From 6edf3152bd4c2bc58e3705872642e282d8b3eeb9 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Mon, 10 Feb 2025 21:44:50 +0200 Subject: pwm: lpss: Clarify the bypass member semantics in struct pwm_lpss_boardinfo Instead of an odd comment, cite the documentation, which says more clearly what's going on with the programming flow on some of the Intel SoCs. Signed-off-by: Andy Shevchenko Reviewed-by: Mika Westerberg --- include/linux/platform_data/x86/pwm-lpss.h | 33 +++++++++++++++++++++++++++--- 1 file changed, 30 insertions(+), 3 deletions(-) (limited to 'include/linux') diff --git a/include/linux/platform_data/x86/pwm-lpss.h b/include/linux/platform_data/x86/pwm-lpss.h index 752c06b47cc8..f0349edb47f4 100644 --- a/include/linux/platform_data/x86/pwm-lpss.h +++ b/include/linux/platform_data/x86/pwm-lpss.h @@ -15,9 +15,36 @@ struct pwm_lpss_boardinfo { unsigned int npwm; unsigned long base_unit_bits; /* - * Some versions of the IP may stuck in the state machine if enable - * bit is not set, and hence update bit will show busy status till - * the reset. For the rest it may be otherwise. + * NOTE: + * Intel Broxton, Apollo Lake, and Gemini Lake have different programming flow. + * + * Initial Enable or First Activation + * 1. Program the base unit and on time divisor values. + * 2. Set the software update bit. + * 3. Poll in a loop on the PWMCTRL bit until software update bit is cleared.+ + * 4. Enable the PWM output by setting PWM Enable. + * 5. Repeat the above steps for the next PWM Module. + * + * Dynamic update while PWM is Enabled + * 1. Program the base unit and on-time divisor values. + * 2. Set the software update bit. + * 3. Repeat the above steps for the next PWM module. + * + * + After setting PWMCTRL register's SW update bit, hardware automatically + * deasserts the SW update bit after a brief delay. It was observed that + * setting of PWM enable is typically done via read-modify-write of the PWMCTRL + * register. If there is no/little delay between setting software update bit + * and setting enable bit via read-modify-write, it is possible that the read + * could return with software enable as 1. In that case, the last write to set + * enable to 1 could also set sw_update to 1. If this happens, sw_update gets + * stuck and the driver code can hang as it explicitly waits for sw_update bit + * to be 0 after setting the enable bit to 1. To avoid this race condition, + * SW should poll on the software update bit to make sure that it is 0 before + * doing the read-modify-write to set the enable bit to 1. + * + * Also, we noted that if sw_update bit was set in step #1 above then when it + * is set again in step #2, sw_update bit never gets cleared and the flow hangs. + * As such, we need to make sure that sw_update bit is 0 when doing step #1. */ bool bypass; /* -- cgit v1.2.3 From 7112c05fff83e15726dd60a10248b76474e3cdf9 Mon Sep 17 00:00:00 2001 From: Xianwei Zhao Date: Wed, 12 Feb 2025 13:20:51 +0800 Subject: pinctrl: pinconf-generic: Add API for pinmux propertity in DTS file When describing pin mux func through pinmux propertity, a standard API is added for support. The pinmux contains pin identification and mux values, which can include multiple pins. And groups configuration use other word. DTS such as: func-name { group_alias: group-name{ pinmux= , ; bias-pull-up; drive-strength-microamp = <4000>; }; }; Signed-off-by: Xianwei Zhao Link: https://lore.kernel.org/20250212-amlogic-pinctrl-v5-2-282bc2516804@amlogic.com Signed-off-by: Linus Walleij --- drivers/pinctrl/pinconf-generic.c | 130 ++++++++++++++++++++++++++++++++ drivers/pinctrl/pinconf.h | 4 + include/linux/pinctrl/pinconf-generic.h | 4 + 3 files changed, 138 insertions(+) (limited to 'include/linux') diff --git a/drivers/pinctrl/pinconf-generic.c b/drivers/pinctrl/pinconf-generic.c index 0b13d7f17b32..b8e5e441e67c 100644 --- a/drivers/pinctrl/pinconf-generic.c +++ b/drivers/pinctrl/pinconf-generic.c @@ -233,6 +233,67 @@ static void parse_dt_cfg(struct device_node *np, } } +/** + * pinconf_generic_parse_dt_pinmux() + * parse the pinmux properties into generic pin mux values. + * @np: node containing the pinmux properties + * @dev: pincontrol core device + * @pid: array with pin identity entries + * @pmux: