forked from mirrors/linux
		
	spi: Add driver for Cadence SPI controller
Add driver for Cadence SPI controller. This is used in Xilinx Zynq. Signed-off-by: Harini Katakam <harinik@xilinx.com> Signed-off-by: Mark Brown <broonie@linaro.org>
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		|  | @ -148,6 +148,13 @@ config SPI_BUTTERFLY | ||||||
| 	  inexpensive battery powered microcontroller evaluation board. | 	  inexpensive battery powered microcontroller evaluation board. | ||||||
| 	  This same cable can be used to flash new firmware. | 	  This same cable can be used to flash new firmware. | ||||||
| 
 | 
 | ||||||
|  | config SPI_CADENCE | ||||||
|  | 	tristate "Cadence SPI controller" | ||||||
|  | 	depends on SPI_MASTER | ||||||
|  | 	help | ||||||
|  | 	  This selects the Cadence SPI controller master driver | ||||||
|  | 	  used by Xilinx Zynq. | ||||||
|  | 
 | ||||||
| config SPI_CLPS711X | config SPI_CLPS711X | ||||||
| 	tristate "CLPS711X host SPI controller" | 	tristate "CLPS711X host SPI controller" | ||||||
| 	depends on ARCH_CLPS711X || COMPILE_TEST | 	depends on ARCH_CLPS711X || COMPILE_TEST | ||||||
|  |  | ||||||
|  | @ -22,6 +22,7 @@ obj-$(CONFIG_SPI_BFIN_V3)               += spi-bfin-v3.o | ||||||
| obj-$(CONFIG_SPI_BFIN_SPORT)		+= spi-bfin-sport.o | obj-$(CONFIG_SPI_BFIN_SPORT)		+= spi-bfin-sport.o | ||||||
| obj-$(CONFIG_SPI_BITBANG)		+= spi-bitbang.o | obj-$(CONFIG_SPI_BITBANG)		+= spi-bitbang.o | ||||||
| obj-$(CONFIG_SPI_BUTTERFLY)		+= spi-butterfly.o | obj-$(CONFIG_SPI_BUTTERFLY)		+= spi-butterfly.o | ||||||
|  | obj-$(CONFIG_SPI_CADENCE)		+= spi-cadence.o | ||||||
| obj-$(CONFIG_SPI_CLPS711X)		+= spi-clps711x.o | obj-$(CONFIG_SPI_CLPS711X)		+= spi-clps711x.o | ||||||
| obj-$(CONFIG_SPI_COLDFIRE_QSPI)		+= spi-coldfire-qspi.o | obj-$(CONFIG_SPI_COLDFIRE_QSPI)		+= spi-coldfire-qspi.o | ||||||
| obj-$(CONFIG_SPI_DAVINCI)		+= spi-davinci.o | obj-$(CONFIG_SPI_DAVINCI)		+= spi-davinci.o | ||||||
|  |  | ||||||
							
								
								
									
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								drivers/spi/spi-cadence.c
									
									
									
									
									
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								drivers/spi/spi-cadence.c
									
									
									
									
									
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							|  | @ -0,0 +1,673 @@ | ||||||
|  | /*
 | ||||||
|  |  * Cadence SPI controller driver (master mode only) | ||||||
|  |  * | ||||||
|  |  * Copyright (C) 2008 - 2014 Xilinx, Inc. | ||||||
|  |  * | ||||||
|  |  * based on Blackfin On-Chip SPI Driver (spi_bfin5xx.c) | ||||||
|  |  * | ||||||
|  |  * This program is free software; you can redistribute it and/or modify it under | ||||||
|  |  * the terms of the GNU General Public License version 2 as published by the | ||||||
|  |  * Free Software Foundation; either version 2 of the License, or (at your | ||||||
|  |  * option) any later version. | ||||||
|  |  */ | ||||||
|  | 
 | ||||||
|  | #include <linux/clk.h> | ||||||
|  | #include <linux/delay.h> | ||||||
|  | #include <linux/interrupt.h> | ||||||
|  | #include <linux/io.h> | ||||||
|  | #include <linux/module.h> | ||||||
|  | #include <linux/of_irq.h> | ||||||
|  | #include <linux/of_address.h> | ||||||
|  | #include <linux/platform_device.h> | ||||||
|  | #include <linux/spi/spi.h> | ||||||
|  | 
 | ||||||
|  | /* Name of this driver */ | ||||||
|  | #define CDNS_SPI_NAME		"cdns-spi" | ||||||
|  | 
 | ||||||
|  | /* Register offset definitions */ | ||||||
|  | #define CDNS_SPI_CR_OFFSET	0x00 /* Configuration  Register, RW */ | ||||||
|  | #define CDNS_SPI_ISR_OFFSET	0x04 /* Interrupt Status Register, RO */ | ||||||
|  | #define CDNS_SPI_IER_OFFSET	0x08 /* Interrupt Enable Register, WO */ | ||||||
|  | #define CDNS_SPI_IDR_OFFSET	0x0c /* Interrupt Disable Register, WO */ | ||||||
|  | #define CDNS_SPI_IMR_OFFSET	0x10 /* Interrupt Enabled Mask Register, RO */ | ||||||
|  | #define CDNS_SPI_ER_OFFSET	0x14 /* Enable/Disable Register, RW */ | ||||||
