed, 359 insertions(+) create mode 100644 drivers/i2c/busses/i2c-sun6i-p2wi.c diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index 759ee30dc63a..9f7d5859cf65 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -774,6 +774,19 @@ config I2C_STU300 This driver can also be built as a module. If so, the module will be called i2c-stu300. +config I2C_SUN6I_P2WI + tristate "Allwinner sun6i internal P2WI controller" + depends on RESET_CONTROLLER + depends on MACH_SUN6I || COMPILE_TEST + help + If you say yes to this option, support will be included for the + P2WI (Push/Pull 2 Wire Interface) controller embedded in some sunxi + SOCs. + The P2WI looks like an SMBus controller (which supports only byte + accesses), except that it only supports one slave device. + This interface is used to connect to specific PMIC devices (like the + AXP221). + config I2C_TEGRA tristate "NVIDIA Tegra internal I2C controller" depends on ARCH_TEGRA diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index 8ac83374cf7e..dd9a7f8e873f 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -75,6 +75,7 @@ obj-$(CONFIG_I2C_SIMTEC) += i2c-simtec.o obj-$(CONFIG_I2C_SIRF) += i2c-sirf.o obj-$(CONFIG_I2C_ST) += i2c-st.o obj-$(CONFIG_I2C_STU300) += i2c-stu300.o +obj-$(CONFIG_I2C_SUN6I_P2WI) += i2c-sun6i-p2wi.o obj-$(CONFIG_I2C_TEGRA) += i2c-tegra.o obj-$(CONFIG_I2C_VERSATILE) += i2c-versatile.o obj-$(CONFIG_I2C_WMT) += i2c-wmt.o diff --git a/drivers/i2c/busses/i2c-sun6i-p2wi.c b/drivers/i2c/busses/i2c-sun6i-p2wi.c new file mode 100644 index 000000000000..f1d3e6f1a409 --- /dev/null +++ b/drivers/i2c/busses/i2c-sun6i-p2wi.c @@ -0,0 +1,345 @@ +/* + * P2WI (Push-Pull Two Wire Interface) bus driver. + * + * Author: Boris BREZILLON + * + * This file is licensed under the terms of the GNU General Public License + * version 2. This program is licensed "as is" without any warranty of any + * kind, whether express or implied. + * + * The P2WI controller looks like an SMBus controller which only supports byte + * data transfers. But, it differs from standard SMBus protocol on several + * aspects: + * - it supports only one slave device, and thus drop the address field + * - it adds a parity bit every 8bits of data + * - only one read access is required to read a byte (instead of a write + * followed by a read access in standard SMBus protocol) + * - there's no Ack bit after each byte transfer + * + * This means this bus cannot be used to interface with standard SMBus + * devices (the only known device to support this interface is the AXP221 + * PMIC). + * + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include + + +/* P2WI registers */ +#define P2WI_CTRL 0x0 +#define P2WI_CCR 0x4 +#define P2WI_INTE 0x8 +#define P2WI_INTS 0xc +#define P2WI_DADDR0 0x10 +#define P2WI_DADDR1 0x14 +#define P2WI_DLEN 0x18 +#define P2WI_DATA0 0x1c +#define P2WI_DATA1 0x20 +#define P2WI_LCR 0x24 +#define P2WI_PMCR 0x28 + +/* CTRL fields */ +#define P2WI_CTRL_START_TRANS BIT(7) +#define P2WI_CTRL_ABORT_TRANS BIT(6) +#define P2WI_CTRL_GLOBAL_INT_ENB BIT(1) +#define P2WI_CTRL_SOFT_RST BIT(0) + +/* CLK CTRL fields */ +#define P2WI_CCR_SDA_OUT_DELAY(v) (((v) & 0x7) << 8) +#define P2WI_CCR_MAX_CLK_DIV 0xff +#define P2WI_CCR_CLK_DIV(v) ((v) & P2WI_CCR_MAX_CLK_DIV) + +/* STATUS fields */ +#define P2WI_INTS_TRANS_ERR_ID(v) (((v) >> 8) & 0xff) +#define