array with pin mux value entries + * @npins: number of pins + * + * pinmux propertity: mux value [0,7]bits and pin identity [8,31]bits. + */ +int pinconf_generic_parse_dt_pinmux(struct device_node *np, struct device *dev, + unsigned int **pid, unsigned int **pmux, + unsigned int *npins) +{ + unsigned int *pid_t; + unsigned int *pmux_t; + struct property *prop; + unsigned int npins_t, i; + u32 value; + int ret; + + prop = of_find_property(np, "pinmux", NULL); + if (!prop) { + dev_info(dev, "Missing pinmux property\n"); + return -ENOENT; + } + + if (!pid || !pmux || !npins) { + dev_err(dev, "paramers error\n"); + return -EINVAL; + } + + npins_t = prop->length / sizeof(u32); + pid_t = devm_kcalloc(dev, npins_t, sizeof(*pid_t), GFP_KERNEL); + pmux_t = devm_kcalloc(dev, npins_t, sizeof(*pmux_t), GFP_KERNEL); + if (!pid_t || !pmux_t) { + dev_err(dev, "kalloc memory fail\n"); + return -ENOMEM; + } + for (i = 0; i < npins_t; i++) { + ret = of_property_read_u32_index(np, "pinmux", i, &value); + if (ret) { + dev_err(dev, "get pinmux value fail\n"); + goto exit; + } + pmux_t[i] = value & 0xff; + pid_t[i] = (value >> 8) & 0xffffff; + } + *pid = pid_t; + *pmux = pmux_t; + *npins = npins_t; + + return 0; +exit: + devm_kfree(dev, pid_t); + devm_kfree(dev, pmux_t); + return ret; +} +EXPORT_SYMBOL_GPL(pinconf_generic_parse_dt_pinmux); + /** * pinconf_generic_parse_dt_config() * parse the config properties into generic pinconfig values. @@ -295,6 +356,75 @@ out: } EXPORT_SYMBOL_GPL(pinconf_generic_parse_dt_config); +int pinconf_generic_dt_node_to_map_pinmux(struct pinctrl_dev *pctldev, + struct device_node *np, + struct pinctrl_map **map, + unsigned int *num_maps) +{ + struct device *dev = pctldev->dev; + struct device_node *pnode; + unsigned long *configs = NULL; + unsigned int num_configs = 0; + struct property *prop; + unsigned int reserved_maps; + int reserve; + int ret; + + prop = of_find_property(np, "pinmux", NULL); + if (!prop) { + dev_info(dev, "Missing pinmux property\n"); + return -ENOENT; + } + + pnode = of_get_parent(np); + if (!pnode) { + dev_info(dev, "Missing function node\n"); + return -EINVAL; + } + + reserved_maps = 0; + *map = NULL; + *num_maps = 0; + + ret = pinconf_generic_parse_dt_config(np, pctldev, &configs, + &num_configs); + if (ret < 0) { + dev_err(dev, "%pOF: could not parse node property\n", np); + return ret; + } + + reserve = 1; + if (num_configs) + reserve++; + + ret = pinctrl_utils_reserve_map(pctldev, map, &reserved_maps, + num_maps, reserve); + if (ret < 0) + goto exit; + + ret = pinctrl_utils_add_map_mux(pctldev, map, + &reserved_maps, num_maps, np->name, + pnode->name); + if (ret < 0) + goto exit; + + if (num_configs) { + ret = pinctrl_utils_add_map_configs(pctldev, map, &reserved_maps, + num_maps, np->name, configs, + num_configs, PIN_MAP_TYPE_CONFIGS_GROUP); + if (ret < 0) + goto exit; + } + +exit: + kfree(configs); + if (ret) + pinctrl_utils_free_map(pctldev, *map, *num_maps); + + return ret; +} +EXPORT_SYMBOL_GPL(pinconf_generic_dt_node_to_map_pinmux); + int pinconf_generic_dt_subnode_to_map(struct pinctrl_dev *pctldev, struct device_node *np, struct pinctrl_map **map, unsigned int *reserved_maps, unsigned int *num_maps, diff --git a/drivers/pinctrl/pinconf.h b/drivers/pinctrl/pinconf.h index a14c950bc700..a171195b3615 100644 --- a/drivers/pinctrl/pinconf.h +++ b/drivers/pinctrl/pinconf.h @@ -138,4 +138,8 @@ int pinconf_generic_parse_dt_config(struct device_node *np, struct pinctrl_dev *pctldev, unsigned long **configs, unsigned int *nconfigs); + +int pinconf_generic_parse_dt_pinmux(struct device_node *np, struct device *dev, + unsigned int **pid, unsigned int **pmux, + unsigned int *npins); #endif diff --git a/include/linux/pinctrl/pinconf-generic.h b/include/linux/pinctrl/pinconf-generic.h index 53cfde98433d..1bcf071b860e 100644 --- a/include/linux/pinctrl/pinconf-generic.h +++ b/include/linux/pinctrl/pinconf-generic.h @@ -232,4 +232,8 @@ static inline int pinconf_generic_dt_node_to_map_all(struct pinctrl_dev *pctldev PIN_MAP_TYPE_INVALID); } +int pinconf_generic_dt_node_to_map_pinmux(struct pinctrl_dev *pctldev, + struct device_node *np, + struct pinctrl_map **map, + unsigned int *num_maps); #endif /* __LINUX_PINCTRL_PINCONF_GENERIC_H */ -- cgit v1.2.3