2 * Copyright (c) 2006 Dave Airlie <airlied@linux.ie>
3 * Copyright © 2006-2008,2010 Intel Corporation
4 * Jesse Barnes <jesse.barnes@intel.com>
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the "Software"),
8 * to deal in the Software without restriction, including without limitation
9 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10 * and/or sell copies of the Software, and to permit persons to whom the
11 * Software is furnished to do so, subject to the following conditions:
13 * The above copyright notice and this permission notice (including the next
14 * paragraph) shall be included in all copies or substantial portions of the
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
22 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
23 * DEALINGS IN THE SOFTWARE.
26 * Eric Anholt <eric@anholt.net>
27 * Chris Wilson <chris@chris-wilson.co.uk>
29 #include <linux/i2c.h>
30 #include <linux/i2c-algo-bit.h>
31 #include <linux/export.h>
33 #include "intel_drv.h"
34 #include <drm/i915_drm.h>
42 static const struct gmbus_port gmbus_ports[] = {
51 /* Intel GPIO access functions */
53 #define I2C_RISEFALL_TIME 10
55 static inline struct intel_gmbus *
56 to_intel_gmbus(struct i2c_adapter *i2c)
58 return container_of(i2c, struct intel_gmbus, adapter);
62 intel_i2c_reset(struct drm_device *dev)
64 struct drm_i915_private *dev_priv = dev->dev_private;
66 I915_WRITE(dev_priv->gpio_mmio_base + GMBUS0, 0);
67 I915_WRITE(dev_priv->gpio_mmio_base + GMBUS4, 0);
70 static void intel_i2c_quirk_set(struct drm_i915_private *dev_priv, bool enable)
74 /* When using bit bashing for I2C, this bit needs to be set to 1 */
75 if (!IS_PINEVIEW(dev_priv->dev))
78 val = I915_READ(DSPCLK_GATE_D);
80 val |= DPCUNIT_CLOCK_GATE_DISABLE;
82 val &= ~DPCUNIT_CLOCK_GATE_DISABLE;
83 I915_WRITE(DSPCLK_GATE_D, val);
86 static u32 get_reserved(struct intel_gmbus *bus)
88 struct drm_i915_private *dev_priv = bus->dev_priv;
89 struct drm_device *dev = dev_priv->dev;
92 /* On most chips, these bits must be preserved in software. */
93 if (!IS_I830(dev) && !IS_845G(dev))
94 reserved = I915_READ_NOTRACE(bus->gpio_reg) &
95 (GPIO_DATA_PULLUP_DISABLE |
96 GPIO_CLOCK_PULLUP_DISABLE);
101 static int get_clock(void *data)
103 struct intel_gmbus *bus = data;
104 struct drm_i915_private *dev_priv = bus->dev_priv;
105 u32 reserved = get_reserved(bus);
106 I915_WRITE_NOTRACE(bus->gpio_reg, reserved | GPIO_CLOCK_DIR_MASK);
107 I915_WRITE_NOTRACE(bus->gpio_reg, reserved);
108 return (I915_READ_NOTRACE(bus->gpio_reg) & GPIO_CLOCK_VAL_IN) != 0;
111 static int get_data(void *data)
113 struct intel_gmbus *bus = data;
114 struct drm_i915_private *dev_priv = bus->dev_priv;
115 u32 reserved = get_reserved(bus);
116 I915_WRITE_NOTRACE(bus->gpio_reg, reserved | GPIO_DATA_DIR_MASK);
117 I915_WRITE_NOTRACE(bus->gpio_reg, reserved);
118 return (I915_READ_NOTRACE(bus->gpio_reg) & GPIO_DATA_VAL_IN) != 0;
