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Commit ec9b3a9d authored by Ben Skeggs's avatar Ben Skeggs Committed by Dave Airlie
Browse files

drm/nouveau/i2c: resume use of i2c-algo-bit, rather than custom stack 



Previous issues with i2c-algo-bit have now been resolved.

This is a revert of f553b79c mostly,
due to fixes in the i2c core repairing the original issue, this code
isn't required and was causing regressions.

Signed-off-by: default avatarBen Skeggs <bskeggs@redhat.com>
Reported-by: default avatarNick Bowler <nbowler@elliptictech.com>
Tested-by: default avatarNick Bowler <nbowler@elliptictech.com>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent c42b5da2

drivers/gpu/drm/nouveau/nouveau_i2c.c

+21 −178
Original line number Diff line number Diff line
@@ -29,10 +29,6 @@ 
#include "nouveau_i2c.h"

#include "nouveau_hw.h"



#define T_TIMEOUT  2200000

#define T_RISEFALL 1000

#define T_HOLD     5000



static void

i2c_drive_scl(void *data, int state)

{
@@ -113,175 +109,6 @@ i2c_sense_sda(void *data) 
	return 0;

}



static void

i2c_delay(struct nouveau_i2c_chan *port, u32 nsec)

{

	udelay((nsec + 500) / 1000);

}



static bool

i2c_raise_scl(struct nouveau_i2c_chan *port)

{

	u32 timeout = T_TIMEOUT / T_RISEFALL;



	i2c_drive_scl(port, 1);

	do {

		i2c_delay(port, T_RISEFALL);

	} while (!i2c_sense_scl(port) && --timeout);



	return timeout != 0;

}



static int

i2c_start(struct nouveau_i2c_chan *port)

{

	int ret = 0;



	port->state  = i2c_sense_scl(port);

	port->state |= i2c_sense_sda(port) << 1;

	if (port->state != 3) {

		i2c_drive_scl(port, 0);

		i2c_drive_sda(port, 1);

		if (!i2c_raise_scl(port))

			ret = -EBUSY;

	}



	i2c_drive_sda(port, 0);

	i2c_delay(port, T_HOLD);

	i2c_drive_scl(port, 0);

	i2c_delay(port, T_HOLD);

	return ret;

}



static void

i2c_stop(struct nouveau_i2c_chan *port)

{

	i2c_drive_scl(port, 0);

	i2c_drive_sda(port, 0);

	i2c_delay(port, T_RISEFALL);



	i2c_drive_scl(port, 1);

	i2c_delay(port, T_HOLD);

	i2c_drive_sda(port, 1);

	i2c_delay(port, T_HOLD);

}



static int

i2c_bitw(struct nouveau_i2c_chan *port, int sda)

{

	i2c_drive_sda(port, sda);

	i2c_delay(port, T_RISEFALL);



	if (!i2c_raise_scl(port))

		return -ETIMEDOUT;

	i2c_delay(port, T_HOLD);



	i2c_drive_scl(port, 0);

	i2c_delay(port, T_HOLD);

	return 0;

}



static int

i2c_bitr(struct nouveau_i2c_chan *port)

{

	int sda;



	i2c_drive_sda(port, 1);

	i2c_delay(port, T_RISEFALL);



	if (!i2c_raise_scl(port))

		return -ETIMEDOUT;

	i2c_delay(port, T_HOLD);



	sda = i2c_sense_sda(port);



	i2c_drive_scl(port, 0);

	i2c_delay(port, T_HOLD);

	return sda;

}



static int

i2c_get_byte(struct nouveau_i2c_chan *port, u8 *byte, bool last)

{

	int i, bit;



	*byte = 0;

	for (i = 7; i >= 0; i--) {

		bit = i2c_bitr(port);

		if (bit < 0)

			return bit;

		*byte |= bit << i;

	}



	return i2c_bitw(port, last ? 1 : 0);

}



static int

i2c_put_byte(struct nouveau_i2c_chan *port, u8 byte)

{

	int i, ret;

	for (i = 7; i >= 0; i--) {

		ret = i2c_bitw(port, !!(byte & (1 << i)));

		if (ret < 0)

			return ret;

	}



	ret = i2c_bitr(port);

	if (ret == 1) /* nack */

		ret = -EIO;

	return ret;

