Version:  2.0.40 2.2.26 2.4.37 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0

Linux/drivers/i2c/busses/i2c-tegra.c

  1 /*
  2  * drivers/i2c/busses/i2c-tegra.c
  3  *
  4  * Copyright (C) 2010 Google, Inc.
  5  * Author: Colin Cross <ccross@android.com>
  6  *
  7  * This software is licensed under the terms of the GNU General Public
  8  * License version 2, as published by the Free Software Foundation, and
  9  * may be copied, distributed, and modified under those terms.
 10  *
 11  * This program is distributed in the hope that it will be useful,
 12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 14  * GNU General Public License for more details.
 15  *
 16  */
 17 
 18 #include <linux/kernel.h>
 19 #include <linux/init.h>
 20 #include <linux/platform_device.h>
 21 #include <linux/clk.h>
 22 #include <linux/err.h>
 23 #include <linux/i2c.h>
 24 #include <linux/io.h>
 25 #include <linux/interrupt.h>
 26 #include <linux/delay.h>
 27 #include <linux/slab.h>
 28 #include <linux/of_device.h>
 29 #include <linux/module.h>
 30 #include <linux/reset.h>
 31 
 32 #include <asm/unaligned.h>
 33 
 34 #define TEGRA_I2C_TIMEOUT (msecs_to_jiffies(1000))
 35 #define BYTES_PER_FIFO_WORD 4
 36 
 37 #define I2C_CNFG                                0x000
 38 #define I2C_CNFG_DEBOUNCE_CNT_SHIFT             12
 39 #define I2C_CNFG_PACKET_MODE_EN                 (1<<10)
 40 #define I2C_CNFG_NEW_MASTER_FSM                 (1<<11)
 41 #define I2C_STATUS                              0x01C
 42 #define I2C_SL_CNFG                             0x020
 43 #define I2C_SL_CNFG_NACK                        (1<<1)
 44 #define I2C_SL_CNFG_NEWSL                       (1<<2)
 45 #define I2C_SL_ADDR1                            0x02c
 46 #define I2C_SL_ADDR2                            0x030
 47 #define I2C_TX_FIFO                             0x050
 48 #define I2C_RX_FIFO                             0x054
 49 #define I2C_PACKET_TRANSFER_STATUS              0x058
 50 #define I2C_FIFO_CONTROL                        0x05c
 51 #define I2C_FIFO_CONTROL_TX_FLUSH               (1<<1)
 52 #define I2C_FIFO_CONTROL_RX_FLUSH               (1<<0)
 53 #define I2C_FIFO_CONTROL_TX_TRIG_SHIFT          5
 54 #define I2C_FIFO_CONTROL_RX_TRIG_SHIFT          2
 55 #define I2C_FIFO_STATUS                         0x060
 56 #define I2C_FIFO_STATUS_TX_MASK                 0xF0
 57 #define I2C_FIFO_STATUS_TX_SHIFT                4
 58 #define I2C_FIFO_STATUS_RX_MASK                 0x0F
 59 #define I2C_FIFO_STATUS_RX_SHIFT                0
 60 #define I2C_INT_MASK                            0x064
 61 #define I2C_INT_STATUS                          0x068
 62 #define I2C_INT_PACKET_XFER_COMPLETE            (1<<7)
 63 #define I2C_INT_ALL_PACKETS_XFER_COMPLETE       (1<<6)
 64 #define I2C_INT_TX_FIFO_OVERFLOW                (1<<5)
 65 #define I2C_INT_RX_FIFO_UNDERFLOW               (1<<4)
 66 #define I2C_INT_NO_ACK                          (1<<3)
 67 #define I2C_INT_ARBITRATION_LOST                (1<<2)
 68 #define I2C_INT_TX_FIFO_DATA_REQ                (1<<1)
 69 #define I2C_INT_RX_FIFO_DATA_REQ                (1<<0)
 70 #define I2C_CLK_DIVISOR                         0x06c
 71 #define I2C_CLK_DIVISOR_STD_FAST_MODE_SHIFT     16
 72 #define I2C_CLK_MULTIPLIER_STD_FAST_MODE        8
 73 
 74 #define DVC_CTRL_REG1                           0x000
 75 #define DVC_CTRL_REG1_INTR_EN                   (1<<10)
 76 #define DVC_CTRL_REG2                           0x004
 77 #define DVC_CTRL_REG3                           0x008
 78 #define DVC_CTRL_REG3_SW_PROG                   (1<<26)
 79 #define DVC_CTRL_REG3_I2C_DONE_INTR_EN          (1<<30)
 80 #define DVC_STATUS                              0x00c
 81 #define DVC_STATUS_I2C_DONE_INTR                (1<<30)
 82 
 83 #define I2C_ERR_NONE                            0x00
 84 #define I2C_ERR_NO_ACK                          0x01
 85 #define I2C_ERR_ARBITRATION_LOST                0x02
 86 #define I2C_ERR_UNKNOWN_INTERRUPT               0x04
 87 
 88 #define PACKET_HEADER0_HEADER_SIZE_SHIFT        28
 89 #define PACKET_HEADER0_PACKET_ID_SHIFT          16
 90 #define PACKET_HEADER0_CONT_ID_SHIFT            12
 91 #define PACKET_HEADER0_PROTOCOL_I2C             (1<<4)
 92 
 93 #define I2C_HEADER_HIGHSPEED_MODE               (1<<22)
 94 #define I2C_HEADER_CONT_ON_NAK                  (1<<21)
 95 #define I2C_HEADER_SEND_START_BYTE              (1<<20)
 96 #define I2C_HEADER_READ                         (1<<19)
 97 #define I2C_HEADER_10BIT_ADDR                   (1<<18)
 98 #define I2C_HEADER_IE_ENABLE                    (1<<17)
 99 #define I2C_HEADER_REPEAT_START                 (1<<16)
100 #define I2C_HEADER_CONTINUE_XFER                (1<<15)
101 #define I2C_HEADER_MASTER_ADDR_SHIFT            12
102 #define I2C_HEADER_SLAVE_ADDR_SHIFT             1
103 /*
104  * msg_end_type: The bus control which need to be send at end of transfer.