121 static void set_clock(void *data, int state_high)
123 struct intel_gmbus *bus = data;
124 struct drm_i915_private *dev_priv = bus->dev_priv;
125 u32 reserved = get_reserved(bus);
129 clock_bits = GPIO_CLOCK_DIR_IN | GPIO_CLOCK_DIR_MASK;
131 clock_bits = GPIO_CLOCK_DIR_OUT | GPIO_CLOCK_DIR_MASK |
134 I915_WRITE_NOTRACE(bus->gpio_reg, reserved | clock_bits);
135 POSTING_READ(bus->gpio_reg);
138 static void set_data(void *data, int state_high)
140 struct intel_gmbus *bus = data;
141 struct drm_i915_private *dev_priv = bus->dev_priv;
142 u32 reserved = get_reserved(bus);
146 data_bits = GPIO_DATA_DIR_IN | GPIO_DATA_DIR_MASK;
148 data_bits = GPIO_DATA_DIR_OUT | GPIO_DATA_DIR_MASK |
151 I915_WRITE_NOTRACE(bus->gpio_reg, reserved | data_bits);
152 POSTING_READ(bus->gpio_reg);
156 intel_gpio_pre_xfer(struct i2c_adapter *adapter)
158 struct intel_gmbus *bus = container_of(adapter,
161 struct drm_i915_private *dev_priv = bus->dev_priv;
163 intel_i2c_reset(dev_priv->dev);
164 intel_i2c_quirk_set(dev_priv, true);
167 udelay(I2C_RISEFALL_TIME);
172 intel_gpio_post_xfer(struct i2c_adapter *adapter)
174 struct intel_gmbus *bus = container_of(adapter,
177 struct drm_i915_private *dev_priv = bus->dev_priv;
181 intel_i2c_quirk_set(dev_priv, false);
185 intel_gpio_setup(struct intel_gmbus *bus, u32 pin)
187 struct drm_i915_private *dev_priv = bus->dev_priv;
188 struct i2c_algo_bit_data *algo;
190 algo = &bus->bit_algo;
192 /* -1 to map pin pair to gmbus index */
193 bus->gpio_reg = dev_priv->gpio_mmio_base + gmbus_ports[pin - 1].reg;
195 bus->adapter.algo_data = algo;
196 algo->setsda = set_data;
197 algo->setscl = set_clock;
198 algo->getsda = get_data;
199 algo->getscl = get_clock;
200 algo->pre_xfer = intel_gpio_pre_xfer;
201 algo->post_xfer = intel_gpio_post_xfer;
202 algo->udelay = I2C_RISEFALL_TIME;
203 algo->timeout = usecs_to_jiffies(2200);
208 gmbus_wait_hw_status(struct drm_i915_private *dev_priv,
213 int reg_offset = dev_priv->gpio_mmio_base;
217 if (!HAS_GMBUS_IRQ(dev_priv->dev))
220 /* Important: The hw handles only the first bit, so set only one! Since
221 * we also need to check for NAKs besides the hw ready/idle signal, we
222 * need to wake up periodically and check that ourselves. */
223 I915_WRITE(GMBUS4 + reg_offset, gmbus4_irq_en);
225 for (i = 0; i < msecs_to_jiffies_timeout(50); i++) {
226 prepare_to_wait(&dev_priv->gmbus_wait_queue, &wait,
227 TASK_UNINTERRUPTIBLE);
229 gmbus2 = I915_READ_NOTRACE(GMBUS2 + reg_offset);
230 if (gmbus2 & (GMBUS_SATOER | gmbus2_status))
235 finish_wait(&dev_priv->gmbus_wait_queue, &wait);
237 I915_WRITE(GMBUS4 + reg_offset, 0);
239 if (gmbus2 & GMBUS_SATOER)
241 if (gmbus2 & gmbus2_status)
247 gmbus_wait_idle(struct drm_i915_private *dev_priv)
250 int reg_offset = dev_priv->gpio_mmio_base;
252 #define C ((I915_READ_NOTRACE(GMBUS2 + reg_offset) & GMBUS_ACTIVE) == 0)
