diff options
| -rw-r--r-- | Documentation/devicetree/bindings/i2c/i2c-st.txt | 41 | ||||
| -rw-r--r-- | drivers/i2c/busses/Kconfig | 10 | ||||
| -rw-r--r-- | drivers/i2c/busses/Makefile | 1 | ||||
| -rw-r--r-- | drivers/i2c/busses/i2c-st.c | 872 |
4 files changed, 924 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/i2c/i2c-st.txt b/Documentation/devicetree/bindings/i2c/i2c-st.txt new file mode 100644 index 000000000000..437e0db3823c --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-st.txt @@ -0,0 +1,41 @@ +ST SSC binding, for I2C mode operation + +Required properties : +- compatible : Must be "st,comms-ssc-i2c" or "st,comms-ssc4-i2c" +- reg : Offset and length of the register set for the device +- interrupts : the interrupt specifier +- clock-names: Must contain "ssc". +- clocks: Must contain an entry for each name in clock-names. See the common + clock bindings. +- A pinctrl state named "default" must be defined to set pins in mode of + operation for I2C transfer. + +Optional properties : +- clock-frequency : Desired I2C bus clock frequency in Hz. If not specified, + the default 100 kHz frequency will be used. As only Normal and Fast modes + are supported, possible values are 100000 and 400000. +- st,i2c-min-scl-pulse-width-us : The minimum valid SCL pulse width that is + allowed through the deglitch circuit. In units of us. +- st,i2c-min-sda-pulse-width-us : The minimum valid SDA pulse width that is + allowed through the deglitch circuit. In units of us. +- A pinctrl state named "idle" could be defined to set pins in idle state + when I2C instance is not performing a transfer. +- A pinctrl state named "sleep" could be defined to set pins in sleep state + when driver enters in suspend. + + + +Example : + +i2c0: i2c@fed40000 { + compatible = "st,comms-ssc4-i2c"; + reg = <0xfed40000 0x110>; + interrupts = <GIC_SPI 187 IRQ_TYPE_LEVEL_HIGH>; + clocks = <&CLK_S_ICN_REG_0>; + clock-names = "ssc"; + clock-frequency = <400000>; + pinctrl-names = "default"; + pinctrl-0 = <&pinctrl_i2c0_default>; + st,i2c-min-scl-pulse-width-us = <0>; + st,i2c-min-sda-pulse-width-us = <5>; +}; diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index 80e55305656f..012646215e7e 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -702,6 +702,16 @@ config I2C_SIRF This driver can also be built as a module. If so, the module will be called i2c-sirf. +config I2C_ST + tristate "STMicroelectronics SSC I2C support" + depends on ARCH_STI + help + Enable this option to add support for STMicroelectronics SoCs + hardware SSC (Synchronous Serial Controller) as an I2C controller. + + This driver can also be built as module. If so, the module + will be called i2c-st. + config I2C_STU300 tristate "ST Microelectronics DDC I2C interface" depends on MACH_U300 diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index d1ad3712d905..e129486c828f 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -69,6 +69,7 @@ obj-$(CONFIG_I2C_SH7760) += i2c-sh7760.o obj-$(CONFIG_I2C_SH_MOBILE) += i2c-sh_mobile.o 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-$(CONFIG_I2C_TEGRA) += i2c-tegra.o obj-$(CONFIG_I2C_VERSATILE) += i2c-versatile.o diff --git a/drivers/i2c/busses/i2c-st.c