105  * @MSG_END_STOP: Send stop pulse at end of transfer.
106  * @MSG_END_REPEAT_START: Send repeat start at end of transfer.
107  * @MSG_END_CONTINUE: The following on message is coming and so do not send
108  *              stop or repeat start.
109  */
110 enum msg_end_type {
111         MSG_END_STOP,
112         MSG_END_REPEAT_START,
113         MSG_END_CONTINUE,
114 };
115 
116 /**
117  * struct tegra_i2c_hw_feature : Different HW support on Tegra
118  * @has_continue_xfer_support: Continue transfer supports.
119  * @has_per_pkt_xfer_complete_irq: Has enable/disable capability for transfer
120  *              complete interrupt per packet basis.
121  * @has_single_clk_source: The i2c controller has single clock source. Tegra30
122  *              and earlier Socs has two clock sources i.e. div-clk and
123  *              fast-clk.
124  * @clk_divisor_hs_mode: Clock divisor in HS mode.
125  * @clk_divisor_std_fast_mode: Clock divisor in standard/fast mode. It is
126  *              applicable if there is no fast clock source i.e. single clock
127  *              source.
128  */
129 
130 struct tegra_i2c_hw_feature {
131         bool has_continue_xfer_support;
132         bool has_per_pkt_xfer_complete_irq;
133         bool has_single_clk_source;
134         int clk_divisor_hs_mode;
135         int clk_divisor_std_fast_mode;
136 };
137 
138 /**
139  * struct tegra_i2c_dev - per device i2c context
140  * @dev: device reference for power management
141  * @hw: Tegra i2c hw feature.
142  * @adapter: core i2c layer adapter information
143  * @div_clk: clock reference for div clock of i2c controller.
144  * @fast_clk: clock reference for fast clock of i2c controller.
145  * @base: ioremapped registers cookie
146  * @cont_id: i2c controller id, used for for packet header
147  * @irq: irq number of transfer complete interrupt
148  * @is_dvc: identifies the DVC i2c controller, has a different register layout
149  * @msg_complete: transfer completion notifier
150  * @msg_err: error code for completed message
151  * @msg_buf: pointer to current message data
152  * @msg_buf_remaining: size of unsent data in the message buffer
153  * @msg_read: identifies read transfers
154  * @bus_clk_rate: current i2c bus clock rate
155  * @is_suspended: prevents i2c controller accesses after suspend is called
156  */
157 struct tegra_i2c_dev {
158         struct device *dev;
159         const struct tegra_i2c_hw_feature *hw;
160         struct i2c_adapter adapter;
161         struct clk *div_clk;
162         struct clk *fast_clk;
163         struct reset_control *rst;
164         void __iomem *base;
165         int cont_id;
166         int irq;
167         bool irq_disabled;
168         int is_dvc;
169         struct completion msg_complete;
170         int msg_err;
171         u8 *msg_buf;
172         size_t msg_buf_remaining;
173         int msg_read;
174         u32 bus_clk_rate;
175         bool is_suspended;
176 };
177 
178 static void dvc_writel(struct tegra_i2c_dev *i2c_dev, u32 val, unsigned long reg)
179 {
180         writel(val, i2c_dev->base + reg);
181 }
182 
183 static u32 dvc_readl(struct tegra_i2c_dev *i2c_dev, unsigned long reg)
184 {
185         return readl(i2c_dev->base + reg);
186 }
187 
188 /*
189  * i2c_writel and i2c_readl will offset the register if necessary to talk
190  * to the I2C block inside the DVC block
191  */
192 static unsigned long tegra_i2c_reg_addr(struct tegra_i2c_dev *i2c_dev,
193         unsigned long reg)
194 {
195         if (i2c_dev->is_dvc)
196                 reg += (reg >= I2C_TX_FIFO) ? 0x10 : 0x40;
197         return reg;
198 }
199 
200 static void i2c_writel(struct tegra_i2c_dev *i2c_dev, u32 val,
201         unsigned long reg)
202 {
203         writel(val, i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg));
204 
205         /* Read back register to make sure that register writes completed */
206         if (reg != I2C_TX_FIFO)
207                 readl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg));
208 }
209 
210 static u32 i2c_readl(struct tegra_i2c_dev *i2c_dev, unsigned long reg)
211 {
212         return readl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg));
213 }
214 
215 static void i2c_writesl(struct tegra_i2c_dev *i2c_dev, void *data,
216         unsigned long reg, int len)
217 {
218         writesl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg), data, len);
