Re: [PATCH v1 1/1] timer: npcm: Add driver for Nuvoton NPCM SoCs

On 2/7/22 01:02, Stanley Chu wrote:

This driver enables a periodic timer on NPCM SoCs and implements the get_count timer ops.

Signed-off-by: Stanley Chu yschu@nuvoton.com

drivers/timer/Kconfig | 6 ++ drivers/timer/Makefile | 1 + drivers/timer/npcm-timer.c | 111 +++++++++++++++++++++++++++++++++++++ 3 files changed, 118 insertions(+) create mode 100644 drivers/timer/npcm-timer.c

diff --git a/drivers/timer/Kconfig b/drivers/timer/Kconfig index 8913142654..f22c46f44e 100644 --- a/drivers/timer/Kconfig +++ b/drivers/timer/Kconfig @@ -143,6 +143,12 @@ config NOMADIK_MTU_TIMER The MTU provides 4 decrementing free-running timers. At the moment, only the first timer is used by the driver.

+config NPCM_TIMER

• bool "Nuvoton NPCM timer support"
• depends on TIMER
• help

•  Select this to enable a timer on Nuvoton NPCM SoCs.
  

• config OMAP_TIMER bool "Omap timer support" depends on TIMER

diff --git a/drivers/timer/Makefile b/drivers/timer/Makefile index e2bd530eb0..39bda1ea79 100644 --- a/drivers/timer/Makefile +++ b/drivers/timer/Makefile @@ -14,6 +14,7 @@ obj-$(CONFIG_CADENCE_TTC_TIMER) += cadence-ttc.o obj-$(CONFIG_DESIGNWARE_APB_TIMER) += dw-apb-timer.o obj-$(CONFIG_MPC83XX_TIMER) += mpc83xx_timer.o obj-$(CONFIG_NOMADIK_MTU_TIMER) += nomadik-mtu-timer.o +obj-$(CONFIG_NPCM_TIMER) += npcm-timer.o obj-$(CONFIG_OMAP_TIMER) += omap-timer.o obj-$(CONFIG_RENESAS_OSTM_TIMER) += ostm_timer.o obj-$(CONFIG_RISCV_TIMER) += riscv_timer.o diff --git a/drivers/timer/npcm-timer.c b/drivers/timer/npcm-timer.c new file mode 100644 index 0000000000..f7d95d4bfa --- /dev/null +++ b/drivers/timer/npcm-timer.c @@ -0,0 +1,111 @@ +// SPDX-License-Identifier: GPL-2.0+ +/*

• • Copyright (c) 2022 Nuvoton Technology Corp.
• */

+#include <common.h> +#include <clk.h> +#include <dm.h> +#include <timer.h> +#include <asm/io.h>

+#define NPCM_TIMER_CLOCK_RATE 1000000UL /* 1MHz timer */ +#define NPCM_TIMER_INPUT_RATE 25000000UL /* Rate of input clock */ +#define NPCM_TIMER_TDR_MASK GENMASK(23, 0) +#define NPCM_TIMER_MAX_VAL NPCM_TIMER_TDR_MASK /* max counter value */

+/* Register offsets */ +#define TCR0 0x0 /* Timer Control and Status Register */ +#define TICR0 0x8 /* Timer Initial Count Register */ +#define TDR0 0x10 /* Timer Data Register */

+/* TCR fields */ +#define TCR_MODE_PERIODIC BIT(27) +#define TCR_EN BIT(30) +#define TCR_PRESCALE_25 (25 - 1)

Should this be calculated by NPCM_TIMER_INPUT_RATE/NPCM_TIMER_CLOCK_RATE

Also thanks for including me I always love the attention, but I'm not sure why I have been CCed in many of you recent patches is there a reason for this?

Thank you, Jesse Taube

+/*

• • 24-bits down-counting hw timer.
• • last_count: last hw counter value.
• • counter: the value to be returned for get_count ops.
• */

+struct npcm_timer_priv {

• void __iomem *base;
• u32 last_count;
• u64 counter;

+};

+static u64 npcm_timer_get_count(struct udevice *dev) +{

• struct npcm_timer_priv *priv = dev_get_priv(dev);
• u32 val;
• /* The timer is couting down */
• val = readl(priv->base + TDR0) & NPCM_TIMER_TDR_MASK;
• if (val <= priv->last_count)

• priv->counter += priv->last_count - val;
  

• else

• priv->counter += priv->last_count + (NPCM_TIMER_MAX_VAL + 1 - val);
  

• priv->last_count = val;
• return priv->counter;

+}

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

• struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
• struct npcm_timer_priv *priv = dev_get_priv(dev);
• struct clk clk;
• int ret;
• priv->base = dev_read_addr_ptr(dev);
• if (!priv->base)

• return -ENOENT;
  

• priv->counter = 0;
• priv->last_count = 0;
• uc_priv->clock_rate = NPCM_TIMER_CLOCK_RATE;
• if (IS_ENABLED(CONFIG_ARCH_NPCM750)) {

• ret = clk_get_by_index(dev, 0, &clk);
  

• if (ret < 0)
  

• 	return ret;
  

• ret = clk_set_rate(&clk, NPCM_TIMER_INPUT_RATE);
  

• if (ret < 0)
  

• 	return ret;
  

• }
• /*

• * Configure timer and start
  

• * periodic mode
  

• * input clock freq = 25Mhz
  

• * prescale = 25
  

• * timer clock rate = 25Mhz/25
  

• */
  

• writel(0, priv->base + TCR0);
• writel(NPCM_TIMER_MAX_VAL, priv->base + TICR0);
• writel(TCR_EN | TCR_MODE_PERIODIC | TCR_PRESCALE_25,

•       priv->base + TCR0);
  

• return 0;

+}

+static const struct timer_ops npcm_timer_ops = {

• .get_count = npcm_timer_get_count,

+};

+static const struct udevice_id npcm_timer_ids[] = {

• { .compatible = "nuvoton,npcm845-timer" },
• { .compatible = "nuvoton,npcm750-timer" },
• {}

+};

+U_BOOT_DRIVER(npcm_timer) = {

• .name = "npcm_timer",
• .id = UCLASS_TIMER,
• .of_match = npcm_timer_ids,
• .priv_auto = sizeof(struct npcm_timer_priv),
• .probe = npcm_timer_probe,
• .ops = &npcm_timer_ops,
• .flags = DM_FLAG_PRE_RELOC,

+};