|  | #define CDNS_SPI_DR_OFFSET	0x18 /* Delay Register, RW */ | ||||||
|  | #define CDNS_SPI_TXD_OFFSET	0x1C /* Data Transmit Register, WO */ | ||||||
|  | #define CDNS_SPI_RXD_OFFSET	0x20 /* Data Receive Register, RO */ | ||||||
|  | #define CDNS_SPI_SICR_OFFSET	0x24 /* Slave Idle Count Register, RW */ | ||||||
|  | #define CDNS_SPI_THLD_OFFSET	0x28 /* Transmit FIFO Watermark Register,RW */ | ||||||
|  | 
 | ||||||
|  | /*
 | ||||||
|  |  * SPI Configuration Register bit Masks | ||||||
|  |  * | ||||||
|  |  * This register contains various control bits that affect the operation | ||||||
|  |  * of the SPI controller | ||||||
|  |  */ | ||||||
|  | #define CDNS_SPI_CR_MANSTRT_MASK	0x00010000 /* Manual TX Start */ | ||||||
|  | #define CDNS_SPI_CR_CPHA_MASK		0x00000004 /* Clock Phase Control */ | ||||||
|  | #define CDNS_SPI_CR_CPOL_MASK		0x00000002 /* Clock Polarity Control */ | ||||||
|  | #define CDNS_SPI_CR_SSCTRL_MASK		0x00003C00 /* Slave Select Mask */ | ||||||
|  | #define CDNS_SPI_CR_BAUD_DIV_MASK	0x00000038 /* Baud Rate Divisor Mask */ | ||||||
|  | #define CDNS_SPI_CR_MSTREN_MASK		0x00000001 /* Master Enable Mask */ | ||||||
|  | #define CDNS_SPI_CR_MANSTRTEN_MASK	0x00008000 /* Manual TX Enable Mask */ | ||||||
|  | #define CDNS_SPI_CR_SSFORCE_MASK	0x00004000 /* Manual SS Enable Mask */ | ||||||
|  | #define CDNS_SPI_CR_BAUD_DIV_4_MASK	0x00000008 /* Default Baud Div Mask */ | ||||||
|  | #define CDNS_SPI_CR_DEFAULT_MASK	(CDNS_SPI_CR_MSTREN_MASK | \ | ||||||
|  | 					CDNS_SPI_CR_SSCTRL_MASK | \ | ||||||
|  | 					CDNS_SPI_CR_SSFORCE_MASK | \ | ||||||
|  | 					CDNS_SPI_CR_BAUD_DIV_4_MASK) | ||||||
|  | 
 | ||||||
|  | /*
 | ||||||
|  |  * SPI Configuration Register - Baud rate and slave select | ||||||
|  |  * | ||||||
|  |  * These are the values used in the calculation of baud rate divisor and | ||||||
|  |  * setting the slave select. | ||||||
|  |  */ | ||||||
|  | 
 | ||||||
|  | #define CDNS_SPI_BAUD_DIV_MAX		7 /* Baud rate divisor maximum */ | ||||||
|  | #define CDNS_SPI_BAUD_DIV_MIN		1 /* Baud rate divisor minimum */ | ||||||
|  | #define CDNS_SPI_BAUD_DIV_SHIFT		3 /* Baud rate divisor shift in CR */ | ||||||
|  | #define CDNS_SPI_SS_SHIFT		10 /* Slave Select field shift in CR */ | ||||||
|  | #define CDNS_SPI_SS0			0x1 /* Slave Select zero */ | ||||||
|  | 
 | ||||||
|  | /*
 | ||||||
|  |  * SPI Interrupt Registers bit Masks | ||||||
|  |  * | ||||||
|  |  * All the four interrupt registers (Status/Mask/Enable/Disable) have the same | ||||||
|  |  * bit definitions. | ||||||
|  |  */ | ||||||
|  | #define CDNS_SPI_IXR_TXOW_MASK	0x00000004 /* SPI TX FIFO Overwater */ | ||||||
|  | #define CDNS_SPI_IXR_MODF_MASK	0x00000002 /* SPI Mode Fault */ | ||||||
|  | #define CDNS_SPI_IXR_RXNEMTY_MASK 0x00000010 /* SPI RX FIFO Not Empty */ | ||||||
|  | #define CDNS_SPI_IXR_DEFAULT_MASK	(CDNS_SPI_IXR_TXOW_MASK | \ | ||||||
|  | 					CDNS_SPI_IXR_MODF_MASK) | ||||||
|  | #define CDNS_SPI_IXR_TXFULL_MASK	0x00000008 /* SPI TX Full */ | ||||||
|  | #define CDNS_SPI_IXR_ALL_MASK	0x0000007F /* SPI all interrupts */ | ||||||
|  | 
 | ||||||
|  | /*
 | ||||||
|  |  * SPI Enable Register bit Masks | ||||||
|  |  * | ||||||
|  |  * This register is used to enable or disable the SPI controller | ||||||
|  |  */ | ||||||
|  | #define CDNS_SPI_ER_ENABLE_MASK	0x00000001 /* SPI Enable Bit Mask */ | ||||||
|  | #define CDNS_SPI_ER_DISABLE_MASK	0x0 /* SPI Disable Bit Mask */ | ||||||
|  | 
 | ||||||
|  | /* SPI FIFO depth in bytes */ | ||||||
|  | #define CDNS_SPI_FIFO_DEPTH	128 | ||||||
|  | 
 | ||||||
|  | /* Default number of chip select lines */ | ||||||
|  | #define CDNS_SPI_DEFAULT_NUM_CS		4 | ||||||
|  | 
 | ||||||
|  | /**
 | ||||||
|  |  * struct cdns_spi - This definition defines spi driver instance | ||||||
|  |  * @regs:		Virtual address of the SPI controller registers | ||||||
|  |  * @ref_clk:		Pointer to the peripheral clock | ||||||
|  |  * @pclk:		Pointer to the APB clock | ||||||
