diff options
| -rw-r--r-- | drivers/i2c/busses/i2c-stu300.c | 157 |
1 files changed, 92 insertions, 65 deletions
diff --git a/drivers/i2c/busses/i2c-stu300.c b/drivers/i2c/busses/i2c-stu300.c index 182e711318b..d2728a28a8d 100644 --- a/drivers/i2c/busses/i2c-stu300.c +++ b/drivers/i2c/busses/i2c-stu300.c @@ -117,7 +117,8 @@ enum stu300_error { STU300_ERROR_NONE = 0, STU300_ERROR_ACKNOWLEDGE_FAILURE, STU300_ERROR_BUS_ERROR, - STU300_ERROR_ARBITRATION_LOST + STU300_ERROR_ARBITRATION_LOST, + STU300_ERROR_UNKNOWN }; /* timeout waiting for the controller to respond */ @@ -127,7 +128,7 @@ enum stu300_error { * The number of address send athemps tried before giving up. * If the first one failes it seems like 5 to 8 attempts are required. */ -#define NUM_ADDR_RESEND_ATTEMPTS 10 +#define NUM_ADDR_RESEND_ATTEMPTS 12 /* I2C clock speed, in Hz 0-400kHz*/ static unsigned int scl_frequency = 100000; @@ -149,6 +150,7 @@ module_param(scl_frequency, uint, 0644); * @msg_index: index of current message * @msg_len: length of current message */ + struct stu300_dev { struct platform_device *pdev; struct i2c_adapter adapter; @@ -188,6 +190,27 @@ static inline u32 stu300_r8(void __iomem *address) return readl(address) & 0x000000FFU; } +static void stu300_irq_enable(struct stu300_dev *dev) +{ + u32 val; + val = stu300_r8(dev->virtbase + I2C_CR); + val |= I2C_CR_INTERRUPT_ENABLE; + /* Twice paranoia (possible HW glitch) */ + stu300_wr8(val, dev->virtbase + I2C_CR); + stu300_wr8(val, dev->virtbase + I2C_CR); +} + +static void stu300_irq_disable(struct stu300_dev *dev) +{ + u32 val; + val = stu300_r8(dev->virtbase + I2C_CR); + val &= ~I2C_CR_INTERRUPT_ENABLE; + /* Twice paranoia (possible HW glitch) */ + stu300_wr8(val, dev->virtbase + I2C_CR); + stu300_wr8(val, dev->virtbase + I2C_CR); +} + + /* * Tells whether a certain event or events occurred in * response to a command. The events represent states in @@ -196,9 +219,10 @@ static inline u32 stu300_r8(void __iomem *address) * documentation and can only be treated as abstract state * machine states. * - * @ret 0 = event has not occurred, any other value means - * the event occurred. + * @ret 0 = event has not occurred or unknown error, any + * other value means the correct event occurred or an error. */ + static int stu300_event_occurred(struct stu300_dev *dev, enum stu300_event mr_event) { u32 status1; @@ -206,11 +230,28 @@ static int stu300_event_occurred(struct stu300_dev *dev, /* What event happened? */ status1 = stu300_r8(dev->virtbase + I2C_SR1); + if (!(status1 & I2C_SR1_EVF_IND)) /* No event at all */ return 0; + status2 = stu300_r8(dev->virtbase + I2C_SR2); + /* Block any multiple interrupts */ + stu300_irq_disable(dev); + + /* Check for errors first */ + if (status2 & I2C_SR2_AF_IND) { + dev->cmd_err = STU300_ERROR_ACKNOWLEDGE_FAILURE; + return 1; + } else if (status2 & I2C_SR2_BERR_IND) { + dev->cmd_err = STU300_ERROR_BUS_ERROR; + return 1; + } else if (status2 & I2C_SR2_ARLO_IND) { + dev->cmd_err = STU300_ERROR_ARBITRATION_LOST; + return 1; + } + switch (mr_event) { case STU300_EVENT_1: if (status1 & I2C_SR1_ADSL_IND) @@ -221,10 +262,6 @@ static int stu300_event_occurred(struct stu300_dev *dev, case STU300_EVENT_7: case STU300_EVENT_8: if (status1 & I2C_SR1_BTF_IND) { - if (status2 & I2C_SR2_AF_IND) - dev->cmd_err = STU300_ERROR_ACKNOWLEDGE_FAILURE; - else if (status2 & I2C_SR2_BERR_IND) - dev->cmd_err = STU300_ERROR_BUS_ERROR; return 1; } break; @@ -240,8 +277,6 @@ static