diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-pasemi-core.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-pasemi-core.c | 119 |
1 files changed, 94 insertions, 25 deletions
diff --git a/drivers/i2c/busses/i2c-pasemi-core.c b/drivers/i2c/busses/i2c-pasemi-core.c index bd128ab2e2eb..f4eca44ed183 100644 --- a/drivers/i2c/busses/i2c-pasemi-core.c +++ b/drivers/i2c/busses/i2c-pasemi-core.c @@ -5,22 +5,24 @@ * SMBus host driver for PA Semi PWRficient */ -#include <linux/bitfield.h> +#include <linux/bits.h> +#include <linux/delay.h> +#include <linux/i2c.h> +#include <linux/io.h> +#include <linux/iopoll.h> +#include <linux/kernel.h> #include <linux/module.h> #include <linux/pci.h> -#include <linux/kernel.h> -#include <linux/stddef.h> #include <linux/sched.h> -#include <linux/i2c.h> -#include <linux/delay.h> #include <linux/slab.h> -#include <linux/io.h> +#include <linux/stddef.h> #include "i2c-pasemi-core.h" /* Register offsets */ #define REG_MTXFIFO 0x00 #define REG_MRXFIFO 0x04 +#define REG_XFSTA 0x0c #define REG_SMSTA 0x14 #define REG_IMASK 0x18 #define REG_CTL 0x1c @@ -52,6 +54,12 @@ #define CTL_UJM BIT(8) #define CTL_CLK_M GENMASK(7, 0) +/* + * The hardware (supposedly) has a 25ms timeout for clock stretching, thus + * use 100ms here which should be plenty. + */ +#define PASEMI_TRANSFER_TIMEOUT_MS 100 + static inline void reg_write(struct pasemi_smbus *smbus, int reg, int val) { dev_dbg(smbus->dev, "smbus write reg %x val %08x\n", reg, val); @@ -71,7 +79,7 @@ static inline int reg_read(struct pasemi_smbus *smbus, int reg) static void pasemi_reset(struct pasemi_smbus *smbus) { - u32 val = (CTL_MTR | CTL_MRR | (smbus->clk_div & CTL_CLK_M)); + u32 val = (CTL_MTR | CTL_MRR | CTL_UJM | (smbus->clk_div & CTL_CLK_M)); if (smbus->hw_rev >= 6) val |= CTL_EN; @@ -80,43 +88,102 @@ static void pasemi_reset(struct pasemi_smbus *smbus) reinit_completion(&smbus->irq_completion); } -static void pasemi_smb_clear(struct pasemi_smbus *smbus) +static int pasemi_smb_clear(struct pasemi_smbus *smbus) { unsigned int status; + int ret; + + /* First wait for the bus to go idle */ + ret = readx_poll_timeout(ioread32, smbus->ioaddr + REG_SMSTA, + status, !(status & (SMSTA_XIP | SMSTA_JAM)), + USEC_PER_MSEC, + USEC_PER_MSEC * PASEMI_TRANSFER_TIMEOUT_MS); + + if (ret < 0) { + dev_err(smbus->dev, "Bus is still stuck (status 0x%08x xfstatus 0x%08x)\n", + status, reg_read(smbus, REG_XFSTA)); + return -EIO; + } + + /* If any badness happened or there is data in the FIFOs, reset the FIFOs */ + if ((status & (SMSTA_MRNE | SMSTA_JMD | SMSTA_MTO | SMSTA_TOM | SMSTA_MTN | SMSTA_MTA)) || + !(status & SMSTA_MTE)) { + dev_warn(smbus->dev, "Issuing reset due to status 0x%08x (xfstatus 0x%08x)\n", + status, reg_read(smbus, REG_XFSTA)); + pasemi_reset(smbus); + } - status = reg_read(smbus, REG_SMSTA); + /* Clear the flags */ reg_write(smbus, REG_SMSTA, status); + + return 0; } static int pasemi_smb_waitready(struct pasemi_smbus *smbus) { - int timeout = 100; unsigned int status; if (smbus->use_irq) { reinit_completion(&smbus->irq_completion); reg_write(smbus, REG_IMASK, SMSTA_XEN | SMSTA_MTN); - wait_for_completion_timeout(&smbus->irq_completion, msecs_to_jiffies(100)); + int ret = wait_for_completion_timeout( + &smbus->irq_completion, + msecs_to_jiffies(PASEMI_TRANSFER_TIMEOUT_MS)); reg_write(smbus, REG_IMASK, 0); status = reg_read(smbus, REG_SMSTA); + + if (ret < 0) { + dev_err(smbus->dev, + "Completion wait failed with %d, status 0x%08x\n", + ret, status); + return ret; + } else if (ret == 0) { + dev_err(smbus->dev, "Timeout, status 0x%08x\n", status); + return -ETIME; + } } else { - status = reg_read(smbus, REG_SMSTA); - while (!(status & SMSTA_XEN) && timeout--) { - msleep(1); - status = reg_read(smbus, REG_SMSTA); + int ret = readx_poll_timeout( + ioread32, smbus->ioaddr + REG_SMSTA, + status, status & SMSTA_XEN, + USEC_PER_MSEC, + USEC_PER_MSEC * PASEMI_TRANSFER_TIMEOUT_MS); + + if (ret < 0) { + dev_err(smbus->dev, "Timeout, status 0x%08x\n", status); + return -ETIME; } } - /* Got NACK? */ - if (status & SMSTA_MTN) - return -ENXIO; + /* Controller timeout? */ + if (status & SMSTA_TOM) { + dev_err(smbus->dev, "Controller timeout, status 0x%08x\n", status); + return -EIO; + } - if (timeout < 0) { - dev_warn(smbus->dev, "Timeout, status 0x%08x\n", status); - reg_write(smbus, REG_SMSTA, status); + /* Peripheral timeout? */ + if (status & SMSTA_MTO) { + dev_err(smbus->dev, "Peripheral timeout, status 0x%08x\n", status); return -ETIME; } + /* Still stuck in a transaction? */ + if (status & SMSTA_XIP) { + dev_err(smbus->dev, "Bus stuck, status 0x%08x\n", status); + return -EIO; + } + + /* Arbitration loss? */ + if (status & SMSTA_MTA) { + dev_err(smbus->dev, "Arbitration loss, status 0x%08x\n", status); + return -EBUSY; + } + + /* Got NACK? */ + if (status & SMSTA_MTN) { + dev_err(smbus->dev, "NACK, status 0x%08x\n", status); + return -ENXIO; + } + /* Clear XEN */ reg_write(smbus, REG_SMSTA, SMSTA_XEN); @@ -177,9 +244,9 @@ static int pasemi_i2c_xfer(struct i2c_adapter *adapter, struct pasemi_smbus *smbus = adapter->algo_data; int ret, i; - pasemi_smb_clear(smbus); - - ret = 0; + ret = pasemi_smb_clear(smbus); + if (ret) + return ret; for (i = 0; i < num && !ret; i++) ret = pasemi_i2c_xfer_msg(adapter, &msgs[i], (i == (num - 1))); @@ -200,7 +267,9 @@ static int pasemi_smb_xfer(struct i2c_adapter *adapter, addr <<= 1; read_flag = read_write == I2C_SMBUS_READ; - pasemi_smb_clear(smbus); + err = pasemi_smb_clear(smbus); + if (err) + return err; switch (size) { case I2C_SMBUS_QUICK: |