|  |  * @speed_hz:		Current SPI bus clock speed in Hz | ||||||
|  |  * @txbuf:		Pointer	to the TX buffer | ||||||
|  |  * @rxbuf:		Pointer to the RX buffer | ||||||
|  |  * @tx_bytes:		Number of bytes left to transfer | ||||||
|  |  * @rx_bytes:		Number of bytes requested | ||||||
|  |  * @dev_busy:		Device busy flag | ||||||
|  |  * @is_decoded_cs:	Flag for decoder property set or not | ||||||
|  |  */ | ||||||
|  | struct cdns_spi { | ||||||
|  | 	void __iomem *regs; | ||||||
|  | 	struct clk *ref_clk; | ||||||
|  | 	struct clk *pclk; | ||||||
|  | 	u32 speed_hz; | ||||||
|  | 	const u8 *txbuf; | ||||||
|  | 	u8 *rxbuf; | ||||||
|  | 	int tx_bytes; | ||||||
|  | 	int rx_bytes; | ||||||
|  | 	u8 dev_busy; | ||||||
|  | 	u32 is_decoded_cs; | ||||||
|  | }; | ||||||
|  | 
 | ||||||
|  | /* Macros for the SPI controller read/write */ | ||||||
|  | static inline u32 cdns_spi_read(struct cdns_spi *xspi, u32 offset) | ||||||
|  | { | ||||||
|  | 	return readl_relaxed(xspi->regs + offset); | ||||||
|  | } | ||||||
|  | 
 | ||||||
|  | static inline void cdns_spi_write(struct cdns_spi *xspi, u32 offset, u32 val) | ||||||
|  | { | ||||||
|  | 	writel_relaxed(val, xspi->regs + offset); | ||||||
|  | } | ||||||
|  | 
 | ||||||
|  | /**
 | ||||||
|  |  * cdns_spi_init_hw - Initialize the hardware and configure the SPI controller | ||||||
|  |  * @xspi:	Pointer to the cdns_spi structure | ||||||
|  |  * | ||||||
|  |  * On reset the SPI controller is configured to be in master mode, baud rate | ||||||
|  |  * divisor is set to 4, threshold value for TX FIFO not full interrupt is set | ||||||
|  |  * to 1 and size of the word to be transferred as 8 bit. | ||||||
|  |  * This function initializes the SPI controller to disable and clear all the | ||||||
|  |  * interrupts, enable manual slave select and manual start, deselect all the | ||||||
|  |  * chip select lines, and enable the SPI controller. | ||||||
|  |  */ | ||||||
|  | static void cdns_spi_init_hw(struct cdns_spi *xspi) | ||||||
|  | { | ||||||
|  | 	cdns_spi_write(xspi, CDNS_SPI_ER_OFFSET, | ||||||
|  | 		       CDNS_SPI_ER_DISABLE_MASK); | ||||||
|  | 	cdns_spi_write(xspi, CDNS_SPI_IDR_OFFSET, | ||||||
|  | 		       CDNS_SPI_IXR_ALL_MASK); | ||||||
|  | 
 | ||||||
|  | 	/* Clear the RX FIFO */ | ||||||
|  | 	while (cdns_spi_read(xspi, CDNS_SPI_ISR_OFFSET) & | ||||||
|  | 	       CDNS_SPI_IXR_RXNEMTY_MASK) | ||||||
|  | 		cdns_spi_read(xspi, CDNS_SPI_RXD_OFFSET); | ||||||
|  | 
 | ||||||
|  | 	cdns_spi_write(xspi, CDNS_SPI_ISR_OFFSET, | ||||||
|  | 		       CDNS_SPI_IXR_ALL_MASK); | ||||||
|  | 	cdns_spi_write(xspi, CDNS_SPI_CR_OFFSET, | ||||||
|  | 		       CDNS_SPI_CR_DEFAULT_MASK); | ||||||
|  | 	cdns_spi_write(xspi, CDNS_SPI_ER_OFFSET, | ||||||
|  | 		       CDNS_SPI_ER_ENABLE_MASK); | ||||||
|  | } | ||||||
|  | 
 | ||||||
|  | /**
 | ||||||
|  |  * cdns_spi_chipselect - Select or deselect the chip select line | ||||||
|  |  * @spi:	Pointer to the spi_device structure | ||||||
|  |  * @is_on:	Select(0) or deselect (1) the chip select line | ||||||
|  |  */ | ||||||
|  | static void cdns_spi_chipselect(struct spi_device *spi, bool is_high) | ||||||
|  | { | ||||||
|  | 	struct cdns_spi *xspi = spi_master_get_devdata(spi->master); | ||||||
|  | 	u32 ctrl_reg; | ||||||
|  | 
 | ||||||
|  | 	ctrl_reg = cdns_spi_read(xspi, CDNS_SPI_CR_OFFSET); | ||||||
|  | 
 | ||||||
|  | 	if (is_high) { | ||||||
|  | 		/* Deselect the slave */ | ||||||
|  | 		ctrl_reg |= CDNS_SPI_CR_SSCTRL_MASK; | ||||||
|  | 	} else { | ||||||
|  | 		/* Select the slave */ | ||||||
|  | 		ctrl_reg &= ~CDNS_SPI_CR_SSCTRL_MASK; | ||||||
|  | 		if (!(xspi->is_decoded_cs)) | ||||||
|  | 			ctrl_reg |= ((~(CDNS_SPI_SS0 << spi->chip_select)) << | ||||||
|  | 				     CDNS_SPI_SS_SHIFT) & | ||||||
|  | 				     CDNS_SPI_CR_SSCTRL_MASK; | ||||||
|  | 		else | ||||||
|  | 			ctrl_reg |= (spi->chip_select << CDNS_SPI_SS_SHIFT) & | ||||||
|  | 				     CDNS_SPI_CR_SSCTRL_MASK; | ||||||
|  | 	} | ||||||
|  | 
 | ||||||