219 }
220 
221 static void i2c_readsl(struct tegra_i2c_dev *i2c_dev, void *data,
222         unsigned long reg, int len)
223 {
224         readsl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg), data, len);
225 }
226 
227 static void tegra_i2c_mask_irq(struct tegra_i2c_dev *i2c_dev, u32 mask)
228 {
229         u32 int_mask = i2c_readl(i2c_dev, I2C_INT_MASK);
230         int_mask &= ~mask;
231         i2c_writel(i2c_dev, int_mask, I2C_INT_MASK);
232 }
233 
234 static void tegra_i2c_unmask_irq(struct tegra_i2c_dev *i2c_dev, u32 mask)
235 {
236         u32 int_mask = i2c_readl(i2c_dev, I2C_INT_MASK);
237         int_mask |= mask;
238         i2c_writel(i2c_dev, int_mask, I2C_INT_MASK);
239 }
240 
241 static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev)
242 {
243         unsigned long timeout = jiffies + HZ;
244         u32 val = i2c_readl(i2c_dev, I2C_FIFO_CONTROL);
245         val |= I2C_FIFO_CONTROL_TX_FLUSH | I2C_FIFO_CONTROL_RX_FLUSH;
246         i2c_writel(i2c_dev, val, I2C_FIFO_CONTROL);
247 
248         while (i2c_readl(i2c_dev, I2C_FIFO_CONTROL) &
249                 (I2C_FIFO_CONTROL_TX_FLUSH | I2C_FIFO_CONTROL_RX_FLUSH)) {
250                 if (time_after(jiffies, timeout)) {
251                         dev_warn(i2c_dev->dev, "timeout waiting for fifo flush\n");
252                         return -ETIMEDOUT;
253                 }
254                 msleep(1);
255         }
256         return 0;
257 }
258 
259 static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev)
260 {
261         u32 val;
262         int rx_fifo_avail;
263         u8 *buf = i2c_dev->msg_buf;
264         size_t buf_remaining = i2c_dev->msg_buf_remaining;
265         int words_to_transfer;
266 
267         val = i2c_readl(i2c_dev, I2C_FIFO_STATUS);
268         rx_fifo_avail = (val & I2C_FIFO_STATUS_RX_MASK) >>
269                 I2C_FIFO_STATUS_RX_SHIFT;
270 
271         /* Rounds down to not include partial word at the end of buf */
272         words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD;
273         if (words_to_transfer > rx_fifo_avail)
274                 words_to_transfer = rx_fifo_avail;
275 
276         i2c_readsl(i2c_dev, buf, I2C_RX_FIFO, words_to_transfer);
277 
278         buf += words_to_transfer * BYTES_PER_FIFO_WORD;
279         buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD;
280         rx_fifo_avail -= words_to_transfer;
281 
282         /*
283          * If there is a partial word at the end of buf, handle it manually to
284          * prevent overwriting past the end of buf
285          */
286         if (rx_fifo_avail > 0 && buf_remaining > 0) {
287                 BUG_ON(buf_remaining > 3);
288                 val = i2c_readl(i2c_dev, I2C_RX_FIFO);
289                 val = cpu_to_le32(val);
290                 memcpy(buf, &val, buf_remaining);
291                 buf_remaining = 0;
292                 rx_fifo_avail--;
293         }
294 
295         BUG_ON(rx_fifo_avail > 0 && buf_remaining > 0);
296         i2c_dev->msg_buf_remaining = buf_remaining;
297         i2c_dev->msg_buf = buf;
298         return 0;
299 }
300 
301 static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
302 {
303         u32 val;
304         int tx_fifo_avail;
305         u8 *buf = i2c_dev->msg_buf;
306         size_t buf_remaining = i2c_dev->msg_buf_remaining;
307         int words_to_transfer;
308 
309         val = i2c_readl(i2c_dev, I2C_FIFO_STATUS);
310         tx_fifo_avail = (val & I2C_FIFO_STATUS_TX_MASK) >>
311                 I2C_FIFO_STATUS_TX_SHIFT;
312 
313         /* Rounds down to not include partial word at the end of buf */
314         words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD;
315 
316         /* It's very common to have < 4 bytes, so optimize that case. */
317         if (words_to_transfer) {
318                 if (words_to_transfer > tx_fifo_avail)
319                         words_to_transfer = tx_fifo_avail;
320 
321                 /*
322                  * Update state before writing to FIFO.  If this casues us
323                  * to finish writing all bytes (AKA buf_remaining goes to 0) we
324                  * have a potential for an interrupt (PACKET_XFER_COMPLETE is
325                  * not maskable).  We need to make sure that the isr sees
326                  * buf_remaining as 0 and doesn't call us back re-entrantly.
