Re: [U-Boot] [PATCH 2/2] i2c: at91_i2c: remove the .probe_chip function

[Yang, Wenyou]

On 2017/11/29 11:25, Alan Ott wrote:

The .probe_chip function is supposed to probe an i2c device on the bus to
determine whether a device is answering to a particular address.
at91_i2c_probe_chip() did not do anything resembling this and always
returned 0.

It looks as though at91_i2c_probe_chip() was intended to be a .probe
function for the controller, as it was copied-and-pasted to become
at91_i2c_probe() in 0bc8f640a4d7ed.

Removing the at91_i2c_probe_chip() function makes the higher layer
(i2c_probe_chip()) try a zero-length read transfer to test for the
presence of a device instead, which does work.

Signed-off-by: Alan Ott <a...@softiron.com>
---

Acked-by: Wenyou Yang <wenyou.y...@microchip.com>

Thank you for your patch.

  drivers/i2c/at91_i2c.c | 22 ----------------------
  1 file changed, 22 deletions(-)

diff --git a/drivers/i2c/at91_i2c.c b/drivers/i2c/at91_i2c.c
index 20d0929..7917ca1 100644
--- a/drivers/i2c/at91_i2c.c
+++ b/drivers/i2c/at91_i2c.c
@@ -201,27 +201,6 @@ static int at91_i2c_enable_clk(struct udevice *dev)
        return 0;
  }

-static int at91_i2c_probe_chip(struct udevice *dev, uint chip, uint chip_flags)

-{
-       struct at91_i2c_bus *bus = dev_get_priv(dev);
-       struct at91_i2c_regs *reg = bus->regs;
-       int ret;
-
-       ret = at91_i2c_enable_clk(dev);
-       if (ret)
-               return ret;
-
-       writel(TWI_CR_SWRST, &reg->cr);
-
-       at91_calc_i2c_clock(dev, bus->clock_frequency);
-
-       writel(bus->cwgr_val, &reg->cwgr);
-       writel(TWI_CR_MSEN, &reg->cr);
-       writel(TWI_CR_SVDIS, &reg->cr);
-
-       return 0;
-}
-
  static int at91_i2c_set_bus_speed(struct udevice *dev, unsigned int speed)
  {
        struct at91_i2c_bus *bus = dev_get_priv(dev);
@@ -256,7 +235,6 @@ static int at91_i2c_ofdata_to_platdata(struct udevice *dev)

static const struct dm_i2c_ops at91_i2c_ops = {

        .xfer           = at91_i2c_xfer,
-       .probe_chip     = at91_i2c_probe_chip,
        .set_bus_speed  = at91_i2c_set_bus_speed,
        .get_bus_speed  = at91_i2c_get_bus_speed,
  };

Best Regards,
Wenyou Yang
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