|  | 	cdns_spi_write(xspi, CDNS_SPI_CR_OFFSET, ctrl_reg); | ||||||
|  | } | ||||||
|  | 
 | ||||||
|  | /**
 | ||||||
|  |  * cdns_spi_config_clock_mode - Sets clock polarity and phase | ||||||
|  |  * @spi:	Pointer to the spi_device structure | ||||||
|  |  * | ||||||
|  |  * Sets the requested clock polarity and phase. | ||||||
|  |  */ | ||||||
|  | static void cdns_spi_config_clock_mode(struct spi_device *spi) | ||||||
|  | { | ||||||
|  | 	struct cdns_spi *xspi = spi_master_get_devdata(spi->master); | ||||||
|  | 	u32 ctrl_reg; | ||||||
|  | 
 | ||||||
|  | 	ctrl_reg = cdns_spi_read(xspi, CDNS_SPI_CR_OFFSET); | ||||||
|  | 
 | ||||||
|  | 	/* Set the SPI clock phase and clock polarity */ | ||||||
|  | 	ctrl_reg &= ~(CDNS_SPI_CR_CPHA_MASK | CDNS_SPI_CR_CPOL_MASK); | ||||||
|  | 	if (spi->mode & SPI_CPHA) | ||||||
|  | 		ctrl_reg |= CDNS_SPI_CR_CPHA_MASK; | ||||||
|  | 	if (spi->mode & SPI_CPOL) | ||||||
|  | 		ctrl_reg |= CDNS_SPI_CR_CPOL_MASK; | ||||||
|  | 
 | ||||||
|  | 	cdns_spi_write(xspi, CDNS_SPI_CR_OFFSET, ctrl_reg); | ||||||
|  | } | ||||||
|  | 
 | ||||||
|  | /**
 | ||||||
|  |  * cdns_spi_config_clock_freq - Sets clock frequency | ||||||
|  |  * @spi:	Pointer to the spi_device structure | ||||||
|  |  * @transfer:	Pointer to the spi_transfer structure which provides | ||||||
|  |  *		information about next transfer setup parameters | ||||||
|  |  * | ||||||
|  |  * Sets the requested clock frequency. | ||||||
|  |  * Note: If the requested frequency is not an exact match with what can be | ||||||
|  |  * obtained using the prescalar value the driver sets the clock frequency which | ||||||
|  |  * is lower than the requested frequency (maximum lower) for the transfer. If | ||||||
|  |  * the requested frequency is higher or lower than that is supported by the SPI | ||||||
|  |  * controller the driver will set the highest or lowest frequency supported by | ||||||
|  |  * controller. | ||||||
|  |  */ | ||||||
|  | static void cdns_spi_config_clock_freq(struct spi_device *spi, | ||||||
|  | 				  struct spi_transfer *transfer) | ||||||
|  | { | ||||||
|  | 	struct cdns_spi *xspi = spi_master_get_devdata(spi->master); | ||||||
|  | 	u32 ctrl_reg, baud_rate_val; | ||||||
|  | 	unsigned long frequency; | ||||||
|  | 
 | ||||||
|  | 	frequency = clk_get_rate(xspi->ref_clk); | ||||||
|  | 
 | ||||||
|  | 	ctrl_reg = cdns_spi_read(xspi, CDNS_SPI_CR_OFFSET); | ||||||
|  | 
 | ||||||
|  | 	/* Set the clock frequency */ | ||||||
|  | 	if (xspi->speed_hz != transfer->speed_hz) { | ||||||
|  | 		/* first valid value is 1 */ | ||||||
|  | 		baud_rate_val = CDNS_SPI_BAUD_DIV_MIN; | ||||||
|  | 		while ((baud_rate_val < CDNS_SPI_BAUD_DIV_MAX) && | ||||||
|  | 		       (frequency / (2 << baud_rate_val)) > transfer->speed_hz) | ||||||
|  | 			baud_rate_val++; | ||||||
|  | 
 | ||||||
|  | 		ctrl_reg &= ~CDNS_SPI_CR_BAUD_DIV_MASK; | ||||||
|  | 		ctrl_reg |= baud_rate_val << CDNS_SPI_BAUD_DIV_SHIFT; | ||||||
|  | 
 | ||||||
|  | 		xspi->speed_hz = frequency / (2 << baud_rate_val); | ||||||
|  | 	} | ||||||
|  | 	cdns_spi_write(xspi, CDNS_SPI_CR_OFFSET, ctrl_reg); | ||||||
|  | } | ||||||
|  | 
 | ||||||
|  | /**
 | ||||||
|  |  * cdns_spi_setup_transfer - Configure SPI controller for specified transfer | ||||||
|  |  * @spi:	Pointer to the spi_device structure | ||||||
|  |  * @transfer:	Pointer to the spi_transfer structure which provides | ||||||
|  |  *		information about next transfer setup parameters | ||||||
|  |  * | ||||||
|  |  * Sets the operational mode of SPI controller for the next SPI transfer and | ||||||
|  |  * sets the requested clock frequency. | ||||||
|  |  * | ||||||
|  |  * Return:	Always 0 | ||||||
|  |  */ | ||||||
|  | static int cdns_spi_setup_transfer(struct spi_device *spi, | ||||||
|  | 				   struct spi_transfer *transfer) | ||||||
|  | { | ||||||
|  | 	struct cdns_spi *xspi = spi_master_get_devdata(spi->master); | ||||||
|  | 
 | ||||||
|  | 	cdns_spi_config_clock_freq(spi, transfer); | ||||||
|  | 
 | ||||||
