diff options
Diffstat (limited to 'kernel/drivers/i2c/busses/i2c-nomadik.c')
| -rw-r--r-- | kernel/drivers/i2c/busses/i2c-nomadik.c | 1135 |
1 files changed, 1135 insertions, 0 deletions
diff --git a/kernel/drivers/i2c/busses/i2c-nomadik.c b/kernel/drivers/i2c/busses/i2c-nomadik.c new file mode 100644 index 000000000..bcd17e8cb --- /dev/null +++ b/kernel/drivers/i2c/busses/i2c-nomadik.c @@ -0,0 +1,1135 @@ +/* + * Copyright (C) 2009 ST-Ericsson SA + * Copyright (C) 2009 STMicroelectronics + * + * I2C master mode controller driver, used in Nomadik 8815 + * and Ux500 platforms. + * + * Author: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com> + * Author: Sachin Verma <sachin.verma@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/init.h> +#include <linux/module.h> +#include <linux/amba/bus.h> +#include <linux/slab.h> +#include <linux/interrupt.h> +#include <linux/i2c.h> +#include <linux/err.h> +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/pm_runtime.h> +#include <linux/of.h> +#include <linux/pinctrl/consumer.h> + +#define DRIVER_NAME "nmk-i2c" + +/* I2C Controller register offsets */ +#define I2C_CR (0x000) +#define I2C_SCR (0x004) +#define I2C_HSMCR (0x008) +#define I2C_MCR (0x00C) +#define I2C_TFR (0x010) +#define I2C_SR (0x014) +#define I2C_RFR (0x018) +#define I2C_TFTR (0x01C) +#define I2C_RFTR (0x020) +#define I2C_DMAR (0x024) +#define I2C_BRCR (0x028) +#define I2C_IMSCR (0x02C) +#define I2C_RISR (0x030) +#define I2C_MISR (0x034) +#define I2C_ICR (0x038) + +/* Control registers */ +#define I2C_CR_PE (0x1 << 0) /* Peripheral Enable */ +#define I2C_CR_OM (0x3 << 1) /* Operating mode */ +#define I2C_CR_SAM (0x1 << 3) /* Slave addressing mode */ +#define I2C_CR_SM (0x3 << 4) /* Speed mode */ +#define I2C_CR_SGCM (0x1 << 6) /* Slave general call mode */ +#define I2C_CR_FTX (0x1 << 7) /* Flush Transmit */ +#define I2C_CR_FRX (0x1 << 8) /* Flush Receive */ +#define I2C_CR_DMA_TX_EN (0x1 << 9) /* DMA Tx enable */ +#define I2C_CR_DMA_RX_EN (0x1 << 10) /* DMA Rx Enable */ +#define I2C_CR_DMA_SLE (0x1 << 11) /* DMA sync. logic enable */ +#define I2C_CR_LM (0x1 << 12) /* Loopback mode */ +#define I2C_CR_FON (0x3 << 13) /* Filtering on */ +#define I2C_CR_FS (0x3 << 15) /* Force stop enable */ + +/* Master controller (MCR) register */ +#define I2C_MCR_OP (0x1 << 0) /* Operation */ +#define I2C_MCR_A7 (0x7f << 1) /* 7-bit address */ +#define I2C_MCR_EA10 (0x7 << 8) /* 10-bit Extended address */ +#define I2C_MCR_SB (0x1 << 11) /* Extended address */ +#define I2C_MCR_AM (0x3 << 12) /* Address type */ +#define I2C_MCR_STOP (0x1 << 14) /* Stop condition */ +#define I2C_MCR_LENGTH (0x7ff << 15) /* Transaction length */ + +/* Status register (SR) */ +#define I2C_SR_OP (0x3 << 0) /* Operation */ +#define I2C_SR_STATUS (0x3 << 2) /* controller status */ +#define I2C_SR_CAUSE (0x7 << 4) /* Abort cause */ +#define I2C_SR_TYPE (0x3 << 7) /* Receive type */ +#define I2C_SR_LENGTH (0x7ff << 9) /* Transfer length */ + +/* Interrupt mask set/clear (IMSCR) bits */ +#define I2C_IT_TXFE (0x1 << 0) +#define I2C_IT_TXFNE (0x1 << 1) +#define I2C_IT_TXFF (0x1 << 2) +#define I2C_IT_TXFOVR (0x1 << 3) +#define I2C_IT_RXFE (0x1 << 4) +#define I2C_IT_RXFNF (0x1 << 5) +#define I2C_IT_RXFF (0x1 << 6) +#define I2C_IT_RFSR (0x1 << 16) +#define I2C_IT_RFSE (0x1 << 17) +#define I2C_IT_WTSR (0x1 << 18) +#define I2C_IT_MTD (0x1 << 19) +#define I2C_IT_STD (0x1 << 20) +#define I2C_IT_MAL (0x1 << 24) +#define I2C_IT_BERR (0x1 << 25) +#define I2C_IT_MTDWS (0x1 << 28) + +#define GEN_MASK(val, mask, sb) (((val) << (sb)) & (mask)) + +/* some bits in ICR are reserved */ +#define I2C_CLEAR_ALL_INTS 0x131f007f + +/* first three msb bits are