[U-Boot] [PATCH v6 08/10] mips: ath79: add spi driver

Wills Wang
2016-01-09T17:51:29Z

On 01/06/2016 08:16 PM, Jagan Teki wrote:
> On 4 January 2016 at 16:44, Wills Wang <wills.wang@live.com> wrote:
>> Signed-off-by: Wills Wang <wills.wang@live.com>
>> ---
>>
>> Changes in v6:
>> - Add rrw_delay in ath79_spi_priv for more accurate timing
>> - Remove ath79_spi_delay
>> - Calculate delay in ath79_spi_set_speed
>>
>> Changes in v5:
>> - remove ar933x_spi_platdata
>> - Import document "spi-ath79.txt" from kernel
>> - Add delay for bitbang operation
>>
>> Changes in v4:
>> - Use get_bus_freq instead of hardcode in SPI driver
>>
>> Changes in v3:
>> - Convert spi driver to driver model
>> - Same code style convertion
>>
>> Changes in v2:
>> - Add a compatible spi driver
>>
>> doc/device-tree-bindings/spi/spi-ath79.txt | 19 +++
>> drivers/spi/Kconfig | 8 +
>> drivers/spi/Makefile | 1 +
>> drivers/spi/ath79_spi.c | 230 +++++++++++++++++++++++++++++
>> 4 files changed, 258 insertions(+)
>> create mode 100644 doc/device-tree-bindings/spi/spi-ath79.txt
>> create mode 100644 drivers/spi/ath79_spi.c
>>
>> diff --git a/doc/device-tree-bindings/spi/spi-ath79.txt b/doc/device-tree-bindings/spi/spi-ath79.txt
>> new file mode 100644
>> index 0000000..3fd9d67
>> --- /dev/null
>> +++ b/doc/device-tree-bindings/spi/spi-ath79.txt
>> @@ -0,0 +1,19 @@
>> +Binding for Qualcomm Atheros AR7xxx/AR9xxx SPI controller
>> +
>> +Required properties:
>> +- compatible: has to be "qca,<soc-type>-spi", "qca,ar7100-spi" as fallback.
>> +- reg: Base address and size of the controllers memory area
>> +- #address-cells: <1>, as required by generic SPI binding.
>> +- #size-cells: <0>, also as required by generic SPI binding.
>> +
>> +Child nodes as per the generic SPI binding.
>> +
>> +Example:
>> +
>> + spi at 1f000000 {
>> + compatible = "qca,ar9132-spi", "qca,ar7100-spi";
>> + reg = <0x1f000000 0x10>;
>> +
>> + #address-cells = <1>;
>> + #size-cells = <0>;
>> + };
>> diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
>> index 2cdb110..0ab2741 100644
>> --- a/drivers/spi/Kconfig
>> +++ b/drivers/spi/Kconfig
>> @@ -23,6 +23,14 @@ config ALTERA_SPI
>> IP core. Please find details on the "Embedded Peripherals IP
>> User Guide" of Altera.
>>
>> +config ATH79_SPI
>> + bool "Atheros SPI driver"
>> + help
>> + Enable the Atheros ar7xxx/ar9xxx SoC SPI driver, it was used
>> + to access SPI NOR flash and other SPI peripherals. This driver
>> + uses driver model and requires a device tree binding to operate.
>> + please refer to doc/device-tree-bindings/spi/spi-ath79.txt.
>> +
>> config CADENCE_QSPI
>> bool "Cadence QSPI driver"
>> help
>> diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
>> index 3eca745..7fb2926 100644
>> --- a/drivers/spi/Makefile
>> +++ b/drivers/spi/Makefile
>> @@ -17,6 +17,7 @@ endif
>>
>> obj-$(CONFIG_ALTERA_SPI) += altera_spi.o
>> obj-$(CONFIG_ARMADA100_SPI) += armada100_spi.o
>> +obj-$(CONFIG_ATH79_SPI) += ath79_spi.o
>> obj-$(CONFIG_ATMEL_DATAFLASH_SPI) += atmel_dataflash_spi.o
>> obj-$(CONFIG_ATMEL_SPI) += atmel_spi.o
>> obj-$(CONFIG_BFIN_SPI) += bfin_spi.o
>> diff --git a/drivers/spi/ath79_spi.c b/drivers/spi/ath79_spi.c
>> new file mode 100644
>> index 0000000..3912332
>> --- /dev/null
>> +++ b/drivers/spi/ath79_spi.c
>> @@ -0,0 +1,230 @@
>> +/*
>> + * (C) Copyright 2015
>> + * Wills Wang, <wills.wang@live.com>
> Append this above the line with space.
Where?