|  | 	dev_dbg(&spi->dev, "%s, mode %d, %u bits/w, %u clock speed\n", | ||||||
|  | 		__func__, spi->mode, spi->bits_per_word, | ||||||
|  | 		xspi->speed_hz); | ||||||
|  | 
 | ||||||
|  | 	return 0; | ||||||
|  | } | ||||||
|  | 
 | ||||||
|  | /**
 | ||||||
|  |  * cdns_spi_fill_tx_fifo - Fills the TX FIFO with as many bytes as possible | ||||||
|  |  * @xspi:	Pointer to the cdns_spi structure | ||||||
|  |  */ | ||||||
|  | static void cdns_spi_fill_tx_fifo(struct cdns_spi *xspi) | ||||||
|  | { | ||||||
|  | 	unsigned long trans_cnt = 0; | ||||||
|  | 
 | ||||||
|  | 	while ((trans_cnt < CDNS_SPI_FIFO_DEPTH) && | ||||||
|  | 	       (xspi->tx_bytes > 0)) { | ||||||
|  | 		if (xspi->txbuf) | ||||||
|  | 			cdns_spi_write(xspi, CDNS_SPI_TXD_OFFSET, | ||||||
|  | 				       *xspi->txbuf++); | ||||||
|  | 		else | ||||||
|  | 			cdns_spi_write(xspi, CDNS_SPI_TXD_OFFSET, 0); | ||||||
|  | 
 | ||||||
|  | 		xspi->tx_bytes--; | ||||||
|  | 		trans_cnt++; | ||||||
|  | 	} | ||||||
|  | } | ||||||
|  | 
 | ||||||
|  | /**
 | ||||||
|  |  * cdns_spi_irq - Interrupt service routine of the SPI controller | ||||||
|  |  * @irq:	IRQ number | ||||||
|  |  * @dev_id:	Pointer to the xspi structure | ||||||
|  |  * | ||||||
|  |  * This function handles TX empty and Mode Fault interrupts only. | ||||||
|  |  * On TX empty interrupt this function reads the received data from RX FIFO and | ||||||
|  |  * fills the TX FIFO if there is any data remaining to be transferred. | ||||||
|  |  * On Mode Fault interrupt this function indicates that transfer is completed, | ||||||
|  |  * the SPI subsystem will identify the error as the remaining bytes to be | ||||||
|  |  * transferred is non-zero. | ||||||
|  |  * | ||||||
|  |  * Return:	IRQ_HANDLED when handled; IRQ_NONE otherwise. | ||||||
|  |  */ | ||||||
|  | static irqreturn_t cdns_spi_irq(int irq, void *dev_id) | ||||||
|  | { | ||||||
|  | 	struct spi_master *master = dev_id; | ||||||
|  | 	struct cdns_spi *xspi = spi_master_get_devdata(master); | ||||||
|  | 	u32 intr_status, status; | ||||||
|  | 
 | ||||||
|  | 	status = IRQ_NONE; | ||||||
|  | 	intr_status = cdns_spi_read(xspi, CDNS_SPI_ISR_OFFSET); | ||||||
|  | 	cdns_spi_write(xspi, CDNS_SPI_ISR_OFFSET, intr_status); | ||||||
|  | 
 | ||||||
|  | 	if (intr_status & CDNS_SPI_IXR_MODF_MASK) { | ||||||
|  | 		/* Indicate that transfer is completed, the SPI subsystem will
 | ||||||
|  | 		 * identify the error as the remaining bytes to be | ||||||
|  | 		 * transferred is non-zero | ||||||
|  | 		 */ | ||||||
|  | 		cdns_spi_write(xspi, CDNS_SPI_IDR_OFFSET, | ||||||
|  | 			       CDNS_SPI_IXR_DEFAULT_MASK); | ||||||
|  | 		spi_finalize_current_transfer(master); | ||||||
|  | 		status = IRQ_HANDLED; | ||||||
|  | 	} else if (intr_status & CDNS_SPI_IXR_TXOW_MASK) { | ||||||
|  | 		unsigned long trans_cnt; | ||||||
|  | 
 | ||||||
|  | 		trans_cnt = xspi->rx_bytes - xspi->tx_bytes; | ||||||
|  | 
 | ||||||
|  | 		/* Read out the data from the RX FIFO */ | ||||||
|  | 		while (trans_cnt) { | ||||||
|  | 			u8 data; | ||||||
|  | 
 | ||||||
|  | 			data = cdns_spi_read(xspi, CDNS_SPI_RXD_OFFSET); | ||||||
|  | 			if (xspi->rxbuf) | ||||||
|  | 				*xspi->rxbuf++ = data; | ||||||
|  | 
 | ||||||
|  | 			xspi->rx_bytes--; | ||||||
|  | 			trans_cnt--; | ||||||
|  | 		} | ||||||
|  | 
 | ||||||
|  | 		if (xspi->tx_bytes) { | ||||||
|  | 			/* There is more data to send */ | ||||||
|  | 			cdns_spi_fill_tx_fifo(xspi); | ||||||
|  | 		} else { | ||||||
|  | 			/* Transfer is completed */ | ||||||
|  | 			cdns_spi_write(xspi, CDNS_SPI_IDR_OFFSET, | ||||||
|  | 				       CDNS_SPI_IXR_DEFAULT_MASK); | ||||||
|  | 			spi_finalize_current_transfer(master); | ||||||
|  | 		} | ||||||
|  | 		status = IRQ_HANDLED; | ||||||
|  | 	} | ||||||
|  | 
 | ||||||
|  | 	return status; | ||||||
|  | } | ||||||
|  | 
 | ||||||
|  | /**
 | ||||||
|  |  * cdns_transfer_one - Initiates the SPI transfer | ||||||
|  |  * @master:	Pointer to spi_master structure | ||||||
