532 lines
12 KiB
C
532 lines
12 KiB
C
/*
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* PWM Greybus driver.
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*
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* Copyright 2014 Google Inc.
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* Copyright 2014 Linaro Ltd.
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*
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* Released under the GPLv2 only.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/pwm.h>
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#include "greybus.h"
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struct gb_pwm_chip {
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struct gb_connection *connection;
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u8 version_major;
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u8 version_minor;
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u8 pwm_max; /* max pwm number */
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struct pwm_chip chip;
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struct pwm_chip *pwm;
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};
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#define pwm_chip_to_gb_pwm_chip(chip) \
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container_of(chip, struct gb_pwm_chip, chip)
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/* Version of the Greybus PWM protocol we support */
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#define GB_PWM_VERSION_MAJOR 0x00
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#define GB_PWM_VERSION_MINOR 0x01
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/* Greybus PWM request types */
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#define GB_PWM_TYPE_INVALID 0x00
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#define GB_PWM_TYPE_PROTOCOL_VERSION 0x01
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#define GB_PWM_TYPE_PWM_COUNT 0x02
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#define GB_PWM_TYPE_ACTIVATE 0x03
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#define GB_PWM_TYPE_DEACTIVATE 0x04
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#define GB_PWM_TYPE_CONFIG 0x05
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#define GB_PWM_TYPE_POLARITY 0x06
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#define GB_PWM_TYPE_ENABLE 0x07
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#define GB_PWM_TYPE_DISABLE 0x08
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#define GB_PWM_TYPE_RESPONSE 0x80 /* OR'd with rest */
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struct gb_pwm_simple_response {
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__u8 status;
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};
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/* version request has no payload */
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struct gb_pwm_proto_version_response {
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__u8 status;
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__u8 major;
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__u8 minor;
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};
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/* pwm count request has no payload */
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struct gb_pwm_count_response {
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__u8 status;
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__u8 count;
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};
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struct gb_pwm_activate_request {
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__u8 which;
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};
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struct gb_pwm_deactivate_request {
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__u8 which;
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};
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struct gb_pwm_config_request {
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__u8 which;
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__u32 duty;
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__u32 period;
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};
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struct gb_pwm_polarity_request {
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__u8 which;
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__u8 polarity;
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};
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struct gb_pwm_enable_request {
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__u8 which;
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};
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struct gb_pwm_disable_request {
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__u8 which;
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};
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/*
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* This request only uses the connection field, and if successful,
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* fills in the major and minor protocol version of the target.
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*/
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static int gb_pwm_proto_version_operation(struct gb_pwm_chip *pwmc)
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{
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struct gb_connection *connection = pwmc->connection;
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struct gb_operation *operation;
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struct gb_pwm_proto_version_response *response;
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int ret;
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/* protocol version request has no payload */
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operation = gb_operation_create(connection,
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GB_PWM_TYPE_PROTOCOL_VERSION,
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0, sizeof(*response));
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if (!operation)
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return -ENOMEM;
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/* Synchronous operation--no callback */
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ret = gb_operation_request_send(operation, NULL);
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if (ret) {
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pr_err("version operation failed (%d)\n", ret);
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goto out;
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}
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response = operation->response.payload;
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if (response->status) {
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gb_connection_err(connection, "version response %hhu",
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response->status);
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ret = -EIO;
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} else {
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if (response->major > GB_PWM_VERSION_MAJOR) {
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pr_err("unsupported major version (%hhu > %hhu)\n",
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response->major, GB_PWM_VERSION_MAJOR);
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ret = -ENOTSUPP;
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goto out;
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}
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pwmc->version_major = response->major;
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pwmc->version_minor = response->minor;
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}
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out:
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gb_operation_destroy(operation);
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return ret;
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}
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static int gb_pwm_count_operation(struct gb_pwm_chip *pwmc)
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{
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struct gb_connection *connection = pwmc->connection;
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struct gb_operation *operation;
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struct gb_pwm_count_response *response;
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int ret;
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/* pwm count request has no payload */
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operation = gb_operation_create(connection, GB_PWM_TYPE_PWM_COUNT,
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0, sizeof(*response));
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if (!operation)
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return -ENOMEM;
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/* Synchronous operation--no callback */
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ret = gb_operation_request_send(operation, NULL);
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if (ret) {
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pr_err("line count operation failed (%d)\n", ret);
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goto out;
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}
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response = operation->response.payload;
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if (response->status) {
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gb_connection_err(connection, "pwm count response %hhu",
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response->status);
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ret = -EIO;
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} else
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pwmc->pwm_max = response->count;
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out:
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gb_operation_destroy(operation);
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return ret;
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}
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static int gb_pwm_activate_operation(struct gb_pwm_chip *pwmc,
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u8 which)
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{
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struct gb_connection *connection = pwmc->connection;
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struct gb_operation *operation;
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struct gb_pwm_activate_request *request;
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struct gb_pwm_simple_response *response;
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int ret;
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if (which > pwmc->pwm_max)