327                  */
328                 buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD;
329                 tx_fifo_avail -= words_to_transfer;
330                 i2c_dev->msg_buf_remaining = buf_remaining;
331                 i2c_dev->msg_buf = buf +
332                         words_to_transfer * BYTES_PER_FIFO_WORD;
333                 barrier();
334 
335                 i2c_writesl(i2c_dev, buf, I2C_TX_FIFO, words_to_transfer);
336 
337                 buf += words_to_transfer * BYTES_PER_FIFO_WORD;
338         }
339 
340         /*
341          * If there is a partial word at the end of buf, handle it manually to
342          * prevent reading past the end of buf, which could cross a page
343          * boundary and fault.
344          */
345         if (tx_fifo_avail > 0 && buf_remaining > 0) {
346                 BUG_ON(buf_remaining > 3);
347                 memcpy(&val, buf, buf_remaining);
348                 val = le32_to_cpu(val);
349 
350                 /* Again update before writing to FIFO to make sure isr sees. */
351                 i2c_dev->msg_buf_remaining = 0;
352                 i2c_dev->msg_buf = NULL;
353                 barrier();
354 
355                 i2c_writel(i2c_dev, val, I2C_TX_FIFO);
356         }
357 
358         return 0;
359 }
360 
361 /*
362  * One of the Tegra I2C blocks is inside the DVC (Digital Voltage Controller)
363  * block.  This block is identical to the rest of the I2C blocks, except that
364  * it only supports master mode, it has registers moved around, and it needs
365  * some extra init to get it into I2C mode.  The register moves are handled
366  * by i2c_readl and i2c_writel
367  */
368 static void tegra_dvc_init(struct tegra_i2c_dev *i2c_dev)
369 {
370         u32 val = 0;
371         val = dvc_readl(i2c_dev, DVC_CTRL_REG3);
372         val |= DVC_CTRL_REG3_SW_PROG;
373         val |= DVC_CTRL_REG3_I2C_DONE_INTR_EN;
374         dvc_writel(i2c_dev, val, DVC_CTRL_REG3);
375 
376         val = dvc_readl(i2c_dev, DVC_CTRL_REG1);
377         val |= DVC_CTRL_REG1_INTR_EN;
378         dvc_writel(i2c_dev, val, DVC_CTRL_REG1);
379 }
380 
381 static inline int tegra_i2c_clock_enable(struct tegra_i2c_dev *i2c_dev)
382 {
383         int ret;
384         if (!i2c_dev->hw->has_single_clk_source) {
385                 ret = clk_enable(i2c_dev->fast_clk);
386                 if (ret < 0) {
387                         dev_err(i2c_dev->dev,
388                                 "Enabling fast clk failed, err %d\n", ret);
389                         return ret;
390                 }
391         }
392         ret = clk_enable(i2c_dev->div_clk);
393         if (ret < 0) {
394                 dev_err(i2c_dev->dev,
395                         "Enabling div clk failed, err %d\n", ret);
396                 clk_disable(i2c_dev->fast_clk);
397         }
398         return ret;
399 }
400 
401 static inline void tegra_i2c_clock_disable(struct tegra_i2c_dev *i2c_dev)
402 {
403         clk_disable(i2c_dev->div_clk);
404         if (!i2c_dev->hw->has_single_clk_source)
405                 clk_disable(i2c_dev->fast_clk);
406 }
407 
408 static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
409 {
410         u32 val;
411         int err = 0;
412         u32 clk_divisor;
413 
414         err = tegra_i2c_clock_enable(i2c_dev);
415         if (err < 0) {
416                 dev_err(i2c_dev->dev, "Clock enable failed %d\n", err);
417                 return err;
418         }
419 
420         reset_control_assert(i2c_dev->rst);
421         udelay(2);
422         reset_control_deassert(i2c_dev->rst);
423 
424         if (i2c_dev->is_dvc)
425                 tegra_dvc_init(i2c_dev);
426 
427         val = I2C_CNFG_NEW_MASTER_FSM | I2C_CNFG_PACKET_MODE_EN |
428                 (0x2 << I2C_CNFG_DEBOUNCE_CNT_SHIFT);
429         i2c_writel(i2c_dev, val, I2C_CNFG);
430         i2c_writel(i2c_dev, 0, I2C_INT_MASK);
431 
432         /* Make sure clock divisor programmed correctly */
433         clk_divisor = i2c_dev->hw->clk_divisor_hs_mode;
434         clk_divisor |= i2c_dev->hw->clk_divisor_std_fast_mode <<
435                                         I2C_CLK_DIVISOR_STD_FAST_MODE_SHIFT;
436         i2c_writel(i2c_dev, clk_divisor, I2C_CLK_DIVISOR);
437 
438         if (!i2c_dev->is_dvc) {
439                 u32 sl_cfg = i2c_readl(i2c_dev, I2C_SL_CNFG);
440                 sl_cfg |= I2C_SL_CNFG_NACK | I2C_SL_CNFG_NEWSL;
441                 i2c_writel(i2c_dev, sl_cfg, I2C_SL_CNFG);