254 if (!HAS_GMBUS_IRQ(dev_priv->dev))
255 return wait_for(C, 10);
257 /* Important: The hw handles only the first bit, so set only one! */
258 I915_WRITE(GMBUS4 + reg_offset, GMBUS_IDLE_EN);
260 ret = wait_event_timeout(dev_priv->gmbus_wait_queue, C,
261 msecs_to_jiffies_timeout(10));
263 I915_WRITE(GMBUS4 + reg_offset, 0);
273 gmbus_xfer_read_chunk(struct drm_i915_private *dev_priv,
274 unsigned short addr, u8 *buf, unsigned int len,
277 int reg_offset = dev_priv->gpio_mmio_base;
279 I915_WRITE(GMBUS1 + reg_offset,
282 (len << GMBUS_BYTE_COUNT_SHIFT) |
283 (addr << GMBUS_SLAVE_ADDR_SHIFT) |
284 GMBUS_SLAVE_READ | GMBUS_SW_RDY);
289 ret = gmbus_wait_hw_status(dev_priv, GMBUS_HW_RDY,
294 val = I915_READ(GMBUS3 + reg_offset);
298 } while (--len && ++loop < 4);
305 gmbus_xfer_read(struct drm_i915_private *dev_priv, struct i2c_msg *msg,
309 unsigned int rx_size = msg->len;
314 len = min(rx_size, GMBUS_BYTE_COUNT_MAX);
316 ret = gmbus_xfer_read_chunk(dev_priv, msg->addr,
317 buf, len, gmbus1_index);
323 } while (rx_size != 0);
329 gmbus_xfer_write_chunk(struct drm_i915_private *dev_priv,
330 unsigned short addr, u8 *buf, unsigned int len)
332 int reg_offset = dev_priv->gpio_mmio_base;
333 unsigned int chunk_size = len;
337 while (len && loop < 4) {
338 val |= *buf++ << (8 * loop++);
342 I915_WRITE(GMBUS3 + reg_offset, val);
343 I915_WRITE(GMBUS1 + reg_offset,
345 (chunk_size << GMBUS_BYTE_COUNT_SHIFT) |
346 (addr << GMBUS_SLAVE_ADDR_SHIFT) |
347 GMBUS_SLAVE_WRITE | GMBUS_SW_RDY);
353 val |= *buf++ << (8 * loop);
354 } while (--len && ++loop < 4);
356 I915_WRITE(GMBUS3 + reg_offset, val);
358 ret = gmbus_wait_hw_status(dev_priv, GMBUS_HW_RDY,
368 gmbus_xfer_write(struct drm_i915_private *dev_priv, struct i2c_msg *msg)
371 unsigned int tx_size = msg->len;
376 len = min(tx_size, GMBUS_BYTE_COUNT_MAX);
378 ret = gmbus_xfer_write_chunk(dev_priv, msg->addr, buf, len);
384 } while (tx_size != 0);
390 * The gmbus controller can combine a 1 or 2 byte write with a read that
391 * immediately follows it by using an "INDEX" cycle.
394 gmbus_is_index_read(struct i2c_msg *msgs, int i, int num)
396 return (i + 1 < num &&
397 !(msgs[i].flags & I2C_M_RD) && msgs[i].len <= 2 &&
398 (msgs[i + 1].flags & I2C_M_RD));
402 gmbus_xfer_index_read(struct drm_i915_private *dev_priv, struct i2c_msg *msgs)
404 int reg_offset = dev_priv->gpio_mmio_base;
405 u32 gmbus1_index = 0;
409 if (msgs[0].len == 2)
410 gmbus5 = GMBUS_2BYTE_INDEX_EN |
411 msgs[0].buf[1] | (msgs[0].buf[0] << 8);
412 if (msgs[0].len == 1)
413 gmbus1_index = GMBUS_CYCLE_INDEX |
414 (msgs[0].buf[0] << GMBUS_SLAVE_INDEX_SHIFT);
416 /* GMBUS5 holds 16-bit index */
418 I915_WRITE(GMBUS5 + reg_offset, gmbus5);
420 ret = gmbus_xfer_read(dev_priv, &msgs[1], gmbus1_index);
422 /* Clear GMBUS5 after each index transfer */
424 I915_WRITE(GMBUS5 + reg_offset, 0);
430 gmbus_xfer(struct i2c_adapter *adapter,
431 struct i2c_msg *msgs,