b/drivers/i2c/busses/i2c-st.c new file mode 100644 index 000000000000..fa57c5e57efa --- /dev/null +++ b/drivers/i2c/busses/i2c-st.c @@ -0,0 +1,872 @@ +/* + * Copyright (C) 2013 STMicroelectronics + * + * I2C master mode controller driver, used in STMicroelectronics devices. + * + * Author: Maxime Coquelin <maxime.coquelin@st.com> + * + * 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 <linux/module.h> +#include <linux/platform_device.h> +#include <linux/i2c.h> +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/delay.h> +#include <linux/interrupt.h> +#include <linux/err.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> + +/* SSC registers */ +#define SSC_BRG 0x000 +#define SSC_TBUF 0x004 +#define SSC_RBUF 0x008 +#define SSC_CTL 0x00C +#define SSC_IEN 0x010 +#define SSC_STA 0x014 +#define SSC_I2C 0x018 +#define SSC_SLAD 0x01C +#define SSC_REP_START_HOLD 0x020 +#define SSC_START_HOLD 0x024 +#define SSC_REP_START_SETUP 0x028 +#define SSC_DATA_SETUP 0x02C +#define SSC_STOP_SETUP 0x030 +#define SSC_BUS_FREE 0x034 +#define SSC_TX_FSTAT 0x038 +#define SSC_RX_FSTAT 0x03C +#define SSC_PRE_SCALER_BRG 0x040 +#define SSC_CLR 0x080 +#define SSC_NOISE_SUPP_WIDTH 0x100 +#define SSC_PRSCALER 0x104 +#define SSC_NOISE_SUPP_WIDTH_DATAOUT 0x108 +#define SSC_PRSCALER_DATAOUT 0x10c + +/* SSC Control */ +#define SSC_CTL_DATA_WIDTH_9 0x8 +#define SSC_CTL_DATA_WIDTH_MSK 0xf +#define SSC_CTL_BM 0xf +#define SSC_CTL_HB BIT(4) +#define SSC_CTL_PH BIT(5) +#define SSC_CTL_PO BIT(6) +#define SSC_CTL_SR BIT(7) +#define SSC_CTL_MS BIT(8) +#define SSC_CTL_EN BIT(9) +#define SSC_CTL_LPB BIT(10) +#define SSC_CTL_EN_TX_FIFO BIT(11) +#define SSC_CTL_EN_RX_FIFO BIT(12) +#define SSC_CTL_EN_CLST_RX BIT(13) + +/* SSC Interrupt Enable */ +#define SSC_IEN_RIEN BIT(0) +#define SSC_IEN_TIEN BIT(1) +#define SSC_IEN_TEEN BIT(2) +#define SSC_IEN_REEN BIT(3) +#define SSC_IEN_PEEN BIT(4) +#define SSC_IEN_AASEN BIT(6) +#define SSC_IEN_STOPEN BIT(7) +#define SSC_IEN_ARBLEN BIT(8) +#define SSC_IEN_NACKEN BIT(10) +#define SSC_IEN_REPSTRTEN BIT(11) +#define SSC_IEN_TX_FIFO_HALF BIT(12) +#define SSC_IEN_RX_FIFO_HALF_FULL BIT(14) + +/* SSC Status */ +#define SSC_STA_RIR BIT(0) +#define SSC_STA_TIR BIT(1) +#define SSC_STA_TE BIT(2) +#define SSC_STA_RE BIT(3) +#define SSC_STA_PE BIT(4) +#define SSC_STA_CLST BIT(5) +#define SSC_STA_AAS BIT(6) +#define SSC_STA_STOP BIT(7) +#define SSC_STA_ARBL BIT(8) +#define SSC_STA_BUSY BIT(9) +#define SSC_STA_NACK BIT(10) +#define SSC_STA_REPSTRT BIT(11) +#define SSC_STA_TX_FIFO_HALF BIT(12) +#define SSC_STA_TX_FIFO_FULL BIT(13) +#define SSC_STA_RX_FIFO_HALF BIT(14) + +/* SSC I2C Control */ +#define SSC_I2C_I2CM BIT(0) +#define SSC_I2C_STRTG BIT(1) +#define SSC_I2C_STOPG BIT(2) +#define SSC_I2C_ACKG BIT(3) +#define SSC_I2C_AD10 BIT(4) +#define SSC_I2C_TXENB BIT(5) +#define SSC_I2C_REPSTRTG BIT(11) +#define SSC_I2C_SLAVE_DISABLE BIT(12) + +/* SSC Tx FIFO Status */ +#define SSC_TX_FSTAT_STATUS 0x07 + +/* SSC Rx FIFO Status */ +#define SSC_RX_FSTAT_STATUS 0x07 + +/* SSC Clear bit operation */ +#define SSC_CLR_SSCAAS BIT(6) +#define SSC_CLR_SSCSTOP BIT(7) +#define SSC_CLR_SSCARBL BIT(8) +#define SSC_CLR_NACK BIT(10) +#define SSC_CLR_REPSTRT BIT(11) + +/* SSC Clock Prescaler */ +#define SSC_PRSC_VALUE 0x0f + + +#define SSC_TXFIFO_SIZE 0x8 +#define SSC_RXFIFO_SIZE 0x8 + +enum st_i2c_mode { + I2C_MODE_STANDARD, + I2C_MODE_FAST, + I2C_MODE_END, +}; + +/** + * struct st_i2c_timings - per-Mode tuning parameters + * @rate: I2C bus rate + * @rep_start_hold: I2C repeated start hold time requirement + * @rep_start_setup: I2C repeated start set up time requirement + * @start_hold: I2C start hold time requirement + * @data_setup_time: I2C data set up time requirement + * @stop_setup_time: I2C stop set up time requirement + * @bus_free_time: I2C bus free time requirement + * @sda_pulse_min_limit: I2C SDA pulse mini width limit + */ +struct st_i2c_timings { + u32 rate; + u32 rep_start_hold; + u32 rep_start_setup; + u32 start_hold; + u32 data_setup_time; + u32 stop_setup_time; + u32 bus_free_time; + u32 sda_pulse_min_limit; +}; + +/** + * struct st_i2c_client - client specific data + * @addr: 8-bit slave addr, including r/w bit + * @count: number of bytes to be transfered + * @xfered: number of bytes already transferred + * @buf: data buffer + * @result: result of the transfer + * @stop: last I2C msg to be sent, i.e. STOP to be generated + */ +struct st_i2c_client { + u8 addr; + u32 count; + u32 xfered; + u8 *buf; + int result; + bool stop; +}; + +/** + * struct st_i2c_dev - private data of the controller + * @adap: I2C adapter for this controller + * @dev: device for this controller + * @base: virtual memory area + * @complete: completion of I2C message + * @irq: interrupt line for th controller + * @clk: hw ssc block clock + * @mode: I2C mode of the controller. Standard or Fast only supported + * @scl_min_width_us: SCL line minimum pulse width in us + * @sda_min_width_us: SDA line minimum pulse width in us + * @client: I2C transfert information + * @busy: I2C transfer on-going + */ +struct st_i2c_dev { + struct i2c_adapter adap; + struct device *dev; + void __iomem *base; + struct completion complete; + int irq; + struct clk *clk; + int mode; + u32 scl_min_width_us; + u32 sda_min_width_us; + struct st_i2c_client client; + bool busy; +}; + +static inline void st_i2c_set_bits(void __iomem *reg, u32 mask) +{ + writel_relaxed(readl_relaxed(reg) | mask, reg); +} + +static inline void st_i2c_clr_bits(void __iomem *reg, u32 mask) +{ + writel_relaxed(readl_relaxed(reg) & ~mask, reg); +} + +/* From I2C Specifications v0.5 */ +static struct st_i2c_timings i2c_timings[] = { + [I2C_MODE_STANDARD] = { + .rate = 100000, + .rep_start_hold = 4000, + .rep_start_setup = 4700, + .start_hold = 4000, + .data_setup_time = 250, + .stop_setup_time = 4000, + .bus_free_time = 4700, + }, + [I2C_MODE_FAST] = { + .rate = 400000, + .rep_start_hold = 600, + .rep_start_setup = 600, + .start_hold = 600, + .data_setup_time = 100, + .stop_setup_time = 600, + .bus_free_time = 1300, + }, +}; + +static void st_i2c_flush_rx_fifo(struct st_i2c_dev *i2c_dev) +{ + int count, i; + + /* + * Counter only counts up to 7 but fifo size is 8... + * When fifo is full, counter is 0 and RIR bit of status register is + * set + */ + if (readl_relaxed(i2c_dev->base + SSC_STA) & SSC_STA_RIR) + count = SSC_RXFIFO_SIZE; + else + count = readl_relaxed(i2c_dev->base + SSC_RX_FSTAT) & + SSC_RX_FSTAT_STATUS; + + for (i = 0; i < count; i++) + readl_relaxed(i2c_dev->base + SSC_RBUF); +} + +static void st_i2c_soft_reset(struct st_i2c_dev *i2c_dev) +{ + /* + * FIFO needs to be emptied before reseting the IP, + * else the controller raises a BUSY error. + */ + st_i2c_flush_rx_fifo(i2c_dev); + + st_i2c_set_bits(i2c_dev->base + SSC_CTL, SSC_CTL_SR); + st_i2c_clr_bits(i2c_dev->base + SSC_CTL, SSC_CTL_SR); +} + +/** + * st_i2c_hw_config() - Prepare SSC block, calculate and apply tuning timings + * @i2c_dev: Controller's private data + */ +static void st_i2c_hw_config(struct st_i2c_dev *i2c_dev) +{ + unsigned long rate; + u32 val, ns_per_clk; + struct st_i2c_timings *t = &i2c_timings[i2c_dev->mode]; + + st_i2c_soft_reset(i2c_dev); + + val = SSC_CLR_REPSTRT | SSC_CLR_NACK | SSC_CLR_SSCARBL | + SSC_CLR_SSCAAS | SSC_CLR_SSCSTOP; + writel_relaxed(val, i2c_dev->base + SSC_CLR); + + /* SSC Control register setup */ + val = SSC_CTL_PO | SSC_CTL_PH | SSC_CTL_HB | SSC_CTL_DATA_WIDTH_9; + writel_relaxed(val, i2c_dev->base + SSC_CTL); + + rate = clk_get_rate(i2c_dev->clk); + ns_per_clk = 1000000000 / rate; + + /* Baudrate */ + val = rate / (2 * t->rate); + writel_relaxed(val, i2c_dev->base + SSC_BRG); + + /* Pre-scaler baudrate */ + writel_relaxed(1, i2c_dev->base + SSC_PRE_SCALER_BRG); + + /* Enable I2C mode */ + writel_relaxed(SSC_I2C_I2CM, i2c_dev->base + SSC_I2C); + + /* Repeated start hold time */ + val = t->rep_start_hold / ns_per_clk; + writel_relaxed(val, i2c_dev->base + SSC_REP_START_HOLD); + + /* Repeated start set up time */ + val = t->rep_start_setup / ns_per_clk; + writel_relaxed(val, i2c_dev->base + SSC_REP_START_SETUP); + + /* Start hold time */ + val = t->start_hold / ns_per_clk; + writel_relaxed(val, i2c_dev->base + SSC_START_HOLD); + + /* Data set up time */ + val = t->data_setup_time / ns_per_clk; + writel_relaxed(val, i2c_dev->base + SSC_DATA_SETUP); + + /* Stop set up time */ + val = t->stop_setup_time / ns_per_clk; + writel_relaxed(val, i2c_dev->base + SSC_STOP_SETUP); + + /* Bus free time */ + val = t->bus_free_time / ns_per_clk; + writel_relaxed(val, i2c_dev->base + SSC_BUS_FREE); + + /* Prescalers set up */ + val = rate / 10000000; + writel_relaxed(val, i2c_dev->base + SSC_PRSCALER); + writel_relaxed(val, i2c_dev->base + SSC_PRSCALER_DATAOUT); + + /* Noise suppression witdh */ + val = i2c_dev->scl_min_width_us * rate / 100000000; + writel_relaxed(val, i2c_dev->base + SSC_NOISE_SUPP_WIDTH); + + /* Noise suppression max output data delay width */ + val = i2c_dev->sda_min_width_us * rate / 100000000; + writel_relaxed(val, i2c_dev->base + SSC_NOISE_SUPP_WIDTH_DATAOUT); +} + +static int st_i2c_wait_free_bus(struct st_i2c_dev *i2c_dev) +{ + u32 sta; + int i; + + for (i = 0; i < 10; i++) { + sta = readl_relaxed(i2c_dev->base + SSC_STA); + if (!