spi/pl022: Add chip select handling via GPIO

This patch adds the ability for the driver to control the chip select directly. This enables independence from cs_control callbacks. Configurable via platform_data, to be extended as DT in the following patch. Based on the initial patch by Alexandre Pereira da Silva <aletes.xgr@gmail.com> Signed-off-by: Roland Stigge <stigge@antcom.de> Acked-by: Alexandre Pereira da Silva <aletes.xgr@gmail.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

spi/pl022: Add chip select handling via GPIO
This patch adds the ability for the driver to control the chip select directly. This enables independence from cs_control callbacks. Configurable via platform_data, to be extended as DT in the following patch. Based on the initial patch by Alexandre Pereira da Silva <aletes.xgr@gmail.com> Signed-off-by: Roland Stigge <stigge@antcom.de> Acked-by: Alexandre Pereira da Silva <aletes.xgr@gmail.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Roland Stigge · Mark Brown
1 parent 3ce8859e2e
Showing 2 changed files with 36 additions and 14 deletions Side-by-side Diff
drivers/spi/spi-pl022.c
include/linux/amba/pl022.h
@@ -40,6 +40,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/scatterlist.h>
 #include <linux/pm_runtime.h>
+#include <linux/gpio.h>
  
 /*
  * This macro is used to define some register default values.
@@ -356,6 +357,8 @@
  * @sgt_rx: scattertable for the RX transfer
  * @sgt_tx: scattertable for the TX transfer
  * @dummypage: a dummy page used for driving data on the bus with DMA
+ * @cur_cs: current chip select (gpio)
+ * @chipselects: list of chipselects (gpios)
  */
 struct pl022 {
 	struct amba_device		*adev;
@@ -389,6 +392,8 @@
 	char				*dummypage;
 	bool				dma_running;
 #endif
+	int cur_cs;
+	int *chipselects;
 };
  
 /**
@@ -433,6 +438,14 @@
 	pr_debug("pl022: dummy chip select control, CS=0x%x\n", command);
 }
  
+static void pl022_cs_control(struct pl022 *pl022, u32 command)
+{
+	if (gpio_is_valid(pl022->cur_cs))
+		gpio_set_value(pl022->cur_cs, command);
+	else
+		pl022->cur_chip->cs_control(command);
+}
+
 /**
  * giveback - current spi_message is over, schedule next message and call
  * callback of this message. Assumes that caller already
@@ -479,7 +492,7 @@
 		if (next_msg && next_msg->spi != pl022->cur_msg->spi)
 			next_msg = NULL;
 		if (!next_msg || pl022->cur_msg->state == STATE_ERROR)
-			pl022->cur_chip->cs_control(SSP_CHIP_DESELECT);
+			pl022_cs_control(pl022, SSP_CHIP_DESELECT);
 		else
 			pl022->next_msg_cs_active = true;
  
@@ -818,8 +831,7 @@
 	/* Update total bytes transferred */
 	msg->actual_length += pl022->cur_transfer->len;
 	if (pl022->cur_transfer->cs_change)
-		pl022->cur_chip->
-			cs_control(SSP_CHIP_DESELECT);
+		pl022_cs_control(pl022, SSP_CHIP_DESELECT);
  
 	/* Move to next transfer */
 	msg->state = next_transfer(pl022);
@@ -1252,8 +1264,7 @@
 		/* Update total bytes transferred */
 		msg->actual_length += pl022->cur_transfer->len;
 		if (pl022->cur_transfer->cs_change)
-			pl022->cur_chip->
-				cs_control(SSP_CHIP_DESELECT);
+			pl022_cs_control(pl022, SSP_CHIP_DESELECT);
 		/* Move to next transfer */
 		msg->state = next_transfer(pl022);
 		tasklet_schedule(&pl022->pump_transfers);
@@ -1338,7 +1349,7 @@
  
 		/* Reselect chip select only if cs_change was requested */
 		if (previous->cs_change)
-			pl022->cur_chip->cs_control(SSP_CHIP_SELECT);
+			pl022_cs_control(pl022, SSP_CHIP_SELECT);
 	} else {
 		/* STATE_START */
 		message->state = STATE_RUNNING;
@@ -1377,7 +1388,7 @@
  