|  |  * @spi:	Pointer to the spi_device structure | ||||||
|  |  * @transfer:	Pointer to the spi_transfer structure which provides | ||||||
|  |  *		information about next transfer parameters | ||||||
|  |  * | ||||||
|  |  * This function fills the TX FIFO, starts the SPI transfer and | ||||||
|  |  * returns a positive transfer count so that core will wait for completion. | ||||||
|  |  * | ||||||
|  |  * Return:	Number of bytes transferred in the last transfer | ||||||
|  |  */ | ||||||
|  | static int cdns_transfer_one(struct spi_master *master, | ||||||
|  | 			     struct spi_device *spi, | ||||||
|  | 			     struct spi_transfer *transfer) | ||||||
|  | { | ||||||
|  | 	struct cdns_spi *xspi = spi_master_get_devdata(master); | ||||||
|  | 
 | ||||||
|  | 	xspi->txbuf = transfer->tx_buf; | ||||||
|  | 	xspi->rxbuf = transfer->rx_buf; | ||||||
|  | 	xspi->tx_bytes = transfer->len; | ||||||
|  | 	xspi->rx_bytes = transfer->len; | ||||||
|  | 
 | ||||||
|  | 	cdns_spi_setup_transfer(spi, transfer); | ||||||
|  | 
 | ||||||
|  | 	cdns_spi_fill_tx_fifo(xspi); | ||||||
|  | 
 | ||||||
|  | 	cdns_spi_write(xspi, CDNS_SPI_IER_OFFSET, | ||||||
|  | 		       CDNS_SPI_IXR_DEFAULT_MASK); | ||||||
|  | 	return transfer->len; | ||||||
|  | } | ||||||
|  | 
 | ||||||
|  | /**
 | ||||||
|  |  * cdns_prepare_transfer_hardware - Prepares hardware for transfer. | ||||||
|  |  * @master:	Pointer to the spi_master structure which provides | ||||||
|  |  *		information about the controller. | ||||||
|  |  * | ||||||
|  |  * This function enables SPI master controller. | ||||||
|  |  * | ||||||
|  |  * Return:	0 always | ||||||
|  |  */ | ||||||
|  | static int cdns_prepare_transfer_hardware(struct spi_master *master) | ||||||
|  | { | ||||||
|  | 	struct cdns_spi *xspi = spi_master_get_devdata(master); | ||||||
|  | 
 | ||||||
|  | 	cdns_spi_config_clock_mode(master->cur_msg->spi); | ||||||
|  | 
 | ||||||
|  | 	cdns_spi_write(xspi, CDNS_SPI_ER_OFFSET, | ||||||
|  | 		       CDNS_SPI_ER_ENABLE_MASK); | ||||||
|  | 
 | ||||||
|  | 	return 0; | ||||||
|  | } | ||||||
|  | 
 | ||||||
|  | /**
 | ||||||
|  |  * cdns_unprepare_transfer_hardware - Relaxes hardware after transfer | ||||||
|  |  * @master:	Pointer to the spi_master structure which provides | ||||||
|  |  *		information about the controller. | ||||||
|  |  * | ||||||
|  |  * This function disables the SPI master controller. | ||||||
|  |  * | ||||||
|  |  * Return:	0 always | ||||||
|  |  */ | ||||||
|  | static int cdns_unprepare_transfer_hardware(struct spi_master *master) | ||||||
|  | { | ||||||
|  | 	struct cdns_spi *xspi = spi_master_get_devdata(master); | ||||||
|  | 
 | ||||||
|  | 	cdns_spi_write(xspi, CDNS_SPI_ER_OFFSET, | ||||||
|  | 		       CDNS_SPI_ER_DISABLE_MASK); | ||||||
|  | 
 | ||||||
|  | 	return 0; | ||||||
|  | } | ||||||
|  | 
 | ||||||
|  | /**
 | ||||||
|  |  * cdns_spi_probe - Probe method for the SPI driver | ||||||
|  |  * @pdev:	Pointer to the platform_device structure | ||||||
|  |  * | ||||||
|  |  * This function initializes the driver data structures and the hardware. | ||||||
|  |  * | ||||||
|  |  * Return:	0 on success and error value on error | ||||||
|  |  */ | ||||||
|  | static int cdns_spi_probe(struct platform_device *pdev) | ||||||
|  | { | ||||||
|  | 	int ret = 0, irq; | ||||||
|  | 	struct spi_master *master; | ||||||
|  | 	struct cdns_spi *xspi; | ||||||
|  | 	struct resource *res; | ||||||
|  | 	u32 num_cs; | ||||||
|  | 
 | ||||||
|  | 	master = spi_alloc_master(&pdev->dev, sizeof(*xspi)); | ||||||
|  | 	if (master == NULL) | ||||||
|  | 		return -ENOMEM; | ||||||
|  | 
 | ||||||
|  | 	xspi = spi_master_get_devdata(master); | ||||||
|  | 	master->dev.of_node = pdev->dev.of_node; | ||||||
|  | 	platform_set_drvdata(pdev, master); | ||||||
|  | 
 | ||||||
|  | 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | ||||||
|  | 	xspi->regs = devm_ioremap_resource(&pdev->dev, res); | ||||||
|  | 	if (IS_ERR(xspi->regs)) { | ||||||