442                 i2c_writel(i2c_dev, 0xfc, I2C_SL_ADDR1);
443                 i2c_writel(i2c_dev, 0x00, I2C_SL_ADDR2);
444 
445         }
446 
447         val = 7 << I2C_FIFO_CONTROL_TX_TRIG_SHIFT |
448                 0 << I2C_FIFO_CONTROL_RX_TRIG_SHIFT;
449         i2c_writel(i2c_dev, val, I2C_FIFO_CONTROL);
450 
451         if (tegra_i2c_flush_fifos(i2c_dev))
452                 err = -ETIMEDOUT;
453 
454         tegra_i2c_clock_disable(i2c_dev);
455 
456         if (i2c_dev->irq_disabled) {
457                 i2c_dev->irq_disabled = 0;
458                 enable_irq(i2c_dev->irq);
459         }
460 
461         return err;
462 }
463 
464 static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
465 {
466         u32 status;
467         const u32 status_err = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST;
468         struct tegra_i2c_dev *i2c_dev = dev_id;
469 
470         status = i2c_readl(i2c_dev, I2C_INT_STATUS);
471 
472         if (status == 0) {
473                 dev_warn(i2c_dev->dev, "irq status 0 %08x %08x %08x\n",
474                          i2c_readl(i2c_dev, I2C_PACKET_TRANSFER_STATUS),
475                          i2c_readl(i2c_dev, I2C_STATUS),
476                          i2c_readl(i2c_dev, I2C_CNFG));
477                 i2c_dev->msg_err |= I2C_ERR_UNKNOWN_INTERRUPT;
478 
479                 if (!i2c_dev->irq_disabled) {
480                         disable_irq_nosync(i2c_dev->irq);
481                         i2c_dev->irq_disabled = 1;
482                 }
483                 goto err;
484         }
485 
486         if (unlikely(status & status_err)) {
487                 if (status & I2C_INT_NO_ACK)
488                         i2c_dev->msg_err |= I2C_ERR_NO_ACK;
489                 if (status & I2C_INT_ARBITRATION_LOST)
490                         i2c_dev->msg_err |= I2C_ERR_ARBITRATION_LOST;
491                 goto err;
492         }
493 
494         if (i2c_dev->msg_read && (status & I2C_INT_RX_FIFO_DATA_REQ)) {
495                 if (i2c_dev->msg_buf_remaining)
496                         tegra_i2c_empty_rx_fifo(i2c_dev);
497                 else
498                         BUG();
499         }
500 
501         if (!i2c_dev->msg_read && (status & I2C_INT_TX_FIFO_DATA_REQ)) {
502                 if (i2c_dev->msg_buf_remaining)
503                         tegra_i2c_fill_tx_fifo(i2c_dev);
504                 else
505                         tegra_i2c_mask_irq(i2c_dev, I2C_INT_TX_FIFO_DATA_REQ);
506         }
507 
508         i2c_writel(i2c_dev, status, I2C_INT_STATUS);
509         if (i2c_dev->is_dvc)
510                 dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS);
511 
512         if (status & I2C_INT_PACKET_XFER_COMPLETE) {
513                 BUG_ON(i2c_dev->msg_buf_remaining);
514                 complete(&i2c_dev->msg_complete);
515         }
516         return IRQ_HANDLED;
517 err:
518         /* An error occurred, mask all interrupts */
519         tegra_i2c_mask_irq(i2c_dev, I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST |
520                 I2C_INT_PACKET_XFER_COMPLETE | I2C_INT_TX_FIFO_DATA_REQ |
521                 I2C_INT_RX_FIFO_DATA_REQ);
522         i2c_writel(i2c_dev, status, I2C_INT_STATUS);
523         if (i2c_dev->is_dvc)
524                 dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS);
525 
526         complete(&i2c_dev->msg_complete);
527         return IRQ_HANDLED;
528 }
529 
530 static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
531         struct i2c_msg *msg, enum msg_end_type end_state)
532 {
533         u32 packet_header;
534         u32 int_mask;
535         int ret;
536 
537         tegra_i2c_flush_fifos(i2c_dev);
538 
539         if (msg->len == 0)
540                 return -EINVAL;
541 
542         i2c_dev->msg_buf = msg->buf;
543         i2c_dev->msg_buf_remaining = msg->len;
544         i2c_dev->msg_err = I2C_ERR_NONE;
545         i2c_dev->msg_read = (msg->flags & I2C_M_RD);
546         reinit_completion(&i2c_dev->msg_complete);
547 
548         packet_header = (0 << PACKET_HEADER0_HEADER_SIZE_SHIFT) |
549                         PACKET_HEADER0_PROTOCOL_I2C |
550                         (i2c_dev->cont_id << PACKET_HEADER0_CONT_ID_SHIFT) |
551                         (1 << PACKET_HEADER0_PACKET_ID_SHIFT);
552         i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
553 
554         packet_header = msg->len - 1;
555         i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
556 
557         packet_header = I2C_HEADER_IE_ENABLE;