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return -EINVAL;
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/* activate response has no payload */
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operation = gb_operation_create(connection, GB_PWM_TYPE_ACTIVATE,
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sizeof(*request), sizeof(*response));
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if (!operation)
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return -ENOMEM;
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request = operation->request.payload;
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request->which = which;
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/* Synchronous operation--no callback */
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ret = gb_operation_request_send(operation, NULL);
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if (ret) {
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pr_err("activate operation failed (%d)\n", ret);
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goto out;
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}
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response = operation->response.payload;
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if (response->status) {
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gb_connection_err(connection, "activate response %hhu",
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response->status);
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ret = -EIO;
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}
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out:
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gb_operation_destroy(operation);
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return ret;
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}
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static int gb_pwm_deactivate_operation(struct gb_pwm_chip *pwmc,
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u8 which)
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{
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struct gb_connection *connection = pwmc->connection;
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struct gb_operation *operation;
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struct gb_pwm_deactivate_request *request;
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struct gb_pwm_simple_response *response;
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int ret;
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if (which > pwmc->pwm_max)
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return -EINVAL;
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/* deactivate response has no payload */
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operation = gb_operation_create(connection, GB_PWM_TYPE_DEACTIVATE,
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sizeof(*request), sizeof(*response));
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if (!operation)
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return -ENOMEM;
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request = operation->request.payload;
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request->which = which;
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/* Synchronous operation--no callback */
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ret = gb_operation_request_send(operation, NULL);
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if (ret) {
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pr_err("deactivate operation failed (%d)\n", ret);
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goto out;
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}
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response = operation->response.payload;
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if (response->status) {
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gb_connection_err(connection, "deactivate response %hhu",
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response->status);
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ret = -EIO;
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}
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out:
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gb_operation_destroy(operation);
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return ret;
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}
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static int gb_pwm_config_operation(struct gb_pwm_chip *pwmc,
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u8 which, u32 duty, u32 period)
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{
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struct gb_connection *connection = pwmc->connection;
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struct gb_operation *operation;
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struct gb_pwm_config_request *request;
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struct gb_pwm_simple_response *response;
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int ret;
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if (which > pwmc->pwm_max)
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return -EINVAL;
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operation = gb_operation_create(connection, GB_PWM_TYPE_CONFIG,
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sizeof(*request), sizeof(*response));
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if (!operation)
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return -ENOMEM;
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request = operation->request.payload;
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request->which = which;
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request->duty = duty;
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request->period = period;
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/* Synchronous operation--no callback */
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ret = gb_operation_request_send(operation, NULL);
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if (ret) {
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pr_err("config operation failed (%d)\n", ret);
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goto out;
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}
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response = operation->response.payload;
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if (response->status) {
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gb_connection_err(connection, "config response %hhu",
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response->status);
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ret = -EIO;
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}
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out:
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gb_operation_destroy(operation);
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return ret;
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}
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static int gb_pwm_set_polarity_operation(struct gb_pwm_chip *pwmc,
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u8 which, u8 polarity)
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{
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struct gb_connection *connection = pwmc->connection;
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struct gb_operation *operation;
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struct gb_pwm_polarity_request *request;
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struct gb_pwm_simple_response *response;
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int ret;
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if (which > pwmc->pwm_max)
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return -EINVAL;
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operation = gb_operation_create(connection, GB_PWM_TYPE_POLARITY,
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sizeof(*request), sizeof(*response));
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if (!operation)
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return -ENOMEM;
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request = operation->request.payload;
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request->which = which;
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request->polarity = polarity;
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/* Synchronous operation--no callback */
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ret = gb_operation_request_send(operation, NULL);
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if (ret) {
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pr_err("set polarity operation failed (%d)\n", ret);
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goto out;
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}
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response = operation->response.payload;
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if (response->status) {
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gb_connection_err(connection, "set polarity response %hhu",
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response->status);
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ret = -EIO;
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}
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out:
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gb_operation_destroy(operation);
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return ret;
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}
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static int gb_pwm_enable_operation(struct gb_pwm_chip *pwmc,
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u8 which)
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{
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struct gb_connection *connection = pwmc->connection;
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struct gb_operation *operation;
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struct gb_pwm_enable_request *request;
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struct gb_pwm_simple_response *response;
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int ret;
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if (which > pwmc->pwm_max)
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return -EINVAL;
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/* enable response has no payload */
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operation = gb_operation_create(connection, GB_PWM_TYPE_ENABLE,
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sizeof(*request), sizeof(*response));
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if (!operation)
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return -ENOMEM;
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request = operation->request.payload;
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request->which = which;
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/* Synchronous operation--no callback */