|  | 		ret = PTR_ERR(xspi->regs); | ||||||
|  | 		goto remove_master; | ||||||
|  | 	} | ||||||
|  | 
 | ||||||
|  | 	xspi->pclk = devm_clk_get(&pdev->dev, "pclk"); | ||||||
|  | 	if (IS_ERR(xspi->pclk)) { | ||||||
|  | 		dev_err(&pdev->dev, "pclk clock not found.\n"); | ||||||
|  | 		ret = PTR_ERR(xspi->pclk); | ||||||
|  | 		goto remove_master; | ||||||
|  | 	} | ||||||
|  | 
 | ||||||
|  | 	xspi->ref_clk = devm_clk_get(&pdev->dev, "ref_clk"); | ||||||
|  | 	if (IS_ERR(xspi->ref_clk)) { | ||||||
|  | 		dev_err(&pdev->dev, "ref_clk clock not found.\n"); | ||||||
|  | 		ret = PTR_ERR(xspi->ref_clk); | ||||||
|  | 		goto remove_master; | ||||||
|  | 	} | ||||||
|  | 
 | ||||||
|  | 	ret = clk_prepare_enable(xspi->pclk); | ||||||
|  | 	if (ret) { | ||||||
|  | 		dev_err(&pdev->dev, "Unable to enable APB clock.\n"); | ||||||
|  | 		goto remove_master; | ||||||
|  | 	} | ||||||
|  | 
 | ||||||
|  | 	ret = clk_prepare_enable(xspi->ref_clk); | ||||||
|  | 	if (ret) { | ||||||
|  | 		dev_err(&pdev->dev, "Unable to enable device clock.\n"); | ||||||
|  | 		goto clk_dis_apb; | ||||||
|  | 	} | ||||||
|  | 
 | ||||||
|  | 	/* SPI controller initializations */ | ||||||
|  | 	cdns_spi_init_hw(xspi); | ||||||
|  | 
 | ||||||
|  | 	irq = platform_get_irq(pdev, 0); | ||||||
|  | 	if (irq <= 0) { | ||||||
|  | 		ret = -ENXIO; | ||||||
|  | 		dev_err(&pdev->dev, "irq number is invalid\n"); | ||||||
|  | 		goto remove_master; | ||||||
|  | 	} | ||||||
|  | 
 | ||||||
|  | 	ret = devm_request_irq(&pdev->dev, irq, cdns_spi_irq, | ||||||
|  | 			       0, pdev->name, master); | ||||||
|  | 	if (ret != 0) { | ||||||
|  | 		ret = -ENXIO; | ||||||
|  | 		dev_err(&pdev->dev, "request_irq failed\n"); | ||||||
|  | 		goto remove_master; | ||||||
|  | 	} | ||||||
|  | 
 | ||||||
|  | 	ret = of_property_read_u32(pdev->dev.of_node, "num-cs", &num_cs); | ||||||
|  | 
 | ||||||
|  | 	if (ret < 0) | ||||||
|  | 		master->num_chipselect = CDNS_SPI_DEFAULT_NUM_CS; | ||||||
|  | 	else | ||||||
|  | 		master->num_chipselect = num_cs; | ||||||
|  | 
 | ||||||
|  | 	ret = of_property_read_u32(pdev->dev.of_node, "is-decoded-cs", | ||||||
|  | 				   &xspi->is_decoded_cs); | ||||||
|  | 
 | ||||||
|  | 	if (ret < 0) | ||||||
|  | 		xspi->is_decoded_cs = 0; | ||||||
|  | 
 | ||||||
|  | 	master->prepare_transfer_hardware = cdns_prepare_transfer_hardware; | ||||||
|  | 	master->transfer_one = cdns_transfer_one; | ||||||
|  | 	master->unprepare_transfer_hardware = cdns_unprepare_transfer_hardware; | ||||||
|  | 	master->set_cs = cdns_spi_chipselect; | ||||||
|  | 	master->mode_bits = SPI_CPOL | SPI_CPHA; | ||||||
|  | 
 | ||||||
|  | 	/* Set to default valid value */ | ||||||
|  | 	master->max_speed_hz = clk_get_rate(xspi->ref_clk) / 4; | ||||||
|  | 	xspi->speed_hz = master->max_speed_hz; | ||||||
|  | 
 | ||||||
|  | 	master->bits_per_word_mask = SPI_BPW_MASK(8); | ||||||
|  | 
 | ||||||
|  | 	ret = spi_register_master(master); | ||||||
|  | 	if (ret) { | ||||||
|  | 		dev_err(&pdev->dev, "spi_register_master failed\n"); | ||||||
|  | 		goto clk_dis_all; | ||||||
|  | 	} | ||||||
|  | 
 | ||||||
|  | 	return ret; | ||||||
|  | 
 | ||||||
|  | clk_dis_all: | ||||||
|  | 	clk_disable_unprepare(xspi->ref_clk); | ||||||
|  | clk_dis_apb: | ||||||
|  | 	clk_disable_unprepare(xspi->pclk); | ||||||
|  | remove_master: | ||||||
|  | 	spi_master_put(master); | ||||||
|  | 	return ret; | ||||||
|  | } | ||||||
|  | 
 | ||||||
|  | /**
 | ||||||
|  |  * cdns_spi_remove - Remove method for the SPI driver | ||||||
|  |  * @pdev:	Pointer to the platform_device structure | ||||||
|  |  * | ||||||
|  |  * This function is called if a device is physically removed from the system or | ||||||
|  |  * if the driver module is being unloaded. It frees all resources allocated to | ||||||
|  |  * the device. | ||||||
|  |  * | ||||||
|  |  * Return:	0 on success and error value on error | ||||||
|  |  */ | ||||||
|  | static int cdns_spi_remove(struct platform_device *pdev) | ||||||
|  | { | ||||||