P2WI_INTS_LOAD_BSY BIT(2) +#define P2WI_INTS_TRANS_ERR BIT(1) +#define P2WI_INTS_TRANS_OVER BIT(0) + +/* DATA LENGTH fields*/ +#define P2WI_DLEN_READ BIT(4) +#define P2WI_DLEN_DATA_LENGTH(v) ((v - 1) & 0x7) + +/* LINE CTRL fields*/ +#define P2WI_LCR_SCL_STATE BIT(5) +#define P2WI_LCR_SDA_STATE BIT(4) +#define P2WI_LCR_SCL_CTL BIT(3) +#define P2WI_LCR_SCL_CTL_EN BIT(2) +#define P2WI_LCR_SDA_CTL BIT(1) +#define P2WI_LCR_SDA_CTL_EN BIT(0) + +/* PMU MODE CTRL fields */ +#define P2WI_PMCR_PMU_INIT_SEND BIT(31) +#define P2WI_PMCR_PMU_INIT_DATA(v) (((v) & 0xff) << 16) +#define P2WI_PMCR_PMU_MODE_REG(v) (((v) & 0xff) << 8) +#define P2WI_PMCR_PMU_DEV_ADDR(v) ((v) & 0xff) + +#define P2WI_MAX_FREQ 6000000 + +struct p2wi { + struct i2c_adapter adapter; + struct completion complete; + unsigned int status; + void __iomem *regs; + struct clk *clk; + struct reset_control *rstc; + int slave_addr; +}; + +static irqreturn_t p2wi_interrupt(int irq, void *dev_id) +{ + struct p2wi *p2wi = dev_id; + unsigned long status; + + status = readl(p2wi->regs + P2WI_INTS); + p2wi->status = status; + + /* Clear interrupts */ + status &= (P2WI_INTS_LOAD_BSY | P2WI_INTS_TRANS_ERR | + P2WI_INTS_TRANS_OVER); + writel(status, p2wi->regs + P2WI_INTS); + + complete(&p2wi->complete); + + return IRQ_HANDLED; +} + +static u32 p2wi_functionality(struct i2c_adapter *adap) +{ + return I2C_FUNC_SMBUS_BYTE_DATA; +} + +static int p2wi_smbus_xfer(struct i2c_adapter *adap, u16 addr, + unsigned short flags, char read_write, + u8 command, int size, union i2c_smbus_data *data) +{ + struct p2wi *p2wi = i2c_get_adapdata(adap); + unsigned long dlen = P2WI_DLEN_DATA_LENGTH(1); + + if (p2wi->slave_addr >= 0 && addr != p2wi->slave_addr) { + dev_err(&adap->dev, "invalid P2WI address\n"); + return -EINVAL; + } + + if (!data) + return -EINVAL; + + writel(command, p2wi->regs + P2WI_DADDR0); + + if (read_write == I2C_SMBUS_READ) + dlen |= P2WI_DLEN_READ; + else + writel(data->byte, p2wi->regs + P2WI_DATA0); + + writel(dlen, p2wi->regs + P2WI_DLEN); + + if (readl(p2wi->regs + P2WI_CTRL) & P2WI_CTRL_START_TRANS) { + dev_err(&adap->dev, "P2WI bus busy\n"); + return -EBUSY; + } + + reinit_completion(&p2wi->complete); + + writel(P2WI_INTS_LOAD_BSY | P2WI_INTS_TRANS_ERR | P2WI_INTS_TRANS_OVER, + p2wi->regs + P2WI_INTE); + + writel(P2WI_CTRL_START_TRANS | P2WI_CTRL_GLOBAL_INT_ENB, + p2wi->regs + P2WI_CTRL); + + wait_for_completion(&p2wi->complete); + + if (p2wi->status & P2WI_INTS_LOAD_BSY) { + dev_err(&adap->dev, "P2WI bus busy\n"); + return -EBUSY; + } + + if (p2wi->status & P2WI_INTS_TRANS_ERR) { + dev_err(&adap->dev, "P2WI bus xfer error\n"); + return -ENXIO; + } + + if (read_write == I2C_SMBUS_READ) + data->byte = readl(p2wi->regs + P2WI_DATA0); + + return 0; +} + +static const struct i2c_algorithm p2wi_algo = { + .smbus_xfer = p2wi_smbus_xfer, + .functionality = p2wi_functionality, +}; + +static const struct of_device_id p2wi_of_match_table[] = { + { .compatible = "allwinner,sun6i-a31-p2wi" }, + {} +}; +MODULE_DEVICE_TABLE(of, p2wi_of_match_table); + +static int p2wi_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct device_node *np = dev->of_node; + struct device_node *childnp; + unsigned long parent_clk_freq; + u32 clk_freq = 100000; + struct resource *r; + struct p2wi *p2wi; + u32 slave_addr; + int clk_div; + int irq; + int