From 5bfa26ca1332780dfeeabafd7f169fc6fb48ba30 Mon Sep 17 00:00:00 2001 From: Haavard Skinnemoen Date: Tue, 6 Jan 2009 14:41:42 -0800 Subject: atmel_spi: clean up SPIv1 quirk handling Currently, we have a flag called "new_1" which is basically equivalent to cpu_is_at91rm9200(). The latter is also called directly a few places. Clean up this mess by introducing a atmel_spi_v2() function for determining the controller version, and move all version dependent code over to use it. This allows us to remove the new_1 flag. Signed-off-by: Haavard Skinnemoen Signed-off-by: David Brownell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/spi/atmel_spi.c | 40 ++++++++++++++++++++++------------------ 1 file changed, 22 insertions(+), 18 deletions(-) (limited to 'drivers/spi/atmel_spi.c') diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c index 8abae4ad0fa..b4f7f1c286e 100644 --- a/drivers/spi/atmel_spi.c +++ b/drivers/spi/atmel_spi.c @@ -30,13 +30,6 @@ * The core SPI transfer engine just talks to a register bank to set up * DMA transfers; transfer queue progress is driven by IRQs. The clock * framework provides the base clock, subdivided for each spi_device. - * - * Newer controllers, marked with "new_1" flag, have: - * - CR.LASTXFER - * - SPI_MR.DIV32 may become FDIV or must-be-zero (here: always zero) - * - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs) - * - SPI_CSRx.CSAAT - * - SPI_CSRx.SBCR allows faster clocking */ struct atmel_spi { spinlock_t lock; @@ -45,7 +38,6 @@ struct atmel_spi { int irq; struct clk *clk; struct platform_device *pdev; - unsigned new_1:1; struct spi_device *stay; u8 stopping; @@ -62,6 +54,23 @@ struct atmel_spi { #define BUFFER_SIZE PAGE_SIZE #define INVALID_DMA_ADDRESS 0xffffffff +/* + * Version 2 of the SPI controller has + * - CR.LASTXFER + * - SPI_MR.DIV32 may become FDIV or must-be-zero (here: always zero) + * - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs) + * - SPI_CSRx.CSAAT + * - SPI_CSRx.SBCR allows faster clocking + * + * We can determine the controller version by reading the VERSION + * register, but I haven't checked that it exists on all chips, and + * this is cheaper anyway. + */ +static bool atmel_spi_is_v2(void) +{ + return !cpu_is_at91rm9200(); +} + /* * Earlier SPI controllers (e.g. on at91rm9200) have a design bug whereby * they assume that spi slave device state will not change on deselect, so @@ -105,7 +114,7 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi) gpio, active ? " (high)" : "", mr); - if (!(cpu_is_at91rm9200() && spi->chip_select == 0)) + if (atmel_spi_is_v2() || spi->chip_select != 0) gpio_set_value(gpio, active); spi_writel(as, MR, mr); } @@ -129,7 +138,7 @@ static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi) gpio, active ? " (low)" : "", mr); - if (!(cpu_is_at91rm9200() && spi->chip_select == 0)) + if (atmel_spi_is_v2() || spi->chip_select != 0) gpio_set_value(gpio, !active); } @@ -536,19 +545,16 @@ static int atmel_spi_setup(struct spi_device *spi) } /* see notes above re chipselect */ - if (cpu_is_at91rm9200() + if (!atmel_spi_is_v2() && spi->chip_select == 0 && (spi->mode & SPI_CS_HIGH)) { dev_dbg(&spi->dev, "setup: can't be active-high\n"); return -EINVAL; } - /* - * Pre-new_1 chips start out at half the peripheral - * bus speed. - */ + /* v1 chips start out at