spi: npcm-pspi: modify reset support

Modify NPCM perphiral SPI reset support from
direct register access to reset controller support.
Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
Link: https://lore.kernel.org/r/20200115162301.235926-5-tmaimon77@gmail.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-npcm-pspi.c

@@ -12,6 +12,7 @@
 #include <linux/spi/spi.h>
 #include <linux/gpio.h>
 #include <linux/of_gpio.h>
+#include <linux/reset.h>
 
 #include <asm/unaligned.h>
 
@@ -20,7 +21,7 @@
 
 struct npcm_pspi {
 	struct completion xfer_done;
-	struct regmap *rst_regmap;
+	struct reset_control *reset;
 	struct spi_master *master;
 	unsigned int tx_bytes;
 	unsigned int rx_bytes;
@@ -59,12 +60,6 @@ struct npcm_pspi {
 #define NPCM_PSPI_MIN_CLK_DIVIDER	4
 #define NPCM_PSPI_DEFAULT_CLK		25000000
 
-/* reset register */
-#define NPCM7XX_IPSRST2_OFFSET	0x24
-
-#define NPCM7XX_PSPI1_RESET	BIT(22)
-#define NPCM7XX_PSPI2_RESET	BIT(23)
-
 static inline unsigned int bytes_per_word(unsigned int bits)
 {
 	return bits <= 8 ? 1 : 2;
@@ -292,9 +287,9 @@ static int npcm_pspi_unprepare_transfer_hardware(struct spi_master *master)
 
 static void npcm_pspi_reset_hw(struct npcm_pspi *priv)
 {
-	regmap_write(priv->rst_regmap, NPCM7XX_IPSRST2_OFFSET,
-		     NPCM7XX_PSPI1_RESET << priv->id);
-	regmap_write(priv->rst_regmap, NPCM7XX_IPSRST2_OFFSET, 0x0);
+	reset_control_assert(priv->reset);
+	udelay(5);
+	reset_control_deassert(priv->reset);
 }
 
 static irqreturn_t npcm_pspi_handler(int irq, void *dev_id)
@@ -358,10 +353,6 @@ static int npcm_pspi_probe(struct platform_device *pdev)
 	if (num_cs < 0)
 		return num_cs;
 
-	pdev->id = of_alias_get_id(np, "spi");
-	if (pdev->id < 0)
-		pdev->id = 0;
-
 	master = spi_alloc_master(&pdev->dev, sizeof(*priv));
 	if (!master)
 		return -ENOMEM;
@@ -371,7 +362,6 @@ static int npcm_pspi_probe(struct platform_device *pdev)
 	priv = spi_master_get_devdata(master);
 	priv->master = master;
 	priv->is_save_param = false;
-	priv->id = pdev->id;
 
 	priv->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(priv->base)) {
@@ -396,11 +386,10 @@ static int npcm_pspi_probe(struct platform_device *pdev)
 		goto out_disable_clk;
 	}
 
-	priv->rst_regmap =
-		syscon_regmap_lookup_by_compatible("nuvoton,npcm750-rst");
-	if (IS_ERR(priv->rst_regmap)) {
-		dev_err(&pdev->dev, "failed to find nuvoton,npcm750-rst\n");
-		return PTR_ERR(priv->rst_regmap);
+	priv->reset = devm_reset_control_get(&pdev->dev, NULL);
+	if (IS_ERR(priv->reset)) {
+		ret = PTR_ERR(priv->reset);
+		goto out_disable_clk;
 	}
 
 	/* reset SPI-HW block */
@@ -421,7 +410,7 @@ static int npcm_pspi_probe(struct platform_device *pdev)
 	master->min_speed_hz = DIV_ROUND_UP(clk_hz, NPCM_PSPI_MAX_CLK_DIVIDER);
 	master->mode_bits = SPI_CPHA | SPI_CPOL;
 	master->dev.of_node = pdev->dev.of_node;
-	master->bus_num = pdev->id;
+	master->bus_num = -1;
 	master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(16);
 	master->transfer_one = npcm_pspi_transfer_one;
 	master->prepare_transfer_hardware =
@@ -454,7 +443,7 @@ static int npcm_pspi_probe(struct platform_device *pdev)
 	if (ret)
 		goto out_disable_clk;
 
-	pr_info("NPCM Peripheral SPI %d probed\n", pdev->id);
+	pr_info("NPCM Peripheral SPI %d probed\n", master->bus_num);
 
 	return 0;