 	/* Enable target chip, if not already active */
 	if (!pl022->next_msg_cs_active)
-		pl022->cur_chip->cs_control(SSP_CHIP_SELECT);
+		pl022_cs_control(pl022, SSP_CHIP_SELECT);
  
 	if (set_up_next_transfer(pl022, pl022->cur_transfer)) {
 		/* Error path */
  
@@ -1429,12 +1440,12 @@
 			if (previous->delay_usecs)
 				udelay(previous->delay_usecs);
 			if (previous->cs_change)
-				pl022->cur_chip->cs_control(SSP_CHIP_SELECT);
+				pl022_cs_control(pl022, SSP_CHIP_SELECT);
 		} else {
 			/* STATE_START */
 			message->state = STATE_RUNNING;
 			if (!pl022->next_msg_cs_active)
-				pl022->cur_chip->cs_control(SSP_CHIP_SELECT);
+				pl022_cs_control(pl022, SSP_CHIP_SELECT);
 		}
  
 		/* Configuration Changing Per Transfer */
@@ -1466,7 +1477,7 @@
 		/* Update total byte transferred */
 		message->actual_length += pl022->cur_transfer->len;
 		if (pl022->cur_transfer->cs_change)
-			pl022->cur_chip->cs_control(SSP_CHIP_DESELECT);
+			pl022_cs_control(pl022, SSP_CHIP_DESELECT);
 		/* Move to next transfer */
 		message->state = next_transfer(pl022);
 	}
@@ -1495,6 +1506,7 @@
  
 	/* Setup the SPI using the per chip configuration */
 	pl022->cur_chip = spi_get_ctldata(msg->spi);
+	pl022->cur_cs = pl022->chipselects[msg->spi->chip_select];
  
 	restore_state(pl022);
 	flush(pl022);
@@ -1840,8 +1852,9 @@
 	chip->xfer_type = chip_info->com_mode;
 	if (!chip_info->cs_control) {
 		chip->cs_control = null_cs_control;
-		dev_warn(&spi->dev,
-			 "chip select function is NULL for this chip\n");
+		if (!gpio_is_valid(pl022->chipselects[spi->chip_select]))
+			dev_warn(&spi->dev,
+				 "invalid chip select\n");
 	} else
 		chip->cs_control = chip_info->cs_control;
  
@@ -1993,7 +2006,7 @@
 	struct pl022_ssp_controller *platform_info = adev->dev.platform_data;
 	struct spi_master *master;
 	struct pl022 *pl022 = NULL;	/*Data for this driver */
-	int status = 0;
+	int status = 0, i;
  
 	dev_info(&adev->dev,
 		 "ARM PL022 driver, device ID: 0x%08x\n", adev->periphid);
@@ -2004,7 +2017,8 @@
 	}
  
 	/* Allocate master with space for data */
-	master = spi_alloc_master(dev, sizeof(struct pl022));
+	master = spi_alloc_master(dev, sizeof(struct pl022) + sizeof(int) *
+				  platform_info->num_chipselect);
 	if (master == NULL) {
 		dev_err(&adev->dev, "probe - cannot alloc SPI master\n");
 		status = -ENOMEM;
@@ -2016,6 +2030,8 @@
 	pl022->master_info = platform_info;
 	pl022->adev = adev;
 	pl022->vendor = id->data;
+	/* Point chipselects to allocated memory beyond the main struct */
+	pl022->chipselects = (int *) pl022 + sizeof(struct pl022);
  
 	/*
 	 * Bus Number Which has been Assigned to this SSP controller
@@ -2029,6 +2045,10 @@
 	master->transfer_one_message = pl022_transfer_one_message;
 	master->unprepare_transfer_hardware = pl022_unprepare_transfer_hardware;
 	master->rt = platform_info->rt;
+
+	if (platform_info->num_chipselect && platform_info->chipselects)
+		for (i = 0; i < platform_info->num_chipselect; i++)
+			pl022->chipselects[i] = platform_info->chipselects[i];
  
 	/*
 	 * Supports mode 0-3, loopback, and active low CS. Transfers are
@@ -244,6 +244,7 @@
  *     indicates no delay and the device will be suspended immediately.
  * @rt: indicates the controller should run the message pump with realtime
  *     priority to minimise the transfer latency on the bus.
+ * @chipselects: list of <num_chipselects> chip select gpios
  */
 struct pl022_ssp_controller {
 	u16 bus_id;
@@ -254,6 +255,7 @@
 	void *dma_tx_param;
 	int autosuspend_delay;
 	bool rt;
+	int *chipselects;
 };
  