reserved */ +#define IRQ_MASK(mask) (mask & 0x1fffffff) + +/* maximum threshold value */ +#define MAX_I2C_FIFO_THRESHOLD 15 + +enum i2c_freq_mode { + I2C_FREQ_MODE_STANDARD, /* up to 100 Kb/s */ + I2C_FREQ_MODE_FAST, /* up to 400 Kb/s */ + I2C_FREQ_MODE_HIGH_SPEED, /* up to 3.4 Mb/s */ + I2C_FREQ_MODE_FAST_PLUS, /* up to 1 Mb/s */ +}; + +/** + * struct i2c_vendor_data - per-vendor variations + * @has_mtdws: variant has the MTDWS bit + * @fifodepth: variant FIFO depth + */ +struct i2c_vendor_data { + bool has_mtdws; + u32 fifodepth; +}; + +enum i2c_status { + I2C_NOP, + I2C_ON_GOING, + I2C_OK, + I2C_ABORT +}; + +/* operation */ +enum i2c_operation { + I2C_NO_OPERATION = 0xff, + I2C_WRITE = 0x00, + I2C_READ = 0x01 +}; + +/** + * struct i2c_nmk_client - client specific data + * @slave_adr: 7-bit slave address + * @count: no. bytes to be transferred + * @buffer: client data buffer + * @xfer_bytes: bytes transferred till now + * @operation: current I2C operation + */ +struct i2c_nmk_client { + unsigned short slave_adr; + unsigned long count; + unsigned char *buffer; + unsigned long xfer_bytes; + enum i2c_operation operation; +}; + +/** + * struct nmk_i2c_dev - private data structure of the controller. + * @vendor: vendor data for this variant. + * @adev: parent amba device. + * @adap: corresponding I2C adapter. + * @irq: interrupt line for the controller. + * @virtbase: virtual io memory area. + * @clk: hardware i2c block clock. + * @cli: holder of client specific data. + * @clk_freq: clock frequency for the operation mode + * @tft: Tx FIFO Threshold in bytes + * @rft: Rx FIFO Threshold in bytes + * @timeout Slave response timeout (ms) + * @sm: speed mode + * @stop: stop condition. + * @xfer_complete: acknowledge completion for a I2C message. + * @result: controller propogated result. + */ +struct nmk_i2c_dev { + struct i2c_vendor_data *vendor; + struct amba_device *adev; + struct i2c_adapter adap; + int irq; + void __iomem *virtbase; + struct clk *clk; + struct i2c_nmk_client cli; + u32 clk_freq; + unsigned char tft; + unsigned char rft; + int timeout; + enum i2c_freq_mode sm; + int stop; + struct completion xfer_complete; + int result; +}; + +/* controller's abort causes */ +static const char *abort_causes[] = { + "no ack received after address transmission", + "no ack received during data phase", + "ack received after xmission of master code", + "master lost arbitration", + "slave restarts", + "slave reset", + "overflow, maxsize is 2047 bytes", +}; + +static inline void i2c_set_bit(void __iomem *reg, u32 mask) +{ + writel(readl(reg) | mask, reg); +} + +static inline void i2c_clr_bit(void __iomem *reg, u32 mask) +{ + writel(readl(reg) & ~mask, reg); +} + +/** + * flush_i2c_fifo() - This function flushes the I2C FIFO + * @dev: private data of I2C Driver + * + * This function flushes the I2C Tx and Rx FIFOs. It returns + * 0 on successful flushing of FIFO + */ +static int flush_i2c_fifo(struct nmk_i2c_dev *dev) +{ +#define LOOP_ATTEMPTS 10 + int i; + unsigned long timeout; + + /* + * flush the transmit and receive FIFO. The flushing + * operation takes several cycles before to be completed. + * On the completion, the I2C internal logic clears these + * bits, until then no one must access Tx, Rx FIFO and + * should poll on these bits waiting for the completion. + */ + writel((I2C_CR_FTX | I2C_CR_FRX), dev->virtbase + I2C_CR); + + for (i = 0; i < LOOP_ATTEMPTS; i++) { + timeout = jiffies + dev->adap.timeout; + + while (!time_after(jiffies, timeout)) { + if ((readl(dev->virtbase + I2C_CR) & + (I2C_CR_FTX | I2C_CR_FRX)) == 0) + return 0; + } + } + + dev_err(&dev->adev->dev, + "flushing operation timed out giving up after %d attempts", + LOOP_ATTEMPTS); + + return -ETIMEDOUT; +} + +/** + * disable_all_interrupts() - Disable all interrupts of this I2c Bus + * @dev: private data of I2C Driver + */ +static void disable_all_interrupts(struct nmk_i2c_dev *dev) +{ + u32 mask = IRQ_MASK(0); + writel(mask, dev->virtbase + I2C_IMSCR); +} + +/** + * clear_all_interrupts() - Clear all interrupts of I2C Controller + * @dev: private data of I2C Driver + */ +static void clear_all_interrupts(struct nmk_i2c_dev *dev) +{ + u32 mask; + mask = IRQ_MASK(I2C_CLEAR_ALL_INTS); + writel(mask, dev->virtbase + I2C_ICR); +} + +/** + * init_hw() - initialize the I2C hardware + * @dev: private data of I2C Driver + */ +static int init_hw(struct nmk_i2c_dev *dev) +{ + int stat; + + stat = flush_i2c_fifo(dev); + if (stat) + goto exit; + + /* disable the controller */ + i2c_clr_bit(dev->virtbase + I2C_CR , I2C_CR_PE); + + disable_all_interrupts(dev); + + clear_all_interrupts(dev); + + dev->cli.operation = I2C_NO_OPERATION; + +exit: + return stat; +} + +/* enable peripheral, master mode operation */ +#define DEFAULT_I2C_REG_CR ((1 << 1) | I2C_CR_PE) + +/** + * load_i2c_mcr_reg() - load the MCR register + * @dev: private data of controller + * @flags: message flags + */ +static u32 load_i2c_mcr_reg(struct nmk_i2c_dev *dev, u16 flags) +{ + u32 mcr = 0; + unsigned short slave_adr_3msb_bits; + + mcr |= GEN_MASK(dev->cli.slave_adr, I2C_MCR_A7, 1); + + if (unlikely(flags & I2C_M_TEN)) { + /* 10-bit address transaction */ + mcr |= GEN_MASK(2, I2C_MCR_AM, 12); + /* + * Get the top 3 bits. + * EA10 represents extended address in MCR. This includes + * the extension (MSB bits) of the 7 bit address loaded + * in A7 + */ + slave_adr_3msb_bits = (dev->cli.slave_adr >> 7) & 0x7; + + mcr |= GEN_MASK(slave_adr_3msb_bits, I2C_MCR_EA10, 8); + } else { + /* 7-bit address transaction */ + mcr |= GEN_MASK(1, I2C_MCR_AM, 12); + } + + /* start byte procedure not applied */ + mcr |= GEN_MASK(0, I2C_MCR_SB, 11); + + /* check the operation, master read/write? */ + if (dev->cli.operation == I2C_WRITE) + mcr |= GEN_MASK(I2C_WRITE, I2C_MCR_OP, 0); + else + mcr |= GEN_MASK(I2C_READ, I2C_MCR_OP, 0); + + /* stop or repeated start? */ + if (dev->stop) + mcr |= GEN_MASK(1, I2C_MCR_STOP, 14); + else + mcr &= ~(GEN_MASK(1, I2C_MCR_STOP, 14)); + + mcr |= GEN_MASK(dev->cli.count, I2C_MCR_LENGTH, 15); + + return mcr; +} + +/** + * setup_i2c_controller() - setup the controller + * @dev: private data of controller + */ +static void setup_i2c_controller(struct nmk_i2c_dev *dev) +{ + u32 brcr1, brcr2; + u32 i2c_clk, div; + u32 ns; + u16 slsu; + + writel(0x0, dev->virtbase + I2C_CR); + writel(0x0, dev->virtbase + I2C_HSMCR); + writel(0x0, dev->virtbase + I2C_TFTR); + writel(0x0, dev->virtbase + I2C_RFTR); + writel(0x0, dev->virtbase + I2C_DMAR); + + i2c_clk = clk_get_rate(dev->clk); + + /* + * set the slsu: + * + * slsu defines the data setup time after SCL clock + * stretching in terms of i2c clk cycles + 1 (zero means + * "wait one cycle"), the needed setup time for the three + * modes are 250ns, 100ns, 10ns respectively. + * + * As the time for one cycle T in nanoseconds is + * T = (1/f) * 1000000000 => + * slsu = cycles / (1000000000 / f) + 1 + */ + ns = DIV_ROUND_UP_ULL(1000000000ULL, i2c_clk); + switch (dev->sm) { + case I2C_FREQ_MODE_FAST: + case I2C_FREQ_MODE_FAST_PLUS: + slsu = DIV_ROUND_UP(100, ns); /* Fast */ + break; + case I2C_FREQ_MODE_HIGH_SPEED: + slsu = DIV_ROUND_UP(10, ns); /* High */ + break; + case I2C_FREQ_MODE_STANDARD: + default: + slsu = DIV_ROUND_UP(250, ns); /* Standard */ + break; + } + slsu += 1; + + dev_dbg(&dev->adev->dev, "calculated SLSU = %04x\n", slsu); + writel(slsu << 16, dev->virtbase + I2C_SCR); + + /* + * The spec says, in case of std. mode the divider is + * 2 whereas it is 3 for fast and fastplus mode of + * operation. TODO - high speed support. + */ + div = (dev->clk_freq > 100000) ? 