|  | 	struct spi_master *master = platform_get_drvdata(pdev); | ||||||
|  | 	struct cdns_spi *xspi = spi_master_get_devdata(master); | ||||||
|  | 
 | ||||||
|  | 	cdns_spi_write(xspi, CDNS_SPI_ER_OFFSET, | ||||||
|  | 		       CDNS_SPI_ER_DISABLE_MASK); | ||||||
|  | 
 | ||||||
|  | 	clk_disable_unprepare(xspi->ref_clk); | ||||||
|  | 	clk_disable_unprepare(xspi->pclk); | ||||||
|  | 
 | ||||||
|  | 	spi_unregister_master(master); | ||||||
|  | 
 | ||||||
|  | 	return 0; | ||||||
|  | } | ||||||
|  | 
 | ||||||
|  | /**
 | ||||||
|  |  * cdns_spi_suspend - Suspend method for the SPI driver | ||||||
|  |  * @dev:	Address of the platform_device structure | ||||||
|  |  * | ||||||
|  |  * This function disables the SPI controller and | ||||||
|  |  * changes the driver state to "suspend" | ||||||
|  |  * | ||||||
|  |  * Return:	Always 0 | ||||||
|  |  */ | ||||||
|  | static int __maybe_unused cdns_spi_suspend(struct device *dev) | ||||||
|  | { | ||||||
|  | 	struct platform_device *pdev = container_of(dev, | ||||||
|  | 			struct platform_device, dev); | ||||||
|  | 	struct spi_master *master = platform_get_drvdata(pdev); | ||||||
|  | 	struct cdns_spi *xspi = spi_master_get_devdata(master); | ||||||
|  | 
 | ||||||
|  | 	spi_master_suspend(master); | ||||||
|  | 
 | ||||||
|  | 	clk_disable_unprepare(xspi->ref_clk); | ||||||
|  | 
 | ||||||
|  | 	clk_disable_unprepare(xspi->pclk); | ||||||
|  | 
 | ||||||
|  | 	return 0; | ||||||
|  | } | ||||||
|  | 
 | ||||||
|  | /**
 | ||||||
|  |  * cdns_spi_resume - Resume method for the SPI driver | ||||||
|  |  * @dev:	Address of the platform_device structure | ||||||
|  |  * | ||||||
|  |  * This function changes the driver state to "ready" | ||||||
|  |  * | ||||||
|  |  * Return:	0 on success and error value on error | ||||||
|  |  */ | ||||||
|  | static int __maybe_unused cdns_spi_resume(struct device *dev) | ||||||
|  | { | ||||||
|  | 	struct platform_device *pdev = container_of(dev, | ||||||
|  | 			struct platform_device, dev); | ||||||
|  | 	struct spi_master *master = platform_get_drvdata(pdev); | ||||||
|  | 	struct cdns_spi *xspi = spi_master_get_devdata(master); | ||||||
|  | 	int ret = 0; | ||||||
|  | 
 | ||||||
|  | 	ret = clk_prepare_enable(xspi->pclk); | ||||||
|  | 	if (ret) { | ||||||
|  | 		dev_err(dev, "Cannot enable APB clock.\n"); | ||||||
|  | 		return ret; | ||||||
|  | 	} | ||||||
|  | 
 | ||||||
|  | 	ret = clk_prepare_enable(xspi->ref_clk); | ||||||
|  | 	if (ret) { | ||||||
|  | 		dev_err(dev, "Cannot enable device clock.\n"); | ||||||
|  | 		clk_disable(xspi->pclk); | ||||||
|  | 		return ret; | ||||||
|  | 	} | ||||||
|  | 	spi_master_resume(master); | ||||||
|  | 
 | ||||||
|  | 	return 0; | ||||||
|  | } | ||||||
|  | 
 | ||||||
|  | static SIMPLE_DEV_PM_OPS(cdns_spi_dev_pm_ops, cdns_spi_suspend, | ||||||
|  | 			 cdns_spi_resume); | ||||||
|  | 
 | ||||||
|  | static struct of_device_id cdns_spi_of_match[] = { | ||||||
|  | 	{ .compatible = "xlnx,zynq-spi-r1p6" }, | ||||||
|  | 	{ .compatible = "cdns,spi-r1p6" }, | ||||||
|  | 	{ /* end of table */ } | ||||||
|  | }; | ||||||
|  | MODULE_DEVICE_TABLE(of, cdns_spi_of_match); | ||||||
|  | 
 | ||||||
|  | /* cdns_spi_driver - This structure defines the SPI subsystem platform driver */ | ||||||
|  | static struct platform_driver cdns_spi_driver = { | ||||||
|  | 	.probe	= cdns_spi_probe, | ||||||
|  | 	.remove	= cdns_spi_remove, | ||||||
|  | 	.driver = { | ||||||
|  | 		.name = CDNS_SPI_NAME, | ||||||
|  | 		.owner = THIS_MODULE, | ||||||
|  | 		.of_match_table = cdns_spi_of_match, | ||||||
|  | 		.pm = &cdns_spi_dev_pm_ops, | ||||||
|  | 	}, | ||||||
|  | }; | ||||||
|  | 
 | ||||||
|  | module_platform_driver(cdns_spi_driver); | ||||||
|  | 
 | ||||||
|  | MODULE_AUTHOR("Xilinx, Inc."); | ||||||
|  | MODULE_DESCRIPTION("Cadence SPI driver"); | ||||||
|  | MODULE_LICENSE("GPL"); | ||||||
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		Reference in a new issue
	
	 Harini Katakam
						Harini Katakam