 /**
...	...	@@ -40,6 +40,7 @@
40	40	#include <linux/dma-mapping.h>
41	41	#include <linux/scatterlist.h>
42	42	#include <linux/pm_runtime.h>
	43	+#include <linux/gpio.h>
43	44
44	45	/*
45	46	* This macro is used to define some register default values.
...	...	@@ -356,6 +357,8 @@
356	357	* @sgt_rx: scattertable for the RX transfer
357	358	* @sgt_tx: scattertable for the TX transfer
358	359	* @dummypage: a dummy page used for driving data on the bus with DMA
	360	+ * @cur_cs: current chip select (gpio)
	361	+ * @chipselects: list of chipselects (gpios)
359	362	*/
360	363	struct pl022 {
361	364	struct amba_device *adev;
...	...	@@ -389,6 +392,8 @@
389	392	char *dummypage;
390	393	bool dma_running;
391	394	#endif
	395	+ int cur_cs;
	396	+ int *chipselects;
392	397	};
393	398
394	399	/**
...	...	@@ -433,6 +438,14 @@
433	438	pr_debug("pl022: dummy chip select control, CS=0x%x\n", command);
434	439	}
435	440
	441	+static void pl022_cs_control(struct pl022 *pl022, u32 command)
	442	+{
	443	+ if (gpio_is_valid(pl022->cur_cs))
	444	+ gpio_set_value(pl022->cur_cs, command);
	445	+ else
	446	+ pl022->cur_chip->cs_control(command);
	447	+}
	448	+
436	449	/**
437	450	* giveback - current spi_message is over, schedule next message and call
438	451	* callback of this message. Assumes that caller already
...	...	@@ -479,7 +492,7 @@
479	492	if (next_msg && next_msg->spi != pl022->cur_msg->spi)
480	493	next_msg = NULL;
481	494	if (!next_msg \|\| pl022->cur_msg->state == STATE_ERROR)
482		- pl022->cur_chip->cs_control(SSP_CHIP_DESELECT);
	495	+ pl022_cs_control(pl022, SSP_CHIP_DESELECT);
483	496	else
484	497	pl022->next_msg_cs_active = true;
485	498
...	...	@@ -818,8 +831,7 @@
818	831	/* Update total bytes transferred */
819	832	msg->actual_length += pl022->cur_transfer->len;
820	833	if (pl022->cur_transfer->cs_change)
821		- pl022->cur_chip->
822		- cs_control(SSP_CHIP_DESELECT);
	834	+ pl022_cs_control(pl022, SSP_CHIP_DESELECT);
823	835
824	836	/* Move to next transfer */
825	837	msg->state = next_transfer(pl022);
...	...	@@ -1252,8 +1264,7 @@
1252	1264	/* Update total bytes transferred */
1253	1265	msg->actual_length += pl022->cur_transfer->len;
1254	1266	if (pl022->cur_transfer->cs_change)
1255		- pl022->cur_chip->
1256		- cs_control(SSP_CHIP_DESELECT);
	1267	+ pl022_cs_control(pl022, SSP_CHIP_DESELECT);
1257	1268	/* Move to next transfer */
1258	1269	msg->state = next_transfer(pl022);
1259	1270	tasklet_schedule(&pl022->pump_transfers);
...	...	@@ -1338,7 +1349,7 @@
1338	1349
1339	1350	/* Reselect chip select only if cs_change was requested */
1340	1351	if (previous->cs_change)
1341		- pl022->cur_chip->cs_control(SSP_CHIP_SELECT);
	1352	+ pl022_cs_control(pl022, SSP_CHIP_SELECT);
1342	1353	} else {
1343	1354	/* STATE_START */
1344	1355	message->state = STATE_RUNNING;
...	...	@@ -1377,7 +1388,7 @@
1377	1388
1378	1389	/* Enable target chip, if not already active */
1379	1390	if (!pl022->next_msg_cs_active)
1380		- pl022->cur_chip->cs_control(SSP_CHIP_SELECT);
	1391	+ pl022_cs_control(pl022, SSP_CHIP_SELECT);
1381	1392
1382	1393	if (set_up_next_transfer(pl022, pl022->cur_transfer)) {
1383	1394	/* Error path */
1384	1395
...	...	@@ -1429,12 +1440,12 @@
1429	1440	if (previous->delay_usecs)
1430	1441	udelay(previous->delay_usecs);
1431	1442	if (previous->cs_change)
1432		- pl022->cur_chip->cs_control(SSP_CHIP_SELECT);
	1443	+ pl022_cs_control(pl022, SSP_CHIP_SELECT);
1433	1444	} else {
1434	1445	/* STATE_START */
1435	1446	message->state = STATE_RUNNING;
1436	1447	if (!pl022->next_msg_cs_active)