(sta & SSC_STA_BUSY)) + return 0; + + usleep_range(2000, 4000); + } + + dev_err(i2c_dev->dev, "bus not free (status = 0x%08x)\n", sta); + + return -EBUSY; +} + +/** + * st_i2c_write_tx_fifo() - Write a byte in the Tx FIFO + * @i2c_dev: Controller's private data + * @byte: Data to write in the Tx FIFO + */ +static inline void st_i2c_write_tx_fifo(struct st_i2c_dev *i2c_dev, u8 byte) +{ + u16 tbuf = byte << 1; + + writel_relaxed(tbuf | 1, i2c_dev->base + SSC_TBUF); +} + +/** + * st_i2c_wr_fill_tx_fifo() - Fill the Tx FIFO in write mode + * @i2c_dev: Controller's private data + * + * This functions fills the Tx FIFO with I2C transfert buffer when + * in write mode. + */ +static void st_i2c_wr_fill_tx_fifo(struct st_i2c_dev *i2c_dev) +{ + struct st_i2c_client *c = &i2c_dev->client; + u32 tx_fstat, sta; + int i; + + sta = readl_relaxed(i2c_dev->base + SSC_STA); + if (sta & SSC_STA_TX_FIFO_FULL) + return; + + tx_fstat = readl_relaxed(i2c_dev->base + SSC_TX_FSTAT); + tx_fstat &= SSC_TX_FSTAT_STATUS; + + if (c->count < (SSC_TXFIFO_SIZE - tx_fstat)) + i = c->count; + else + i = SSC_TXFIFO_SIZE - tx_fstat; + + for (; i > 0; i--, c->count--, c->buf++) + st_i2c_write_tx_fifo(i2c_dev, *c->buf); +} + +/** + * st_i2c_rd_fill_tx_fifo() - Fill the Tx FIFO in read mode + * @i2c_dev: Controller's private data + * + * This functions fills the Tx FIFO with fixed pattern when + * in read mode to trigger clock. + */ +static void st_i2c_rd_fill_tx_fifo(struct st_i2c_dev *i2c_dev, int max) +{ + struct st_i2c_client *c = &i2c_dev->client; + u32 tx_fstat, sta; + int i; + + sta = readl_relaxed(i2c_dev->base + SSC_STA); + if (sta & SSC_STA_TX_FIFO_FULL) + return; + + tx_fstat = readl_relaxed(i2c_dev->base + SSC_TX_FSTAT); + tx_fstat &= SSC_TX_FSTAT_STATUS; + + if (max < (SSC_TXFIFO_SIZE - tx_fstat)) + i = max; + else + i = SSC_TXFIFO_SIZE - tx_fstat; + + for (; i > 0; i--, c->xfered++) + st_i2c_write_tx_fifo(i2c_dev, 0xff); +} + +static void st_i2c_read_rx_fifo(struct st_i2c_dev *i2c_dev) +{ + struct st_i2c_client *c = &i2c_dev->client; + u32 i, sta; + u16 rbuf; + + sta = readl_relaxed(i2c_dev->base + SSC_STA); + if (sta & SSC_STA_RIR) { + i = SSC_RXFIFO_SIZE; + } else { + i = readl_relaxed(i2c_dev->base + SSC_RX_FSTAT); + i &= SSC_RX_FSTAT_STATUS; + } + + for (; (i > 0) && (c->count > 0); i--, c->count--) { + rbuf = readl_relaxed(i2c_dev->base + SSC_RBUF) >> 1; + *c->buf++ = (u8)rbuf & 0xff; + } + + if (i) { + dev_err(i2c_dev->dev, "Unexpected %d bytes in rx fifo\n", i); + st_i2c_flush_rx_fifo(i2c_dev); + } +} + +/** + * st_i2c_terminate_xfer() - Send either STOP or REPSTART condition + * @i2c_dev: Controller's private data + */ +static void st_i2c_terminate_xfer(struct st_i2c_dev *i2c_dev) +{ + struct st_i2c_client *c = &i2c_dev->client; + + st_i2c_clr_bits(i2c_dev->base + SSC_IEN, SSC_IEN_TEEN); + st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STRTG); + + if (c->stop) { + st_i2c_set_bits(i2c_dev->base + SSC_IEN, SSC_IEN_STOPEN); + st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STOPG); + } else { + st_i2c_set_bits(i2c_dev->base + SSC_IEN, SSC_IEN_REPSTRTEN); + st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_REPSTRTG); + } +} + +/** + * st_i2c_handle_write() - Handle FIFO empty interrupt in case of write + * @i2c_dev: Controller's private data + */ +static void st_i2c_handle_write(struct st_i2c_dev *i2c_dev) +{ + struct st_i2c_client *c = &i2c_dev->client; + + st_i2c_flush_rx_fifo(i2c_dev); + + if (!c->count) + /* End of xfer, send stop or repstart */ + st_i2c_terminate_xfer(i2c_dev); + else + st_i2c_wr_fill_tx_fifo(i2c_dev); +} + +/** + * st_i2c_handle_write() - Handle