half the peripheral bus speed. */ bus_hz = clk_get_rate(as->clk); - if (!as->new_1) + if (!atmel_spi_is_v2()) bus_hz /= 2; if (spi->max_speed_hz) { @@ -755,8 +761,6 @@ static int __init atmel_spi_probe(struct platform_device *pdev) goto out_free_buffer; as->irq = irq; as->clk = clk; - if (!cpu_is_at91rm9200()) - as->new_1 = 1; ret = request_irq(irq, atmel_spi_interrupt, 0, pdev->dev.bus_id, master); -- cgit v1.2.3-70-g09d2 From 5ee36c989831ab720eee282521462cce0a3c4900 Mon Sep 17 00:00:00 2001 From: Haavard Skinnemoen Date: Tue, 6 Jan 2009 14:41:43 -0800 Subject: spi: atmel_spi update chipselect handling This solves several issues: * It fixes the wrong idle clock polarity issue in a cleaner and less expensive way. * It handles the AT32AP7000 errata "SPI Chip Select 0 BITS field overrides other Chip Selects". Other chips, e.g. AT91SAM9261, have similar issues. Currently, the AT91RM9200 code path is left alone. But it might be interesting to try the same technique on RM9200 using a different CSR register. [dbrownell@users.sourceforge.net: restore debug message for activation] Signed-off-by: Haavard Skinnemoen Signed-off-by: David Brownell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/spi/atmel_spi.c | 93 +++++++++++++++++++++++++++++++++++-------------- 1 file changed, 67 insertions(+), 26 deletions(-) (limited to 'drivers/spi/atmel_spi.c') diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c index b4f7f1c286e..5e39bac9c51 100644 --- a/drivers/spi/atmel_spi.c +++ b/drivers/spi/atmel_spi.c @@ -51,6 +51,12 @@ struct atmel_spi { dma_addr_t buffer_dma; }; +/* Controller-specific per-slave state */ +struct atmel_spi_device { + unsigned int npcs_pin; + u32 csr; +}; + #define BUFFER_SIZE PAGE_SIZE #define INVALID_DMA_ADDRESS 0xffffffff @@ -89,39 +95,58 @@ static bool atmel_spi_is_v2(void) * Master on Chip Select 0.") No workaround exists for that ... so for * nCS0 on that chip, we (a) don't use the GPIO, (b) can't support CS_HIGH, * and (c) will trigger that first erratum in some cases. + * + * TODO: Test if the atmel_spi_is_v2() branch below works on + * AT91RM9200 if we use some other register than CSR0. However, don't + * do this unconditionally since AP7000 has an errata where the BITS + * field in CSR0 overrides all other CSRs. */ static void cs_activate(struct atmel_spi *as, struct spi_device *spi) { - unsigned gpio = (unsigned) spi->controller_data; + struct atmel_spi_device *asd = spi->controller_state; unsigned active = spi->mode & SPI_CS_HIGH; u32 mr; - int i; - u32 csr; - u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0; - - /* Make sure clock polarity is correct */ - for (i = 0; i < spi->master->num_chipselect; i++) { - csr = spi_readl(as, CSR0 + 4 * i); - if ((csr ^ cpol) & SPI_BIT(CPOL)) - spi_writel(as, CSR0 + 4 * i, csr ^ SPI_BIT(CPOL)); - } - mr = spi_readl(as, MR); - mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr); + if (atmel_spi_is_v2()) { + /* + * Always use CSR0. This ensures that the clock + * switches to the correct idle polarity before we + * toggle the CS. + */ + spi_writel(as, CSR0, asd->csr); + spi_writel(as, MR, SPI_BF(PCS, 0x0e) | SPI_BIT(MODFDIS) + | SPI_BIT(MSTR)); + mr = spi_readl(as, MR); + gpio_set_value(asd->npcs_pin, active); + } else { + u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0; + int