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2024-05-14 bedbef8ad3e75a304af6361af235302bcc61d06b 
 kernel/drivers/i2c/busses/i2c-meson.c
....@@ -1,11 +1,8 @@
1
+// SPDX-License-Identifier: GPL-2.0-only
12 /*
23  * I2C bus driver for Amlogic Meson SoCs
34  *
45  * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
5
- *
6
- * This program is free software; you can redistribute it and/or modify
7
- * it under the terms of the GNU General Public License version 2 as
8
- * published by the Free Software Foundation.
96  */
107 
118 #include <linux/bitfield.h>
....@@ -14,6 +11,7 @@
1411 #include <linux/i2c.h>
1512 #include <linux/interrupt.h>
1613 #include <linux/io.h>
14
+#include <linux/iopoll.h>
1715 #include <linux/kernel.h>
1816 #include <linux/module.h>
1917 #include <linux/of.h>
....@@ -227,6 +225,30 @@
227225 	writel(i2c->tokens[1], i2c->regs + REG_TOK_LIST1);
228226 }
229227 
228
+static void meson_i2c_transfer_complete(struct meson_i2c *i2c, u32 ctrl)
229
+{
230
+	if (ctrl & REG_CTRL_ERROR) {
231
+		/*
232
+		 * The bit is set when the IGNORE_NAK bit is cleared
233
+		 * and the device didn't respond. In this case, the
234
+		 * I2C controller automatically generates a STOP
235
+		 * condition.
236
+		 */
237
+		dev_dbg(i2c->dev, "error bit set\n");
238
+		i2c->error = -ENXIO;
239
+		i2c->state = STATE_IDLE;
240
+	} else {
241
+		if (i2c->state == STATE_READ && i2c->count)
242
+			meson_i2c_get_data(i2c, i2c->msg->buf + i2c->pos,
243
+					   i2c->count);
244
+
245
+		i2c->pos += i2c->count;
246
+
247
+		if (i2c->pos >= i2c->msg->len)
248
+			i2c->state = STATE_IDLE;
249
+	}
250
+}
251
+
230252 static irqreturn_t meson_i2c_irq(int irqno, void *dev_id)
231253 {
232254 	struct meson_i2c *i2c = dev_id;
....@@ -246,27 +268,9 @@
246268 		return IRQ_NONE;
247269 	}
248270 
249
-	if (ctrl & REG_CTRL_ERROR) {
250
-		/*
251
-		 * The bit is set when the IGNORE_NAK bit is cleared
252
-		 * and the device didn't respond. In this case, the
253
-		 * I2C controller automatically generates a STOP
254
-		 * condition.
255
-		 */
256
-		dev_dbg(i2c->dev, "error bit set\n");
257
-		i2c->error = -ENXIO;
258
-		i2c->state = STATE_IDLE;
259
-		complete(&i2c->done);
260
-		goto out;
261
-	}
271
+	meson_i2c_transfer_complete(i2c, ctrl);
262272 
263
-	if (i2c->state == STATE_READ && i2c->count)
264
-		meson_i2c_get_data(i2c, i2c->msg->buf + i2c->pos, i2c->count);
265
-
266
-	i2c->pos += i2c->count;
267
-
268
-	if (i2c->pos >= i2c->msg->len) {
269
-		i2c->state = STATE_IDLE;
273
+	if (i2c->state == STATE_IDLE) {
270274 		complete(&i2c->done);
271275 		goto out;
272276 	}
....@@ -296,10 +300,11 @@
296300 }
297301 
298302 static int meson_i2c_xfer_msg(struct meson_i2c *i2c, struct i2c_msg *msg,
299
-			      int last)
303
+			      int last, bool atomic)
300304 {
301305 	unsigned long time_left, flags;
302306 	int ret = 0;
307
+	u32 ctrl;
303308 
304309 	i2c->msg = msg;
305310 	i2c->last = last;
....@@ -317,13 +322,24 @@
317322 
318323 	i2c->state = (msg->flags & I2C_M_RD) ? STATE_READ : STATE_WRITE;
319324 	meson_i2c_prepare_xfer(i2c);
320
-	reinit_completion(&i2c->done);
325
+
326
+	if (!atomic)
327
+		reinit_completion(&i2c->done);
321328 
322329 	/* Start the transfer */
323330 	meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_START, REG_CTRL_START);
324331 
325
-	time_left = msecs_to_jiffies(I2C_TIMEOUT_MS);
326
-	time_left = wait_for_completion_timeout(&i2c->done, time_left);
332
+	if (atomic) {
333
+		ret = readl_poll_timeout_atomic(i2c->regs + REG_CTRL, ctrl,
334
+						!(ctrl & REG_CTRL_STATUS),
335
+						10, I2C_TIMEOUT_MS * 1000);
336
+	} else {
337
+		time_left = msecs_to_jiffies(I2C_TIMEOUT_MS);
338
+		time_left = wait_for_completion_timeout(&i2c->done, time_left);
339
+
340
+		if (!time_left)
341
+			ret = -ETIMEDOUT;
342
+	}
327343 
328344 	/*
329345 	 * Protect access to i2c struct and registers from interrupt