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ret = gb_operation_request_send(operation, NULL);
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if (ret) {
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pr_err("enable operation failed (%d)\n", ret);
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goto out;
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}
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response = operation->response.payload;
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if (response->status) {
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gb_connection_err(connection, "enable response %hhu",
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response->status);
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ret = -EIO;
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}
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out:
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gb_operation_destroy(operation);
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return ret;
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}
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static int gb_pwm_disable_operation(struct gb_pwm_chip *pwmc,
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u8 which)
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{
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struct gb_connection *connection = pwmc->connection;
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struct gb_operation *operation;
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struct gb_pwm_disable_request *request;
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struct gb_pwm_simple_response *response;
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int ret;
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if (which > pwmc->pwm_max)
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return -EINVAL;
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/* disable response has no payload */
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operation = gb_operation_create(connection, GB_PWM_TYPE_DISABLE,
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sizeof(*request), sizeof(*response));
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if (!operation)
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return -ENOMEM;
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request = operation->request.payload;
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request->which = which;
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/* Synchronous operation--no callback */
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ret = gb_operation_request_send(operation, NULL);
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if (ret) {
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pr_err("disable operation failed (%d)\n", ret);
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goto out;
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}
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response = operation->response.payload;
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if (response->status) {
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gb_connection_err(connection, "disable response %hhu",
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response->status);
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ret = -EIO;
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}
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out:
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gb_operation_destroy(operation);
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return ret;
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}
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static int gb_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
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return gb_pwm_activate_operation(pwmc, pwm->hwpwm);
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};
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static void gb_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
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if (test_bit(PWMF_ENABLED, &pwm->flags))
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dev_warn(chip->dev, "freeing PWM device without disabling\n");
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gb_pwm_deactivate_operation(pwmc, pwm->hwpwm);
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}
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static int gb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
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int duty_ns, int period_ns)
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{
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struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
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return gb_pwm_config_operation(pwmc, pwm->hwpwm, duty_ns, period_ns);
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};
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static int gb_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
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enum pwm_polarity polarity)
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{
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struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
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return gb_pwm_set_polarity_operation(pwmc, pwm->hwpwm, polarity);
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};
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static int gb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
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return gb_pwm_enable_operation(pwmc, pwm->hwpwm);
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};
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static void gb_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
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gb_pwm_disable_operation(pwmc, pwm->hwpwm);
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};
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static const struct pwm_ops gb_pwm_ops = {
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.request = gb_pwm_request,
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.free = gb_pwm_free,
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.config = gb_pwm_config,
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.set_polarity = gb_pwm_set_polarity,
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.enable = gb_pwm_enable,
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.disable = gb_pwm_disable,
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.owner = THIS_MODULE,
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};
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static int gb_pwm_connection_init(struct gb_connection *connection)
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{
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struct gb_pwm_chip *pwmc;
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struct pwm_chip *pwm;
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int ret;
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pwmc = kzalloc(sizeof(*pwmc), GFP_KERNEL);
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if (!pwmc)
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return -ENOMEM;
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pwmc->connection = connection;
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/* Check for compatible protocol version */
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ret = gb_pwm_proto_version_operation(pwmc);
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if (ret)
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goto out_err;
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/* Query number of pwms present */
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ret = gb_pwm_count_operation(pwmc);
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if (ret)
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goto out_err;
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pwm = &pwmc->chip;
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pwm->dev = &connection->dev;
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pwm->ops = &gb_pwm_ops;
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pwm->base = -1; /* Allocate base dynamically */
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pwm->npwm = pwmc->pwm_max + 1;
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pwm->can_sleep = true; /* FIXME */
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ret = pwmchip_add(pwm);
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if (ret) {
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pr_err("Failed to register PWM\n");
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return ret;
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}
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connection->private = pwmc;
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return 0;
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out_err:
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kfree(pwmc);
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return ret;
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}
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static void gb_pwm_connection_exit(struct gb_connection *connection)
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{
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struct gb_pwm_chip *pwmc = connection->private;
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if (!pwmc)
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return;
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pwmchip_remove(&pwmc->chip);
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/* kref_put(pwmc->connection) */
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kfree(pwmc);
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}
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static struct gb_protocol pwm_protocol = {
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.id = GREYBUS_PROTOCOL_PWM,
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.major = 0,
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.minor = 1,
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.connection_init = gb_pwm_connection_init,
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.connection_exit = gb_pwm_connection_exit,
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.request_recv = NULL, /* no incoming requests */
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};
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bool gb_pwm_protocol_init(void)
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{
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return gb_protocol_register(&pwm_protocol);
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}
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void gb_pwm_protocol_exit(void)
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{
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gb_protocol_deregister(&pwm_protocol);
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}
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