Re: [PATCH 1/4] timer: imx-gpt: Add timer support for i.MX SoCs family

On 2/7/21 7:24 PM, Jesse Taube wrote:

This timer driver is using GPT Timer (General Purpose Timer) available on almost all i.MX SoCs family.

Signed-off-by: Giulio Benetti giulio.benetti@benettiengineering.com Cc: Stefano Babic tsbabic@denx.de Cc: Giulio Benetti giulio.benetti@benettiengineering.com Cc: Jesse Taube mr.bossman075@gmail.com

---

drivers/timer/Kconfig | 7 ++ drivers/timer/Makefile | 1 + drivers/timer/imx-gpt-timer.c | 118 ++++++++++++++++++++++++++++++++++ 3 files changed, 126 insertions(+) create mode 100644 drivers/timer/imx-gpt-timer.c

diff --git a/drivers/timer/Kconfig b/drivers/timer/Kconfig index 80743a2551..ee81dfa776 100644 --- a/drivers/timer/Kconfig +++ b/drivers/timer/Kconfig @@ -227,4 +227,11 @@ config MCHP_PIT64B_TIMER Select this to enable support for Microchip 64-bit periodic interval timer.

+config IMX_GPT_TIMER

• bool "NXP i.MX GPT timer support"
• depends on TIMER
• help

•  Select this to enable support for the timer found on
  

•  NXP i.MX devices.
  

• endmenu

diff --git a/drivers/timer/Makefile b/drivers/timer/Makefile index eb5c48cc6c..e214ba7268 100644 --- a/drivers/timer/Makefile +++ b/drivers/timer/Makefile @@ -25,3 +25,4 @@ obj-$(CONFIG_STM32_TIMER) += stm32_timer.o obj-$(CONFIG_X86_TSC_TIMER) += tsc_timer.o obj-$(CONFIG_MTK_TIMER) += mtk_timer.o obj-$(CONFIG_MCHP_PIT64B_TIMER) += mchp-pit64b-timer.o +obj-$(CONFIG_IMX_GPT_TIMER) += imx-gpt-timer.o diff --git a/drivers/timer/imx-gpt-timer.c b/drivers/timer/imx-gpt-timer.c new file mode 100644 index 0000000000..c4e8c12a42 --- /dev/null +++ b/drivers/timer/imx-gpt-timer.c @@ -0,0 +1,118 @@ +// SPDX-License-Identifier: GPL-2.0+ +/*

• • Copyright (C) 2020
• • Author(s): Giulio Benetti giulio.benetti@benettiengineering.com
• */

+#include <common.h> +#include <clk.h> +#include <dm.h> +#include <fdtdec.h> +#include <timer.h> +#include <dm/device_compat.h>

+#include <asm/io.h>

+#define GPT_CR_SWR 0x00008000

+struct imx_gpt_timer_regs {

Typical style is to use offsets for this. Though I don't think it matters.

• u32 cr;
• u32 pr;
• u32 sr;
• u32 ir;
• u32 ocr1;
• u32 ocr2;
• u32 ocr3;
• u32 icr1;
• u32 icr2;
• u32 cnt;

+};

+struct imx_gpt_timer_priv {

• struct imx_gpt_timer_regs *base;

+};

+static int imx_gpt_timer_get_count(struct udevice *dev, u64 *count)

This signature is incorrect since 8af7bb914f ("timer: Return count from timer_ops.get_count"). Please rebase onto u-boot/master.

+{

• struct imx_gpt_timer_priv *priv = dev_get_priv(dev);
• struct imx_gpt_timer_regs *regs = priv->base;
• *count = readl(&regs->cnt);
• return 0;

+}

+static int imx_gpt_timer_probe(struct udevice *dev) +{

• struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
• struct imx_gpt_timer_priv *priv = dev_get_priv(dev);
• struct imx_gpt_timer_regs *regs;
• struct clk clk;
• fdt_addr_t addr;
• u32 prescaler;
• u32 rate, pr;
• int ret;
• addr = dev_read_addr(dev);
• if (addr == FDT_ADDR_T_NONE)

• return -EINVAL;
  

• priv->base = (struct imx_gpt_timer_regs *)addr;
• /* TODO: Retrieve clock-source */
• /* TODO: Retrieve prescaler */
• ret = clk_get_by_index(dev, 0, &clk);
• if (ret < 0)

• return ret;
  

• ret = clk_enable(&clk);
• if (ret) {

• dev_err(dev, "failed to enable clock\n");
  

• return ret;
  

• }
• regs = priv->base;
• /* Reset the timer */
• setbits_le32(&regs->cr, GPT_CR_SWR);
• /* Wait for timer to finish reset */
• while(readl(&regs->cr) & GPT_CR_SWR)

• ;
  

• /* Get timer clock rate */
• rate = clk_get_rate(&clk);
• /* we set timer prescaler to obtain a 1MHz timer counter frequency */

+// pr = (rate / CONFIG_SYS_HZ_CLOCK) - 1;

Should this be uncommented?

• writel(pr, &regs->pr);
• /* Set timer frequency to 1MHz */
• uc_priv->clock_rate = rate / prescaler;
• /* start timer */

+// setbits_le32(&regs->cr1, CR1_CEN);

ditto

• return 0;

+}

+static const struct timer_ops imx_gpt_timer_ops = {

• .get_count = imx_gpt_timer_get_count,

+};

+static const struct udevice_id imx_gpt_timer_ids[] = {

• { .compatible = "fsl,imxrt-gpt" },

I believe this clock is present on other i.MX processors as well (not just RT ones). Though those typically can use the armv7 cp15 clock.

--Sean

• {}

+};

+U_BOOT_DRIVER(imx_gpt_timer) = {

• .name = "imx_gpt_timer",
• .id = UCLASS_TIMER,
• .of_match = imx_gpt_timer_ids,
• .priv_auto_alloc_size = sizeof(struct imx_gpt_timer_priv),
• .probe = imx_gpt_timer_probe,
• .ops = &imx_gpt_timer_ops,

+};