FIFO enmpty interrupt in case of read + * @i2c_dev: Controller's private data + */ +static void st_i2c_handle_read(struct st_i2c_dev *i2c_dev) +{ + struct st_i2c_client *c = &i2c_dev->client; + u32 ien; + + /* Trash the address read back */ + if (!c->xfered) { + readl_relaxed(i2c_dev->base + SSC_RBUF); + st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_TXENB); + } else { + st_i2c_read_rx_fifo(i2c_dev); + } + + if (!c->count) { + /* End of xfer, send stop or repstart */ + st_i2c_terminate_xfer(i2c_dev); + } else if (c->count == 1) { + /* Penultimate byte to xfer, disable ACK gen. */ + st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_ACKG); + + /* Last received byte is to be handled by NACK interrupt */ + ien = SSC_IEN_NACKEN | SSC_IEN_ARBLEN; + writel_relaxed(ien, i2c_dev->base + SSC_IEN); + + st_i2c_rd_fill_tx_fifo(i2c_dev, c->count); + } else { + st_i2c_rd_fill_tx_fifo(i2c_dev, c->count - 1); + } +} + +/** + * st_i2c_isr() - Interrupt routine + * @irq: interrupt number + * @data: Controller's private data + */ +static irqreturn_t st_i2c_isr_thread(int irq, void *data) +{ + struct st_i2c_dev *i2c_dev = data; + struct st_i2c_client *c = &i2c_dev->client; + u32 sta, ien; + int it; + + ien = readl_relaxed(i2c_dev->base + SSC_IEN); + sta = readl_relaxed(i2c_dev->base + SSC_STA); + + /* Use __fls() to check error bits first */ + it = __fls(sta & ien); + if (it < 0) { + dev_dbg(i2c_dev->dev, "spurious it (sta=0x%04x, ien=0x%04x)\n", + sta, ien); + return IRQ_NONE; + } + + switch (1 << it) { + case SSC_STA_TE: + if (c->addr & I2C_M_RD) + st_i2c_handle_read(i2c_dev); + else + st_i2c_handle_write(i2c_dev); + break; + + case SSC_STA_STOP: + case SSC_STA_REPSTRT: + writel_relaxed(0, i2c_dev->base + SSC_IEN); + complete(&i2c_dev->complete); + break; + + case SSC_STA_NACK: + writel_relaxed(SSC_CLR_NACK, i2c_dev->base + SSC_CLR); + + /* Last received byte handled by NACK interrupt */ + if ((c->addr & I2C_M_RD) && (c->count == 1) && (c->xfered)) { + st_i2c_handle_read(i2c_dev); + break; + } + + it = SSC_IEN_STOPEN | SSC_IEN_ARBLEN; + writel_relaxed(it, i2c_dev->base + SSC_IEN); + + st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STOPG); + c->result = -EIO; + break; + + case SSC_STA_ARBL: + writel_relaxed(SSC_CLR_SSCARBL, i2c_dev->base + SSC_CLR); + + it = SSC_IEN_STOPEN | SSC_IEN_ARBLEN; + writel_relaxed(it, i2c_dev->base + SSC_IEN); + + st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STOPG); + c->result = -EIO; + break; + + default: + dev_err(i2c_dev->dev, + "it %d unhandled (sta=0x%04x)\n", it, sta); + } + + /* + * Read IEN register to ensure interrupt mask write is effective + * before re-enabling interrupt at GIC level, and thus avoid spurious + * interrupts. + */ + readl(i2c_dev->base + SSC_IEN); + + return IRQ_HANDLED; +} + +/** + * st_i2c_xfer_msg() - Transfer a single I2C message + * @i2c_dev: Controller's private data + * @msg: I2C message to transfer + * @is_first: first message of the sequence + * @is_last: last message of the sequence + */ +static int st_i2c_xfer_msg(struct st_i2c_dev *i2c_dev, struct i2c_msg *msg, + bool is_first, bool is_last) +{ + struct st_i2c_client *c = &i2c_dev->client; + u32 