>> + *
>> + * SPDX-License-Identifier: GPL-2.0+
>> + */
>> +
>> +#include <common.h>
>> +#include <spi.h>
>> +#include <dm.h>
>> +#include <div64.h>
>> +#include <errno.h>
>> +#include <asm/io.h>
>> +#include <asm/addrspace.h>
>> +#include <asm/types.h>
>> +#include <mach/ar71xx_regs.h>
> Does this regs common for ar71xx or for spi?
Yes
>> +
>> +/* CLOCK_DIVIDER = 3 (SPI clock = 200 / 8 ~ 25 MHz) */
>> +#define ATH79_SPI_CLK_DIV(x) (((x) >> 1) - 1)
>> +#define ATH79_SPI_RRW_DELAY_FACTOR 12000
>> +#define MHZ (1000 * 1000)
> Rename MHZ to ATH79_SPI_MHZ or similar
Ok.
>> +
>> +struct ath79_spi_priv {
>> + void __iomem *regs;
>> + u32 rrw_delay;
>> +};
>> +
>> +static inline u32 ath79_spi_read(struct udevice *bus, u32 offset)
>> +{
>> + struct ath79_spi_priv *priv = dev_get_priv(bus);
>> + return readl(priv->regs + offset);
>> +}
>> +
>> +static inline void ath79_spi_write(struct udevice *bus,
>> + u32 val, u32 offset)
>> +{
>> + struct ath79_spi_priv *priv = dev_get_priv(bus);
>> + writel(val, priv->regs + offset);
>> +}
> Instead of adding these new read|write calls, use readl and writel
> directly since we can get bus any where using dev
>
There is an inline function.
>> +
>> +static int ath79_spi_claim_bus(struct udevice *dev)
>> +{
>> + return 0;
>> +}
>> +
>> +static int ath79_spi_release_bus(struct udevice *dev)
>> +{
>> + return 0;
>> +}
>> +
>> +static int ath79_spi_xfer(struct udevice *dev, unsigned int bitlen,
>> + const void *dout, void *din, unsigned long flags)
>> +{
>> + struct udevice *bus = dev->parent;
>> + struct ath79_spi_priv *priv = dev_get_priv(bus);
>> + struct dm_spi_slave_platdata *slave = dev_get_parent_platdata(dev);
>> + u8 *rx = din;
>> + const u8 *tx = dout;
>> + u8 curbyte, curbitlen, restbits;
>> + u32 bytes = bitlen / 8;
>> + u32 out, in;
>> + u64 tick;
>> +
>> +
>> + if (flags & SPI_XFER_BEGIN) {
>> + ath79_spi_write(bus, AR71XX_SPI_FS_GPIO, AR71XX_SPI_REG_FS);
>> + ath79_spi_write(bus, AR71XX_SPI_IOC_CS_ALL, AR71XX_SPI_REG_IOC);
> Move this code to local spi_cs_activate and use clrbits_xxx or
> setbits_xxxx if required for just to activate or deactivate specific
> bits.
Ok.
>> + }
>> +
>> + restbits = (bitlen % 8);
>> + if (restbits)
>> + bytes++;
>> +
>> + out = AR71XX_SPI_IOC_CS_ALL & ~(AR71XX_SPI_IOC_CS(slave->cs));
>> + while (bytes > 0) {
>> + bytes--;
>> + curbyte = 0;
>> + if (tx)
>> + curbyte = *tx++;
>> +
>> + if (restbits && !bytes) {
>> + curbitlen = restbits;
>> + curbyte <<= 8 - restbits;
>> + } else {
>> + curbitlen = 8;
>> + }
>> +
>> + for (curbyte <<= (8 - curbitlen); curbitlen; curbitlen--) {
>> + if (curbyte & 0x80)
>> + out |= AR71XX_SPI_IOC_DO;
>> + else
>> + out &= ~(AR71XX_SPI_IOC_DO);
>> +
>> + ath79_spi_write(bus, out, AR71XX_SPI_REG_IOC);
>> +
>> + /* delay for low level */
>> + if (priv->rrw_delay) {
>> + tick = get_ticks() + priv->rrw_delay;
>> + while (get_ticks() < tick)
>> + /*NOP*/;
>> + }
>> +
>> + ath79_spi_write(bus, out | AR71XX_SPI_IOC_CLK,
>> + AR71XX_SPI_REG_IOC);
>> +
>> + /* delay for high level */
>> + if (priv->rrw_delay) {
>> + tick = get_ticks() + priv->rrw_delay;
>> + while (get_ticks() < tick)
>> + /*NOP*/;
> Better to do timeout check instead of infinite while.
I think it is a timeout check.