558         if (end_state == MSG_END_CONTINUE)
559                 packet_header |= I2C_HEADER_CONTINUE_XFER;
560         else if (end_state == MSG_END_REPEAT_START)
561                 packet_header |= I2C_HEADER_REPEAT_START;
562         if (msg->flags & I2C_M_TEN) {
563                 packet_header |= msg->addr;
564                 packet_header |= I2C_HEADER_10BIT_ADDR;
565         } else {
566                 packet_header |= msg->addr << I2C_HEADER_SLAVE_ADDR_SHIFT;
567         }
568         if (msg->flags & I2C_M_IGNORE_NAK)
569                 packet_header |= I2C_HEADER_CONT_ON_NAK;
570         if (msg->flags & I2C_M_RD)
571                 packet_header |= I2C_HEADER_READ;
572         i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
573 
574         if (!(msg->flags & I2C_M_RD))
575                 tegra_i2c_fill_tx_fifo(i2c_dev);
576 
577         int_mask = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST;
578         if (i2c_dev->hw->has_per_pkt_xfer_complete_irq)
579                 int_mask |= I2C_INT_PACKET_XFER_COMPLETE;
580         if (msg->flags & I2C_M_RD)
581                 int_mask |= I2C_INT_RX_FIFO_DATA_REQ;
582         else if (i2c_dev->msg_buf_remaining)
583                 int_mask |= I2C_INT_TX_FIFO_DATA_REQ;
584         tegra_i2c_unmask_irq(i2c_dev, int_mask);
585         dev_dbg(i2c_dev->dev, "unmasked irq: %02x\n",
586                 i2c_readl(i2c_dev, I2C_INT_MASK));
587 
588         ret = wait_for_completion_timeout(&i2c_dev->msg_complete, TEGRA_I2C_TIMEOUT);
589         tegra_i2c_mask_irq(i2c_dev, int_mask);
590 
591         if (ret == 0) {
592                 dev_err(i2c_dev->dev, "i2c transfer timed out\n");
593 
594                 tegra_i2c_init(i2c_dev);
595                 return -ETIMEDOUT;
596         }
597 
598         dev_dbg(i2c_dev->dev, "transfer complete: %d %d %d\n",
599                 ret, completion_done(&i2c_dev->msg_complete), i2c_dev->msg_err);
600 
601         if (likely(i2c_dev->msg_err == I2C_ERR_NONE))
602                 return 0;
603 
604         /*
605          * NACK interrupt is generated before the I2C controller generates the
606          * STOP condition on the bus. So wait for 2 clock periods before resetting
607          * the controller so that STOP condition has been delivered properly.
608          */
609         if (i2c_dev->msg_err == I2C_ERR_NO_ACK)
610                 udelay(DIV_ROUND_UP(2 * 1000000, i2c_dev->bus_clk_rate));
611 
612         tegra_i2c_init(i2c_dev);
613         if (i2c_dev->msg_err == I2C_ERR_NO_ACK) {
614                 if (msg->flags & I2C_M_IGNORE_NAK)
615                         return 0;
616                 return -EREMOTEIO;
617         }
618 
619         return -EIO;
620 }
621 
622 static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
623         int num)
624 {
625         struct tegra_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
626         int i;
627         int ret = 0;
628 
629         if (i2c_dev->is_suspended)
630                 return -EBUSY;
631 
632         ret = tegra_i2c_clock_enable(i2c_dev);
633         if (ret < 0) {
634                 dev_err(i2c_dev->dev, "Clock enable failed %d\n", ret);
635                 return ret;
636         }
637 
638         for (i = 0; i < num; i++) {
639                 enum msg_end_type end_type = MSG_END_STOP;
640                 if (i < (num - 1)) {
641                         if (msgs[i + 1].flags & I2C_M_NOSTART)
642                                 end_type = MSG_END_CONTINUE;
643                         else
644                                 end_type = MSG_END_REPEAT_START;
645                 }
646                 ret = tegra_i2c_xfer_msg(i2c_dev, &msgs[i], end_type);
647                 if (ret)
648                         break;
649         }
650         tegra_i2c_clock_disable(i2c_dev);
651         return ret ?: i;
652 }
653 
654 static u32 tegra_i2c_func(struct i2c_adapter *adap)
655 {
656         struct tegra_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
657         u32 ret = I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR |
658                                 I2C_FUNC_PROTOCOL_MANGLING;
659 
660         if (i2c_dev->hw->has_continue_xfer_support)
661                 ret |= I2C_FUNC_NOSTART;
662         return ret;
663 }
664 
665 static const struct i2c_algorithm tegra_i2c_algo = {
666         .master_xfer    = tegra_i2c_xfer,
667         .functionality  = tegra_i2c_func,
668 };
669 