ret; + + of_property_read_u32(np, "clock-frequency", &clk_freq); + if (clk_freq > P2WI_MAX_FREQ) { + dev_err(dev, + "required clock-frequency (%u Hz) is too high (max = 6MHz)", + clk_freq); + return -EINVAL; + } + + if (of_get_child_count(np) > 1) { + dev_err(dev, "P2WI only supports one slave device\n"); + return -EINVAL; + } + + p2wi = devm_kzalloc(dev, sizeof(struct p2wi), GFP_KERNEL); + if (!p2wi) + return -ENOMEM; + + p2wi->slave_addr = -1; + + /* + * Authorize a p2wi node without any children to be able to use an + * i2c-dev from userpace. + * In this case the slave_addr is set to -1 and won't be checked when + * launching a P2WI transfer. + */ + childnp = of_get_next_available_child(np, NULL); + if (childnp) { + ret = of_property_read_u32(childnp, "reg", &slave_addr); + if (ret) { + dev_err(dev, "invalid slave address on node %s\n", + childnp->full_name); + return -EINVAL; + } + + p2wi->slave_addr = slave_addr; + } + + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + p2wi->regs = devm_ioremap_resource(dev, r); + if (IS_ERR(p2wi->regs)) + return PTR_ERR(p2wi->regs); + + snprintf(p2wi->adapter.name, sizeof(p2wi->adapter.name), pdev->name); + irq = platform_get_irq(pdev, 0); + if (irq < 0) { + dev_err(dev, "failed to retrieve irq: %d\n", ret); + return irq; + } + + p2wi->clk = devm_clk_get(dev, NULL); + if (IS_ERR(p2wi->clk)) { + ret = PTR_ERR(p2wi->clk); + dev_err(dev, "failed to retrieve clk: %d\n", ret); + return ret; + } + + ret = clk_prepare_enable(p2wi->clk); + if (ret) { + dev_err(dev, "failed to enable clk: %d\n", ret); + return ret; + } + + parent_clk_freq = clk_get_rate(p2wi->clk); + + p2wi->rstc = devm_reset_control_get(dev, NULL); + if (IS_ERR(p2wi->rstc)) { + ret = PTR_ERR(p2wi->rstc); + dev_err(dev, "failed to retrieve reset controller: %d\n", ret); + goto err_clk_disable; + } + + ret = reset_control_deassert(p2wi->rstc); + if (ret) { + dev_err(dev, "failed to deassert reset line: %d\n", ret); + goto err_clk_disable; + } + + init_completion(&p2wi->complete); + p2wi->adapter.dev.parent = dev; + p2wi->adapter.algo = &p2wi_algo; + p2wi->adapter.owner = THIS_MODULE; + p2wi->adapter.dev.of_node = pdev->dev.of_node; + platform_set_drvdata(pdev, p2wi); + i2c_set_adapdata(&p2wi->adapter, p2wi); + + ret = devm_request_irq(dev, irq, p2wi_interrupt, 0, pdev->name, p2wi); + if (ret) { + dev_err(dev, "can't register interrupt handler irq%d: %d\n", + irq, ret); + goto err_reset_assert; + } + + writel(P2WI_CTRL_SOFT_RST, p2wi->regs + P2WI_CTRL); + + clk_div = parent_clk_freq / clk_freq; + if (!clk_div) { + dev_warn(dev, + "clock-frequency is too high, setting it to %lu Hz\n", + parent_clk_freq); + clk_div = 1; + } else if (clk_div > P2WI_CCR_MAX_CLK_DIV) { + dev_warn(dev, + "clock-frequency is too low, setting it to %lu Hz\n", + parent_clk_freq / P2WI_CCR_MAX_CLK_DIV); + clk_div = P2WI_CCR_MAX_CLK_DIV; + } + + writel(P2WI_CCR_SDA_OUT_DELAY(1) | P2WI_CCR_CLK_DIV(clk_div), + p2wi->regs + P2WI_CCR); + + ret = i2c_add_adapter(&p2wi->adapter); + if (!ret) + return 0; + +err_reset_assert: + reset_control_assert(p2wi->rstc); + +err_clk_disable: + clk_disable_unprepare(p2wi->clk); + + return ret; +} + +static int p2wi_remove(struct platform_device *dev) +{ + struct p2wi *p2wi = platform_get_drvdata(dev); + + reset_control_assert(p2wi->rstc); + clk_disable_unprepare(p2wi->clk); + i2c_del_adapter(&p2wi->adapter); + + return 