434 struct intel_gmbus *bus = container_of(adapter,
437 struct drm_i915_private *dev_priv = bus->dev_priv;
438 int i = 0, inc, try = 0, reg_offset;
441 intel_aux_display_runtime_get(dev_priv);
442 mutex_lock(&dev_priv->gmbus_mutex);
444 if (bus->force_bit) {
445 ret = i2c_bit_algo.master_xfer(adapter, msgs, num);
449 reg_offset = dev_priv->gpio_mmio_base;
452 I915_WRITE(GMBUS0 + reg_offset, bus->reg0);
454 for (; i < num; i += inc) {
456 if (gmbus_is_index_read(msgs, i, num)) {
457 ret = gmbus_xfer_index_read(dev_priv, &msgs[i]);
458 inc = 2; /* an index read is two msgs */
459 } else if (msgs[i].flags & I2C_M_RD) {
460 ret = gmbus_xfer_read(dev_priv, &msgs[i], 0);
462 ret = gmbus_xfer_write(dev_priv, &msgs[i]);
465 if (ret == -ETIMEDOUT)
470 ret = gmbus_wait_hw_status(dev_priv, GMBUS_HW_WAIT_PHASE,
478 /* Generate a STOP condition on the bus. Note that gmbus can't generata
479 * a STOP on the very first cycle. To simplify the code we
480 * unconditionally generate the STOP condition with an additional gmbus
482 I915_WRITE(GMBUS1 + reg_offset, GMBUS_CYCLE_STOP | GMBUS_SW_RDY);
484 /* Mark the GMBUS interface as disabled after waiting for idle.
485 * We will re-enable it at the start of the next xfer,
486 * till then let it sleep.
488 if (gmbus_wait_idle(dev_priv)) {
489 DRM_DEBUG_KMS("GMBUS [%s] timed out waiting for idle\n",
493 I915_WRITE(GMBUS0 + reg_offset, 0);
499 * Wait for bus to IDLE before clearing NAK.
500 * If we clear the NAK while bus is still active, then it will stay
501 * active and the next transaction may fail.
503 * If no ACK is received during the address phase of a transaction, the
504 * adapter must report -ENXIO. It is not clear what to return if no ACK
505 * is received at other times. But we have to be careful to not return
506 * spurious -ENXIO because that will prevent i2c and drm edid functions
507 * from retrying. So return -ENXIO only when gmbus properly quiescents -
508 * timing out seems to happen when there _is_ a ddc chip present, but
509 * it's slow responding and only answers on the 2nd retry.
512 if (gmbus_wait_idle(dev_priv)) {
513 DRM_DEBUG_KMS("GMBUS [%s] timed out after NAK\n",
518 /* Toggle the Software Clear Interrupt bit. This has the effect
519 * of resetting the GMBUS controller and so clearing the
520 * BUS_ERROR raised by the slave's NAK.
522 I915_WRITE(GMBUS1 + reg_offset, GMBUS_SW_CLR_INT);
523 I915_WRITE(GMBUS1 + reg_offset, 0);
524 I915_WRITE(GMBUS0 + reg_offset, 0);
526 DRM_DEBUG_KMS("GMBUS [%s] NAK for addr: %04x %c(%d)\n",
527 adapter->name, msgs[i].addr,
528 (msgs[i].flags & I2C_M_RD) ? 'r' : 'w', msgs[i].len);
531 * Passive adapters sometimes NAK the first probe. Retry the first
532 * message once on -ENXIO for GMBUS transfers; the bit banging algorithm
533 * has retries internally. See also the retry loop in
534 * drm_do_probe_ddc_edid, which bails out on the first -ENXIO.
