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    Subject[PATCH v3 08/14] i2c-octeon: Add support for cn78XX chips
    Date
    From: David Daney <david.daney@cavium.com>

    cn78XX has a different interrupt architecture, so we have to manage
    the interrupts differently.

    Signed-off-by: David Daney <ddaney@caviumnetworks.com>
    Signed-off-by: Jan Glauber <jglauber@cavium.com>
    ---
    drivers/i2c/busses/i2c-octeon.c | 149 +++++++++++++++++++++++++++++++++++-----
    1 file changed, 133 insertions(+), 16 deletions(-)

    diff --git a/drivers/i2c/busses/i2c-octeon.c b/drivers/i2c/busses/i2c-octeon.c
    index 8762473..b76ccd5 100644
    --- a/drivers/i2c/busses/i2c-octeon.c
    +++ b/drivers/i2c/busses/i2c-octeon.c
    @@ -11,6 +11,7 @@
    * warranty of any kind, whether express or implied.
    */

    +#include <linux/atomic.h>
    #include <linux/platform_device.h>
    #include <linux/interrupt.h>
    #include <linux/kernel.h>
    @@ -105,11 +106,18 @@ struct octeon_i2c {
    wait_queue_head_t queue;
    struct i2c_adapter adap;
    int irq;
    + int hlc_irq; /* For cn7890 only */
    u32 twsi_freq;
    int sys_freq;
    void __iomem *twsi_base;
    struct device *dev;
    bool hlc_enabled;
    + void (*int_en)(struct octeon_i2c *);
    + void (*int_dis)(struct octeon_i2c *);
    + void (*hlc_int_en)(struct octeon_i2c *);
    + void (*hlc_int_dis)(struct octeon_i2c *);
    + atomic_t int_en_cnt;
    + atomic_t hlc_int_en_cnt;
    };

    static int reset_how;
    @@ -211,6 +219,58 @@ static void octeon_i2c_disable_hlc(struct octeon_i2c *i2c)
    }

    /**
    + * octeon_i2c_int_enable78 - enable the CORE interrupt
    + * @i2c: The struct octeon_i2c
    + *
    + * The interrupt will be asserted when there is non-STAT_IDLE state in the
    + * SW_TWSI_EOP_TWSI_STAT register.
    + */
    +static void octeon_i2c_int_enable78(struct octeon_i2c *i2c)
    +{
    + atomic_inc_return(&i2c->int_en_cnt);
    + enable_irq(i2c->irq);
    +}
    +
    +static void __octeon_i2c_irq_disable(atomic_t *cnt, int irq)
    +{
    + int count;
    +
    + /*
    + * The interrupt can be disabled in two places, but we only
    + * want to make the disable_irq_nosync() call once, so keep
    + * track with the atomic variable.
    + */
    + count = atomic_dec_if_positive(cnt);
    + if (count >= 0)
    + disable_irq_nosync(irq);
    +}
    +
    +/* disable the CORE interrupt */
    +static void octeon_i2c_int_disable78(struct octeon_i2c *i2c)
    +{
    + __octeon_i2c_irq_disable(&i2c->int_en_cnt, i2c->irq);
    +}
    +
    +/**
    + * octeon_i2c_hlc_int_enable78 - enable the ST interrupt
    + * @i2c: The struct octeon_i2c
    + *
    + * The interrupt will be asserted when there is non-STAT_IDLE state in
    + * the SW_TWSI_EOP_TWSI_STAT register.
    + */
    +static void octeon_i2c_hlc_int_enable78(struct octeon_i2c *i2c)
    +{
    + atomic_inc_return(&i2c->hlc_int_en_cnt);
    + enable_irq(i2c->hlc_irq);
    +}
    +
    +/* disable the ST interrupt */
    +static void octeon_i2c_hlc_int_disable78(struct octeon_i2c *i2c)
    +{
    + __octeon_i2c_irq_disable(&i2c->hlc_int_en_cnt, i2c->hlc_irq);
    +}
    +
    +/**
    * octeon_i2c_unblock - unblock the bus
    * @i2c: The struct octeon_i2c
    *
    @@ -247,7 +307,18 @@ static irqreturn_t octeon_i2c_isr(int irq, void *dev_id)
    {
    struct octeon_i2c *i2c = dev_id;

    - octeon_i2c_int_disable(i2c);
    + i2c->int_dis(i2c);
    + wake_up(&i2c->queue);
    +
    + return IRQ_HANDLED;
    +}
    +
    +/* HLC interrupt service routine */
    +static irqreturn_t octeon_i2c_hlc_isr78(int irq, void *dev_id)
    +{
    + struct octeon_i2c *i2c = dev_id;
    +
    + i2c->hlc_int_dis(i2c);
    wake_up(&i2c->queue);

    return IRQ_HANDLED;
    @@ -273,10 +344,10 @@ static int octeon_i2c_wait(struct octeon_i2c *i2c)
    {
    long time_left;