0; +} + +static struct platform_driver p2wi_driver = { + .probe = p2wi_probe, + .remove = p2wi_remove, + .driver = { + .owner = THIS_MODULE, + .name = "i2c-sunxi-p2wi", + .of_match_table = p2wi_of_match_table, + }, +}; +module_platform_driver(p2wi_driver); + +MODULE_AUTHOR("Boris BREZILLON "); +MODULE_DESCRIPTION("Allwinner P2WI driver"); +MODULE_LICENSE("GPL v2"); From c155ba884f68b5447529bc75bcb54e68130fd774 Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Thu, 12 Jun 2014 08:52:17 +0200 Subject: [PATCH 4/6] i2c: sun6i-p2wi: use proper return value in probe Fixes: >> drivers/i2c/busses/i2c-sun6i-p2wi.c:243:10: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized] Reported-by: kbuild test robot Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-sun6i-p2wi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-sun6i-p2wi.c b/drivers/i2c/busses/i2c-sun6i-p2wi.c index f1d3e6f1a409..5d2d67820c98 100644 --- a/drivers/i2c/busses/i2c-sun6i-p2wi.c +++ b/drivers/i2c/busses/i2c-sun6i-p2wi.c @@ -240,7 +240,7 @@ static int p2wi_probe(struct platform_device *pdev) snprintf(p2wi->adapter.name, sizeof(p2wi->adapter.name), pdev->name); irq = platform_get_irq(pdev, 0); if (irq < 0) { - dev_err(dev, "failed to retrieve irq: %d\n", ret); + dev_err(dev, "failed to retrieve irq: %d\n", irq); return irq; } From c51bd6acf59f24f2ec4334689329f1741f071621 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Thu, 12 Jun 2014 23:56:09 +0200 Subject: [PATCH 5/6] i2c: rk3x: add NULL entry to the end of_device_id array drivers/i2c/busses/i2c-rk3x.c:610:69-70: rk3x_i2c_match is not NULL terminated at line 610 Make sure of_device_id tables are NULL terminated Generated by: /kbuild/src/linux/scripts/coccinelle/misc/of_table.cocci Signed-off-by: Dan Carpenter Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-rk3x.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c index 9e3084c5e343..a9791509966a 100644 --- a/drivers/i2c/busses/i2c-rk3x.c +++ b/drivers/i2c/busses/i2c-rk3x.c @@ -608,6 +608,7 @@ static const struct of_device_id rk3x_i2c_match[] = { { .compatible = "rockchip,rk3066-i2c", .data = (void *)&soc_data[0] }, { .compatible = "rockchip,rk3188-i2c", .data = (void *)&soc_data[1] }, { .compatible = "rockchip,rk3288-i2c", .data = (void *)&soc_data[2] }, + {}, }; static int rk3x_i2c_probe(struct platform_device *pdev) From 4632a93f015caf6d7db4352f37aab74a39e60d7a Mon Sep 17 00:00:00 2001 From: Boris BREZILLON Date: Fri, 13 Jun 2014 12:23:48 +0200 Subject: [PATCH 6/6] i2c: sun6-p2wi: fix call to snprintf Fixes possible issue in case pdev name contains formatting characters. Signed-off-by: Boris BREZILLON Reported-by: Kees Cook Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-sun6i-p2wi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-sun6i-p2wi.c b/drivers/i2c/busses/i2c-sun6i-p2wi.c index 5d2d67820c98..09de4fd12d57 100644 --- a/drivers/i2c/busses/i2c-sun6i-p2wi.c +++ b/drivers/i2c/busses/i2c-sun6i-p2wi.c @@ -237,7 +237,7 @@ static int p2wi_probe(struct platform_device *pdev) if (IS_ERR(p2wi->regs)) return PTR_ERR(p2wi->regs); - snprintf(p2wi->adapter.name, sizeof(p2wi->adapter.name), pdev->name); + strlcpy(p2wi->adapter.name, pdev->name, sizeof(p2wi->adapter.name)); irq = platform_get_irq(pdev, 0); if (irq < 0) { dev_err(dev, "failed to retrieve irq: %d\n", irq);