670 static const struct tegra_i2c_hw_feature tegra20_i2c_hw = {
671         .has_continue_xfer_support = false,
672         .has_per_pkt_xfer_complete_irq = false,
673         .has_single_clk_source = false,
674         .clk_divisor_hs_mode = 3,
675         .clk_divisor_std_fast_mode = 0,
676 };
677 
678 static const struct tegra_i2c_hw_feature tegra30_i2c_hw = {
679         .has_continue_xfer_support = true,
680         .has_per_pkt_xfer_complete_irq = false,
681         .has_single_clk_source = false,
682         .clk_divisor_hs_mode = 3,
683         .clk_divisor_std_fast_mode = 0,
684 };
685 
686 static const struct tegra_i2c_hw_feature tegra114_i2c_hw = {
687         .has_continue_xfer_support = true,
688         .has_per_pkt_xfer_complete_irq = true,
689         .has_single_clk_source = true,
690         .clk_divisor_hs_mode = 1,
691         .clk_divisor_std_fast_mode = 0x19,
692 };
693 
694 /* Match table for of_platform binding */
695 static const struct of_device_id tegra_i2c_of_match[] = {
696         { .compatible = "nvidia,tegra114-i2c", .data = &tegra114_i2c_hw, },
697         { .compatible = "nvidia,tegra30-i2c", .data = &tegra30_i2c_hw, },
698         { .compatible = "nvidia,tegra20-i2c", .data = &tegra20_i2c_hw, },
699         { .compatible = "nvidia,tegra20-i2c-dvc", .data = &tegra20_i2c_hw, },
700         {},
701 };
702 MODULE_DEVICE_TABLE(of, tegra_i2c_of_match);
703 
704 static int tegra_i2c_probe(struct platform_device *pdev)
705 {
706         struct tegra_i2c_dev *i2c_dev;
707         struct resource *res;
708         struct clk *div_clk;
709         struct clk *fast_clk;
710         void __iomem *base;
711         int irq;
712         int ret = 0;
713         int clk_multiplier = I2C_CLK_MULTIPLIER_STD_FAST_MODE;
714 
715         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
716         base = devm_ioremap_resource(&pdev->dev, res);
717         if (IS_ERR(base))
718                 return PTR_ERR(base);
719 
720         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
721         if (!res) {
722                 dev_err(&pdev->dev, "no irq resource\n");
723                 return -EINVAL;
724         }
725         irq = res->start;
726 
727         div_clk = devm_clk_get(&pdev->dev, "div-clk");
728         if (IS_ERR(div_clk)) {
729                 dev_err(&pdev->dev, "missing controller clock");
730                 return PTR_ERR(div_clk);
731         }
732 
733         i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL);
734         if (!i2c_dev)
735                 return -ENOMEM;
736 
737         i2c_dev->base = base;
738         i2c_dev->div_clk = div_clk;
739         i2c_dev->adapter.algo = &tegra_i2c_algo;
740         i2c_dev->irq = irq;
741         i2c_dev->cont_id = pdev->id;
742         i2c_dev->dev = &pdev->dev;
743 
744         i2c_dev->rst = devm_reset_control_get(&pdev->dev, "i2c");
745         if (IS_ERR(i2c_dev->rst)) {
746                 dev_err(&pdev->dev, "missing controller reset");
747                 return PTR_ERR(i2c_dev->rst);
748         }
749 
750         ret = of_property_read_u32(i2c_dev->dev->of_node, "clock-frequency",
751                                         &i2c_dev->bus_clk_rate);
752         if (ret)
753                 i2c_dev->bus_clk_rate = 100000; /* default clock rate */
754 
755         i2c_dev->hw = &tegra20_i2c_hw;
756 
757         if (pdev->dev.of_node) {
758                 const struct of_device_id *match;
759                 match = of_match_device(tegra_i2c_of_match, &pdev->dev);
760                 i2c_dev->hw = match->data;
761                 i2c_dev->is_dvc = of_device_is_compatible(pdev->dev.of_node,
762                                                 "nvidia,tegra20-i2c-dvc");
763         } else if (pdev->id == 3) {
764                 i2c_dev->is_dvc = 1;
765         }
766         init_completion(&i2c_dev->msg_complete);
767 
768         if (!i2c_dev->hw->has_single_clk_source) {
769                 fast_clk = devm_clk_get(&pdev->dev, "fast-clk");
770                 if (IS_ERR(fast_clk)) {
771                         dev_err(&pdev->dev, "missing fast clock");
772                         return PTR_ERR(fast_clk);
773                 }
774                 i2c_dev->fast_clk = fast_clk;
775         }
776 
777         platform_set_drvdata(pdev, i2c_dev);
778 
779         if (!i2c_dev->hw->has_single_clk_source) {
780                 ret = clk_prepare(i2c_dev->fast_clk);
781                 if (ret < 0) {
782                         dev_err(i2c_dev->dev, "Clock prepare failed %d\n", ret);