    - octeon_i2c_int_enable(i2c);
    + i2c->int_en(i2c);
    time_left = wait_event_timeout(i2c->queue, octeon_i2c_test_iflg(i2c),
    i2c->adap.timeout);
    - octeon_i2c_int_disable(i2c);
    + i2c->int_dis(i2c);
    if (!time_left) {
    dev_dbg(i2c->dev, "%s: timeout\n", __func__);
    return -ETIMEDOUT;
    @@ -411,11 +482,11 @@ static int octeon_i2c_hlc_wait(struct octeon_i2c *i2c)
    {
    int result;

    - octeon_i2c_hlc_int_enable(i2c);
    + i2c->hlc_int_en(i2c);
    result = wait_event_interruptible_timeout(i2c->queue,
    octeon_i2c_hlc_test_ready(i2c),
    i2c->adap.timeout);
    - octeon_i2c_int_disable(i2c);
    + i2c->hlc_int_dis(i2c);
    if (!result)
    octeon_i2c_hlc_int_clear(i2c);
    if (result < 0) {
    @@ -966,14 +1037,26 @@ static struct i2c_adapter octeon_i2c_ops = {
    static int octeon_i2c_probe(struct platform_device *pdev)
    {
    struct device_node *node = pdev->dev.of_node;
    + int irq, result = 0, hlc_irq = 0;
    struct resource *res_mem;
    struct octeon_i2c *i2c;
    - int irq, result = 0;
    -
    - /* All adaptors have an irq. */
    - irq = platform_get_irq(pdev, 0);
    - if (irq < 0)
    - return irq;
    + bool cn78xx_style;
    +
    + cn78xx_style = of_device_is_compatible(node, "cavium,octeon-7890-twsi");
    + if (cn78xx_style) {
    + hlc_irq = platform_get_irq(pdev, 0);
    + if (hlc_irq < 0)
    + return hlc_irq;
    +
    + irq = platform_get_irq(pdev, 2);
    + if (irq < 0)
    + return irq;
    + } else {
    + /* All adaptors have an irq. */
    + irq = platform_get_irq(pdev, 0);
    + if (irq < 0)
    + return irq;
    + }

    i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
    if (!i2c) {
    @@ -1017,11 +1100,44 @@ static int octeon_i2c_probe(struct platform_device *pdev)

    i2c->irq = irq;

    - result = devm_request_irq(&pdev->dev, i2c->irq,
    - octeon_i2c_isr, 0, DRV_NAME, i2c);
    - if (result < 0) {
    - dev_err(i2c->dev, "failed to attach interrupt\n");
    - goto out;
    + if (cn78xx_style) {
    + i2c->hlc_irq = hlc_irq;
    +
    + i2c->int_en = octeon_i2c_int_enable78;
    + i2c->int_dis = octeon_i2c_int_disable78;
    + i2c->hlc_int_en = octeon_i2c_hlc_int_enable78;
    + i2c->hlc_int_dis = octeon_i2c_hlc_int_disable78;
    +
    + irq_set_status_flags(i2c->irq, IRQ_NOAUTOEN);
    + irq_set_status_flags(i2c->hlc_irq, IRQ_NOAUTOEN);
    +
    + result = devm_request_irq(&pdev->dev, i2c->irq,
    + octeon_i2c_isr, 0, DRV_NAME, i2c);
    +
    + if (result < 0) {
    + dev_err(i2c->dev, "failed to attach interrupt\n");
    + goto out;
    + }
    + result = devm_request_irq(&pdev->dev, i2c->hlc_irq,
    + octeon_i2c_hlc_isr78, 0,
    + DRV_NAME, i2c);
    +
    + if (result < 0) {
    + dev_err(i2c->dev, "failed to attach interrupt\n");
    + goto out;
    + }
    + } else {
    + i2c->int_en = octeon_i2c_int_enable;
    + i2c->int_dis = octeon_i2c_int_disable;
    + i2c->hlc_int_en = octeon_i2c_hlc_int_enable;
    + i2c->hlc_int_dis = octeon_i2c_int_disable;
    +
    + result = devm_request_irq(&pdev->dev, i2c->irq,
    + octeon_i2c_isr, 0, DRV_NAME, i2c);
    + if (result < 0) {
    + dev_err(i2c->dev, "failed to attach interrupt\n");
    + goto out;
    + }
    }

    result = octeon_i2c_initlowlevel(i2c);
    @@ -1062,6 +1178,7 @@ static int octeon_i2c_remove(struct platform_device *pdev)

    static const struct of_device_id octeon_i2c_match[] = {
    { .compatible = "cavium,octeon-3860-twsi", },
    + { .compatible = "cavium,octeon-7890-twsi", },
    {},
    };
    MODULE_DEVICE_TABLE(of, octeon_i2c_match);
    --
    1.9.1
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