3 : 2; + + /* + * generate the mask for baud rate counters. The controller + * has two baud rate counters. One is used for High speed + * operation, and the other is for std, fast mode, fast mode + * plus operation. Currently we do not supprt high speed mode + * so set brcr1 to 0. + */ + brcr1 = 0 << 16; + brcr2 = (i2c_clk/(dev->clk_freq * div)) & 0xffff; + + /* set the baud rate counter register */ + writel((brcr1 | brcr2), dev->virtbase + I2C_BRCR); + + /* + * set the speed mode. Currently we support + * only standard and fast mode of operation + * TODO - support for fast mode plus (up to 1Mb/s) + * and high speed (up to 3.4 Mb/s) + */ + if (dev->sm > I2C_FREQ_MODE_FAST) { + dev_err(&dev->adev->dev, + "do not support this mode defaulting to std. mode\n"); + brcr2 = i2c_clk/(100000 * 2) & 0xffff; + writel((brcr1 | brcr2), dev->virtbase + I2C_BRCR); + writel(I2C_FREQ_MODE_STANDARD << 4, + dev->virtbase + I2C_CR); + } + writel(dev->sm << 4, dev->virtbase + I2C_CR); + + /* set the Tx and Rx FIFO threshold */ + writel(dev->tft, dev->virtbase + I2C_TFTR); + writel(dev->rft, dev->virtbase + I2C_RFTR); +} + +/** + * read_i2c() - Read from I2C client device + * @dev: private data of I2C Driver + * @flags: message flags + * + * This function reads from i2c client device when controller is in + * master mode. There is a completion timeout. If there is no transfer + * before timeout error is returned. + */ +static int read_i2c(struct nmk_i2c_dev *dev, u16 flags) +{ + int status = 0; + u32 mcr, irq_mask; + unsigned long timeout; + + mcr = load_i2c_mcr_reg(dev, flags); + writel(mcr, dev->virtbase + I2C_MCR); + + /* load the current CR value */ + writel(readl(dev->virtbase + I2C_CR) | DEFAULT_I2C_REG_CR, + dev->virtbase + I2C_CR); + + /* enable the controller */ + i2c_set_bit(dev->virtbase + I2C_CR, I2C_CR_PE); + + init_completion(&dev->xfer_complete); + + /* enable interrupts by setting the mask */ + irq_mask = (I2C_IT_RXFNF | I2C_IT_RXFF | + I2C_IT_MAL | I2C_IT_BERR); + + if (dev->stop || !dev->vendor->has_mtdws) + irq_mask |= I2C_IT_MTD; + else + irq_mask |= I2C_IT_MTDWS; + + irq_mask = I2C_CLEAR_ALL_INTS & IRQ_MASK(irq_mask); + + writel(readl(dev->virtbase + I2C_IMSCR) | irq_mask, + dev->virtbase + I2C_IMSCR); + + timeout = wait_for_completion_timeout( + &dev->xfer_complete, dev->adap.timeout); + + if (timeout == 0) { + /* Controller timed out */ + dev_err(&dev->adev->dev, "read from slave 0x%x timed out\n", + dev->cli.slave_adr); + status = -ETIMEDOUT; + } + return status; +} + +static void fill_tx_fifo(struct nmk_i2c_dev *dev, int no_bytes) +{ + int count; + + for (count = (no_bytes - 2); + (count > 0) && + (dev->cli.count != 0); + count--) { + /* write to the Tx FIFO */ + writeb(*dev->cli.buffer, + dev->virtbase + I2C_TFR); + dev->cli.buffer++; + dev->cli.count--; + dev->cli.xfer_bytes++; + } + +} + +/** + * write_i2c() - Write data to I2C client. + * @dev: private data of I2C Driver + * @flags: message flags + * + * This function writes data to I2C client + */ +static int write_i2c(struct nmk_i2c_dev *dev, u16 flags) +{ + u32 status = 0; + u32 mcr, irq_mask; + unsigned long timeout; + + mcr = load_i2c_mcr_reg(dev, flags); + + writel(mcr, dev->virtbase + I2C_MCR); + + /* load the current CR value */ + writel(readl(dev->virtbase + I2C_CR) | DEFAULT_I2C_REG_CR, + dev->virtbase + I2C_CR); + + /* enable the controller */ + i2c_set_bit(dev->virtbase + I2C_CR , I2C_CR_PE); + + init_completion(&dev->xfer_complete); + + /* enable