}



static int

i2c_addr(struct nouveau_i2c_chan *port, struct i2c_msg *msg)

{

	u32 addr = msg->addr << 1;

	if (msg->flags & I2C_M_RD)

		addr |= 1;

	return i2c_put_byte(port, addr);

}



static int

i2c_bit_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)

{

	struct nouveau_i2c_chan *port = (struct nouveau_i2c_chan *)adap;

	struct i2c_msg *msg = msgs;

	int ret = 0, mcnt = num;



	while (!ret && mcnt--) {

		u8 remaining = msg->len;

		u8 *ptr = msg->buf;



		ret = i2c_start(port);

		if (ret == 0)

			ret = i2c_addr(port, msg);



		if (msg->flags & I2C_M_RD) {

			while (!ret && remaining--)

				ret = i2c_get_byte(port, ptr++, !remaining);

		} else {

			while (!ret && remaining--)

				ret = i2c_put_byte(port, *ptr++);

		}



		msg++;

	}



	i2c_stop(port);

	return (ret < 0) ? ret : num;

}



static u32

i2c_bit_func(struct i2c_adapter *adap)

{

	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;

}



const struct i2c_algorithm nouveau_i2c_bit_algo = {

	.master_xfer = i2c_bit_xfer,

	.functionality = i2c_bit_func

};



static const uint32_t nv50_i2c_port[] = {

	0x00e138, 0x00e150, 0x00e168, 0x00e180,

	0x00e254, 0x00e274, 0x00e764, 0x00e780,
@@ -384,12 +211,10 @@ nouveau_i2c_init(struct drm_device *dev) 
		case 0: /* NV04:NV50 */

			port->drive = entry[0];

			port->sense = entry[1];

			port->adapter.algo = &nouveau_i2c_bit_algo;

			break;

		case 4: /* NV4E */

			port->drive = 0x600800 + entry[1];

			port->sense = port->drive;

			port->adapter.algo = &nouveau_i2c_bit_algo;

			break;

		case 5: /* NV50- */

			port->drive = entry[0] & 0x0f;
@@ -402,7 +227,6 @@ nouveau_i2c_init(struct drm_device *dev) 
				port->drive = 0x00d014 + (port->drive * 0x20);

				port->sense = port->drive;

			}

			port->adapter.algo = &nouveau_i2c_bit_algo;

			break;

		case 6: /* NV50- DP AUX */

			port->drive = entry[0];
@@ -413,7 +237,7 @@ nouveau_i2c_init(struct drm_device *dev) 
			break;

		}



		if (!port->adapter.algo) {

		if (!port->adapter.algo && !port->drive) {

			NV_ERROR(dev, "I2C%d: type %d index %x/%x unknown\n",

				 i, port->type, port->drive, port->sense);

			kfree(port);
@@ -429,7 +253,26 @@ nouveau_i2c_init(struct drm_device *dev) 
		port->dcb = ROM32(entry[0]);

		i2c_set_adapdata(&port->adapter, i2c);



		if (port->adapter.algo != &nouveau_dp_i2c_algo) {

			port->adapter.algo_data = &port->bit;

			port->bit.udelay = 10;

			port->bit.timeout = usecs_to_jiffies(2200);

			port->bit.data = port;

			port->bit.setsda = i2c_drive_sda;

			port->bit.setscl = i2c_drive_scl;

			port->bit.getsda = i2c_sense_sda;

			port->bit.getscl = i2c_sense_scl;



			i2c_drive_scl(port, 0);

			i2c_drive_sda(port, 1);

			i2c_drive_scl(port, 1);



			ret = i2c_bit_add_bus(&port->adapter);

		} else {

			port->adapter.algo = &nouveau_dp_i2c_algo;

			ret = i2c_add_adapter(&port->adapter);

		}



		if (ret) {

			NV_ERROR(dev, "I2C%d: failed register: %d\n", i, ret);

			kfree(port);

drivers/gpu/drm/nouveau/nouveau_i2c.h

+1 −0
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ 
struct nouveau_i2c_chan {

	struct i2c_adapter adapter;

	struct drm_device *dev;

	struct i2c_algo_bit_data bit;

	struct list_head head;

	u8  index;

	u8  type;