536 if (ret == -ENXIO && i == 0 && try++ == 0) {
537 DRM_DEBUG_KMS("GMBUS [%s] NAK on first message, retry\n",
545 DRM_INFO("GMBUS [%s] timed out, falling back to bit banging on pin %d\n",
546 bus->adapter.name, bus->reg0 & 0xff);
547 I915_WRITE(GMBUS0 + reg_offset, 0);
549 /* Hardware may not support GMBUS over these pins? Try GPIO bitbanging instead. */
551 ret = i2c_bit_algo.master_xfer(adapter, msgs, num);
554 mutex_unlock(&dev_priv->gmbus_mutex);
555 intel_aux_display_runtime_put(dev_priv);
559 static u32 gmbus_func(struct i2c_adapter *adapter)
561 return i2c_bit_algo.functionality(adapter) &
562 (I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
563 /* I2C_FUNC_10BIT_ADDR | */
564 I2C_FUNC_SMBUS_READ_BLOCK_DATA |
565 I2C_FUNC_SMBUS_BLOCK_PROC_CALL);
568 static const struct i2c_algorithm gmbus_algorithm = {
569 .master_xfer = gmbus_xfer,
570 .functionality = gmbus_func
574 * intel_gmbus_setup - instantiate all Intel i2c GMBuses
577 int intel_setup_gmbus(struct drm_device *dev)
579 struct drm_i915_private *dev_priv = dev->dev_private;
582 if (HAS_PCH_NOP(dev))
584 else if (HAS_PCH_SPLIT(dev))
585 dev_priv->gpio_mmio_base = PCH_GPIOA - GPIOA;
586 else if (IS_VALLEYVIEW(dev))
587 dev_priv->gpio_mmio_base = VLV_DISPLAY_BASE;
589 dev_priv->gpio_mmio_base = 0;
591 mutex_init(&dev_priv->gmbus_mutex);
592 init_waitqueue_head(&dev_priv->gmbus_wait_queue);
594 for (i = 0; i < GMBUS_NUM_PORTS; i++) {
595 struct intel_gmbus *bus = &dev_priv->gmbus[i];
596 u32 port = i + 1; /* +1 to map gmbus index to pin pair */
598 bus->adapter.owner = THIS_MODULE;
599 bus->adapter.class = I2C_CLASS_DDC;
600 snprintf(bus->adapter.name,
601 sizeof(bus->adapter.name),
603 gmbus_ports[i].name);
605 bus->adapter.dev.parent = &dev->pdev->dev;
606 bus->dev_priv = dev_priv;
608 bus->adapter.algo = &gmbus_algorithm;
610 /* By default use a conservative clock rate */
611 bus->reg0 = port | GMBUS_RATE_100KHZ;
613 /* gmbus seems to be broken on i830 */
617 intel_gpio_setup(bus, port);
619 ret = i2c_add_adapter(&bus->adapter);
624 intel_i2c_reset(dev_priv->dev);
630 struct intel_gmbus *bus = &dev_priv->gmbus[i];
631 i2c_del_adapter(&bus->adapter);
636 struct i2c_adapter *intel_gmbus_get_adapter(struct drm_i915_private *dev_priv,
639 WARN_ON(!intel_gmbus_is_port_valid(port));
640 /* -1 to map pin pair to gmbus index */
641 return (intel_gmbus_is_port_valid(port)) ?
642 &dev_priv->gmbus[port - 1].adapter : NULL;
645 void intel_gmbus_set_speed(struct i2c_adapter *adapter, int speed)
647 struct intel_gmbus *bus = to_intel_gmbus(adapter);
649 bus->reg0 = (bus->reg0 & ~(0x3 << 8)) | speed;
652 void intel_gmbus_force_bit(struct i2c_adapter *adapter, bool force_bit)
654 struct intel_gmbus *bus = to_intel_gmbus(adapter);
656 bus->force_bit += force_bit ? 1 : -1;
657 DRM_DEBUG_KMS("%sabling bit-banging on %s. force bit now %d\n",
658 force_bit ? "en" : "dis", adapter->name,
662 void intel_teardown_gmbus(struct drm_device *dev)
664 struct drm_i915_private *dev_priv = dev->dev_private;
667 for (i = 0; i < GMBUS_NUM_PORTS; i++) {
668 struct intel_gmbus *bus = &dev_priv->gmbus[i];
669 i2c_del_adapter(&bus->adapter);