i; + u32 csr; + + /* Make sure clock polarity is correct */ + for (i = 0; i < spi->master->num_chipselect; i++) { + csr = spi_readl(as, CSR0 + 4 * i); + if ((csr ^ cpol) & SPI_BIT(CPOL)) + spi_writel(as, CSR0 + 4 * i, + csr ^ SPI_BIT(CPOL)); + } + + mr = spi_readl(as, MR); + mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr); + if (spi->chip_select != 0) + gpio_set_value(asd->npcs_pin, active); + spi_writel(as, MR, mr); + } dev_dbg(&spi->dev, "activate %u%s, mr %08x\n", - gpio, active ? " (high)" : "", + asd->npcs_pin, active ? " (high)" : "", mr); - - if (atmel_spi_is_v2() || spi->chip_select != 0) - gpio_set_value(gpio, active); - spi_writel(as, MR, mr); } static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi) { - unsigned gpio = (unsigned) spi->controller_data; + struct atmel_spi_device *asd = spi->controller_state; unsigned active = spi->mode & SPI_CS_HIGH; u32 mr; @@ -135,11 +160,11 @@ static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi) } dev_dbg(&spi->dev, "DEactivate %u%s, mr %08x\n", - gpio, active ? " (low)" : "", + asd->npcs_pin, active ? " (low)" : "", mr); if (atmel_spi_is_v2() || spi->chip_select != 0) - gpio_set_value(gpio, !active); + gpio_set_value(asd->npcs_pin, !active); } static inline int atmel_spi_xfer_is_last(struct spi_message *msg, @@ -511,6 +536,7 @@ atmel_spi_interrupt(int irq, void *dev_id) static int atmel_spi_setup(struct spi_device *spi) { struct atmel_spi *as; + struct atmel_spi_device *asd; u32 scbr, csr; unsigned int bits = spi->bits_per_word; unsigned long bus_hz; @@ -595,11 +621,20 @@ static int atmel_spi_setup(struct spi_device *spi) /* chipselect must have been muxed as GPIO (e.g. in board setup) */ npcs_pin = (unsigned int)spi->controller_data; - if (!spi->controller_state) { + asd = spi->controller_state; + if (!asd) { + asd = kzalloc(sizeof(struct atmel_spi_device), GFP_KERNEL); + if (!asd) + return -ENOMEM; + ret = gpio_request(npcs_pin, spi->dev.bus_id); - if (ret) + if (ret) { + kfree(asd); return ret; - spi->controller_state = (void *)npcs_pin; + } + + asd->npcs_pin = npcs_pin; + spi->controller_state = asd; gpio_direction_output(npcs_pin, !(spi->mode & SPI_CS_HIGH)); } else { unsigned long flags; @@ -611,11 +646,14 @@ static int atmel_spi_setup(struct spi_device *spi) spin_unlock_irqrestore(&as->lock, flags); } + asd->csr = csr; + dev_dbg(&spi->dev, "setup: %lu Hz bpw %u mode 0x%x -> csr%d %08x\n", bus_hz / scbr, bits, spi->mode, spi->chip_select, csr); - spi_writel(as, CSR0 + 4 * spi->chip_select, csr); + if (!atmel_spi_is_v2()) + spi_writel(as, CSR0 + 4 * spi->chip_select, csr); return 0; } @@ -690,10 +728,11 @@ static int atmel_spi_transfer(struct spi_device *spi, struct spi_message *msg) static void atmel_spi_cleanup(struct spi_device *spi) { struct atmel_spi *as = spi_master_get_devdata(spi->master); + struct atmel_spi_device *asd = spi->controller_state; unsigned gpio = (unsigned) spi->controller_data; unsigned long flags; - if (!spi->controller_state) + if (!asd) return; spin_lock_irqsave(&as->lock, flags); @@ -703,7 +742,9 @@ static void atmel_spi_cleanup(struct spi_device *spi) } spin_unlock_irqrestore(&as->lock, flags); + spi->controller_state = NULL; gpio_free(gpio); + kfree(asd); } /*-------------------------------------------------------------------------*/ -- cgit v1.2.3-70-g09d2