>> + }
>> +
>> + curbyte <<= 1;
>> + }
>> +
>> + if (!bytes)
>> + ath79_spi_write(bus, out, AR71XX_SPI_REG_IOC);
>> +
>> + in = ath79_spi_read(bus, AR71XX_SPI_REG_RDS);
>> + if (rx) {
>> + if (restbits && !bytes)
>> + *rx++ = (in << (8 - restbits));
>> + else
>> + *rx++ = in;
>> + }
>> + }
>> +
>> + if (flags & SPI_XFER_END) {
>> + ath79_spi_write(bus, AR71XX_SPI_IOC_CS(slave->cs),
>> + AR71XX_SPI_REG_IOC);
>> + ath79_spi_write(bus, AR71XX_SPI_IOC_CS_ALL, AR71XX_SPI_REG_IOC);
>> + ath79_spi_write(bus, 0, AR71XX_SPI_REG_FS);
> Same as above use spi_cs_deactivate
>
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +
>> +static int ath79_spi_set_speed(struct udevice *bus, uint speed)
>> +{
>> + struct ath79_spi_priv *priv = dev_get_priv(bus);
>> + u32 val, div = 0;
>> + u64 time;
>> +
>> + if (speed)
>> + div = get_bus_freq(0) / speed;
>> +
>> + if (div > 63)
>> + div = 63;
>> +
>> + if (div < 5)
>> + div = 5;
> Where are these div comparisons? please add clear short comment.
The lower limitation is an empirical value, upper limitation is the
maximum value for register filed.
>> +
>> + /* calculate delay */
>> + time = get_tbclk();
>> + do_div(time, speed / 2);
>> + val = ATH79_SPI_RRW_DELAY_FACTOR / (get_bus_freq(0) / MHZ);
>> + if (time > val)
>> + priv->rrw_delay = time - val + 1;
>> + else
>> + priv->rrw_delay = 0;
>> +
>> + ath79_spi_write(bus, AR71XX_SPI_FS_GPIO, AR71XX_SPI_REG_FS);
>> + val = ath79_spi_read(bus, AR71XX_SPI_REG_CTRL);
>> + val &= ~AR71XX_SPI_CTRL_DIV_MASK;
>> + val |= ATH79_SPI_CLK_DIV(div);
>> + ath79_spi_write(bus, val, AR71XX_SPI_REG_CTRL);
>> + ath79_spi_write(bus, 0, AR71XX_SPI_REG_FS);
> This write also for speed setting, does this function doing other than
> speed_setup?
>
Calculate SPI bitbang delay according to speed.
>> + return 0;
>> +}
>> +
>> +static int ath79_spi_set_mode(struct udevice *bus, uint mode)
>> +{
>> + return 0;
>> +}
>> +
>> +static int ath79_spi_probe(struct udevice *bus)
>> +{
>> + struct ath79_spi_priv *priv = dev_get_priv(bus);
>> + fdt_addr_t addr;
>> +
>> + addr = dev_get_addr(bus);
>> + if (addr == FDT_ADDR_T_NONE)
>> + return -EINVAL;
>> +
>> + priv->regs = map_physmem(addr,
>> + AR71XX_SPI_SIZE,
>> + MAP_NOCACHE);
>> +
>> + /* Init SPI Hardware, disable remap, set clock */
>> + ath79_spi_write(bus, AR71XX_SPI_FS_GPIO, AR71XX_SPI_REG_FS);
>> + ath79_spi_write(bus, AR71XX_SPI_CTRL_RD | ATH79_SPI_CLK_DIV(8),
>> + AR71XX_SPI_REG_CTRL);
>> + ath79_spi_write(bus, 0, AR71XX_SPI_REG_FS);
>> +
>> + return 0;
>> +}
>> +
>> +static int ath79_cs_info(struct udevice *bus, uint cs,
>> + struct spi_cs_info *info)
>> +{
>> + /* Always allow activity on CS 0/1/2 */
>> + if (cs >= 3)
>> + return -ENODEV;
>> +
>> + return 0;
>> +}
>> +
>> +static const struct dm_spi_ops ath79_spi_ops = {
>> + .claim_bus = ath79_spi_claim_bus,
>> + .release_bus = ath79_spi_release_bus,
>> + .xfer = ath79_spi_xfer,
>> + .set_speed = ath79_spi_set_speed,
>> + .set_mode = ath79_spi_set_mode,
>> + .cs_info = ath79_cs_info,
>> +};
>> +
>> +static const struct udevice_id ath79_spi_ids[] = {
>> + { .compatible = "qca,ar7100-spi" },
>> + {}
>> +};
>> +
>> +U_BOOT_DRIVER(ath79_spi) = {
>> + .name = "ath79_spi",
>> + .id = UCLASS_SPI,
>> + .of_match = ath79_spi_ids,
>> + .ops = &ath79_spi_ops,
>> + .priv_auto_alloc_size = sizeof(struct ath79_spi_priv),
>> + .probe = ath79_spi_probe,
>> +};
>> --
> thanks!

--
Best Regards
Wills