....@@ -332,13 +348,14 @@
332348 	 */
333349 	spin_lock_irqsave(&i2c->lock, flags);
334350 
351
+	if (atomic && !ret)
352
+		meson_i2c_transfer_complete(i2c, ctrl);
353
+
335354 	/* Abort any active operation */
336355 	meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_START, 0);
337356 
338
-	if (!time_left) {
357
+	if (ret)
339358 		i2c->state = STATE_IDLE;
340
-		ret = -ETIMEDOUT;
341
-	}
342359 
343360 	if (i2c->error)
344361 		ret = i2c->error;
....@@ -348,23 +365,31 @@
348365 	return ret;
349366 }
350367 
351
-static int meson_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
352
-			  int num)
368
+static int meson_i2c_xfer_messages(struct i2c_adapter *adap,
369
+				   struct i2c_msg *msgs, int num, bool atomic)
353370 {
354371 	struct meson_i2c *i2c = adap->algo_data;
355372 	int i, ret = 0;
356373 
357
-	clk_enable(i2c->clk);
358
-
359374 	for (i = 0; i < num; i++) {
360
-		ret = meson_i2c_xfer_msg(i2c, msgs + i, i == num - 1);
375
+		ret = meson_i2c_xfer_msg(i2c, msgs + i, i == num - 1, atomic);
361376 		if (ret)
362377 			break;
363378 	}
364379 
365
-	clk_disable(i2c->clk);
366
-
367380 	return ret ?: i;
381
+}
382
+
383
+static int meson_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
384
+			  int num)
385
+{
386
+	return meson_i2c_xfer_messages(adap, msgs, num, false);
387
+}
388
+
389
+static int meson_i2c_xfer_atomic(struct i2c_adapter *adap,
390
+				 struct i2c_msg *msgs, int num)
391
+{
392
+	return meson_i2c_xfer_messages(adap, msgs, num, true);
368393 }
369394 
370395 static u32 meson_i2c_func(struct i2c_adapter *adap)
....@@ -373,15 +398,15 @@
373398 }
374399 
375400 static const struct i2c_algorithm meson_i2c_algorithm = {
376
-	.master_xfer	= meson_i2c_xfer,
377
-	.functionality	= meson_i2c_func,
401
+	.master_xfer = meson_i2c_xfer,
402
+	.master_xfer_atomic = meson_i2c_xfer_atomic,
403
+	.functionality = meson_i2c_func,
378404 };
379405 
380406 static int meson_i2c_probe(struct platform_device *pdev)
381407 {
382408 	struct device_node *np = pdev->dev.of_node;
383409 	struct meson_i2c *i2c;
384
-	struct resource *mem;
385410 	struct i2c_timings timings;
386411 	int irq, ret = 0;
387412 
....@@ -406,16 +431,13 @@
406431 		return PTR_ERR(i2c->clk);
407432 	}
408433 
409
-	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
410
-	i2c->regs = devm_ioremap_resource(&pdev->dev, mem);
434
+	i2c->regs = devm_platform_ioremap_resource(pdev, 0);
411435 	if (IS_ERR(i2c->regs))
412436 		return PTR_ERR(i2c->regs);
413437 
414438 	irq = platform_get_irq(pdev, 0);
415
-	if (irq < 0) {
416
-		dev_err(&pdev->dev, "can't find IRQ\n");
439
+	if (irq < 0)
417440 		return irq;
418
-	}
419441 
420442 	ret = devm_request_irq(&pdev->dev, irq, meson_i2c_irq, 0, NULL, i2c);
421443 	if (ret < 0) {
....@@ -423,7 +445,7 @@
423445 		return ret;
424446 	}
425447 
426
-	ret = clk_prepare(i2c->clk);
448
+	ret = clk_prepare_enable(i2c->clk);
427449 	if (ret < 0) {
428450 		dev_err(&pdev->dev, "can't prepare clock\n");
429451 		return ret;
....@@ -443,17 +465,17 @@
443465 	 */
444466 	meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_START, 0);
445467 
446
-	ret = i2c_add_adapter(&i2c->adap);
447
-	if (ret < 0) {
448
-		clk_unprepare(i2c->clk);
449
-		return ret;
450
-	}
451
-
452468 	/* Disable filtering */
453469 	meson_i2c_set_mask(i2c, REG_SLAVE_ADDR,
454470 			   REG_SLV_SDA_FILTER | REG_SLV_SCL_FILTER, 0);
455471 
456472 	meson_i2c_set_clk_div(i2c, timings.bus_freq_hz);
473
+
474
+	ret = i2c_add_adapter(&i2c->adap);
475
+	if (ret < 0) {
476
+		clk_disable_unprepare(i2c->clk);
477
+		return ret;
478
+	}
457479 
458480 	return 0;
459481 }
....@@ -463,7 +485,7 @@
463485 	struct meson_i2c *i2c = platform_get_drvdata(pdev);
464486 
465487 	i2c_del_adapter(&i2c->adap);
466
-	clk_unprepare(i2c->clk);
488
+	clk_disable_unprepare(i2c->clk);
467489 
468490 	return 0;
469491 }