int stu300_event_occurred(struct stu300_dev *dev, case STU300_EVENT_6: if (status2 & I2C_SR2_ENDAD_IND) { /* First check for any errors */ - if (status2 & I2C_SR2_AF_IND) - dev->cmd_err = STU300_ERROR_ACKNOWLEDGE_FAILURE; return 1; } break; @@ -252,8 +287,15 @@ static int stu300_event_occurred(struct stu300_dev *dev, default: break; } - if (status2 & I2C_SR2_ARLO_IND) - dev->cmd_err = STU300_ERROR_ARBITRATION_LOST; + /* If we get here, we're on thin ice. + * Here we are in a status where we have + * gotten a response that does not match + * what we requested. + */ + dev->cmd_err = STU300_ERROR_UNKNOWN; + dev_err(&dev->pdev->dev, + "Unhandled interrupt! %d sr1: 0x%x sr2: 0x%x\n", + mr_event, status1, status2); return 0; } @@ -262,21 +304,20 @@ static irqreturn_t stu300_irh(int irq, void *data) struct stu300_dev *dev = data; int res; + /* Just make sure that the block is clocked */ + clk_enable(dev->clk); + /* See if this was what we were waiting for */ spin_lock(&dev->cmd_issue_lock); - if (dev->cmd_event != STU300_EVENT_NONE) { - res = stu300_event_occurred(dev, dev->cmd_event); - if (res || dev->cmd_err != STU300_ERROR_NONE) { - u32 val; - - complete(&dev->cmd_complete); - /* Block any multiple interrupts */ - val = stu300_r8(dev->virtbase + I2C_CR); - val &= ~I2C_CR_INTERRUPT_ENABLE; - stu300_wr8(val, dev->virtbase + I2C_CR); - } - } + + res = stu300_event_occurred(dev, dev->cmd_event); + if (res || dev->cmd_err != STU300_ERROR_NONE) + complete(&dev->cmd_complete); + spin_unlock(&dev->cmd_issue_lock); + + clk_disable(dev->clk); + return IRQ_HANDLED; } @@ -308,7 +349,6 @@ static int stu300_start_and_await_event(struct stu300_dev *dev, stu300_wr8(cr_value, dev->virtbase + I2C_CR); ret = wait_for_completion_interruptible_timeout(&dev->cmd_complete, STU300_TIMEOUT); - if (ret < 0) { dev_err(&dev->pdev->dev, "wait_for_completion_interruptible_timeout() " @@ -342,7 +382,6 @@ static int stu300_await_event(struct stu300_dev *dev, enum stu300_event mr_event) { int ret; - u32 val; if (unlikely(irqs_disabled())) { /* TODO: implement polling for this case if need be. */ @@ -354,36 +393,18 @@ static int stu300_await_event(struct stu300_dev *dev, /* Is it already here? */ spin_lock_irq(&dev->cmd_issue_lock); dev->cmd_err = STU300_ERROR_NONE; - if (stu300_event_occurred(dev, mr_event)) { - spin_unlock_irq(&dev->cmd_issue_lock); - goto exit_await_check_err; - } - init_completion(&dev->cmd_complete); - dev->cmd_err = STU300_ERROR_NONE; dev->cmd_event = mr_event; - /* Turn on the I2C interrupt for current operation */ - val = stu300_r8(dev->virtbase + I2C_CR); - val |= I2C_CR_INTERRUPT_ENABLE; - stu300_wr8(val, dev->virtbase + I2C_CR); - - /* Twice paranoia (possible HW glitch) */ - stu300_wr8(val, dev->virtbase + I2C_CR); + init_completion(&dev->cmd_complete); - /* Check again: is it already here? */ - if (unlikely(stu300_event_occurred(dev, mr_event))) { - /* Disable IRQ again. */ - val &= ~I2C_CR_INTERRUPT_ENABLE; - stu300_wr8(val, dev->virtbase + I2C_CR); - spin_unlock_irq(&dev->cmd_issue_lock); - goto exit_await_check_err; - } + /* Turn on the I2C interrupt for current operation */ + stu300_irq_enable(dev); /* Unlock the command block and wait for the event to occur */ spin_unlock_irq(&dev->cmd_issue_lock); + ret = wait_for_completion_interruptible_timeout(&dev->cmd_complete, STU300_TIMEOUT); - if (ret < 0) { dev_err(&dev->pdev->dev, "wait_for_completion_interruptible_timeout()" @@ -401,7 +422,6 @@ static int