1437		- pl022->cur_chip->cs_control(SSP_CHIP_SELECT);
	1448	+ pl022_cs_control(pl022, SSP_CHIP_SELECT);
1438	1449	}
1439	1450
1440	1451	/* Configuration Changing Per Transfer */
...	...	@@ -1466,7 +1477,7 @@
1466	1477	/* Update total byte transferred */
1467	1478	message->actual_length += pl022->cur_transfer->len;
1468	1479	if (pl022->cur_transfer->cs_change)
1469		- pl022->cur_chip->cs_control(SSP_CHIP_DESELECT);
	1480	+ pl022_cs_control(pl022, SSP_CHIP_DESELECT);
1470	1481	/* Move to next transfer */
1471	1482	message->state = next_transfer(pl022);
1472	1483	}
...	...	@@ -1495,6 +1506,7 @@
1495	1506
1496	1507	/* Setup the SPI using the per chip configuration */
1497	1508	pl022->cur_chip = spi_get_ctldata(msg->spi);
	1509	+ pl022->cur_cs = pl022->chipselects[msg->spi->chip_select];
1498	1510
1499	1511	restore_state(pl022);
1500	1512	flush(pl022);
...	...	@@ -1840,8 +1852,9 @@
1840	1852	chip->xfer_type = chip_info->com_mode;
1841	1853	if (!chip_info->cs_control) {
1842	1854	chip->cs_control = null_cs_control;
1843		- dev_warn(&spi->dev,
1844		- "chip select function is NULL for this chip\n");
	1855	+ if (!gpio_is_valid(pl022->chipselects[spi->chip_select]))
	1856	+ dev_warn(&spi->dev,
	1857	+ "invalid chip select\n");
1845	1858	} else
1846	1859	chip->cs_control = chip_info->cs_control;
1847	1860
...	...	@@ -1993,7 +2006,7 @@
1993	2006	struct pl022_ssp_controller *platform_info = adev->dev.platform_data;
1994	2007	struct spi_master *master;
1995	2008	struct pl022 pl022 = NULL; /Data for this driver */
1996		- int status = 0;
	2009	+ int status = 0, i;
1997	2010
1998	2011	dev_info(&adev->dev,
1999	2012	"ARM PL022 driver, device ID: 0x%08x\n", adev->periphid);
...	...	@@ -2004,7 +2017,8 @@
2004	2017	}
2005	2018
2006	2019	/* Allocate master with space for data */
2007		- master = spi_alloc_master(dev, sizeof(struct pl022));
	2020	+ master = spi_alloc_master(dev, sizeof(struct pl022) + sizeof(int) *
	2021	+ platform_info->num_chipselect);
2008	2022	if (master == NULL) {
2009	2023	dev_err(&adev->dev, "probe - cannot alloc SPI master\n");
2010	2024	status = -ENOMEM;
...	...	@@ -2016,6 +2030,8 @@
2016	2030	pl022->master_info = platform_info;
2017	2031	pl022->adev = adev;
2018	2032	pl022->vendor = id->data;
	2033	+ /* Point chipselects to allocated memory beyond the main struct */
	2034	+ pl022->chipselects = (int *) pl022 + sizeof(struct pl022);
2019	2035
2020	2036	/*
2021	2037	* Bus Number Which has been Assigned to this SSP controller
...	...	@@ -2029,6 +2045,10 @@
2029	2045	master->transfer_one_message = pl022_transfer_one_message;
2030	2046	master->unprepare_transfer_hardware = pl022_unprepare_transfer_hardware;
2031	2047	master->rt = platform_info->rt;
	2048	+
	2049	+ if (platform_info->num_chipselect && platform_info->chipselects)
	2050	+ for (i = 0; i < platform_info->num_chipselect; i++)
	2051	+ pl022->chipselects[i] = platform_info->chipselects[i];
2032	2052
2033	2053	/*
2034	2054	* Supports mode 0-3, loopback, and active low CS. Transfers are
...	...	@@ -244,6 +244,7 @@
244	244	* indicates no delay and the device will be suspended immediately.
245	245	* @rt: indicates the controller should run the message pump with realtime
246	246	* priority to minimise the transfer latency on the bus.
	247	+ * @chipselects: list of <num_chipselects> chip select gpios
247	248	*/
248	249	struct pl022_ssp_controller {
249	250	u16 bus_id;
...	...	@@ -254,6 +255,7 @@
254	255	void *dma_tx_param;
255	256	int autosuspend_delay;
256	257	bool rt;
	258	+ int *chipselects;
257	259	};
258	260
259	261	/**