783                         return ret;
784                 }
785         }
786 
787         clk_multiplier *= (i2c_dev->hw->clk_divisor_std_fast_mode + 1);
788         ret = clk_set_rate(i2c_dev->div_clk,
789                            i2c_dev->bus_clk_rate * clk_multiplier);
790         if (ret) {
791                 dev_err(i2c_dev->dev, "Clock rate change failed %d\n", ret);
792                 goto unprepare_fast_clk;
793         }
794 
795         ret = clk_prepare(i2c_dev->div_clk);
796         if (ret < 0) {
797                 dev_err(i2c_dev->dev, "Clock prepare failed %d\n", ret);
798                 goto unprepare_fast_clk;
799         }
800 
801         ret = tegra_i2c_init(i2c_dev);
802         if (ret) {
803                 dev_err(&pdev->dev, "Failed to initialize i2c controller");
804                 goto unprepare_div_clk;
805         }
806 
807         ret = devm_request_irq(&pdev->dev, i2c_dev->irq,
808                         tegra_i2c_isr, 0, dev_name(&pdev->dev), i2c_dev);
809         if (ret) {
810                 dev_err(&pdev->dev, "Failed to request irq %i\n", i2c_dev->irq);
811                 goto unprepare_div_clk;
812         }
813 
814         i2c_set_adapdata(&i2c_dev->adapter, i2c_dev);
815         i2c_dev->adapter.owner = THIS_MODULE;
816         i2c_dev->adapter.class = I2C_CLASS_DEPRECATED;
817         strlcpy(i2c_dev->adapter.name, "Tegra I2C adapter",
818                 sizeof(i2c_dev->adapter.name));
819         i2c_dev->adapter.algo = &tegra_i2c_algo;
820         i2c_dev->adapter.dev.parent = &pdev->dev;
821         i2c_dev->adapter.nr = pdev->id;
822         i2c_dev->adapter.dev.of_node = pdev->dev.of_node;
823 
824         ret = i2c_add_numbered_adapter(&i2c_dev->adapter);
825         if (ret) {
826                 dev_err(&pdev->dev, "Failed to add I2C adapter\n");
827                 goto unprepare_div_clk;
828         }
829 
830         return 0;
831 
832 unprepare_div_clk:
833         clk_unprepare(i2c_dev->div_clk);
834 
835 unprepare_fast_clk:
836         if (!i2c_dev->hw->has_single_clk_source)
837                 clk_unprepare(i2c_dev->fast_clk);
838 
839         return ret;
840 }
841 
842 static int tegra_i2c_remove(struct platform_device *pdev)
843 {
844         struct tegra_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
845         i2c_del_adapter(&i2c_dev->adapter);
846 
847         clk_unprepare(i2c_dev->div_clk);
848         if (!i2c_dev->hw->has_single_clk_source)
849                 clk_unprepare(i2c_dev->fast_clk);
850 
851         return 0;
852 }
853 
854 #ifdef CONFIG_PM_SLEEP
855 static int tegra_i2c_suspend(struct device *dev)
856 {
857         struct tegra_i2c_dev *i2c_dev = dev_get_drvdata(dev);
858 
859         i2c_lock_adapter(&i2c_dev->adapter);
860         i2c_dev->is_suspended = true;
861         i2c_unlock_adapter(&i2c_dev->adapter);
862 
863         return 0;
864 }
865 
866 static int tegra_i2c_resume(struct device *dev)
867 {
868         struct tegra_i2c_dev *i2c_dev = dev_get_drvdata(dev);
869         int ret;
870 
871         i2c_lock_adapter(&i2c_dev->adapter);
872 
873         ret = tegra_i2c_init(i2c_dev);
874 
875         if (ret) {
876                 i2c_unlock_adapter(&i2c_dev->adapter);
877                 return ret;
878         }
879 
880         i2c_dev->is_suspended = false;
881 
882         i2c_unlock_adapter(&i2c_dev->adapter);
883 
884         return 0;
885 }
886 
887 static SIMPLE_DEV_PM_OPS(tegra_i2c_pm, tegra_i2c_suspend, tegra_i2c_resume);
888 #define TEGRA_I2C_PM    (&tegra_i2c_pm)
889 #else
890 #define TEGRA_I2C_PM    NULL
891 #endif
892 
893 static struct platform_driver tegra_i2c_driver = {
894         .probe   = tegra_i2c_probe,
895         .remove  = tegra_i2c_remove,
896         .driver  = {
897                 .name  = "tegra-i2c",
898                 .of_match_table = tegra_i2c_of_match,
899                 .pm    = TEGRA_I2C_PM,
900         },
901 };
902 
903 static int __init tegra_i2c_init_driver(void)
904 {
905         return platform_driver_register(&tegra_i2c_driver);
906 }
907 
908 static void __exit tegra_i2c_exit_driver(void)
909 {
910         platform_driver_unregister(&tegra_i2c_driver);
911 }
912 
913 subsys_initcall(tegra_i2c_init_driver);
914 module_exit(tegra_i2c_exit_driver);
915 
916 MODULE_DESCRIPTION("nVidia Tegra2 I2C Bus Controller driver");
917 MODULE_AUTHOR("Colin Cross");
918 MODULE_LICENSE("GPL v2");
919 

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