interrupts by settings the masks */ + irq_mask = (I2C_IT_TXFOVR | I2C_IT_MAL | I2C_IT_BERR); + + /* Fill the TX FIFO with transmit data */ + fill_tx_fifo(dev, MAX_I2C_FIFO_THRESHOLD); + + if (dev->cli.count != 0) + irq_mask |= I2C_IT_TXFNE; + + /* + * check if we want to transfer a single or multiple bytes, if so + * set the MTDWS bit (Master Transaction Done Without Stop) + * to start repeated start operation + */ + if (dev->stop || !dev->vendor->has_mtdws) + irq_mask |= I2C_IT_MTD; + else + irq_mask |= I2C_IT_MTDWS; + + irq_mask = I2C_CLEAR_ALL_INTS & IRQ_MASK(irq_mask); + + writel(readl(dev->virtbase + I2C_IMSCR) | irq_mask, + dev->virtbase + I2C_IMSCR); + + timeout = wait_for_completion_timeout( + &dev->xfer_complete, dev->adap.timeout); + + if (timeout == 0) { + /* Controller timed out */ + dev_err(&dev->adev->dev, "write to slave 0x%x timed out\n", + dev->cli.slave_adr); + status = -ETIMEDOUT; + } + + return status; +} + +/** + * nmk_i2c_xfer_one() - transmit a single I2C message + * @dev: device with a message encoded into it + * @flags: message flags + */ +static int nmk_i2c_xfer_one(struct nmk_i2c_dev *dev, u16 flags) +{ + int status; + + if (flags & I2C_M_RD) { + /* read operation */ + dev->cli.operation = I2C_READ; + status = read_i2c(dev, flags); + } else { + /* write operation */ + dev->cli.operation = I2C_WRITE; + status = write_i2c(dev, flags); + } + + if (status || (dev->result)) { + u32 i2c_sr; + u32 cause; + + i2c_sr = readl(dev->virtbase + I2C_SR); + /* + * Check if the controller I2C operation status + * is set to ABORT(11b). + */ + if (((i2c_sr >> 2) & 0x3) == 0x3) { + /* get the abort cause */ + cause = (i2c_sr >> 4) & 0x7; + dev_err(&dev->adev->dev, "%s\n", + cause >= ARRAY_SIZE(abort_causes) ? + "unknown reason" : + abort_causes[cause]); + } + + (void) init_hw(dev); + + status = status ? status : dev->result; + } + + return status; +} + +/** + * nmk_i2c_xfer() - I2C transfer function used by kernel framework + * @i2c_adap: Adapter pointer to the controller + * @msgs: Pointer to data to be written. + * @num_msgs: Number of messages to be executed + * + * This is the function called by the generic kernel i2c_transfer() + * or i2c_smbus...() API calls. Note that this code is protected by the + * semaphore set in the kernel i2c_transfer() function. + * + * NOTE: + * READ TRANSFER : We impose a restriction of the first message to be the + * index message for any read transaction. + * - a no index is coded as '0', + * - 2byte big endian index is coded as '3' + * !!! msg[0].buf holds the actual index. + * This is compatible with generic messages of smbus emulator + * that send a one byte index. + * eg. a I2C transation to read 2 bytes from index 0 + * idx = 0; + * msg[0].addr = client->addr; + * msg[0].flags = 0x0; + * msg[0].len = 1; + * msg[0].buf = &idx; + * + * msg[1].addr = client->addr; + * msg[1].flags = I2C_M_RD; + * msg[1].len = 2; + * msg[1].buf = rd_buff + * i2c_transfer(adap, msg, 2); + * + * WRITE TRANSFER : The I2C standard interface interprets all data as payload. + * If you want to emulate an SMBUS write transaction put the + * index as first byte(or first and second) in the payload. + * eg. a I2C transation to write 2 bytes from index 1 + * wr_buff[0] = 0x1; + * wr_buff[1] = 0x23; + * wr_buff[2] = 0x46; + * msg[0].flags = 0x0; + * msg[0].len = 3; + * msg[0].buf = wr_buff; + * i2c_transfer(adap, msg, 1); + * + * To read or write a block of data (multiple bytes) using SMBUS emulation + * please use the i2c_smbus_read_i2c_block_data() + * or i2c_smbus_write_i2c_block_data() API + */ +static int nmk_i2c_xfer(struct i2c_adapter *i2c_adap, + struct i2c_msg msgs[], int num_msgs) +{ + int status = 0; + int i; + struct nmk_i2c_dev *dev = i2c_get_adapdata(i2c_adap); + int j; + + pm_runtime_get_sync(&dev->adev->dev); + + /* Attempt three times to send the message queue */ + for (j = 0; j < 3; j++) { + /* setup the i2c controller */ + setup_i2c_controller(dev); + + for (i = 0; i < num_msgs; i++) { + dev->cli.slave_adr = msgs[i].addr; + dev->cli.buffer = msgs[i].buf; + dev->cli.count = msgs[i].len; + dev->stop = (i < (num_msgs - 1)) ? 