stu300_await_event(struct stu300_dev *dev, return -ETIMEDOUT; } - exit_await_check_err: if (dev->cmd_err != STU300_ERROR_NONE) { if (mr_event != STU300_EVENT_6) { dev_err(&dev->pdev->dev, "controller " @@ -457,18 +477,19 @@ struct stu300_clkset { }; static const struct stu300_clkset stu300_clktable[] = { - { 0, 0xFFU }, - { 2500000, I2C_OAR2_FR_25_10MHZ }, - { 10000000, I2C_OAR2_FR_10_1667MHZ }, - { 16670000, I2C_OAR2_FR_1667_2667MHZ }, - { 26670000, I2C_OAR2_FR_2667_40MHZ }, - { 40000000, I2C_OAR2_FR_40_5333MHZ }, - { 53330000, I2C_OAR2_FR_5333_66MHZ }, - { 66000000, I2C_OAR2_FR_66_80MHZ }, - { 80000000, I2C_OAR2_FR_80_100MHZ }, + { 0, 0xFFU }, + { 2500000, I2C_OAR2_FR_25_10MHZ }, + { 10000000, I2C_OAR2_FR_10_1667MHZ }, + { 16670000, I2C_OAR2_FR_1667_2667MHZ }, + { 26670000, I2C_OAR2_FR_2667_40MHZ }, + { 40000000, I2C_OAR2_FR_40_5333MHZ }, + { 53330000, I2C_OAR2_FR_5333_66MHZ }, + { 66000000, I2C_OAR2_FR_66_80MHZ }, + { 80000000, I2C_OAR2_FR_80_100MHZ }, { 100000000, 0xFFU }, }; + static int stu300_set_clk(struct stu300_dev *dev, unsigned long clkrate) { @@ -494,10 +515,10 @@ static int stu300_set_clk(struct stu300_dev *dev, unsigned long clkrate) if (dev->speed > 100000) /* Fast Mode I2C */ - val = ((clkrate/dev->speed)-9)/3; + val = ((clkrate/dev->speed) - 9)/3 + 1; else /* Standard Mode I2C */ - val = ((clkrate/dev->speed)-7)/2; + val = ((clkrate/dev->speed) - 7)/2 + 1; /* According to spec the divider must be > 2 */ if (val < 0x002) { @@ -557,6 +578,7 @@ static int stu300_init_hw(struct stu300_dev *dev) */ clkrate = clk_get_rate(dev->clk); ret = stu300_set_clk(dev, clkrate); + if (ret) return ret; /* @@ -641,7 +663,6 @@ static int stu300_xfer_msg(struct i2c_adapter *adap, int attempts = 0; struct stu300_dev *dev = i2c_get_adapdata(adap); - clk_enable(dev->clk); /* Remove this if (0) to trace each and every message. */ @@ -715,14 +736,15 @@ static int stu300_xfer_msg(struct i2c_adapter *adap, if (attempts < NUM_ADDR_RESEND_ATTEMPTS && attempts > 0) { dev_dbg(&dev->pdev->dev, "managed to get address " - "through after %d attempts\n", attempts); + "through after %d attempts\n", attempts); } else if (attempts == NUM_ADDR_RESEND_ATTEMPTS) { dev_dbg(&dev->pdev->dev, "I give up, tried %d times " - "to resend address.\n", - NUM_ADDR_RESEND_ATTEMPTS); + "to resend address.\n", + NUM_ADDR_RESEND_ATTEMPTS); goto exit_disable; } + if (msg->flags & I2C_M_RD) { /* READ: we read the actual bytes one at a time */ for (i = 0; i < msg->len; i++) { @@ -804,8 +826,10 @@ static int stu300_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, { int ret = -1; int i; + struct stu300_dev *dev = i2c_get_adapdata(adap); dev->msg_len = num; + for (i = 0; i < num; i++) { /* * Another driver appears to send stop for each message, @@ -817,6 +841,7 @@ static int stu300_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, dev->msg_index = i; ret = stu300_xfer_msg(adap, &msgs[i], (i == (num - 1))); + if (ret != 0) { num = ret; break; @@ -845,6 +870,7 @@ stu300_probe(struct platform_device *pdev) struct resource *res; int bus_nr; int ret = 0; + char clk_name[] = "I2C0"; dev = kzalloc(sizeof(struct stu300_dev), GFP_KERNEL); if (!dev) { @@ -854,7 +880,8 @@ stu300_probe(struct platform_device *pdev) } bus_nr = pdev->id; - dev->clk = clk_get(&pdev->dev, NULL); + clk_name[3] += (char)bus_nr; + dev->clk = clk_get(&pdev->dev, clk_name); if (IS_ERR(dev->clk)) { ret = PTR_ERR(dev->clk); dev_err(&pdev->dev, "could not retrieve i2c bus clock\n"); |