ctl, i2c, it; + unsigned long timeout; + int ret; + + c->addr = (u8)(msg->addr << 1); + c->addr |= (msg->flags & I2C_M_RD); + c->buf = msg->buf; + c->count = msg->len; + c->xfered = 0; + c->result = 0; + c->stop = is_last; + + INIT_COMPLETION(i2c_dev->complete); + + ctl = SSC_CTL_EN | SSC_CTL_MS | SSC_CTL_EN_RX_FIFO | SSC_CTL_EN_TX_FIFO; + st_i2c_set_bits(i2c_dev->base + SSC_CTL, ctl); + + i2c = SSC_I2C_TXENB; + if (c->addr & I2C_M_RD) + i2c |= SSC_I2C_ACKG; + st_i2c_set_bits(i2c_dev->base + SSC_I2C, i2c); + + /* Write slave address */ + st_i2c_write_tx_fifo(i2c_dev, c->addr); + + /* Pre-fill Tx fifo with data in case of write */ + if (!(c->addr & I2C_M_RD)) + st_i2c_wr_fill_tx_fifo(i2c_dev); + + it = SSC_IEN_NACKEN | SSC_IEN_TEEN | SSC_IEN_ARBLEN; + writel_relaxed(it, i2c_dev->base + SSC_IEN); + + if (is_first) { + ret = st_i2c_wait_free_bus(i2c_dev); + if (ret) + return ret; + + st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STRTG); + } + + timeout = wait_for_completion_timeout(&i2c_dev->complete, + i2c_dev->adap.timeout); + ret = c->result; + + if (!timeout) { + dev_err(i2c_dev->dev, "Write to slave 0x%x timed out\n", + c->addr); + ret = -ETIMEDOUT; + } + + i2c = SSC_I2C_STOPG | SSC_I2C_REPSTRTG; + st_i2c_clr_bits(i2c_dev->base + SSC_I2C, i2c); + + writel_relaxed(SSC_CLR_SSCSTOP | SSC_CLR_REPSTRT, + i2c_dev->base + SSC_CLR); + + return ret; +} + +/** + * st_i2c_xfer() - Transfer a single I2C message + * @i2c_adap: Adapter pointer to the controller + * @msgs: Pointer to data to be written. + * @num: Number of messages to be executed + */ +static int st_i2c_xfer(struct i2c_adapter *i2c_adap, + struct i2c_msg msgs[], int num) +{ + struct st_i2c_dev *i2c_dev = i2c_get_adapdata(i2c_adap); + int ret, i; + + i2c_dev->busy = true; + + ret = clk_prepare_enable(i2c_dev->clk); + if (ret) { + dev_err(i2c_dev->dev, "Failed to prepare_enable clock\n"); + return ret; + } + + pinctrl_pm_select_default_state(i2c_dev->dev); + + st_i2c_hw_config(i2c_dev); + + for (i = 0; (i < num) && !ret; i++) + ret = st_i2c_xfer_msg(i2c_dev, &msgs[i], i == 0, i == num - 1); + + pinctrl_pm_select_idle_state(i2c_dev->dev); + + clk_disable_unprepare(i2c_dev->clk); + + i2c_dev->busy = false; + + return (ret < 0) ? ret : i; +} + +#ifdef CONFIG_PM_SLEEP +static int st_i2c_suspend(struct device *dev) +{ + struct platform_device *pdev = + container_of(dev, struct platform_device, dev); + struct st_i2c_dev *i2c_dev = platform_get_drvdata(pdev); + + if (i2c_dev->busy) + return -EBUSY; + + pinctrl_pm_select_sleep_state(dev); + + return 0; +} + +static int st_i2c_resume(struct device *dev) +{ + pinctrl_pm_select_default_state(dev); + /* Go in idle state if available */ + pinctrl_pm_select_idle_state(dev); + + return 0; +} + +static SIMPLE_DEV_PM_OPS(st_i2c_pm, st_i2c_suspend, st_i2c_resume); +#define ST_I2C_PM (&st_i2c_pm) +#else +#define ST_I2C_PM NULL +#endif + +static u32 st_i2c_func(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; +} + +static struct i2c_algorithm st_i2c_algo = { + .master_xfer = st_i2c_xfer, + .functionality = st_i2c_func, +}; + +static int st_i2c_of_get_deglitch(struct device_node *np, + struct st_i2c_dev *i2c_dev) +{ + int ret; + + ret = of_property_read_u32(np, "st,i2c-min-scl-pulse-width-us", + &i2c_dev->scl_min_width_us); + if ((ret == -ENODATA) || (ret == -EOVERFLOW)) { + dev_err(i2c_dev->dev, "st,i2c-min-scl-pulse-width-us invalid\n"); + return ret; + } + + ret = of_property_read_u32(np, "st,i2c-min-sda-pulse-width-us", + &i2c_dev->sda_min_width_us); + if ((ret == -ENODATA) || (ret == -EOVERFLOW)) { + dev_err(i2c_dev->dev, "st,i2c-min-sda-pulse-width-us invalid\n"); + return ret; + } + + return 0; +} + +static int st_i2c_probe(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + struct st_i2c_dev *i2c_dev; + struct resource *res; + u32 clk_rate; + struct i2c_adapter *adap; + int ret; + + i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL); + if (!i2c_dev) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + i2c_dev->base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(i2c_dev->base)) + return PTR_ERR(i2c_dev->base); + + i2c_dev->irq = irq_of_parse_and_map(np, 0); + if (!i2c_dev->irq) { + dev_err(&pdev->dev, "IRQ missing or invalid\n"); + return -EINVAL; + } + + i2c_dev->clk = of_clk_get_by_name(np, "ssc"); + if (IS_ERR(i2c_dev->clk)) { + dev_err(&pdev->dev, "Unable to request clock\n"); + return PTR_ERR(i2c_dev->clk); + } + + i2c_dev->mode = I2C_MODE_STANDARD; + ret = of_property_read_u32(np, "clock-frequency", &clk_rate); + if ((!ret) && (clk_rate == 400000)) + i2c_dev->mode = I2C_MODE_FAST; + + i2c_dev->dev = &pdev->dev; + + ret = devm_request_threaded_irq(&pdev->dev, i2c_dev->irq, + NULL, st_i2c_isr_thread, + IRQF_ONESHOT, pdev->name, i2c_dev); + if (ret) { + dev_err(&pdev->dev, "Failed to request irq %i\n", i2c_dev->irq); + return ret; + } + + pinctrl_pm_select_default_state(i2c_dev->dev); + /* In case idle state available, select it */ + pinctrl_pm_select_idle_state(i2c_dev->dev); + + ret = st_i2c_of_get_deglitch(np, i2c_dev); + if (ret) + return ret; + + adap = &i2c_dev->adap; + i2c_set_adapdata(adap, i2c_dev); + snprintf(adap->name, sizeof(adap->name), "ST I2C(0x%x)", res->start); + adap->owner = THIS_MODULE; + adap->timeout = 2 * HZ; + adap->retries = 0; + adap->algo = &st_i2c_algo; + adap->dev.parent = &pdev->dev; + adap->dev.of_node = pdev->dev.of_node; + + init_completion(&i2c_dev->complete); + + ret = i2c_add_adapter(adap); + if (ret) { + dev_err(&pdev->dev, "Failed to add adapter\n"); + return ret; + } + + platform_set_drvdata(pdev, i2c_dev); + + dev_info(i2c_dev->dev, "%s initialized\n", adap->name); + + return 0; +} + +static int st_i2c_remove(struct platform_device *pdev) +{ + struct st_i2c_dev *i2c_dev = platform_get_drvdata(pdev); + + i2c_del_adapter(&i2c_dev->adap); + + return 0; +} + +static struct of_device_id st_i2c_match[] = { + { .compatible = "st,comms-ssc-i2c", }, + { .compatible = "st,comms-ssc4-i2c", }, + {}, +}; +MODULE_DEVICE_TABLE(of, st_i2c_match); + +static struct platform_driver st_i2c_driver = { + .driver = { + .name = "st-i2c", + .owner = THIS_MODULE, + .of_match_table = st_i2c_match, + .pm = ST_I2C_PM, + }, + .probe = st_i2c_probe, + .remove = st_i2c_remove, +}; + +module_platform_driver(st_i2c_driver); + +MODULE_AUTHOR("Maxime Coquelin <maxime.coquelin@st.com>"); +MODULE_DESCRIPTION("STMicroelectronics I2C driver"); +MODULE_LICENSE("GPL v2"); |