0 : 1; + dev->result = 0; + + status = nmk_i2c_xfer_one(dev, msgs[i].flags); + if (status != 0) + break; + } + if (status == 0) + break; + } + + pm_runtime_put_sync(&dev->adev->dev); + + /* return the no. messages processed */ + if (status) + return status; + else + return num_msgs; +} + +/** + * disable_interrupts() - disable the interrupts + * @dev: private data of controller + * @irq: interrupt number + */ +static int disable_interrupts(struct nmk_i2c_dev *dev, u32 irq) +{ + irq = IRQ_MASK(irq); + writel(readl(dev->virtbase + I2C_IMSCR) & ~(I2C_CLEAR_ALL_INTS & irq), + dev->virtbase + I2C_IMSCR); + return 0; +} + +/** + * i2c_irq_handler() - interrupt routine + * @irq: interrupt number + * @arg: data passed to the handler + * + * This is the interrupt handler for the i2c driver. Currently + * it handles the major interrupts like Rx & Tx FIFO management + * interrupts, master transaction interrupts, arbitration and + * bus error interrupts. The rest of the interrupts are treated as + * unhandled. + */ +static irqreturn_t i2c_irq_handler(int irq, void *arg) +{ + struct nmk_i2c_dev *dev = arg; + u32 tft, rft; + u32 count; + u32 misr, src; + + /* load Tx FIFO and Rx FIFO threshold values */ + tft = readl(dev->virtbase + I2C_TFTR); + rft = readl(dev->virtbase + I2C_RFTR); + + /* read interrupt status register */ + misr = readl(dev->virtbase + I2C_MISR); + + src = __ffs(misr); + switch ((1 << src)) { + + /* Transmit FIFO nearly empty interrupt */ + case I2C_IT_TXFNE: + { + if (dev->cli.operation == I2C_READ) { + /* + * in read operation why do we care for writing? + * so disable the Transmit FIFO interrupt + */ + disable_interrupts(dev, I2C_IT_TXFNE); + } else { + fill_tx_fifo(dev, (MAX_I2C_FIFO_THRESHOLD - tft)); + /* + * if done, close the transfer by disabling the + * corresponding TXFNE interrupt + */ + if (dev->cli.count == 0) + disable_interrupts(dev, I2C_IT_TXFNE); + } + } + break; + + /* + * Rx FIFO nearly full interrupt. + * This is set when the numer of entries in Rx FIFO is + * greater or equal than the threshold value programmed + * in RFT + */ + case I2C_IT_RXFNF: + for (count = rft; count > 0; count--) { + /* Read the Rx FIFO */ + *dev->cli.buffer = readb(dev->virtbase + I2C_RFR); + dev->cli.buffer++; + } + dev->cli.count -= rft; + dev->cli.xfer_bytes += rft; + break; + + /* Rx FIFO full */ + case I2C_IT_RXFF: + for (count = MAX_I2C_FIFO_THRESHOLD; count > 0; count--) { + *dev->cli.buffer = readb(dev->virtbase + I2C_RFR); + dev->cli.buffer++; + } + dev->cli.count -= MAX_I2C_FIFO_THRESHOLD; + dev->cli.xfer_bytes += MAX_I2C_FIFO_THRESHOLD; + break; + + /* Master Transaction Done with/without stop */ + case I2C_IT_MTD: + case I2C_IT_MTDWS: + if (dev->cli.operation == I2C_READ) { + while (!(readl(dev->virtbase + I2C_RISR) + & I2C_IT_RXFE)) { + if (dev->cli.count == 0) + break; + *dev->cli.buffer = + readb(dev->virtbase + I2C_RFR); + dev->cli.buffer++; + dev->cli.count--; + dev->cli.xfer_bytes++; + } + } + + disable_all_interrupts(dev); + clear_all_interrupts(dev); + + if (dev->cli.count) { + dev->result = -EIO; + dev_err(&dev->adev->dev, + "%lu bytes still remain to be xfered\n", + dev->cli.count); + (void) init_hw(dev); + } + complete(&dev->xfer_complete); + + break; + + /* Master Arbitration lost interrupt */ + case I2C_IT_MAL: + dev->result = -EIO; + (void) init_hw(dev); + + i2c_set_bit(dev->virtbase + I2C_ICR, I2C_IT_MAL); + complete(&dev->xfer_complete); + + break; + + /* + * Bus Error interrupt. + * This happens when an unexpected start/stop condition occurs + * during the transaction. + */ + case I2C_IT_BERR: + dev->result = -EIO; + /* get the status */ + if (((readl(dev->virtbase + I2C_SR) >> 2) & 0x3) == I2C_ABORT) + (void) init_hw(dev); + + i2c_set_bit(dev->virtbase + I2C_ICR, I2C_IT_BERR); + complete(&dev->xfer_complete); + + break; + + /* + * Tx FIFO overrun interrupt. + * This is set when a write operation in Tx FIFO is performed and + * the Tx FIFO is full. + */ + case I2C_IT_TXFOVR: + dev->result = -EIO; + (void) init_hw(dev); + + dev_err(&dev->adev->dev, "Tx Fifo Over run\n"); + complete(&dev->xfer_complete); + + break; + + /* unhandled interrupts by this driver - TODO*/ + case I2C_IT_TXFE: + case I2C_IT_TXFF: + case I2C_IT_RXFE: + case I2C_IT_RFSR: + case I2C_IT_RFSE: + case I2C_IT_WTSR: + case I2C_IT_STD: + dev_err(&dev->adev->dev, "unhandled Interrupt\n"); + break; + default: + dev_err(&dev->adev->dev, "spurious Interrupt..\n"); + break; + } + + return IRQ_HANDLED; +} + +#ifdef CONFIG_PM_SLEEP +static int nmk_i2c_suspend_late(struct device *dev) +{ + int ret; + + ret = pm_runtime_force_suspend(dev); + if (ret) + return ret; + + pinctrl_pm_select_sleep_state(dev); + return 0; +} + +static int nmk_i2c_resume_early(struct device *dev) +{ + return pm_runtime_force_resume(dev); +} +#endif + +#ifdef CONFIG_PM +static int nmk_i2c_runtime_suspend(struct device *dev) +{ + struct amba_device *adev = to_amba_device(dev); + struct nmk_i2c_dev *nmk_i2c = amba_get_drvdata(adev); + + clk_disable_unprepare(nmk_i2c->clk); + pinctrl_pm_select_idle_state(dev); + return 0; +} + +static int nmk_i2c_runtime_resume(struct device *dev) +{ + struct amba_device *adev = to_amba_device(dev); + struct nmk_i2c_dev *nmk_i2c = amba_get_drvdata(adev); + int ret; + + ret = clk_prepare_enable(nmk_i2c->clk); + if (ret) { + dev_err(dev, "can't prepare_enable clock\n"); + return ret; + } + + pinctrl_pm_select_default_state(dev); + + ret = init_hw(nmk_i2c); + if (ret) { + clk_disable_unprepare(nmk_i2c->clk); + pinctrl_pm_select_idle_state(dev); + } + + return ret; +} +#endif + +static const struct dev_pm_ops nmk_i2c_pm = { + SET_LATE_SYSTEM_SLEEP_PM_OPS(nmk_i2c_suspend_late, nmk_i2c_resume_early) + SET_RUNTIME_PM_OPS(nmk_i2c_runtime_suspend, + nmk_i2c_runtime_resume, + NULL) +}; + +static unsigned int nmk_i2c_functionality(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR; +} + +static const struct i2c_algorithm nmk_i2c_algo = { + .master_xfer = nmk_i2c_xfer, + .functionality = nmk_i2c_functionality +}; + +static void nmk_i2c_of_probe(struct device_node *np, + struct nmk_i2c_dev *nmk) +{ + /* Default to 100 kHz if no frequency is given in the node */ + if (of_property_read_u32(np, "clock-frequency", &nmk->clk_freq)) + nmk->clk_freq = 100000; + + /* This driver only supports 'standard' and 'fast' modes of operation. */ + if (nmk->clk_freq <= 100000) + nmk->sm = I2C_FREQ_MODE_STANDARD; + else + nmk->sm = I2C_FREQ_MODE_FAST; + nmk->tft = 1; /* Tx FIFO threshold */ + nmk->rft = 8; /* Rx FIFO threshold */ + nmk->timeout = 200; /* Slave response timeout(ms) */ +} + +static int nmk_i2c_probe(struct amba_device *adev, const struct amba_id *id) +{ + int ret = 0; + struct device_node *np = adev->dev.of_node; + struct nmk_i2c_dev *dev; + struct i2c_adapter *adap; + struct i2c_vendor_data *vendor = id->data; + u32 max_fifo_threshold = (vendor->fifodepth / 2) - 1; + + dev = devm_kzalloc(&adev->dev, sizeof(struct nmk_i2c_dev), GFP_KERNEL); + if (!dev) { + dev_err(&adev->dev, "cannot allocate memory\n"); + ret = -ENOMEM; + goto err_no_mem; + } + dev->vendor = vendor; + dev->adev = adev; + nmk_i2c_of_probe(np, dev); + + if (dev->tft > max_fifo_threshold) { + dev_warn(&adev->dev, "requested TX FIFO threshold %u, adjusted down to %u\n", + dev->tft, max_fifo_threshold); + dev->tft = max_fifo_threshold; + } + + if (dev->rft > max_fifo_threshold) { + dev_warn(&adev->dev, "requested RX FIFO threshold %u, adjusted down to %u\n", + dev->rft, max_fifo_threshold); + dev->rft = max_fifo_threshold; + } + + amba_set_drvdata(adev, dev); + + dev->virtbase = devm_ioremap(&adev->dev, adev->res.start, + resource_size(&adev->res)); + if (!dev->virtbase) { + ret = -ENOMEM; + goto err_no_mem; + } + + dev->irq = adev->irq[0]; + ret = devm_request_irq(&adev->dev, dev->irq, i2c_irq_handler, 0, + DRIVER_NAME, dev); + if (ret) { + dev_err(&adev->dev, "cannot claim the irq %d\n", dev->irq); + goto err_no_mem; + } + + pm_suspend_ignore_children(&adev->dev, true); + + dev->clk = devm_clk_get(&adev->dev, NULL); + if (IS_ERR(dev->clk)) { + dev_err(&adev->dev, "could not get i2c clock\n"); + ret = PTR_ERR(dev->clk); + goto err_no_mem; + } + + ret = clk_prepare_enable(dev->clk); + if (ret) { + dev_err(&adev->dev, "can't prepare_enable clock\n"); + goto err_no_mem; + } + + init_hw(dev); + + adap = &dev->adap; + adap->dev.of_node = np; + adap->dev.parent = &adev->dev; + adap->owner = THIS_MODULE; + adap->class = I2C_CLASS_DEPRECATED; + adap->algo = &nmk_i2c_algo; + adap->timeout = msecs_to_jiffies(dev->timeout); + snprintf(adap->name, sizeof(adap->name), + "Nomadik I2C at %pR", &adev->res); + + i2c_set_adapdata(adap, dev); + + dev_info(&adev->dev, + "initialize %s on virtual base %p\n", + adap->name, dev->virtbase); + + ret = i2c_add_adapter(adap); + if (ret) { + dev_err(&adev->dev, "failed to add adapter\n"); + goto err_no_adap; + } + + pm_runtime_put(&adev->dev); + + return 0; + + err_no_adap: + clk_disable_unprepare(dev->clk); + err_no_mem: + + return ret; +} + +static int nmk_i2c_remove(struct amba_device *adev) +{ + struct resource *res = &adev->res; + struct nmk_i2c_dev *dev = amba_get_drvdata(adev); + + i2c_del_adapter(&dev->adap); + flush_i2c_fifo(dev); + disable_all_interrupts(dev); + clear_all_interrupts(dev); + /* disable the controller */ + i2c_clr_bit(dev->virtbase + I2C_CR, I2C_CR_PE); + clk_disable_unprepare(dev->clk); + if (res) + release_mem_region(res->start, resource_size(res)); + + return 0; +} + +static struct i2c_vendor_data vendor_stn8815 = { + .has_mtdws = false, + .fifodepth = 16, /* Guessed from TFTR/RFTR = 7 */ +}; + +static struct i2c_vendor_data vendor_db8500 = { + .has_mtdws = true, + .fifodepth = 32, /* Guessed from TFTR/RFTR = 15 */ +}; + +static struct amba_id nmk_i2c_ids[] = { + { + .id = 0x00180024, + .mask = 0x00ffffff, + .data = &vendor_stn8815, + }, + { + .id = 0x00380024, + .mask = 0x00ffffff, + .data = &vendor_db8500, + }, + {}, +}; + +MODULE_DEVICE_TABLE(amba, nmk_i2c_ids); + +static struct amba_driver nmk_i2c_driver = { + .drv = { + .owner = THIS_MODULE, + .name = DRIVER_NAME, + .pm = &nmk_i2c_pm, + }, + .id_table = nmk_i2c_ids, + .probe = nmk_i2c_probe, + .remove = nmk_i2c_remove, +}; + +static int __init nmk_i2c_init(void) +{ + return amba_driver_register(&nmk_i2c_driver); +} + +static void __exit nmk_i2c_exit(void) +{ + amba_driver_unregister(&nmk_i2c_driver); +} + +subsys_initcall(nmk_i2c_init); +module_exit(nmk_i2c_exit); + +MODULE_AUTHOR("Sachin Verma, Srinidhi KASAGAR"); +MODULE_DESCRIPTION("Nomadik/Ux500 I2C driver"); +MODULE_LICENSE("GPL"); |